Engine swap problems
Printed From: West Coast Fieros
Category: Technical Topics Forum
Forum Name: Technical Questions and Discussions
Forum Description: Got a technical question about your fiero? ask it here.
URL: http://www.westcoastfieros.com/forum/forum_posts.asp?TID=2148
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Topic: Engine swap problems
Posted By: orange
Subject: Engine swap problems
Date Posted: 26 October 2010 at 8:08pm
I have some problems that are bothering me...
these problems are not really hindering the engine and
how it runs but i want to check them out... i have a
couple
Its a 4.9 swap with stock computer with rockcrawl chip
and a cam and slightly bigger valve train. Engine sat for
7 years!
Problem 1: When the car has been rinning for about a
couple of mins the crank case breather starts smoking
(steaming?) and it is enough to worry me, i know what it
is, but should it be doing it a lot with an engine that
sat for a long time? Or are my rings bad?
Problem 2: There is a very small amount of black smoke
out the back, running rich is my though, but why?? Could
the chip be programed to increase air fuel ratio for the
cam? The smoke is barely enough to worry but still...
Problem 3: When the car has been running for a short
time, and i stand close to the engine (not really near
exhaust) my eyes burn severely. There is some smoke
(white) coming
from the engine compartment. I have tried to trace this
smoke but its like its coming out of no where. It comes
up the two sides of the engine (bank 1 and 2) but is not
under the exhaust manifolds and there is no type of fluid
anywhere near them. The manifolds were painted and had
new gaskets, is that whats burning?
Problem 4: May be a minor one but when i jump the car
with another one to start it, no mater what kind of car,
i have to let it charge for 5 mins before trying to
start. Do i just have a starter that takes a ton of
energy to turn? Or a loop in the circuit?
Problem 5: CLUTCH!! Ive bled the clutch 100 times and the
air doesnt want to leave. Or the clutch is stuck or
something? I know they can get stuck, my dads did... but
his is a liquid filled trany/bellhousing so the clutch is
in fluid. Could my be stuck, if so how the heck do i
unstick it?
Thanks for sticking with me! I am looking for short
simple answers mostly (unless it calls for a big one),
thats why i have so many questions in one posting. Any
help WILL HELP. Answer one or all... or none i dont care
just give me your input please.
------------- Orange 4.9
|
Replies:
Posted By: orange
Date Posted: 26 October 2010 at 8:30pm
Cam is a 282, also have some steam type stuff floating
gently out the throttle body when recently turned off
------------- Orange 4.9
|
Posted By: Dawg
Date Posted: 27 October 2010 at 12:02am
I'm reading your list and I'm getting the impression you're running WAY too rich. This will wash the cylinder walls and cause ring damage over time. It could in severe cases push fuel fumes into the crank case and sting your eyes after leaving the breather.
I have seen this many times way back in the old days while playing around with jets in race engines.
You definitely have blow by issues. Blow by is usually worse when the engine is cold. After warm up things are tighter and less prone to leaking.
If my theory is true you need to get this dealt with. You might have already contaminated your oil.
The Dawg
------------- You dream it up....I'll make it
|
Posted By: Dr.Fiero
Date Posted: 27 October 2010 at 7:19am
Couple times now we found an easy cause for running rich -- use ONLY a genuine GM/AC-Delco O2 sensor! (or sensorS if you run duals) No logical explanation for it, but all the aftermarkets we tried (on two cars!) failed to read.
If it sat for a long time, and you're only starting it in short spurts (a BAD thing BTW) without it fully heating up, you'll get lots of blowby for a few hundred miles probably.
Manifolds + heat + paint = smoke. Simple math.
Starting issue; a regular 500cca or better battery should zip that thing to life easily. You probably have a bad ground, or a bad battery terminal. Make SURE you hooked up a 'battery light' in the alternator circuit (like the one in the stock dash) or your alternator won't charge. It looks for the resistance of the bulb.
Clutch; describe the actual symptoms.
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Posted By: CFoss
Date Posted: 27 October 2010 at 9:39am
Problem #1...is the blowby white or dark. If it's rings, my experience has been that it will be black/oily. If it's white...could be condensed water (No problem, just takes time to clear) or coolant leaking internally somewhere (Longshot, but possible). Give it time and see if it changes.
Problem #2. Likely rich idle, I agree. If it does this when worm (worm? warm), you might look into it further. When cold, this is somewhat expected. Check your plugs for carbon build up at your first oil change. If none, forget about it.
P3: Sounds like paint. Not a great smell.
P4: Do you men that you need to leave two batteries connected for 5 minute before it will start? If so, this is indicitive of a very weak battery. What happens is that the weak one in your car will consume the available current from the jump battery, and the car will therefore not start due to lack of supply. After time the car battery will charge somewhat, allowing the charge battery to turn the engine over.
Do not continue this situation. The excessive chaerge current into the weak battery is similar to a short circuit and will cause a large buildup of heat, which could lead to explosion. Replace the battery, or just use your 'jump' battery by itself.
P5: Cluthes hydraulics are murder on these cars. Remove the slave. Pop off the rubber end plug, push in the plunger and look for corosion in the cylinder bore. If any, you need a new slave. There is a special bleed procedure as well. Park on an incline, crack the bleeder. Wait for pure fluid to run out. Then , with the bleeder open, vice grip the push rod and push it back into the cylinder. Fluid WILL squirt out. SLOWLY allow the push rod to slide back out. Maintain positive flow out of the bleeder. When the rod is fully out, close the bleeder. This will purge and air bubbles trapped in the cylinder.
On the master end, pull the rubber on the pushrod and look for fluid. If any, replace the master.
I didn't get a good clutch until I replaced the master and slave. Just the way it goes.
------------- 86 SE 3.4
|
Posted By: Dawg
Date Posted: 27 October 2010 at 10:02am
I would add that you can make sure the drivers side of the car is higher than the passenger side while you bleed. Then at the end of your bleed, tap the slave with a small hammer lightly to dislodge and remaining bubbles. This way there is no need to play with the push rod, which if done incorrectly, can add air.
When I did the push rod trick I had someone pump the clutch pedal for me while I held the push rod.
The Dawg
------------- You dream it up....I'll make it
|
Posted By: orange
Date Posted: 27 October 2010 at 3:53pm
Thank you so much!! Ok ill address your comments and
questions now...
Problem 1: the blow by is white... and seems to only exit
the bank close to the trunk.
Problem 2: I am running a bosch o2 sensor so i will try a
delco one, also i retarded the timing (i think, i turned
it counterclock wise) and the black smoke almost completely went away.
Problem 3: I guess im settling that its paint burning off
Problem 4: Battery light in alternator circut... yes but
i need to confirm i did it right, where exactly does the
little red wire go?
Problem 5: My master is leaking slightly but it always
has, ever since i bought the car... maybe 3 drops from
all the bleeding. Im planning on upgrading the master
soon... should i just do that now?
Other comments to add...
-when the car has been on and warmed up (maybe 5 mins
after the blow by starts a lot) i turn off the car and it
just doesnt want to start right up again...
-Clutch- when bled the pedal feels light the first half
but completely normal the second half
-would you guys recommend just running it for a long time
like 30 mins?
-check engine light on but the cods wont flash... i jump
a and b but the light stays lit. someone told me, with a
chipped ecm the light wont go off, you just have to check
for codes... i dont really believed that
I want these problems cleaned up, and thank you so much
for the time! If you need any clarification i can just
shoot a video and post it really easy.
------------- Orange 4.9
|
Posted By: CFoss
Date Posted: 27 October 2010 at 6:02pm
Did you do a comp check on the engine? Any problems found?
"-when the car has been on and warmed up (maybe 5 mins
after the blow by starts a lot) i turn off the car and it
just doesnt want to start right up again...
"
Describe exactly what this is...fires on and off, completely dead, raw fuel smell, etc...
As far as whether to run it for longer...if it was mine I would. It can only do three things...get better, worse or stay the same. My rational is if the cylinder is scored it's a teardown and bore out anyway, so running it a bit more shouldn't hurt. If it's condensation it will clear up when the engine crankcase finally warms up fully(This takes longer than the coolant by quite a while).
As far as timing goes, did you check your marks are correct for tdc (I prefer the screwdriver method)? I'm not sure how advanced timing could cause incomplete combustion (Black smoke). Maybe others can advise on that.
Chay
------------- 86 SE 3.4
|
Posted By: orange
Date Posted: 27 October 2010 at 6:10pm
I have not done a compression test. And describing the
problem... when i turn it off and try to start it again
soon it will turn over and fire a lot but then stop just
before it would start and then i stopped trying and came
here. And for the timing, i did not time it with a light,
just by idle and what felt the best while reving, the
timming is way off from stock anyway because the cam.
right?
------------- Orange 4.9
|
Posted By: Dr.Fiero
Date Posted: 27 October 2010 at 6:16pm
Cam spec has zero to do with ignition timing.
Don't set it by ear - you just can't do that.
It probably isn't wanting to fire now since it's half flooded. These flood easily.
BS on the 'check engine always on'. There's something there.
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Posted By: orange
Date Posted: 27 October 2010 at 6:28pm
Ok i guess ill time it now and see where that gets me. And
yeah the check engine light thing i thought BS too, any
thoughts?
------------- Orange 4.9
|
Posted By: orange
Date Posted: 27 October 2010 at 7:56pm
Something massively wrong!!! This is bad, and now im
scared. Ill explain exactly what happened .When i let it
run for 20 25 mins i was messing with the timing
slightly, and got it almost right when i started to pay
attention to the blow by and it actually stopped but
there was huge deposits of fluid on the lip of the
breather and it was clear and smell strange (like a very
week gas smell) and after a couple seconds the blow by
started coming out the breather with the pcv on it! And i
though it was strange so i was going to turn it off, when
i herd something and i looked under the car and there was
coolant leaking out of some hoses. I shut it off and was
like, crap i didnt tighten the hoses enough, and seeing
that everything else seamed to be fine i was going to try
and start it again. I turned it over maybe one or two
times, stopped, and panicked when i herd a sucking
whistle noise coming from the throttle body, it sounded
like air was being sucked in. And after i looked under
the car i herd the same noise coming from a coolant hose
clamp. Something very wrong is happening, head
gasket? internals?? I have a limited source of money and
if this problem is major then i can forget about this
project, or forget about it being done till spring if im
lucky HELP!
------------- Orange 4.9
|
Posted By: Romeo
Date Posted: 27 October 2010 at 9:42pm
You said the expelled gasses are white, do they smell somewhat sweet? If so, check your coolant levels - you may have a coolant leak on top of everything else...
------------- Never shift into reverse without a back-up plan.
|
Posted By: orange
Date Posted: 27 October 2010 at 10:35pm
The gasses are white, but dont smell sweet, smell more like
a bit of gas mixed with spray paint or acetone or
something. and coolant levels in the reservoir havent
really changed. Oh and before i tried to start it again i
opened the cap on the radiator and had some vacuum on it
but not much. So could it be a head gasket? Ill check the
oil tomorrow and see what it looks like. I drained a drop
and it seemed to be a little lighter brown and a bit
thicker.
------------- Orange 4.9
|
Posted By: Dawg
Date Posted: 27 October 2010 at 11:40pm
Ok buddy....first things first. Pull ALL your spark plugs out and do a compression test. If you have something funky going on this will show it. Do each cylinder dry and then put 2 or 3 squirts of engine oil in the hole and test it again. Mark all this down and get back to us.
I agree, sounds bad but lets try and figure out how bad. Your oil could be so contaminated with fuel by now that it's too thin to do it's job. Lifters could be malfunctioning and so on.
Compression values should tell us if you need to put her away for the winter.
The Dawg.
------------- You dream it up....I'll make it
|
Posted By: CFoss
Date Posted: 28 October 2010 at 10:15am
This is so weird. It does sound like head gasket to me, like the coolant is getting into the combustion chamber. This would account for the black exhaust. I had a intake manifold leak on a v6 chrysler which did a similar thing, only what it did was feed oil and coolant into one of the intake passages. My exhaust had a bit of a sweet smell, and brownish water coming out.
I'm trying to figure out how it could get into your pcv system though. Perhaps there are 2 things messing with you.
On the pcv, to sort this out...most pcv systems have an air 'source' tapped off the clean side of the air cleaner which goes to one side of the engine, then the other side (With the pcv valve) goes to the manifold for vaccuum.
When you are seeing the fluid, are these lines disconnected (IE pressure from inside the crankcase) or is the fluid being drawn up by the engine vaccuum?
How does your oil look on your dipstick??? Is it a milkshake (White, showing water ingress)??
Do you have a coolant line which goes to your throttle body for heating?
Chay
------------- 86 SE 3.4
|
Posted By: orange
Date Posted: 28 October 2010 at 10:32am
For the pcv system, i have a filter on one valve cover and
a pcv valve to a filter on the other... is this wrong?
My oil is not milky but looks a little lighter than the
usual dark brown used oil look and is feels thinner. And i
dont have a coolant line to the throttle body.
------------- Orange 4.9
|
Posted By: Romeo
Date Posted: 28 October 2010 at 12:21pm
Hmm... I'm not saying Damien and I are wrong, but I don't think either of us have nailed it, given what you've said recently. If fuel and oil were mixing, you'd be puking black or blue smoke, not white. If oil and coolant were mixing, you'd notice the the coolant would be dark and chunky looking, and the oil would be light and chunky looking. However, in small doses, we could both be right, as an O2 sensor woefully out of range will set a code (Especially if raw fuel was sealed with coolant on the sensor itself) which would explain your CEL being illuminated. This would also mean Doc's theory would be validated as well (O2 problem). Your best bet would be to grab a scan tool and check the actual voltages of everything in question, especially when the car is puking white and the CEL is illuminated.
------------- Never shift into reverse without a back-up plan.
|
Posted By: orange
Date Posted: 28 October 2010 at 1:09pm
So i really dont know what to do at this point, Should i do
a compression test and then start tearing it down? or
should I just change the oil, o2 sensor, and see what
happens?
I have noticed a somewhat thick layer of pure black oily
feeling stuff under the throttle body blades that wasnt
there before. Also i did a burn test on a sample of the oil
thats in there and it did not really catch on fire, but it
did pop and crackle a bit with some flames, i did the test
to normal oil (thinking the dirt on the ground was
lighting) and no flames, and i did it sample of coolant and
it did not burn, so does that confirm gas in my oil?
------------- Orange 4.9
|
Posted By: Dr.Fiero
Date Posted: 28 October 2010 at 1:31pm
I'd start thus: Cure the (probable) problem making it rich - Non GM O2 sensor. Pull the plugs, clean and dry them. Change the oil (sounds like you washed the cylinders and got gas in the oil) and filter. You COULD do a compression test at this point, but I bet it'll come up uneven and low until you do a wet test.
Put it all back together.
Set the timing with a light (making sure it's in bypass mode).
Cross whatever you've got (fingers etc).
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Posted By: CFoss
Date Posted: 28 October 2010 at 3:40pm
If you don't want to spend money right away (O2 sensor) then pull the plugs and do a comp test. Look at the plugs as you remove them, 1 by one. Note the condition and the cylinder it came from. Now do the comp test.
If you find a funny looking plug, and the comp test backs it up you have 2 indicators as to what's going on.
Re: The pcv...if there are just breathers at either end the system won't work. There should be a connection from the pcv valve to vaccuum. The vaccuum 'pulls' air through the crankcase from the other breather. The other end is fine, it is a source of filtered air into the crankcase.
So, one or both of these lines were puking fluid??? It can only come from under the valve covers which indicates a LARGE quantity of fluid. Sounds like a cracked head where the coolant is coming into the rocker arm gallery under the valve cover.
What I would do is pull a rocker cover and run the engine. You should be able to see where the fluid is coming from. It could be from here the fluid in ingressing through the valve guides into the intake ports and is then being 'burned'.
Just a theroy.
Chay
------------- 86 SE 3.4
|
Posted By: orange
Date Posted: 29 October 2010 at 12:48pm
What is a wet test, and what is bypass mode for the timing?
Also to CFoss... i looked at the rocker arms on one bank
and they looked fine, no fluid there that i could tell
(besides oil obviously)
------------- Orange 4.9
|
Posted By: CFoss
Date Posted: 29 October 2010 at 3:02pm
A wet test is where you squirt a bit of oil into the cylinders which seals the rings. then you redo the results. If there is much of a difference with the numbers wet to dry it indicates ring problems. If not, and the numbers are low, it's likely valves.
With a computer controlled ignition advance, the computer is always controlling the timing. To remove the computers' influence, you go to 'bypass mode' which allows you to set the 'base' timing. This is a value (usually 10deg btdc) that the ecm knows. It controlls advance from this point on.
For example: 10deg base+20deg from computer = 30 deg total advance.
Re:pcv system....now I'm really confused. Post pictures of your system. How could there be fluid coming out of the pcv system without it being in the rocker covers (Where the pcv system connects to). Are you sure you are talking abot the pcv system (Positive crankcase ventilation)?
Chay
------------- 86 SE 3.4
|
Posted By: CFoss
Date Posted: 29 October 2010 at 3:06pm
1 more thing on the compression test...to mean anything the following must be true:
1) All plugs removed
2) throttle wide open
3) Well charged battery/good starter
Otherwise the results are meaningless. If you can, use a partner and see how many 'pumps' it takes to get to 90% of the max reading (In other words, how fast does compression build)? The faster the better the sealing.
Chay
------------- 86 SE 3.4
|
Posted By: orange
Date Posted: 29 October 2010 at 4:59pm
What numbers am I looking for on the compression test?
------------- Orange 4.9
|
Posted By: Romeo
Date Posted: 29 October 2010 at 9:33pm
140-170 psi. Specifically, what you're looking for is consistancy. If 5 out of six are all sealing at 170, and one seals at 135, look at why the one is sealing so poorly. Also, keep an eye out of how long the cylinder can hold the pressure. If pressure drops within a couple seconds of being built up, that can also be problematic.
------------- Never shift into reverse without a back-up plan.
|
Posted By: orange
Date Posted: 29 October 2010 at 11:23pm
After doing the test i read that all plugs needed to be
out... well i guess im doing the test again tomorrow, but
here are the results, i did one plug at a time for the
first bank (even bank), and the second bank (odd)i did
all together.
1 dry 135 wet 137
2 d 115 w 115
3 d 135 w 133
4 d 112 w 116
5 d 142 w 144
6 d 120 w 120
7 d 137 w 140
8 d 125 w 127
All plugs were black and slightly wet with fuel, except
one due to a bad plug wire that is replaced.
They all took 2-3 'pumps' to build up, and they all kept
the pressure good.
I will repeat the test tomorrow correctly i guess... and
ill get the delco o2 sensor. Also, would it be worth it
to pull the fuel rail and injectors and check them?
------------- Orange 4.9
|
Posted By: orange
Date Posted: 29 October 2010 at 11:45pm
I did some math and found that atmospheric pressure here in
Colorado Springs (almost a mile above sea level) is about
12.2 psi and if the 4.9 has a compression of 9.5 then at
TDC i should be hitting about 116 psi in the cylinder.
Sound right?
------------- Orange 4.9
|
Posted By: Dr.Fiero
Date Posted: 30 October 2010 at 5:41am
Those numbers are pretty low (the lowest is too far off the highest) - but this engine sat around for years right? Don't condemn it yet. I've seen worse, and still ran it. And the fact that it built up after 2-3 hits is great.
Clean and dry the plugs now. Swap in the Delco O2. Change the oil and filter (still think you have gas in it).
Hope.
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Posted By: orange
Date Posted: 30 October 2010 at 12:47pm
One thing, how do i time with the bypass? is that just
timing it when off? or what
------------- Orange 4.9
|
Posted By: orange
Date Posted: 30 October 2010 at 2:06pm
Never mind last post, ill figure it out.
------------- Orange 4.9
|
Posted By: Dawg
Date Posted: 30 October 2010 at 11:00pm
I agree with the Doctor, those numbers are bad. Not only too low but way too much difference.
I can't help noticing that the added oil did basically nothing in all cases. At the very least, your low cylinder (112) surely has problems. But oil did nothing. It's got to be valve train problems. Either lifters are not opening for some reason (like really bad oil) or you have burnt/bent valves.
What else can it be? Head gasket maybe? Either way, engine needs it's heads off for a look.
Pray it's really bad oil.....
The Dawg
------------- You dream it up....I'll make it
|
Posted By: orange
Date Posted: 02 November 2010 at 10:38am
Ok, im thinking about doing rings and valves, or at least
valve seals. Some shops are telling me that they dont even
want to touch the head bolts because they almost always
break threads or miss thread and im wondering if i even
want to attempt taking the heads off, is it really this
risky on a 4.9?? Also one shop said it would take 8 or 9
hours to torque the head bolts because they said if you
dont do it one pound at a time then everything gets miss
aligned because the bolts go all the way down to the bottom
of the block... I dont really believe this because even the
owners manual says there are only 3 torquing stages, in
which case i can do... but... give me some feed back
------------- Orange 4.9
|
Posted By: Dr.Fiero
Date Posted: 02 November 2010 at 10:44am
Have you 100% determined that there's REALLY a problem? This thing still has not been run for any length of time (like, a few hundred miles of real world driving)!
You WILL hate yourself if you take this apart from everything I've read & heard.
It's not a conventional engine. They use a wet sleeve, instead of a normal block. Picture a rectangular box, and 4 tubes sitting in the box. Then the lid (head) gets bolted down to the box. You just happen to have two boxes at a 90* angle, and 8 tubes.
If you've ever seen a commercial diesel engine taken apart, that's what they look like (sort of).
edit: Oh yeah, and the bolt holes might end up all needing heli-coils. That's why they don't want to touch it. Labour costs could be astronomical.
edit edit: Found a good picture.

See the cylinder liners? Those 'pop out' (so to speak). They're removable anyhow.
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Posted By: Romeo
Date Posted: 02 November 2010 at 10:53am
Always preferred wet-sleeve, personally... Keep that coolant actually on my sleeves.
------------- Never shift into reverse without a back-up plan.
|
Posted By: Dr.Fiero
Date Posted: 02 November 2010 at 10:56am
Don't get me wrong - not saying there's anything wrong with them (or they wouldn't use them on zillion dollar "gotta run" commercial engines!).
They're just not 'normal' for the average joe to rebuild, and can cause headaches if you don't know what to look for. If you're a certified HD mechanic (which I'm not!) it's all in a days work (literally!).
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Posted By: Romeo
Date Posted: 02 November 2010 at 12:27pm
Oh, okie dokie. Yes, that does make sense...
------------- Never shift into reverse without a back-up plan.
|
Posted By: orange
Date Posted: 02 November 2010 at 12:43pm
Ok, gotcha. I definitely dont want to take the heads off
then, so what if it does need valves or seals? does the
head have to come off? Is there a way to do them with the
bottom end out and through the bottom end of the engine?
Im just thinking... Thats proly a dumb idea. But back to
the engine, when i ran it for a half hour, nothing really
abnormal happened, it did run very smooth (considering
the cam) and reved just great. Im now starting to think
my oil was contaminated before that long run, I did have
major fuel issues in which injectors where clogged and
had to be cleaned and while testing, fuel did get into
the cylinders, and i had a hard time getting it to start
due to stupid things and it was cranked a LOT without any
combustion. So the fuel that contaminated the oil could
have been left over from all that. If it was that would
account for a lot of stuff that was happening, except the
hissing coming from the intake for a good 15 mins after
the "long run" was stopped.
I have now done everything you guys have said and ive
fixed some other things to help cancel out any other
things as potential problems, so soon i will run it again
and maybe drive it around the block and get some more
feedback from the engine.
P.S. Dont know if this is of significance but the
injectors are wired for one bank all firing at the same
time, guy who i bought it from said this is fine and has
been run before on cars, and only effects the power when
under 1200rpms, could this be my slightly rich problem?
------------- Orange 4.9
|
Posted By: Dr.Fiero
Date Posted: 02 November 2010 at 12:57pm
By all means I would affect it. The ECM is set up to do sequential
below 3000 (I think!). So if it fired them all the time it'd be way rich.
You probably won't need to do valves. Well, hope you don't anyhow.
The seals can easily be done without pulling them.
Just get it pretty good, then DRIVE IT. If it's still goofy after a few
hundred miles of hard pulls and vacuum slow downs...... Then go
looking for problems.
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Posted By: orange
Date Posted: 02 November 2010 at 3:46pm
Ok cool. Ill try it, but what i was saying with the
injectors is all 4 on one bank fire at the same time, but
not for every cylinders compression cycle. It fires all 4
then once all 4 cylinders have combusted then it fores them
all again, and same for the other bank. Bank one injectors
are all wired to injector ecm ground 1, and the other bank
is to 8. Is that understandable or am i not making sense?
------------- Orange 4.9
|
Posted By: Dr.Fiero
Date Posted: 02 November 2010 at 4:01pm
Yeah, it's wired for 'bank fire' injection.
Check around though - I really thought those were supposed to be sequential. If they are... it'll just NEVER run right wince it's getting 4X the fuel it's supposed to. Unless the ECM was redone to compensate for it (fat chance!!!).
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Posted By: orange
Date Posted: 02 November 2010 at 7:16pm
But thats the thing, it isnt getting 4x the fuel, each
cylinder gets one squirt of fuel, they just all go at once,
each cylinder gets the fuel at different compression cycle
times.
------------- Orange 4.9
|
Posted By: Dr.Fiero
Date Posted: 03 November 2010 at 4:43am
If the ECM/injector size/fuel pressure/etc is calibrated thus, that it gets ONE shot of fuel each 720* of rotation, then you give the same size shot of fuel every 180* -- tell me how that isn't too much?
Granted, the intake valve still only opens every 360*, but there's now a huge 'pile' of fuel sitting there waiting to enter.
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Posted By: CFoss
Date Posted: 03 November 2010 at 9:14am
It might be good to explain how sequential works...
The way it has been explained to me:
To meet emissions standards at or near idle sequential was used to meter the fuel to each cylinder. Each injector would fire while the intake valve opened to ensure maximum atomization (thus cleaner burn).
When the engine cranks up, the injector needs to be on longer to deliver more fuel. The pulse width exceeds the intake valve opening time, so you're injecting into a closed port, just like our batch fire systems.
So, in batch fire, at idle, lets say you need a 5ms pulse to deliver enough fuel. A single driver hits 3 injectors for 5ms.
In sequential, 3 drivers hit each individual injector for 5 ms. Now, if we wired all the injectors and drivers together, each driver would hit all the injectors for 5ms, totalling 15ms. This could be a bit wrong, because I have assumed there would be no overlap in the injector timing, which there may be. So, the actual pulse could be anywhere from 5-15ms. That kind of idea. I suspect many ecms switch to an electronic batch fire above a certain rpm/load (airflow). They just drive the injectors together instead of sequentially.
It's hard for me to believe it would run at all with that much fuel dumping in though....I wonder if your ecm has been changed out to a batch fire model.
Chay
------------- 86 SE 3.4
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Posted By: Dawg
Date Posted: 03 November 2010 at 11:05am
Ummmm....did he not say it was wired to only two drivers? If this is so, then it should work. Each injector is only firing once per combustion stroke. Why you would want to do such a thing I don't know.
Who knows what ECM he is using. Maybe it can't do sequential.
The Dawg
------------- You dream it up....I'll make it
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Posted By: orange
Date Posted: 03 November 2010 at 3:02pm
YES yes yes! exactly, you've got it Dawg, that is what i
was saying all along. The owner who built the engine was
going to use it for auto cross i think so batch injection
would have aloud more durability maybe? Because if TDC
could not be determined by the ecm for some reason (bad
sensor during race) then it would still run fine, plus
there are a ton less wires and obviously a race car would
not care about emissions. theres my take
------------- Orange 4.9
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