I had originally started to post about this in another thread, but I felt it needed it’s own home. So I’ve transferred over my posts as well as Dave’s responses.

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I failed AirCare miserably. I’m not suggesting it’s the deletion of the EGR or the custom chip, but something is amiss.

The GT failed in two categories. I was rather shocked to see how bad the Driving CO was.

Although I had installed a 180 thermostat before I had my custom chip burned, I put the 195 thermostat back in just for AirCare.

New ACDelco O2 sensor, and the ignition system is basically all new as well (except for the wires) - ACDelco ignition module, pickup coil, MSD Blaster coil, Accel distributor cap and rotor, NGK UR5 plugs gapped to .060" and the timing was set at 10 BTDC with the A and B terminals jumpered.

Motor appears to run fine, idles smooth at 800-850 RPM. Possible lack of power though from mid to high RPM.

Here's my readings. I've added the Allowable readings to the image at the top of the columns. Notice the last time it's been through AirCare! (The car was in storage for six years.)

Thanks for the feedback, Dave. Addressing your points:

1) The timing is currently set at 10 BTDC, set with the A and B terminals jumpered.

2) Yes, I was pretty surprised myself that the NOX readings were that low, especially with the EGR deleted.

3) Not sure why you suggest raising the idle speed as the idle readings are both fine.

4) With the car having sat for six years, I was wondering if perhaps the old gas had gummed up the injectors. I guess a fuel pressure leak-down test would show if one or more of the injectors are leaking (although I would think a leaking injector would also mess up the idle readings which are fine).

5) Just so it's known, the coolant temperature (as shown by WinALDL) was 220 before I entered the AirCare facility.

I can't say I've been very happy with the gas mileage the GT is getting. It would be great if correcting the problem this engine appears to have would also improve its fuel economy.

Dave, the O2 sensor is a brand new ACDelco unit.

Bumping the timing up may help, but I have my doubts that an extra 2 degrees is going to make much of a dent in the Driving CO readings which are almost 6 times the maximum allowable limit.

I have WinALDL and know how to use it, but I don't really know what to be looking for. Is anybody familiar enough with it that I could send a WinALDL log to be looked at? I'm hoping something would jump out at someone who is familar with WinALDL readings.

For anyone who might be interested in having a peek, this is a WinALDL datalog from last week. It was taken before I cooked my ignition module and re-did basically my entire ignition system. However, the car was running fine and I don't think the readings would be a whole lot different than what they would be now.

The file is downloadable from http://rapidshare.com/files/158812066/20081023_141546_LOG.txt.html - Here .

If I go out today in the GT, I'll save another datalog file.

John, is there a chance that there's a problem with this custom PROM and/or it's somehow contributing to the excessive readings?

Were you running win aldl while going into air car..as in then did there test with your running the computer?  winaldl bad !!

My Car Passes Air Care Everytime I Have Gone Through ...But When Running Aldl ..Everything Reads Ok ...Give it A Lil Gas ...And It Stall's...Turn The Car Off ...Take Out Aldl Stuff ..Turn Car Back On ..Revs To 4000 Easy ..With Aldl I Would Be Lucky To See 2000 lol

ZeroC wrote: Were you running win aldl while going into air car..as in then did there test with your running the computer?  winaldl bad !!

No, I certainly didn't do that!

After going for a spin on the freeway I connected the laptop and ran WinALDL a few blocks from the AirCare station just to check what temperature the ECM was seeing. I wanted to make sure it was good and hot, which it was. Then I disconnected the laptop and went in... and failed.

The only thing I notice when running WinALDL is that the idle speed increases 200 RPM from 800 up to 1000 RPM.

Okay, I've got an up to date WinALDL datalog from last night ready for download.

I'm really hoping someone (John, pretty please! ) can have a look at this and perhaps spot something obvious that might help to rectify my GT's AirCare failure.

The file can be downloaded from http://rapidshare.com/files/159116511/20081029_175906_LOG.txt.html - Here .

Thanks.

John, I was babying it to some degree because it's sucking back gas incredibly fast. I filled it up (again) tonight and reset the odometer so I can work out the mileage this time.

I also can't emphasize how gutless the GT is once the revs go up. It starts fine, runs smooth, and responds okay off the line, but there's no power if I rev it over, say 3000 RPM. When I kick it down into second gear on the freeway while doing 50-60 mph, all that happens basically is more intake noise.

Looking at the graph with the TPS values, I'd say that's about how I was actually using the throttle. Being an automatic, it's not like I'm changing the throttle position a lot, as of course I'm not shifting (manually) while accelerating. I'm just pressing the throttle down to a certain point and letting off on it when I have to stop at the next light.

For anyone who isn't familiar with WinALDL and ALDLView, here's what the Throttle Position Sensor data looks like for a short 25 minute or so drive within the city.

Time is along the bottom, but I somehow doubt that each increment is actually one second. I've heard that a snapshot of data is taken every 1.8(?) seconds by WinALDL, so perhaps that is the actual increment.

Chay, thanks for taking an interest in my situation here.

CFoss wrote: You never went over 35km/h and it doesn't look like you throttled up to get there, the acceleration having taken place over 10 seconds or so. This explains the lack of TPS movement.

You’re spot on about not throttling up much. It was rush hour traffic in Vancouver.  One correction though is that the readings are in mph. ALDLView indicates that the highest value for Speed is 37. Whether it was 35 or 37, either figure is certainly in the ballpark.

CFoss wrote: If I remember right 120 is the mimimum the ecm will allow the blm to move to unless it has been modified (To stop a bad 02 from brutally leaning out the engine). This means that the excess fuel may be outside the ecm's ability to correct for.

John burned the PROM for me and he tweaked a couple of items, so I’m hoping he can address the modification question.

CFoss wrote: If this is one cylinder (Stuck injector) that might explain all of your issues.

One question about that - Wouldn’t a stuck and/or leaky injector also throw off the idle readings at AirCare? My idle readings were actually quite good.

[EDIT] Chay, you posted again while I was responding to your first post. It'll take me a few minutes to respond again!

CFoss wrote: The seconds formatting is correct, it just draws a line between data points to fill in the gaps.

The reason I think the increments are not a second apiece is because it seems to me that 800 seconds is too short a time to get to my Dad’s place by Metrotown from my place around Nanaimo and Hastings in rush hour traffic. That’s only 13 minutes! I’ll have to pay attention to the elapsed time next trip.

Also, in my datalog it shows the engine going into closed loop operation at the 75th incremental point. Is it even possible for an engine to go into closed loop operation in one minute and 15 seconds from a cold start on a 55 F degree day (with it just idling at 1000 RPM)?

CFoss wrote: The other way to get a rich engine is an air blockage... Innie: air filter/intake valve not operating fully or not at all(rocker etc) Outtie: CAT, blocked muffler, or above with exhaust valve

You know, I’m beginning to suspect my muffler is clogged with the remnants of either the current cat or the original one. When I was re-doing my ignition components a few days ago and revving the engine by hand while at the back, it seemed to me that I could see fine white "dust" of some sort flying out of the exhaust tips. Hmmmm.....

The day my GT left me stranded (as reported http://www.westcoastfieros.com/forum/forum_posts.asp?TID=942&PN=1 - Here ), I was revving the heck out of the engine on the Upper Levels Highway to get it good and hot for AirCare. I was driving on the highway mostly in second gear (with a 3-speed auto). Perhaps the contents of the current cat (which was sitting for six years before I bought the GT this spring) have broken up and are now choking the muffler? Hmmmm.....

[EDIT] I found something awfully interesting http://www.autofixworld.com/index.php?option=com_content&task=view&id=247&Itemid=84&ed=6 - Here . What do you think, guys?

In ALDLView, I put my MAP readings over top of my RPM readings. I see several examples I believe are similar to what this fella is discussing. I'm not trying to jump to conclusions, but I'm getting a little excited.

Let’s look at the situation:

1) Failed AirCare with high readings for HC and very high for CO in the Driving part of the test, but the Idle readings were quite low and well within limitations.

2) Car starts fine, idles fine, accelerates smoothly, but it’s absolutely gutless at mid to high RPM.

3) Fuel economy is terrible.

4) Saw clouds of fine white “dust” flying out of the exhaust tips while accelerating engine at the TB by hand.

5) MAP sensor readings seem to mimic problem addressed by fella in article I linked to.

Okay, I’m very interested in getting some feedback on all this.

John, the last time I took the GT out on the highway and "BEAT THE CRAP OUT OF IT", it ended up stranding me in North Van (as reported http://www.westcoastfieros.com/forum/forum_posts.asp?TID=942&PN=1 - Here ).

I think I’d rather disconnect the exhaust pipe between the cat and the muffler and see if I can somehow get the cat crap out of the muffler from the inlet end. To tell the truth though, I have no idea what form the cat crap is that would clog up the muffler. What a freakin’ nuisance.

In regards to the PROM, thanks for the offer to burn another one, but unless you believe there’s a problem with it, let’s hold off just for now. Or was there something in the WinALDL datalog that concerned you about the PROM?

I suspect the terrible gas mileage and poor performance I’m experiencing presently is because of the engine not being able to breathe properly, but of course I don’t know for sure.

I know you mentioned to me that you had tweaked something to do with "power enrichment", but was there any tweak you did that would cause poor gas mileage even while "babying it"?

One last question - Is it "normal" for the engine to go into closed loop operation at a coolant temp of 80F degrees? I was surprised when looking at my datalog that closed loop operation had occurred at such a relatively low coolant temperature.

CFoss wrote: I had the cat stuff block up my muffler and didn't know it until it cleared all at once...the exhaust octave dropped about X2 and I took off way faster than ever before.

CFoss wrote: If the cat crap is in there, get a nerw muffler. It will not all come out. Sucks, but there you go.

Which is it, Chay?    Are you trying to confuse me? 

Capt Fiero wrote:     When you do get the car through, please post up the Air Care results.

Oh, believe me, I'll be sharing the results.

Capt Fiero wrote: Here is the breakdown on my 88GT. I am really worried about taking it in next week.

Although you've had a couple of high readings in the past, what makes you worried this time around?

Seems contradictory, but isn't/ My blockage cleared and stayed clear, so it was ok in the short term, BUT there was still stuff in the muffler, so it may have replugged in the future, and the performace may have been affected, so I ended up changing the muffler.

When I got the muffler off and rotated it there were pieces making a clanking sound and rolling around. Not cool!

Chay

Okay, I understand. Thanks Chay.

I found this image of the inside of a Fiero muffler. Looks like lots of places for debris to get stuck.

Well, it's stopped raining. Guess I should crawl under the GT today to see if I can figure out what's going on.

Ah ha !!!

Progress today. I got the cat off and it's plugged solid. Surveying this mess, I can't believe the motor could even run.

Don't know for sure at this point if the muffler is affected or not, but looking at this current cat (it's not the original), I've got my fingers crossed that the muffler is okay.

I'll post some pictures looking in both ends of the cat. It's quite interesting...

Pictures as promised...

With all the symptoms I had observed (and with Chay's helpful comment about a possible "air blockage"), I suspected it was the muffler that was plugged (from the contents of the previous cat) because the current cat looked to be in such good shape from the outside.

Here's the top:

Here's the bottom:

Here's the outlet: (A little difficult aiming the flash down 10 inches or so of pipe.)

Notice how the "honeycomb" looks really good.

Are you now ready for the money shots, two pictures (with slightly different lighting) of the inlet?

Have a good look at why my GT was running so bad!

Remember what I was saying earlier in this thread about a fine white dust?

Patrick wrote: When I was re-doing my ignition components a few days ago and revving the engine by hand while at the back, it seemed to me that I could see fine white "dust" of some sort flying out of the exhaust tips. Hmmmm.....

Well guess what poured out of the outlet (through the intact honeycomb) when I tipped the cat on its end? Yep, you guessed it - a fine white dust! I wasn't hallucinating after all.

I sincerely doubt that this very fine powder would plug the muffler. My fingers are crossed however that the previous cat didn't send chunks of its innards into the muffler.

I think I lucked out as this appears to be the best-case scenario. I can probably beat the rest of the honeycomb out of this cat and then just put it back on. Won't even have to bother buying a straight pipe.

Here's the entire contents of my cat in the bottom of a bucket...

I put the gutted cat back on and started her up... What a difference in sound! 

Didn't get a chance to drive the GT yet after getting the exhaust back together. However, judging from the sound, it should go a heck of a lot better.

While I had the cat off, I took the opportunity to have a look at my front exhaust manifold from underneath. Well, I found the reason for the slight "tick, tick, tick" sound coming from it. The bottom bolt is broken off on #2 cylinder.  That's a chore for another day (next spring).

Next step is going through AirCare again. That'll probably be next week. Reports to follow. 

CFoss wrote: After running it for a while it'd be interesed in seeing another log file to see if the blms numbers get back to around 128.

You bet. Yeah, I'm interested in learning what the numbers should look like when the engine is (hopefully) running normally.

I filled up my gas tank as soon as I drove the car so I could work out what kind of mileage I was getting while the cat was plugged.

Are you ready for this...

9.4 miles per gallon.

John, I hope it's considerably better now or I'll be needing this PROM redone.

I will say that the GT feels a WHOLE lot healthier now. Sounds much better too!

Just want to add that last night was the first time since I unplugged the cat that I was able to take a decent run on the freeway (to the club meeting). Quite a difference in power!

The biggest surprise was that club members in the parking lot thought the GT was "quiet" when I pulled up.  ....

I’ve uploaded another WinALDL log http://rapidshare.com/files/215476298/20081115_230029_LOG.txt.html - Here which was taken last night on a short 10-15 minute drive back to my place (which means the engine wasn’t absolutely cold when the log began).

Since my last log that I linked to earlier, I’ve unclogged the cat and the car goes a heck of a lot better! (I’ve also put the 180 degree thermostat back in, just in case anyone might wonder why the temperatures are different than last time.)

Please download it and have a quick peek if you understand these numbers. My concern is that the engine might still be running a bit rich. I’d appreciate some feedback on this before I take another run through AirCare. Thanks.

I got an informative PM from Chay (CFoss) regarding my WinALDL log. Much appreciated!

I've copied it here so that others might gain from his knowledge.

CFoss wrote: Hey there. I looked at it. It looks much better to me. At idle, the ecm is still compensating for a rich setup, having the blm at 120 still. The good news is that it seems to be successful there, as you notice the 02 readings are varying from low readings to high readings. This means you are in a band around stoich and it's probably ok.The low readings indicate a lean condition, leading me to believe that the fuel is within the ecm's capability to control.  When the throttle is off idle, the blms are consistent around 132, which means the ecm is richening the fuel a bit (128 is the balance). This is a huge change from when the cat was plugged. I'd take a shot at air care. You may still have too much fuel at idle, but it should show marked improvement and then you can contine from there if need be, because that would be conclusive proof you are on the right track.

Could any of you perhaps explain what's happening with the INT readings between 150 and 200. It demonstrates the same behavior elsewhere, but it's more noticeable there. What is actually going on when it peaks like that?

This is some black magic eh?

I read somewhere that the ecm has a 'learn' flag (Toggle, either on or off). The idea is that certain conditions have to be met, then 'learn' will turn on, and the int values will start to affect the blm numbers.

I can't remember all the conditions, but two of them were that the car was running for a certain period of time, and the other was collant up to temp.

So, I have no idea what it is doing, but it's very likely that it's not affecting your fueling at this point, given that the collant is not up to temp. At the point referenced I believe a fule enrichment table would still be in play due to the reduced coolant temperature.

An int (integrator?) is a short term value which will move the blm in time. I've read that the int will not affect fueling that much, but the blm will. There is a weighting algorithm something like the follwing:

100% fueling (duty cycle) = cell value (programmed in eprom)*80%+blm*15%+int*5%

The idea is that the ecm will start off with the cell value as it's base, then get modified somewhat by the blm on a long term basis, then by the int a bit for short term changes.

Chay

CFoss wrote: This is some black magic eh?

Yeah, that's for sure.

Thanks Chay, I appreciate your feedback.

In http://www.westcoastfieros.com/forum/forum_posts.asp?TID=1003&PN=1 - This thread I reported that I'm only getting 15.5 mpg, mostly city driving.

Is it reasonable to be expecting a lot better gas mileage than that if everything is performing as it should, especially considering I am NOT racing around?

Capt Fiero wrote: Is the INT your Intake Air Temp sensor?

Dave, are you perhaps getting that confused with the MAT (Manifold Air Temperature) sensor? If so I believe my MAT is fine, as on a cold  start it registers exactly the same ambient temperature as the coolant temperature sensor which feeds the ECM. The MAT then proceeds to show a higher reading as the temperature under the decklid increases.

The good news...

I passed AirCare !!!!!!!! 

The readings were relatively good...

I went to the Surrey AirCare station today (Thursday afternoon) and was hoping they'd do the same as they did with Dave and NOT do the driving test due to Fieros being "too low" for the dyno as reported http://www.westcoastfieros.com/forum/forum_posts.asp?TID=978&PN=1 - Here . However, they did the whole test and the GT passed easily enough. And keep in mind this was with NO cat. (Well, there is a cat on the car, but it's completely hollow!)

The bad news...

Even with the GT running just fine (supposedly) and passing the AirCare test no problem, the gas mileage is still absolutely pathetic - 14.36 MPG with my last fill up, and that's with me driving like an old lady.   

I've been taking it ever so easy on the gas. I'm even putting the car in neutral every time I slow down and stop so that the transmission isn't putting any drag on the engine while I'm sitting at a light.

I may end up re-connecting the EGR and re-installing the stock PROM to see if that helps as this just isn't good enough.

The O2 sensor is brand new, but yes, the injectors are possibly in need of a proper cleaning/rebuilding as this GT had been sitting for six years when I bought it.