Fuel pressure gauges |
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Patrick
Newbie Joined: 19 April 2008 Location: Vancouver Status: Offline Points: 5 |
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Topic: Fuel pressure gauges Posted: 19 November 2008 at 1:21pm |
I notice several of you have fuel pressure gauges mounted on your fuel rails. Could you please tell me what type of gauge I should be looking for, and what fittings it should come with. I need to find out why my gas mileage is so bad. I just worked it out for the time period after unplugging my cat, and it's still only 15.5 mpg! This is ridiculous as I'm driving the GT like an old lady. With a fuel pressure gauge installed I can at least check to see if my fuel injectors are suffering from leakdown.
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Romeo
Senior Post God Joined: 16 November 2008 Location: Canada Status: Offline Points: 3033 |
Post Options Quote Reply Posted: 19 November 2008 at 1:41pm |
If it makes you feel any better, I'm only getting 15MPG, and I've done all the "mileage mods" I can think of, short of an entire exhaust system upgrade.
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Never shift into reverse without a back-up plan.
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Patrick
Newbie Joined: 19 April 2008 Location: Vancouver Status: Offline Points: 5 |
Post Options Quote Reply Posted: 19 November 2008 at 4:13pm |
No, it doesn't make me feel any better. Some people get over 30 mpg with stock 2.8 - 3.4 engines in their Fieros. I'm not upset because I'm not getting that kind of mileage, but something is wrong when mine (and apparently yours) are getting HALF that!
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kawana
Senior Member Joined: 09 June 2007 Location: Canada Status: Offline Points: 508 |
Post Options Quote Reply Posted: 19 November 2008 at 4:31pm |
well are you getting 15mpg CITY or Highway? Those that claim 30mpg are def. highway mileage. stock 2.8's are rated at 16city/26hwy
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Dr.Fiero
Senior Post God Joined: 12 February 2007 Location: Canada Status: Offline Points: 1726 |
Post Options Quote Reply Posted: 19 November 2008 at 5:10pm |
Yep - you're only a bit low (and that # can shift quite a bit for an auto vs. stick too remember).
For reference: http://www.westcoastfieros.com/forum/forum_posts.asp?TID=594 &PN=1 |
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Patrick
Newbie Joined: 19 April 2008 Location: Vancouver Status: Offline Points: 5 |
Post Options Quote Reply Posted: 20 November 2008 at 1:32am |
I was getting better gas mileage than this years ago with my '78 Z28 Camaro with a high performance 350. I don't understand why the 2.8L in a Fiero is so thirsty. Here's a fella from PFF with a 3.4 in his Fiero - 24 mpg city / 37 mpg highway
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Romeo
Senior Post God Joined: 16 November 2008 Location: Canada Status: Offline Points: 3033 |
Post Options Quote Reply Posted: 20 November 2008 at 12:21pm |
Yeah, the 2.8 does like to bang back the go juice, that's for sure. If you really want to spend some moneyz, Crane Cams has a camshaft with improved economy and power across the curve, a new enhaust never hurt, the guy above is right too, porting and polishing will net you some more MPG. After that, just upgrade the air intake and eletrical system. Just my advice.
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Never shift into reverse without a back-up plan.
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Patrick
Newbie Joined: 19 April 2008 Location: Vancouver Status: Offline Points: 5 |
Post Options Quote Reply Posted: 20 November 2008 at 1:45pm |
Okay, we've gone off on a tangent here (mostly my fault), but the thread was supposed to be about fuel pressure gauges. Whatcha got?
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Capt Fiero
Admin Group Founding Member Joined: 12 February 2007 Location: Canada Status: Offline Points: 4039 |
Post Options Quote Reply Posted: 20 November 2008 at 2:19pm |
I have been too busy to post in this thread, but I have a spare min.
Gauge you want an oil filled 0-60 psi gauge. The oil filled is so that the engine vibrations don't kill the gauge in less than a week. Fittings, you are going to need at least 2 parts, a 90 elbow, and a joiner fitting. (not sure on the official name) It is best if you take a spare fuel rail into Princess Auto/Mopac or Lordco. The adapter we use, threads right onto the stock fuel pressure valve on the rail. You must remove the schrader valve from inside it. Pretty simple same as a valve stem. Once you have the schrader valve out. Thread the gauge into the 90 elbow. Then thread the elbow on the joiner. Your joiner must have one end that can spin when loose. Thread the solid end of the joiner into the elbow. Now put your entire assembly onto the fuel rail and snug up. Someone commented on the Fiero being thirsty. Well the main reason is the batch fire injection system. It fires all 6 injectors at the same time, regardless of if a piston is even on the exhaust stroke. It still fires fuel at it. Which leaves a lot of excess fuel getting spat out the tail pipe. I have found with a good aftermarket ignition system, I gained at least 3-4mpg from a tank. I have recorded over 32mpg on my old V6 85GT 4spd car. Which had a full MSD ignition (6AL box, Blaster II coil, superconductor wires, cap and rotor were all MSD) Plus bumping the time from 10 degrees up to 12 degrees helped. Then the norm due a tune up every 3rd or 4th oil change. Replace what looks bad, and clean what looks OK. Re-Gap the plugs and go on your way. (stock ignition system, gap to .045, MSD coil, gap to .050 MSD Coil, MSD Box and MSD Wires and MSD Cap and Rotor, gap to .060) The bigger the gap the bigger the spark, the bigger the spark, the better the better the burn in the combustion chamber) |
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Capt Fiero
88 Fiero GT 5spd V6 Eight Fifty Seven GT V8 5spd. |
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Patrick
Newbie Joined: 19 April 2008 Location: Vancouver Status: Offline Points: 5 |
Post Options Quote Reply Posted: 20 November 2008 at 2:29pm |
Dave, thanks very much on the fuel pressure gauge info. Just what I needed to hear!
Are you saying the fuel injectors are spraying fuel during the exhaust stroke as well !!!???? I gotta go look that up. I can't believe it. That would be crazy! Good gawd, if that's true it's no wonder the fuel economy sucks.
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Capt Fiero
Admin Group Founding Member Joined: 12 February 2007 Location: Canada Status: Offline Points: 4039 |
Post Options Quote Reply Posted: 20 November 2008 at 2:40pm |
Yep thats exactly what I am saying. Its called "Batch Fire" injection for a reason. The engine has no Crank sensor to tell it what piston is where, all it knows is the RPM of the engine so it speeds up or slows down the firing of all of them. Even if the piston is on the exhaust stroke, squirt, squirt goes the injector.
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Capt Fiero
88 Fiero GT 5spd V6 Eight Fifty Seven GT V8 5spd. |
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Patrick
Newbie Joined: 19 April 2008 Location: Vancouver Status: Offline Points: 5 |
Post Options Quote Reply Posted: 20 November 2008 at 2:56pm |
No no no no no... I refuse to believe it!
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Romeo
Senior Post God Joined: 16 November 2008 Location: Canada Status: Offline Points: 3033 |
Post Options Quote Reply Posted: 20 November 2008 at 5:01pm |
Is there any way to correct it? Theoretically, that would double the fuel economy...
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Never shift into reverse without a back-up plan.
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