2nd Generation Specific (1986-1992) 1986-1992 Discussion including performance modifications and technical support sections.

90 GTU prob. HELP

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Old Jan 14, 2003 | 11:12 PM
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90 GTU prob. HELP

ok im a FB guy so al the fuel infection stuff messes me up. I am helping a friend. heres the low down... its a 90 GTU that has sat for 2 years. its got a new t2 fuel pump in it and a new motor. we drained the gas and put new 93 oct. in it. once we got her to fire up it idles like a bridge port brap. brap. brap. and smokes like a train. black smoke and its REALLY REALLY rich... it burns your eyes FAST. what could cause this? im thinking its got gummed up injectors and they are just dumping in fuel. its not hard to start. what about a bad o2? or a bad mass air or bad map? what is the stock ecu # im at a loss on this and the owner is at the point that he is ready to just give up.
David
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Old Jan 15, 2003 | 01:29 AM
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Hmm. If the injectors were that bad off I would think it would flood instead of start. What kind of injectors were used? Were they the original "sat for two years" ones?

I don't want to insult your intelligence, I'm just throwing things out here. The plug wires aren't crossed? Timing is on? AFM plug is on good? Vacuum hoses all where they s/b? It almost sounds like a timing issue. How does it drive? If it generally runs OK, maybe extremely rich then fuel issue, if it backfires and doesn't want to run right under load then timing issue. Maybe.

Cheers

Last edited by HeffBoost; Jan 15, 2003 at 01:35 AM.
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Old Jan 15, 2003 | 01:33 AM
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First gens aren't FB's, they're SA22C's.
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Old Jan 15, 2003 | 06:50 AM
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not all 1st gens are sa22c's and if you read my sig. i have a 83 from 81+ they are fb....but all this is beside the point
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Old Jan 15, 2003 | 07:01 AM
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Im not insulted at all. and yes we have checked it all.

What kind of injectors were used? Were they the original "sat for two years" ones? YES

The plug wires aren't crossed? NOPE we checked them 5 times.

Timing is on? yep checked that also... my timing light is busted but we pulled the CAS and it was dead on/

AFM plug is on good? yep we checked that a few times. the owner said he thought it might be bad and 89 + is a mass A.F. right?

Vacuum hoses all where they s/b? ? as far as i know they are all there and on.

it drives (off idle) great good power and no back firing. but it uses TONS of gas. and like i said a CLOUD of smoke.
if it was me I would most deff. replace the injection... i would have done that b 4 installing the intake. also there is a BLACK plug and NOBODY can find what it plugs into its a round plug with 2 elct. conections... any ideas? its on the top of the motor and is currently on the spark plug side of the top

Last edited by BadAssRX-7; Jan 15, 2003 at 07:08 AM.
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Old Jan 15, 2003 | 07:19 AM
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you get the black smoke all the time right ? (not just at idle)

leaky fuel injectors (but then you would have flooding issues as well, which you don't have, right ?)

fuel pressure too high

bad spark at the splugs

carbon build-up in the rotor chambers (which acts like a sponge on vaporized gas), that may go away with some spirited driving

Do you have any error codes from the ECU ?

hugues -

Last edited by hugues; Jan 15, 2003 at 07:22 AM.
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Old Jan 15, 2003 | 07:47 AM
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[Byou get the black smoke all the time right ? (not just at idle) I DONT THINK IT SMOKES AT HIGER RPM BUT AROUND 10-15 MPH IT DOES

leaky fuel injectors (but then you would have flooding issues as well, which you don't have, right ?) CORRECT ITS NOT HARD TO START LIKE LEAKY INJECTORS

fuel pressure too high THE T2 PUMP DOES DO HIGHER PSI BUT THE FUEL PSI REG. SHOULD DROP IT ANYWAY

bad spark at the splugs GOOD ?

carbon build-up in the rotor chambers (which acts like a sponge on vaporized gas), that may go away with some spirited driving NEW MOTOR... LESS THAN 1 HOUR OF DRIVE /RUN TIME

Do you have any error codes from the ECU ? NO LIGHTS ARE LIGHTING UP
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Old Jan 15, 2003 | 08:42 AM
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there is a BLACK plug and NOBODY can find what it plugs into its a round plug with 2 elct. conections... any ideas? its on the top of the motor and is currently on the spark plug side of the the top
Can you give the colors for the wires to the connector, plz ?

hugues -
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Old Jan 15, 2003 | 08:57 AM
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A few more possibilies:

bad water thermo sensor (although it should have triggered an error code from the ECU if bad)

boost (pressure) sensor not connected or problem in vacuum line to it or bad sensor (might have triggered an error code as well but not sure on that one)

relatively poor compression on the engine.

carbon build-up in the rotor chambers (which acts like a sponge on vaporized gas), that may go away with some spirited driving NEW MOTOR... LESS THAN 1 HOUR OF DRIVE /RUN TIME
If it's a brand new motor, then it's a different ball game

hugues -
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Old Jan 15, 2003 | 08:58 AM
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Take out the T2 fuel pump and put in a NA pump. That's all there is to it!

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Old Jan 15, 2003 | 09:16 AM
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I don't think a TII pump will overwhelm the fuel pressure regulator, so having an NA or TII pump should not make much of a difference

I think HAILERS made a comparison between the 2 at some time but I can't remember too well

I would check the fuel pressure in the rails to be sure though

hugues -
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Old Jan 15, 2003 | 09:36 AM
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Most seem to believe that a T2 pump on a stock or mildly modified NA will make the car run very rich. I have no first hand experience with this but there is not too many other reasons why a NA would run so rich and not be flooding.
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Old Jan 15, 2003 | 02:22 PM
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I don't think a TII pump will overwhelm the fuel pressure regulator, so having an NA or TII pump should not make much of a difference
- I agree, after looking at the specs for each the TII isn't making that much more pressure.

I haven't looked at an S5 AFM up close yet but if they're as easily recalibrated like the S4s, then this might be something to check. See if it looks like it's been tampered with.
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