ok, i have a fresh rebuilt motor for my 88 gxl. i have headers, no cats, and dual mufflers. the car has been running rich since the new motor was put in. i thought after some break in miles, this problem would go away. the car now has about 500 miles on it, and still the same problem. i did install an air fuel gauge(i know they are not accurate, im just using it for a general idea of where im at). when the car is warm, and at idle it runs at about 1800 rpms and a/f gauge says its rich. when i get on the throttle, it goes totally lean, then jumps back to rich. could this be the maf? the fuel preesure screw is set totally lean also. im stumped on this one. anyone got any ideas?

 

Check the timing and set the tps.
Brent

 

timing is set. im still new to the fc. how do i check the tps?

 

It tells you in the fsm. You can find the info in the archives.

Brent

 

ok i tested the air fuel meter- everything is within spec, but im not sure on one reading. it says in the fsm that resistance should be between 50 and 500 ohms between E2 and Vs when the door is open and closed. my readings were about 250 ohms closed, and 350 ohms open. the other thing i noticed was after the door closes, the resistance goes very slowly back down to 250ish. i can actuall watch it count down every number on my meter. is this normal or should it be more of an instsant change on the meter? this fsm isnt too specific

 

dude... to set tps you can either do the two light method wich i like better or you can use an ohmmeter. to use an ommeter disconnect the tps sensor... the connector that you disconnect should be about at the secondary fuel rail, put the black lead of the ohmeter on the black wire and the red lead on the ohmeter on to the green wire. then turn the screw untill at rest/idle (do this with the car off, but key on in ignition and you have to put a jumper wire in the initial set coupler while doing this so the computer reads the change)... anyway turn the screw so at rest/idle the tps sensor is reading just a little over 1 ohm... prolly about 1.2 would be best, and then do a sweep (very slowly and gradually open the throttle and make sure there are no "opens" in the reading) and when fully open should not read more than 6 ohms, if it does then the sensor is bad. i use the two light method. but thats a whole nother story. pm me if you need more info ill be glad to help out.

 

thanks, ill try that when i get a chance. as far as my air flow sensor goes, does it seem to be functioning properly?

 

When closed it should read b/t 50 and 500 for a non turbo.

It is not a normal pot. As you open it slowly you'll see the reading at first rise, then fall to zero and rise again, and fall to zero and rise again I forget how many times. All that is NORMAL.

But if you were monitoring the voltage output on VS with the key to ON and the harness connected up, you'd not see this rise fall bs. The voltage would start about 4.5 volts and as you open the afm flap to full open, the voltage would read something on the order of 0.5v at full open. Those are GENERAL figures.

 

ok, i used the led check light and got no codes. i also checked the tps the same way and that was good all along. i am stuck on this one. whats going on with my car?

 

i know running no cats makes the car run rich, but this is very rich. whats going on?

 

Running with no cats has no influence on running rich at all... where did you get that from???

and your multiple bumps have been deleted. Bumps are forbidden here in the 2nd gen technical section.

 

just somthing i was told. so what do you think the problem could be?

 

someone else said it may be an ignition problem. any ideas what to check if it is?

 

when were the injectors replaced or rebuilt???

and it would only be the ignition if you were having misfiring issues. Have you checked timing???

 

and have you fixed the idle speed yet... 1800 is about 3 times too high

 

Dittos on the rpms being waaaay to high. You need to get the idle at IDLE. Below 1000 rpm for sure but closer to 750, give or take a few.

I've no idea why your rpms are so high. Some throttle stop screw might be set wrong or....................too many other things could cause it. You can't set the timing at such a high rpm IMHO. The ECU advances the timing above 1100 rpm, load or no load.

And....what *fuel pressure screw* are you refering to???

 

thats what i'm wondering

 

the idle is turned all the way down and thats the idle we are getting. the timing is set though. injectors were replaced. pretty much everything was replaced with the swap.

 

if that is the lowest possible idle (and you should be able to crank it all the way down to stalling) then you have a major intake leak.

You need to fix the basics before anything else