i just did a FSM test for my car, for 8 kilometers of driving , this is what i found out
after the car warmed up and entered close loop mode it was flasing slowly, on and off with the same interevals but when i get to a stop light at idle the light is always on and the rpms sometimes drop below 500 and jump again to around 600, then sometimes during the drives in the middle of the road it decided to go back to open loop mode again(flashing rapidly), then when i was going down a hill using engine braking, the light was off for about 15 seconds after which i swiched to nutral, and the carr STALLED while i was still doing 60 kmh (~30 mph, i think) so i had to start it , while driving which friked the he!! out of me...
but its not the first time it does that after a prolonged engine brake, then after i started it, it entered closed loop right away and did the same thing at stop lights ocassionally staying on for about 5 seconds and then flashing evenly while in gear(most of the time), then it for some reson decided to stay off for about 10 seconds after which it resumed the regular flashing intereval, (staying on at stop lights while idling), when i reached my home and pulled in the driveway it stalled again for an unknown reason,
now please i hope someone will help me diagnose the problem because the computer doesnt give me anything in diagnostic mode exept the prolonged flash and two quick flashes (code 12) .
PLEASE HELP IF U CAN
oh and another thing when i poped up the hood, the EVAP canister was smelling strongly of gasolin.
(if u haven't read my previous posts the top hose to it is broken and sealed at both ends,)(maybe thats the reason for the smell, and eratic idle)
PLEASE HELP IF U CAN
I LOVE THIS CAR, AND CAN"T SEE IT LIKE THAT
THAT BRINGS TEARS TO MY EYES
(and thats not really good, for people around me seeing me crying by my car)(J/K)
but its really sad
i like third gen cars, and i really want to fix it right
PLEASE HELP IF U CAN
I'LL REALLY APPRICIATE THAT
THANKS IN ADVANCE
AK

 

I can help you w/2 answers:

1) Code 12= your engine computer is working (a good thing)

2)Replace that cannister, not just the filter on the bottom. it can effeect how a car performs, but I only heard of that on a crbed engine, not a FI one.

------------------
$150.00 2.8 Auto.
Blown Head Gasket.
turbo has arrived, but put on hold (4 now)
USAF-Giving the enemy the oppertunity to die for their country

 

how do i check the rest of the codes
please help because today on the way to school it surged really badly we were jumping in the car in first and second gear
but not third or forth
PLEASE HELP
(its an 88 2.8 5 spd. manual)

 

My 92 has an evap canister. its MPFI. It can most certainly cause surges. Lack of steady vac/pressure in fuel system. Do get the rest of the codes get a code reader. Or make one, do a search and you'll find the direcetions. I just bought one, alot easier.
To clear the codes, pull ECM fuse for a couple minutes then replace. Restart and drive a a couple to 10 miles for it to get the diagnostic info back. if the code comes back you did'nt fix the prob.

 

i'll get one but still could the EVAP canister cause the stalling after engine braking downhill, and cause a gas milage of 14 mpg (for a 2.8 car!)

 

Yes the EVAP can cause some strang problems. I would definetly replace it and broken parts. Also check the purge valve for the EVAP after running it for about 10 - 15 mintues check to see if it is very hot. If it is replace the purge valve to. They both tend to go out at the same time.

As for the stalling check your EGR valve. make sure it can open and close. If it can't close every time you stop your car will stall.

 

how can i check the purge valve ,and the EGR ?

 

To check the purge valve run your car for 10 - 15 min and then grab it and see how hot it is. It shouldn't be hot. Warm is ok, but if it is hot it is shot.

Locate your EGR and put your finger under it. Do this when the engine is cool so you don't burn your self. Press up on the diaphragm if it comes down it is good. If it doesn't come back down it needs replacing.

 

ok, my purge valve is even hotter then the EGR, i'll replace it today, and about my EGR, i pressed on the diapraghm and it went up fine not too smoth but ok, my engine almost stalled while doing it so i let it go, it wend down fine aswell,
so i guess its ok, but why did the egine almost stall...
i hope my problem was the purge valve although im not sure if it could have affected things like stalling while in idle or surging, or could it ???

 

The engine almost stalled because you let a ton of exhaust gas into it instead of fresh air... exactly what should've happened.

What's the problem with the 88? Does it surge? I missed the question..


------------------
-Tom P (Hot rodded 1986 Firebird 2.8l)

 

the problem is that it sures in first and second, the fuel consumption is huge, and after i use the engine to slow down a hill , and then shift to nutral, the engine stalles, its all in the first post,

 

A bad purge valve can cause a look of wierd problems. It controlls when the fuel that is collected from the tank vapor gets introduced into the intake. If the computer tells it open and purge the stored fuel, but doesn't open the car will have less fuel then the computer belives it has. This can cause a stalling issue.

It sounds like your EGR is fine. It did go up smothly becuase the car was running and you were fighting the vaccum presure, but at lest it's function fine.

Have you check your fuel presure yet?

 

ok, i will replace the purge valve and keep you posted about what happens,
but how could a purge valve cause a huge fuel consumtion 17L / 100 Km (15 or 14 mpg ...i think).
at least i found one of the problems...

thnx for the help
AK

 

i reset the TPS and AIC, and haven't had any problem with stalling (yet)
so thats one more problem gone, now i have to find a time to buy a purge valve and i hope everything will be fine
i'll keep u posted
thnx for the help

 

You should be able to get one fromt he bone yard for a nice price. Any car not running in good condition (one or more parts not function correctly) will use more gas, but that could also be attributed to the TPS and IAC having problems which you all ready fixed. You could havve had a couple of different problems going on.

 

ok, now im wonderng what should the idle be at, because when i just start the car it starts at 1500, then slowly going back to just abouve 1000,
isnt that high for a manual

 

A fully stock manual should idle at 650. At lest thats what the book says. When you first start the car it should start at about 1500, but then should also drop down. With only a few mods my car likes to idle at about 1000 then after a while of running it it will settle in just bellow the 1000 mark. There was once a topic here asking what every one idle speed was. I don't recall one person having the ideal factory idle speed. They all seemed to run around the 1K mark. In short you should be fine. Now that it is colder out they will idle a little faster until they are completly warmed up. Does your car still surge in 1ST and 2ND gear?

I used to idle around 1500 - 2000. Once I found and fixed all of my vaccum leaks it stelled down quite a bit.

 

it doesnt sure as much as it used to, it does it just a bit, i still feel it a bit in second when its around 2000 - 2500 rpm
when it gets abouver that i stops surging but i dont have much power above 2500 which i also weird, the rpms go up but the car doesnt accelerate faster,
e

 

So I was reading this thread eagerly looking for more, and then there wasn't. I have an 86 Firebird 2.8L 5spd manual. So to revive this OLD thread, can anyone please help me?

My car is surging in first and second gear (a little bit in 3rd sometimes) like the original poster. Sometimes it really jerks the car and does it most at the initial application of gas in a given gear. Once I floor it, the surging kinda goes away, and I just quickly get into 3rd 4th or 5th, where the car is comfortable. I also experience a severe drop in idle when the car is cold. After it warms up, the idle is fine. The surging seems to happen worse when the car is warmed up. So I have poor idle when cold, and great idle when warm, and less surging when cold and more surging when warm.

I re-did all of my vacuum lines, plugs, wires, etc. I even replaced the MAF sensor. When I unplug the MAF sensor, the car idles fine when cold, but the surging is still present (just not as bad).

Any direction on where to go next? I am thinking to test my IAC, TPS, EVAP purge system, and go over all vacuum lines again...

HELP?!

 

Ouch, dead thread!

If you didn't replace the MAF with a GM one, well, you'd better do it again WITH a GM one. I've had a couple of the aftermarket ones and neither was built right and failed within a year. Poor cold idle and decent hot idle is a symptom of a bad MAF (I used to have to sit and fast idle the engine until the temp gauge registered 100*F or I couldn't go anywhere without stalling out).

Check to make sure the valve covers aren't leaking (if they're leaking oil, they're leaking engine vacuum thanks to the pipe running to the intake bellows and the PCV) and also that the little boots on the ends of the idle air pipe haven't disintegrated. Also make sure the intake bellows isn't cracked, the PCV valve is tight in the grommet, and that the breather tube elbow isn't damaged as well.

Other than that, check to see if the tach is bouncing when you accelerate. If it is, then the ignition module in the distributor is dying and WILL eventually leave you at the side of the road (been there, done that ).

 

Thanks for the reply! I am a new 3rd Gen owner, so all help is appreciated. I did replace it with an aftermarket one (a cheap one too...). Perhaps I will try to clean my old one and use it again. If that doesn't work, I will either buy a new GM one or find one in a yard. Could the MAF sensor being faulty cause surging during 1st and 2nd gear? It really jerks the car throughout the RPM band.

The tach doesn't bounce, but is there any other signs that the ignition module is dying? Does that get replaced separately from the distributor, or is it all in the one unit?

The only leaking that I notice is around the grommets where the air tubes go in and out. Is that what you are referring to, or also the actual valve cover gaskets leaking?

Thanks again!

 

Remove the dizzy cap and the module is held in with 2 screws...

I'm referring to the valve cover gaskets AND the grommet/elbow in each cover for the breather pipe and PCV. If any of the above are leaking, they need to be replaced (or you could just wrap some electrical tape around the PCV valve when you put it back in... It's supposed to be rather tight). The elbow in the passenger's side cover is referred to as a SBC elbow in the HELP section of your parts store. The valve cover gaskets CANNOT be replaced alone... You will need to pick up a FelPro MS93020 gasket kit and a fuel injector o-ring kit.

While you have things apart, check the resistance on the fuel injectors. Any injector reading below 10.4 ohms needs to be replaced.