My fiero has me drinking.

[ericjon262]

diagnostics =over, swap=nearing completion...

I have an 85 Fiero 2M6 SE automatic, I bought it about 6 months ago, and have put somewhere around 8000 miles on it without any issues. but recently it's been giving me hell, it won't even run right now, and I'm wondering what you guys think the problem may be. when it first started acting up, it was mainly just a matter of the car running like total crap, no power, sputtering and backfiring. I was thinking maybe I got some bad gas, so I dropped the tank, and it was clean, no water or other foreign substances. since I had the tank out I went ahead and put a new fuel pump in with a new filter sock no improvement. then I got the bright idea to check the codes o2 sensor (rich) and map sensor high(low vacuum) I didn't have any vacuum leaks so I replaced the map sensor, helped, but still not running right. the next day I go out and start the car and I noticed the SES light wasn't on with the engine off and the key in the on position. I try starting the car, it starts and runs ok, not good, but ok, no backfires, less sputtering, and still no power. put about 5 miles on it, and when I filled the gas tank up, it gives me code 12 again. but now, it won't run again.

so far the car has a new ignition, cap, rotor, pickup coil, module, plugs, wires. it's got a new map sensor, a newer 02 sensor, a newer fuel filter, and a newer air filter. TPS reads .55-.57 volts with the throttle closed and smoothly goes up to 3.9 volts as throttle increases.

any Ideas as to what it could be?

[Shaun41178(2)]

you able to put a scanner on it and check coolant temps?

You sure you have the plug wires in the correct order? That will cause a backfire and loss of power if not.

[ericjon262]

plug wires are definitely right, I haven't checked coolant temps through the ECM, but the gauge seems to be reading correct. I'll check it tonight

[Fastback86]

Sounds like the only part you haven't thrown at it yet is the fuel filter. Might want to check your fuel pressure and make sure it's not clogged (since you already took care of the pump).

[ericjon262]

well, the fuel filter is fairly new too(less then 3000 miles old), and I have a new development, SES light comes on for code 12, aldl hooked up to my laptop shows no code 12, but it will blink code 12. also, coolant temp showed ambient temp when I plugged into the aldl which would have been correct as I hadn't driven it today. to me, it's starting to sound like I'm having some kind of ecm problem. does that sound plausible?

[CincinnatiFiero]

Code 12 means the pcm is working. Or does it come on as you drive?

Diagnostic Mode Active (ECM OK)
When the diagnostics terminal is grounded, the ignition turned on and the engine is not running, the ECM will flash Code 12 three times. If it's flashing this code while the engine is running (Field Service Mode), then the ECM is not receiving any pulses from the distributor.

[ericjon262]

according to the SES light blinks, it comes on with the engine off, according to tunerpro RT, I have no codes with the engine off and the key on. no codes while the engine is "running" the car is currently undriveable.

[Emc209i]

Do you think the engine and chassy is grounded well? Stab in the dark.

[ericjon262]

I haven't seen any loose or corroded grounds, doesn't mean thats not the problem though, I haven't really looked to hard for one yet, good idea thanks!

if It doesn't get fixed soon, this may become my 3500 swap thread!

[The Dark Side of Will]

is there actually a "code 12" for for TunerPro to report?

Did you set the base timing correctly when you did all that work to the distributor?

Have you checked the injector +12 connections at C203 under the console? Ignition power goes through C500.

[ericjon262]

is there actually a "code 12" for for TunerPro to report?

Did you set the base timing correctly when you did all that work to the distributor?

Have you checked the injector +12 connections at C203 under the console? Ignition power goes through C500.

without the engine running there should be.

I haven't reset base timing yet, but the distributor is in the exact same as it was when it came out.

I haven't checked any voltages under the console, what does the C203 look like, do you have a picture?

Thanks for the help everyone

[jelly2m81]

Check the EGR valve to ensure it is still securely attached to the base. I'd also pull it to check if it is stuck open.

[Fastback86]

I haven't reset base timing yet, but the distributor is in the exact same as it was when it came out.

That doesn't mean anything, unfortunately. I got away with it once, the second time the timing was so far out that the engine wouldn't start at all, much less run. I swore up and down that the distributor was replaced in the exact position it was removed from, but it didn't matter. I spent several days cursing at it and the only thing that eventually cured it was to start over and reset the base timing.

[The Dark Side of Will]

Are you sure the body AND the rotor are back in exactly the same place?

I know your car is an auto, but on a stickshift car, leaning on the back bumper while the car's in gear can turn the engine enough to throw the dizzy off one tooth.

[ericjon262]

That doesn't mean anything, unfortunately. I got away with it once, the second time the timing was so far out that the engine wouldn't start at all, much less run. I swore up and down that the distributor was replaced in the exact position it was removed from, but it didn't matter. I spent several days cursing at it and the only thing that eventually cured it was to start over and reset the base timing.

I know thats if it's off at all, it's definitely close enough to run without feathering the gas nonstop.

Are you sure the body AND the rotor are back in exactly the same place?

I know your car is an auto, but on a stickshift car, leaning on the back bumper while the car's in gear can turn the engine enough to throw the dizzy off one tooth.

Positive.


Where is the timing tab on a 2.8 fiero, I'll put a light on it, but I'm sure it's real close. also, where is the ESC plug for setting base timing on a fiero?

Thanks for any help-

Eric

[ericjon262]

well, still having problems, haven't had a chance to reset base timing yet, I'm wondering if the fuel pressure reg could have gone out, would it produce symptoms like this? anyone have the location of the ESC plug?

[lucky]

Remove the plastic cover set into the top of the rear right shock tower. Look diagonally down through that hole at the harmonic balancer; there's the timing tab. If you're sure pin A of the ALDL, or the wire attached to, it isn't grounded to anything, your ECM shouldn't be showing code 12; if you're not aware, you need to be in diagnostic mode (code 12, pin A to ground) to set the timing. You are correct that it should run in diagnostic mode without messing with the gas pedal.

[ericjon262]

Remove the plastic cover set into the top of the rear right shock tower. Look diagonally down through that hole at the harmonic balancer; there's the timing tab. If you're sure pin A of the ALDL, or the wire attached to, it isn't grounded to anything, your ECM shouldn't be showing code 12; if you're not aware, you need to be in diagnostic mode (code 12, pin A to ground) to set the timing. You are correct that it should run in diagnostic mode without messing with the gas pedal.

A+B had not been jumped while attempting to run the car, I was just saying that I was not getting an SES light with the key on and the engine off. after reading this, I went outside and tried running it with A+B jumped, and it ran better, not good, but better, I don't have to feather the gas to keep it running with them jumped.

[Emc209i]

Set base timing and hope your harmonic balancer hasn't rotated in relation to true TDC.

[lucky]

A+B had not been jumped while attempting to run the car, I was just saying that I was not getting an SES light with the key on and the engine off. after reading this, I went outside and tried running it with A+B jumped, and it ran better, not good, but better, I don't have to feather the gas to keep it running with them jumped.

Sorry. Should have clarified. Code 12 indicates that the ECM is in diagnostic mode. If terminal A is not connected to ground you should not be getting code 12 (sounds like a possible ECM failure). TunerPro theoretically wouldn't report it because it isn't technically a code; merely an indication that you are in diagnostic mode.