Check for a fuel pressure regulator problem. To check the ECM if you have an AutoZone in the immediate area they can test them at no charge. The fuel pump gets two diffrent feeds of voltage..... one feed when the starter is turning the car over and once the car starts it gets a diffrent feed to tell it when it needs more pressure if if you can check to see if you have pressure at the schreoder valve while someone is turning the car over this may help. other than that i'll have to think some more. Hope something helps and good luck. OPERATOR64
IP: Logged
06:10 AM
Formula88 Member
Posts: 53788 From: Raleigh NC Registered: Jan 2001
Thanks for the tip Op, but I've already checked the ECM by putting it in LZeitgeist's Formula and it works fine. I'm getting 45psi fuel pressure while cranking at the schrader valve, which is dead on spec. And yes, the check engine light bulb is good, but the light doesn't come on. Not even when I check codes. That's what leads me to believe the ECM isn't getting power.
To recap the diags so far: New plugs New cap & rotor Ignition module & coil replaced with a known good unit. Fuel pressure: 45 psi New fuel filter (5) fuse links at battery junction block tested ok. ECM tested ok in anther car.
The car is apparently getting spark. It'll trigger a timing light, and when you spray starting fluid into the intake, it tries to fire. Also, the timing appears to be pretty close judging by the timing light, so I doubt it's jumped timing. It looks like that for whatever reason, the ECM isn't getting power, therefore the injectors are firing. Hence, no start.
Also, this is something that happened suddenly. The car ran perfect all week, was driven about 85 miles out of town (figures), left overnight. When I got in it the next day, it started instantly on the first twist of the ignition. I put it into reverse and as I started to let the clutch out, it stalled and wouldn't start back. No backfiring, no dramatics. It was just like you turned the key off and it wouldn't start back. If I can't figure someting out pretty soon, I'm taking it to a dealer, if I can find one who'll work on it, and let them figure it out. God, I don't want to do that!
IP: Logged
10:25 AM
LZeitgeist Member
Posts: 5662 From: Raleigh, NC, U.S.A. Registered: Dec 2000
Thanks, guys (and gals) for all your help... keep it coming, if anything dawns on you... *sigh* I don't know where else to look... something's missing from the equation, but I can't put my finger on just what it is...
Please keep helping! We need it!
IP: Logged
11:40 AM
Formula88 Member
Posts: 53788 From: Raleigh NC Registered: Jan 2001
After reading all of the info, I don't remember seeing anywhere that you looked at the factory service manual. So I went and looked at mine. Page 6E3-A-8 Chart A-1 No "Service Engine Soon" Light 2.8L "P" Series (Port). It show the wiring diagram for the ecm power supply as it relates to the SES light. It also shows a flow chart for what to do.
Does engine start? Your answer would be "No"
1.Is ecm battery feed ckt 240 and ecm fuse ok? Now the battery feed ckt 240 is coming out of your ecm in two locations C16, and B1. Both of these wires are orange, and splice togather at the insterment panel connector. ECM fuse is the Pink/Black wire at A6 on the ecm. It is also called circuit 439. So now you have to answer the question "are they ok?" Yes- Ign. off, disconnect ecm, ign. on, probe ckt 240&439 with test light to ground. Is the light "on" on both circuits? Yes move on to set 2. No repair open in circuit the did not light the test light. No- Locate and correct short to ground in circuit that had a blown fuse.
2.Faulty ECM grounds or ECM (which it shouldn't be the ECM itself, because you tried it in a different Fiero, and the problem did not move over to that Fiero)
Hope this did something positive for you.
------------------ 85 Fiero GT 3.2 Liter Under Construction
IP: Logged
01:38 PM
Formula88 Member
Posts: 53788 From: Raleigh NC Registered: Jan 2001
OK, lets do some steps. First off we need the service engine light to work. 1) Check for a good ground at pin 'A' at the serial port. (ALCL Connector) 2) Check the 'gauge' fuse in the fuse block. 3) Make sure that both the fuel pump relay and the oil pressure switch and relay are connected and good.
Ok, the fuel pump relay may or may not be good. It's not energizing the pump, but then it won't due to the ECM not coming on. The pump does come on via the oil pressure switch. Since the car had no previous hard starting symptoms, the fuel pump relay should be good and is just not activating due to the ECM problem. Everything else I'll need to check.
IP: Logged
02:47 PM
LZeitgeist Member
Posts: 5662 From: Raleigh, NC, U.S.A. Registered: Dec 2000
We may have a winner, people! At first check, it appears that Battery Feed circuit 240 (orange wires to ECM) is dead. Now I gotta go double check and triple check, and then try to trace out the fault. The orange +12V feed to the cigarette lighter is good, but I've also blown a fuse when using the cigarette lighter before. Looks like I've got a bare/pinched wire somewhere (probably broken by now).
Well, she's not running yet, but we're getting very close to the root cause. Thanks so much so far. I'll let you know as soon as I get more definate info - damn weather won't cooperate!
IP: Logged
06:53 PM
LZeitgeist Member
Posts: 5662 From: Raleigh, NC, U.S.A. Registered: Dec 2000
Just got a call from John, so I thought I'd post this info for him, since he was trying to get out the door to get to a local concert...
Inside the passenger compartment, he found that neither of the orange wires in the ECM connectors was getting 12v+DC as they should, so he rigged a temporary jumper wire from the orange wire at the back of the cigarette lighter socket (also 12v+DC) to both the ECM wires...
The "Check Engine" light came on when he turned the key, and the car started normally. Whoohoo!!!!
So... at least we know where the overall problem is... now we just need to trace the orange wires for the ECM up under the dash where they were headed and find the break.
THANK YOU EVERYBODY FOR YOUR HELP!!!!! We couldn't have gotten this far without your input!!! Thank you!!!!
[This message has been edited by LZeitgeist (edited 04-01-2001).]
IP: Logged
08:16 PM
Apr 2nd, 2001
Formula88 Member
Posts: 53788 From: Raleigh NC Registered: Jan 2001