1985 2.5/auto .engine is low mile (Mechanically sound), but lately it has a habit of stalling for no known reason. usually at a light, But did it Once going down the road at 30MPH. Has always started right up again. NEW fuel pump, lines, filter, injector, regulator, Pickup coil, IAC, ICM, (within the last 500 miles !) the Stumble before totally quiting leads me to believe a fuel issue, but everything is NEW. Thinking of installing a fuel Pressure gauge IN the Dash so I can SEE what happens when it stumbles. Volts do not drop, tach does nothing wierd. I've tried jiggling the key switch when it started stumbling,... NOTHING. I dis connected & re-connected all electrical connections. then after it re started, I get on my way, and if I push on the accelerator, does NOTHING ! doesn't quit, but won't speed up either ! TPS is Also NEW. tried switching the AC and fuel pump Relays also. maybe a coinsidense, but the AC (that will usually Freeze me out ) every now and then blows WARM, 2 min later it blows Ice Cold !!?? running out of "what can it be's. Help! Thanks
First thing to try is disconnect the torque converter clutch wire on the transmission and see if the issue continues. As someone else said this is a very common issue.
If you have a spare engine computer you should try swapping it. For stupid reasons I happen to have an 85 2.5 auto engine computer that I know works I could send you for cost of shipping from PA.
Been in this situation with a 2.8, turned out to be a clogged cat. 60k miles on this one. I suggested this to another thread on a super low mile car and it happened to be the cat being clogged even there. Was under 10k miles, IIRC.
Take out the oxygen sensor and see if the problem goes away.
disconnected the lock up. took it for an 8 mile ride, Perfect !....................NOPE, 1/2 hour later went to use it and I didn't even get out of my driveway ! Has NO Cat on it ! how long will it run with the O2 disconnected ??? (am I going to get stuck 2 miles down the road ?) or will it just run rich and throw a code?
I disconnected the O2 sensor, made Not alot of difference except putting the ses light on and a 13 code. disconnected and plugged EGR, no difference, checked wires in console (No mouse chews), r&r all the plugs to make sure they are "Seated". still Sputters for 1 second then quits, will start right up again though. did it 4 times just in the driveway !, then ran fine for about 2 miles before doing it again.
fuel pump was 1st thought. New ac fuel pump and hose, the old hose was Split after 2 years !so I put in a new pump while the tank was Out has 13 psi fuel pressure engine off, engine running. cannot see it when the engine shuts off, (thats why I was thinking of a fuel pressure Gauge in the dash), Happens so Quickly, no warning or time to really see anything "abnormal' happening ! Volts do Not drop ( well goes from 14 to 12 when the engine stops spinning) (normal). Switched AC and Fuel pump Relays, no difference, ordered a new relay anyway,LOL. Running out of "what to try". *Can a OBD1 car (fiero) be hooked to a laptop and driven to SEE what is happening ??* I am totally WILLING to pay the man in a big shopwith latest equipment to "Diagnose" this if it is possible, I'm running out of Ideas. I Know, whatever it is, IS just a "prettymuch" $10 fix, But I just can FIND the "Culprit". Starting to think it's a BAD "Brand New Part" that I already replaced
IS IT Possible ? for the Ign COIL to intermittently overheat and shut the engine down ? the COIL is original to the car and about the only part that has never been replaced, I know, grasping at straws.
Its possible that the ECM, or ignition module may be working intermittently. A scan tool may give you and indication.
------------------ " THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite. "THE COLUSSUS" 87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H " ON THE LOOSE WITHOUT THE JUICE "
just replaced the ignition module, no difference. a rebuilt ecm is on the way. I do not have a way to SCAN it, or I surely would do it. (Not that I would know what the numbers meant anyway)
I CAN read the "flashing codes" by jumping it (Has NO Codes !) But what I Cannot do it (using a "SCANNER") to SEE "what it's DOING when it's DOING IT". it only shows Codes AFTER the fact". and it shows NO Codes
I CAN read the "flashing codes" by jumping it (Has NO Codes !) But what I Cannot do it (using a "SCANNER") to SEE "what it's DOING when it's DOING IT". it only shows Codes AFTER the fact". and it shows NO Codes
here is a list of Whats NEW in this car: (1985 fiero 2.5 /auto) All PARTS less than 100 miles
Fuel pump, hose, pickup, filter, regulator, throttle body, IAC, Map, TPS, Fuel injector, fuel pump relay dist pick up coil, ICM, rotor, cap, wires, plugs rebuilt ECM, ALL temp senders/sensors,(air and fluid) O2 sensor has 10 psi fuel pressure at all times (even when it quits) Extra "Grounds" from bat to engine, engine to frame, frame to body* holds at 14 volts running, drops to 12.5 after it dies* all connections are clean and tight engine (2.5) has 10k since total rebuild * automatic The car has run "flawlessly" for 4 years, then out of the blue it started this: stalling at a light thing, ac on, ac off, with Lockup disconnected, the only thing NOT changed yet is the ign switch (Not Key switch) the car idles just fine, then (with Fuel pressure gauge hooked up) it will die while maintaining 10PSI. I believe I have already looked into or replaced "all the known suspects". I'm out of ideas ! Anyone local to me have a machine that can Properly monitor this thing while it does it's dieing thing ???
a new ignition COIL is on the way, after that, I'm out of ideas. already checked all the connections. cannot FIND anything "when it's not in the act of dieing". it immediately fixes itself, and starts right up. COULD the ORIGINAL "Oil Sender" cause it to shut off fuel supply, then on restart the fuel RELAY brings it back up ???
Originally posted by Lou6t4gto: (...) already checked all the connections(...)
Have you, really? With an ohm-meter across an unplugged wire and wiggling it to see if it breaks connection? ECM reset wire? I had a somewhat "similar" problem to your when my positive battery cable to the junction box was corroded inside the insulation. Couldn't see it. Only realised it was it when I wiggled it when running the engine and it died.
About the oil sender - nope. It acts parallel to the relay. If you hear that pump run, you've got fuel. You also said you've got steady fuel pressure, so no problem there.
Once thing for certain; you are either losing ECM power, spark or fuel. Does the tach work correctly? If not the tach filer may be shorting. Borrow a scan tool and do a datalog.
------------------ " THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite. "THE COLUSSUS" 87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H " ON THE LOOSE WITHOUT THE JUICE "
I "THINK" I finally got it. the ignition Switch was the LAST thing I was "replacing", (Of course they sent me the wrong switch), BUT, the Main" PLUG" going onto the switch, with the main red and yellow 10 gauge wires, the "plastic Plug" was burned at the yellow and red, the wires and switch are fine, But it HAD TO BE a loose connection to generate the HEAT to melt the plastic! so far so good, Probably should Not Celebrate yet, But I'm "thinking" after all this, I finally found it. Heres hoping
Lou welcome to the "its driving me crazy club" . Sounds like you found the problem. I should have mentioned that as I experienced a intermittent ignition switch failure once myself but it was years back. Good job and congrats for staying with it. Problems such as this can make one feel like setting the car on fire but for every problem there is a solution. A good lesson to be shared with everyone.
------------------ " THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite. "THE COLUSSUS" 87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H " ON THE LOOSE WITHOUT THE JUICE "
I should have know better ! after changing to the rebuilt computer, today it acted like it was running out of fuel Twice and did NOT want to start right up again. 5 min before that the converter WAS "locking up" trying to stall it below 25mph. when the (running out of fuel thing happened) it would not start right up ! after coasting to a side road, it did start up again, so at least I did not end up Walking ! going to put the orig computer back in and see what happens. oooooh.......
I'm just gonna throw this out there, but have you replaced the EGR valve? I ask because your stalling problem sounds like what my car was doing. When my EGR failed, it would stall at low RPM's (at a light) and I would have to put it in neutral and rev it to keep it running, but would run smooth as silk at highway speeds. Granted, my EGR valve failed catastrophically and it was obvious that it needed to be replaced, but I'm wondering if yours is on the frits and is about to fail completely.
