92 buick park ave runs when it wants

[ebez1]

Don't know what is wrong with this car. When it is cold it will start no prob. When it is warmed up it will turn over and over but no start. Fuel pressure is good. We have replaced about every sesor we can. When driving you have all the power till after about 30 miles then the car can barely move . Push on the gas and it is like there is nothing there, top speed maybe 15 mph. We are wondering if the ECU is bad or the ignition module. At a stand still on this. any help would be apreciated. Thanks.

[maxwedge]

What is the fuel pressure when this happens? Step one in the diagnosis and any check engine lite? Possible blocked convertor also, if no cel and fuel pressure is in spec at the time then do a back pressure test on the cat. As you have realized by now replacing random parts is both ineffective and expensive. Lecture over. Post back results of tests.

[ebez1]

My bad the way I worded the orginal question. We have fuel pressure in specs. gone through all engine codes that were in the ECM. And we replaced the faulty sensors (only the ones that were bad after we tested them for their vlaues). We also did replace all vaccum lines as a precaution since we found a lot of dry rot through out them. After the car has been ran and we park it it is no start till it cools. Engine turns over but will not start. We checked for spark as we had good fuel delivery. Weak spark and intermitiant spark. So far we haven't got any new codes from the ECM just two that keep coming back 22,21. Both refer to TPS sensor which we replaced due to internal short. Codes stand for high and low voltage from the throtle position sensor.

[Master01]

Tap on the ignition module when the engine is running and see if it faulters. You might need to take it to the dealer\mechanic to get the computer scaned professionaly. Because you can't monitor in real time on how the engine is running with a cheap scanner. Nor the "paper clip" trick will help in this case either. I think it would be money well spent, instead of tearing you hair out to find the cause. One last thought - check the wiring all around the engine and the sensor terminal wires, and make sure none of them are damaged.

[HotZ28]

Remove the ICM and take it to Auto Zone for testing. I assume you have replaced the crank sensor?

[ebez1]

well here is where we stand. Ignition module is bad . Has it tested and it faulted in 3 seconds. Replaced that starts right up. But still have a rough idle when it is warmed up. Then when it idles down it will chug and die out. Last night while I was searching for info I came across a thread that had a ECM reset to learn idle speed for engine. The procedure for it and now I can not find it. If anyone can point me in the direction of that I would appreciate it. It was for GM ECM's to learn a idle speed for the engine after reset. Thanks in advance.

[maxwedge]

Unless you disconnected the battery there really is no idle learn issue.

[HotZ28]

There are a few methods floating around, but this is the one used by GM techs.

1. Reset ECM by pulling the ECM fuse for a few seconds, or remove the negative battery cable.
2. With A/C turned off, start car and immediately put it in Drive
   with your foot on the brake. If the car does not start initially,
   keep trying WITHOUT putting your foot on the accelerator.
3. Let the car idle in gear for at least 5 and no more than 7 minutes.
4. Shut off the car for 10 seconds.
5. Start engine, place in drive and let idle for 5 minutes.
6. Shut off engine.
7. Idle is learned.

[ebez1]

I adjusted the TPS to get it within spec. Unhooked batteries to reset the codes. Test drove to check operation. Engine ran good during test drive and had good power. It idled fine before the engine was shut off. Once I shut it off and tried to restart the engine didn't want to start without slightly pushing on the throttle pedal. When it did run it ran rough and misfired upon acceleration. At idle it would lope and die. Checked engine codes again. Had codes 15, 16, and 21. The check engine light is staying on all the time now and could not retrieve any more diagnostic codes. It wouldn''t return to diagnostic mode. Noticed that the engine temp was up to 220 and the engine fans would not kick in. Also noticed that there was .5 volts on the return wire of the TPS with

[ebez1]

I adjusted the TPS to get it within spec. Unhooked batteries to reset the codes. Test drove to check operation. Engine ran good during test drive and had good power. It idled fine before the engine was shut off. Once I shut it off and tried to restart the engine didn't want to start without slightly pushing on the throttle pedal. When it did run it ran rough and misfired upon acceleration. At idle it would lope and die. Checked engine codes again. Had codes 15, 16, and 21. The check engine light is staying on all the time now and could not retrieve any more diagnostic codes. It wouldn''t return to diagnostic mode. Noticed that the engine temp was up to 220 and the engine fans would not kick in. Also noticed that there was .5 volts on the return wire of the TPS with the key out of the ignition. I am getting frustrated. PLEASE HELP.

[Loekee75]

Code 15: engine coolant temp. sensor indicating low temps, or your engine coolant sensor circuit is open.
Code 16: DIS (distributorless ignition system) circuit fault
Code 21: TPS (throttle position sensor) circuit open, or voltage out of range (more than likely high)
Your fans aren't turning on because the faulty coolant temp. sensor is telling the ECM that your engine is running cooler than normal running temperatures. Replacing the ECT should fix this.
You said you replaced the ignition module, but what about the coils on top? You can have them tested, or just replace them since you got a new module. If they test faulty, this may solve the DIS trouble code you got.

[animekenji]

Originally Posted by HotZ28

There are a few methods floating around, but this is the one used by GM techs.

1. Reset ECM by pulling the ECM fuse for a few seconds, or remove the negative battery cable.
2. With A/C turned off, start car and immediately put it in Drive
   with your foot on the brake. If the car does not start initially,
   keep trying WITHOUT putting your foot on the accelerator.
3. Let the car idle in gear for at least 5 and no more than 7 minutes.
4. Shut off the car for 10 seconds.
5. Start engine, place in drive and let idle for 5 minutes.
6. Shut off engine.
7. Idle is learned.

You have got to be kidding me. Please tell me you are kidding me. Everytime I disconnect the battery for any reason, I will have to go through all this?? Whoever thought not to have the engine idle speed burned into the prom so it doesn't have to to be reset all the time deserves to be shot. What happens if my battery dies on the road and I need a jump start? Will my engine not idle properly because the ECM forgot what it was supposed to be doing and possibly stall out leaving me in search of someone else to jump start me again??

[HotZ28]

92-95 3.8L VIN L CODES

15 Coolant temperature sensor signal indicates a temperature colder than -36° F for at least 4 seconds after the engine had been running for 2 seconds.
16 Charging system voltage was either below 9 volts or above 17 volts for 10 seconds.
21 TPS voltage was above 0.8 volts for 5 seconds when engine was running and air flow was less than 15 gm/sec, or the TPS voltage was over 4.8 volts at any time.

You need to check your alt output!

[ebez1]

ok guys here we go. The darnest thing to be a problem that we overlooked. The water pump, no squeling, no rattling, no seepage.....NO PRESSURE. Top hose hot, lower hose cold as ice..hummm. Pinch the top hose no pulsing. pump was turning but not cicrulating the coolant! thermostat might have been good but we replaced it anyway. After we figured out the ECM was bad and swapped it out the engine ran great just kept building heat, no codes , also noticed the fans were not kicking in...humm. Water not getting to the temperature sensor in the radiator telling the fans to turn on . Once again no circulation, so we go after the water pump and replace it. BINGO water moving, fans kicking in, thermostat opening, engine not overheating! A buddy of mine who works for Freightliner came up with a explanation for the pump's actions. When the pump would get hot from running the impeller would expand just enough to sit on the shaft even though it is turning and not pump. Due to heat expansion the pressure holding on there was gone . We tested the theory by heating up the pump impeller to about 205 degrees after we had it out (no visible signs of damage) and turned it with a drill, held the impeller with pliers ... sure enough the shaft turned and the impeller stayed put easily. now ain't that intersting! It would cool down and grab. Car is now running great, slight lope in idle but nothing to be really concerned with. I just had to share this find. I have never seen anything like it. Thanks for all the help guys.

[animekenji]

Wow, who would have ever expected something like that? Were you still running the original water pump, or was it a rebuild?