'97 Sunfire 2.4 Dies

Always starts fine, runs great until shut off and let sit a minute or two. Then it's hard to start and may suddenly die as you move through the gears (manual trans.). Takes 4-5 tries and then starts. If you punch the accelerator down fully, the engine will die; however, by gradually pushing it down, engine will accelerate normally and car can be driven VERY carefully. Does this sound like a power pack problem? Wondering if underhood temps are causing a problem until engine/car is moving enough to cool things down just a tad. Fuel pump, filter and pressure regulator are fine. I'm seeing a lot of similar posts and just wonder if there's a common thread.

Reply to
Michael1
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Update: doesn't appear to be ignition problem but fuel-related. I have to cycle pump (off-on-off-on etc) 5-6 times to get restarted. "Something" is not telling injectors to stay open longer under load but what?

Reply to
Michael1

I had a cavalier that did the same thing, it was the pump. using the center tube from a paper towel roll listen to the pump running thru the filler neck (engine must be running) if the sound of the pump is oscillating or changing pitch it's the pump

Reply to
DA .

I put a pump in (sigh--$256) and that didn't cure the problem. Something's not telling the injectors to dump in more fuel and it's starving on acceleration. I have to cycle the pump 5-6 times after it dies to get enough fuel in the engine to start it.

Reply to
Michael1

Reply to
jBerg

The one at the tank was changed and the tank itself is free of any contaminents, etc. that might be blocking the strainer at the pump.

Reply to
Michael1

I don't have the 2.4 in my car, but my manual contains info for troubleshooting the 2.4.

Have you scanned the car to see if there are any codes in the PCM?

Is the problem intermittent or Hard. Does it always occur? Does it occur from any speed? (accelerating from 10 mph and also from 40 mph?) Is there any difference if you do a part throttle accel verses a full throttle accel? All vacuum line connected correctly, and in good condition - no leaks/cracks, kinks, etc? Air filter clean (getting sufficient air>?

There is 400 pages of diagnostic troubleshooting for Engine Control. It could be a little hard to find remotely if no DTC's are set.

A quick scan through finds many things that might cause the problem. Two of the possibilities based on our info are Fuel System Lean during Acceleration, Or Just plain and simple, fuel system too lean. Both of these however, should set a DTC (Diagnostic Trouble Code).

DTC P1171 Too lean during accel, asks first if tank has sufficient fuel . If no other component has been flagged by the PCM suggests that O2 Sensor 2 could be the culprit. Although O2S2 should set a DTC P0134 as well.

DTC P0171 Fuel System Trim Lean asks to check All vacuum hoses as above, Crankcase vent and PCV for proper connection and operation, Exhaust for leaks and blockages, O2 Sensor 1 connected and wire not grounding, Fuel contamination (water, alcohol or other), PCM connections tight, PCM ground good. It suggests if all the above is OK to disconnect the MAP sensor electrical connector to force a rich condition and see if there is a difference.

Both also wonder if the injectors are partially clogged/dirty. Have you run any injector cleaner through the car? I have found on many of my cars, that when they start to seem sluggish on accel, that dirty injectors is often the cause, and a good shot of cleaner in the fuel really can help. sometime it takes a couple of double strength additions.

The next obvious section I find is Hesitation, Sag and/or Stumble. Defined as momentary lack of response when accelerator is pressed down. Can occur at all vehicle speeds, Most severe when first trying to get vehicle to move from stop. May cause engine to stall if severe enough. I was not sure if this matches your symptoms or not???

Just in case it's yes. Order of items to check in manual: TP sensor stick, binding, voltage variation good MAP sensor output good Fouled spark plugs Ignition module ground good Fuel system pressure check Contaminated fuel Injector coil test and injector balance test. EVAP system proper operation Correct thermostat operation Alternator voltage correct Dirty intake valves

Good luck.

Reply to
Mike

Yes, I need to have the codes scanned. Outside of the dealer, would most well-equipped shops possess the hardware to do this? Problem of stalling is more before normal operating temp is reached. Going from 2nd to 3rd, and acceleration causes a complete power loss. Have to then cycle the pump

3-4 times to get enough fuel in the engine to start it again. Then, accelerating gradually, the engine warms to norm and all is well. Matter of fact, from about 30 mph on, there is no problem, either gradual or 'foot to the floor' in 5th gear--no problems. Just starting off from 1st to 2nd sometimes and the thing unexpectedly dies but not always. Just when there's a lot of traffic! Air filter is clean, plugs and f/filter are new, all hoses tight and in good order, etc. Figured if it was the injectors, I'd be having problems at higher speeds. As before, from about 30 mph onwards, there's no hint of any problem whatsoever. Thanks for your input--this is very comprehensive and I'm grateful for the time you took to respond!
Reply to
Michael1

Just a further thought after your further info. I have seen this type of problem before, however it was not on a sunfire - but could have a similar effect. The ECT sensor (Eng Coolant Temp). It may not be giving good engine cold info the PCM, making the PCM think the engine is already warmed up, and thus not increasing the pulse width of the injectors to give a richer mixture when the engine really is cold. Once the engine warms up, now everything is normal. The IAT (intake air temp) has a similar function. They also are used to adjust timing. Another possible is the MAP sensor. Adjusts fuel to compensate for changes in intake manifold pressure - important during engine load and speed changes. This however would be less sensitive to engine operating temp - I would think a MAP problem would always be present, warm or cold.

Any car repair shop should be able to scan a car these days. It depends on what they want to charge you. I know in the US many auto parts stores will also be able to scan the car, many will do it for free, figuring you will be buying some parts there. In Canada I don't know of any parts places that do this. Check with any buddies you know that work on their cars. Code readers of various types are very reasonable in price these days, and many do-it-youselvers own their own. Jus make sure it will read GM, or is a universal that will read all types.

Reply to
Mike

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