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1991 Legacy has issues with starting. I've tried EVERYTHING!


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I have a 91 Legacy wagon which constantly has issues with starting. Normally if it has been sitting for a few hours without being driven then it will start up just fine, but if I drive it somewhere and then turn it off and try starting it again shortly afterwards, it will not stay started. The only way I have found to make it stay started when I am having trouble is to press on the accelerator as I am starting it, and then I have to leave my foot on the accelerator for a few minutes to keep the car from turning off again.

 

I recently got a new battery, had the alternator checked (it was said to be fine), new fuel pump, ecm repaired, fuel intake system cleaned and new fuel filter, new air control valve, and plenty of other repairs along with it. Everything is perfectly fine with the car as far as I can tell, so unless there is something else that someone can think of which may be causing the issues I am having, then I have no idea what could be wrong other than it is simply an old car and that alone could be causing problems.

 

I have already put over $1,500 worth of work into this vehicle since the problems started, and I am not ready to try anything else unless it is cheap or easy. Can anyone can suggest anything that I can possibly try to fix the problem which may be cheap or easy to do? Aside from that I will probably unfortunately just have to cut my losses and get rid of the car.

 

The air intake hose was replaced in October, so I doubt if that is the issue even though it sounds like a likely culprit.

Edited by OldSubaru1
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The injectors are a side feed style and when the o rings on the injector start to leak it will cause it to leak fuel into the cylinders causing flooding. When you are opening the throttle to get it started your putting the ecu into a clear flood mode and then it takes a while to clear the excess gas out.

 

The easiest fix is to swap in a set of used injectors with rails and all.

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You'll need to inspect a spark plug after it's been sitting "awhile", then check it again after it'd been running. Basically you want to see IF the plugs are wet and wreak of gas between when it'll actually start and when it won't. If they are dry in both cases, then it's not injectors. If they are wet either after sitting overnight, or 10 minutes after shutting it off, then it's getting flooded. Holding the pedal down might be coincidental in that it might have started anyways.

 

Crank sensors can give erratic starting issues, as can neutral safety switches. Corroded wiring or damaged wires can as well.

 

Would also be helpful to know if it's actually getting spark during the no-start cranking or not.

 

If plugs are not wet whatsoever after sitting, try a spritz of starting fluid and see if it wants to fire or not. If it suddenly sputters then dies and only cranks, that's most likely a fueling issue. If plugs are dry and it does not fire off a short burst of starting fluid, look at ignition including the crank sensor, coil, and wires.

Edited by Bushwick
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Ive worked on a car that did this and it turned out to be the Mass Air Flow Sensor. It wasn't cracked either and looked clean. Figured it out by having someone crank it over when it wasn't starting then I tapped on the square part of the sensor with the handle of a screw driver and it started right up.

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When you say you're pushing on the throttle, how far? All the way to the floor? If that's the case, that is telling the computer to cut fuel entirely to clear a flood-scenario. I can think of a few things that could cause this...

 

Fuel pressure regulator (I don't think quite matches up with your symptoms, but free and easy to check. Pull the vacuum line and see if there is fuel in it. The diaphragm in the regulator can fail, causing fuel to leak past it, and into the vacuum line)

 

Fuel injector O-rings. Harder to diagnose. Very cheap part, fairly easy to do, but slightly time consuming (good DIY job, but still might be costly if you're paying for shop time).

 

Coolant temp sensor. If the ECU thinks the engine is cold, it will use a lot more fuel when starting. I *thought* these usually fail the other way around (ECU thinks the engine is warm, and therefore doesn't get enough cold-start enrichment when it's cold)....but I could be wrong. Not a terribly expensive part, but kind of annoying to get to, even to test....

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