engine problem HELP!!

[NonStopReaper]

Ok it started off that my Engine when start up would start but die's and not idle. i give it gas and nothing. It just dies. I swapped out Fuel pump, Fuel Regulator, fuel filter and now it starts up and idles but really roughly. The idle holds but rough. When i press on the gas the RPM goes up, but then dies back down to idle even with the gas pedal depressed. What else can it be?

 

[syndicate]

Remember, there are 3 main areas that can cause an engine not to operate:
Air: Not enough (which is doubtful), too much (usually associated with too little fuel)

Fuel: Check fuel pump, filter, lines, injectors.

Spark or power: check the vital relays (main, fuel pump relay), fuses, spark plugs and coil packs, battery connection and alternator connection, and GROUNDS.

I know this might seem redundant to say but sometimes seeing a small list of probables can help to find the problem.

You might also want to check your map sensor and Throttle positioning sensor for debris.

Good Luck

 

[Larry Bastanza]

Change the main relay.

39400-SL0-003 this is the part number for the US 1991 part. It may be different for you. BTW, Did you actually check the fuel pressure?

Regards,
LarryB

 

[nsxotic911]

Change the main relay.

39400-SL0-003 this is the part number for the US 1991 part. It may be different for you. BTW, Did you actually check the fuel pressure?

Regards,
LarryB

I thought if the main relay goes out, the car doesn't start at all. That's what I experienced...

 

[Briank]

I thought if the main relay goes out, the car doesn't start at all. That's what I experienced...

Mine would start just fine and then just die while driving and then start right up again.

 

[nsxotic911]

NonStop - Is this with a stock ecu? I imagine you'd have a CEL by now and that will help you pinpoint quite a bit.

If you don't have a stock ECU &/or not getting CEL, in addition to what's been mentioned abouve, a very rough idle and unable to sustain a given rpm range could be other things such as:

1.) Damaged engine - low compression on one or more cylinders. Do a compression/leakdown test.
2.) Clogged spark plugs. You didn't mention that you changed them - but this should be easy and cheap to get out of the way.
3.) Faulty ECU in addition to the REAL electical possible causes listed above.
4.) Bad tune. If you have a flat tune (say in high temperature) and then go to a low temparature to start the car (like I did..) you may very well get a rought tune.

Still..it really sounds like the engine just is not getting the fuel it needs to cause a spark... Check all the little things listed before you keep throwing parts away.

PS: The most important questions, WHAT'S CHANGED? I'm assuming you didn't buy the car as is. Somethine has changed between when it last worked well and now -what is it?

 

[NonStopReaper]

These are the items which they have change the fuel line strainer, main relay fuel pump, fuel filter,fuel line regulator, and PGM f1 relay has been replaced. could it be the oxygen sensor? the first gas depress engine go up smooth but in a few second engine speed goes down and then the second time it doesnt respond. And during cold condition the rpm would jump up and down during idle. and when the engine is warmed up. it will hold idle and sometimes want to stall but holds. I cant take it to the dealership because my rim sticks out beyond my finder and in Japan thats illegal and they cant service it so my friends is gonna ask to borrow some stock rims but for now we are trying to narrow down to a part where the dealership isnt going to be needed. Only thing i've done to this car is install an air intake. I did notice one time as the weather was hot my dash rpm needle and speed needle wouldnt move but when its cold it will work Intermittently.

 

[angus]

I just recently had a car which exhibited almost the identical problem.

Catalytic converter was melted inside and caused a blockage of the exhaust - the car would start up and idle great - when you step on the gas even a little the car stalled.

 

[Jin1976]

I have similar problem after they repair my alternator. My rpm is very low. When depressed the engine died, only when the car is in neutral.

 

[EdinKali]

I just recently had a car which exhibited almost the identical problem.

Catalytic converter was melted inside and caused a blockage of the exhaust - the car would start up and idle great - when you step on the gas even a little the car stalled.

Similar to the ol' banana in the tailpipe trick.

 

[NonStopReaper]

**UPdate** We finally figured out the problem after finding out it wasnt the trottlebody or its positioning sensor. There was a burnt wire bundle that leads to the ECU that was cause this. All fixed and She up an running. Now just await for her to get Re-painted.