bore.me

iTrader: (15)

So i was enjoying having my car out on this nice summer day when all of the sudden the engine just dies on the highway. After dodging a mail truck (no power steering or brakes) i was able to pull over and check out the engine. Battery voltage was fine and no signs of anything on fire. So i started it right up and the engine seemed to run fine and drove off but every few miles the thing would just die suddenly. It seemed as if the longer i let it sit, the longer it would run the next time. The only time it didn't die was when i was pulled over at a garage and talked to a mechanic for a while. Go figure.

My car is a nearly stock '95 Formula with 110k miles. I just flushed the cooling system and installed a 160* thermo, coolant temp sensor and manual fan switch. It used to run really rich because the coolant temp sensor was broken. When i first drove the car this morning it would hesitate and seem as if it wasn't getting enough fuel while accelerating. Then it ran fine. Maybe my fuel pump is dying/overheating? My pump will put out a quart of fuel in 35 seconds and will hold 33 psi fuel pressure at idle and 42 at WOT. Sometimes the fuel pressure will dip lower when revved, other times it will increase as rpm increase. I really don't like the idea of my engine dying every 2 miles so any help is appreciated!

bjamick

iTrader: (31)

Sounds like a possible fuel pump failure to me.

bore.me

iTrader: (15)

Is there a way to test if the pump is getting enough battery power?

LS6427

iTrader: (2)

Man, sounds like there's maybe a leak somewhere and your losing pressure. Maybe a leaky fuel injector and it only leaks at higher rpm's, which kills the pressure and stalls it.

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bore.me

iTrader: (15)

maybe. It has always seemed to hesitate under WOT, as if it wasn't getting enough fuel, but the engine would die today at around 1500 rpm just cruising down the highway. I never really floored it in fear it would stall again. It seems to run fine at idle though.

LS6427

iTrader: (2)

If I were you I would never go WOT again until you fix this...running out of fuel pressure at high rpm's or WOT can fry a piston quick.

I'd probably put a pressure tester on it, and see if it holds pressure with the engine off. If it drops down you have a leak in an injector or maybe at the pump itself.

Maybe take the injectors out and check them all.

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bore.me

iTrader: (15)

My fuel pressure drops down to 0 in 2-3 seconds after i shut it off. I assumed it was the check valve on the fuel pump and it was just a harmless problem. If i remove the injectors how can i check them?

LS6427

iTrader: (2)

Just make sure the atomizers look good with no holes or tears in them. Maybe there's another way mechanics check them besides a visual check, I don't know.

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fleetmgr

I check them into the trash if they fail a visual!!

LS6427

iTrader: (2)

Oh yeah, I just didn't know if there's something internally that can make them leak on the other side of the atomizer.

I would guess you could just keep them attached to the fuel lines but removed from the intake, turn the key on and let the fuel pump prime.....if none of them leak fuel they're good...right????


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fleetmgr

AFAIK, you're right. I don't know of any other way to test them with out a bench.

bore.me

iTrader: (15)

ok so lifted the fuel rail and ran the fuel pump and didn't see any injectors leak. I stuck my finger under them and there was no gas or gas smell. I did have the injectors out just a few months ago to replace the fuel pressure regulator and they all looked clean, but I didn't put them under a microscope or anything.

LS6427

iTrader: (2)

Well damn, maybe a leak at the pump, in the tank. I don't know.

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bore.me

iTrader: (15)

So i don't think it is the injectors because i had a friend come over and crank the engine while i watched the injectors squirt and they all seemed to have a fine spray. I did notice some things though. I let the car idle for about 15 minutes from cold and it died just as i though it would. The fuel pressure remained good as it died, so i don't think it is a fuel problem. The longer i let it sit, the longer it runs the next time i start it. It won't start if i try to start it immediately after it dies. A cylinder or two will fire, but that's it. At some point after it dies, it sometimes makes a high whirling sound (like an electric motor) for about 2 seconds then stops. The sound comes from the front of the engine where the opti and coil are, but i'm not totally sure if that's where it's coming from, and it is not the fans. During that sound, my fuel pressure jumps up to 42 psi (usually at 0 with the engine off) and my tachometer jumped up to about 500 rpm for a split second. I've never seem anything like this.

LS6427

iTrader: (2)

Don;'t those opti's have some strange problems?

Maybe the opti spark is overheating or shorting out after it runs for a little while.

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bore.me

iTrader: (15)

I haven't heard of anything like that but at this point it's the only thing that would explain it. I did just do a coolant flush so maybe i dripped some coolant on it. But I don't know how that could cause something to overhead several days later. My engine temp is fine and everything.

bore.me

iTrader: (15)

So i just talked to my mechanic after i did some ignition tests. Seems like i stop getting spark just before the engine dies, so i found my problem. According to my mechanic, when my engine gets hot enough, the connection on my crank position sensor get broken and basically the car doesn't know that the engine is still running and stops giving it spark. Does anyone know where the crank position sensor is? I want to replace it today and see if that helps.