Random engine cut-off

[Revious]

Hey guys,

So here's the situation, I get in my car, start driving. The standard vacuum leak idle comes on where it revs constantly up and down. That's pretty standard as it goes away as the engine heats up. So, driving along and then all of a sudden, the tach just drops and the engine is now off. Radio is still playing, lights still work, everything.

So, I drift over to the side and try and start it again. Nothing. Wait a minute, try again... nothing. Wait 2 minutes, it starts. What is causing this? I think it has to do with weather as it only does it in the colder seasons.

(I tried searching this, didn't get very many relevant answers, please advise if wrong)

[johnl]

My first guess would be CPS (crankshaft position sensor). When these types of sensors start to fail it's usually when they get hot, then get worse from there, i.e. the failure may start to occur at lower and lower temperature, or it may just completely die at any time. The fault can be intermittent, i.e. the CPS may not stop working every time it reaches X°, or the temperature at which it does stop working only occurs occasionally.

Leaving the engine shut off for a period of time allows the CPS to cool down to the point that it may start working again. Typically the tacho stops registering RPM because the ECU isn't getting a signal to tell it that the crankshaft is rotating, as far as the ECU 'knows' the engine has been turned off, even it the crank is still turning (which it won't be for long, unless the CPS spontaneously starts working again).

Our Saab 9-5 recently had exactly this problem. While waiting for a new CPS to arrive in the post, I made an additional heat shield to supplement the puny stock Saab CPS heat shield (the CPS in quite near the turbocharger and downpipe), and the symptoms disappeared even before the new CPS was fitted.

[Revious]

Hey, I actually had that issue a while ago. It happened to me on the highway and I had to leave the car on the side of the highway overnight.(that was painful)

Ended up getting a junkyard distributor and putting a new chip in it from a local parts place.

I've had the timing checked and it's flawless, and everything else I could think of. Even the mechanics at Toyota where I used to work were stumped. The car ONLY has issues when it's cold. When the engine isn't warmed up to optimal temp, it does this. The vacuum leak erratic rev also goes away once up to optimal.

[sonikaccord]

That's a tough one. Because it's so intermittent you're going to have a hard time reproducing the failure. Do you have any codes?

[Losiracer2]

you mentioned the tach.....was it jumpy before it died completely?

If so, then you igniter unit is failing. It's a classic symptom of a bad igniter

[PakaloloHonda]

you mentioned the tach.....was it jumpy before it died completely?

If so, then you igniter unit is failing. It's a classic symptom of a bad igniter

This ^ .. what we did was just removed the guts of another dizzy I bought on here.
Problem solved .. but yeah, that was a b!tch to figure out. lol ..

btw Losi .. howz PING treating you?

[Losiracer2]

This ^ .. what we did was just removed the guts of another dizzy I bought on here.
Problem solved .. but yeah, that was a b!tch to figure out. lol ..

btw Losi .. howz PING treating you?

I quit there and got an engineering job at ECOtality, then they went out of biz and now I'm doing brake testing for Link Engineering, its a cool gig, get to see prototype cars on a daily basis.

[Revious]

Already had the problem with the distributor, and in fact it happened while I was driving. She died and was on the side of a highway for a day and a half... I was so worried.

Anyway, replaced the igniter, the distributor AND the chip that goes INSIDE-- so it can't be any of that.

I have a vacuum leak but I have no idea where it could be. I don't think this would cause it, but...

Also, my tach still jumps at around 4400-4500 rpm anyway... but I don't suffer any of the symptoms that I had before. It's weird.

No codes. Nothing flashes at me when it starts up. The only thing that's on is my ABS light but I'm fairly certain that's just because there's dirt on the sensor.

[UNeeKToNy]

I've this problem before on 3 separate occasion on the highway:

1st time this happened to me, it was the Igniter
2nd time, it was the Ignition Switch
3rd time, it was the Main Relay

check those three out, i'm almost positive one of those is your problem. btw, where did you get the Igniter from?

[Revious]

I've this problem before on 3 separate occasion on the highway:

1st time this happened to me, it was the Igniter
2nd time, it was the Ignition Switch
3rd time, it was the Main Relay

check those three out, i'm almost positive one of those is your problem. btw, where did you get the Igniter from?

Local parts place. Was brand new in box, so. Distrib was a junkyard one, but I put a new EFC chip or whatever into it.

Is there any way a vaccum leak could cause this stall? My car does the random idle thing and when I'm driving and it decides to do the rev raise and i depress the clutch, it almost seems to kill the engine-- I wonder if there's too much air drowning out the fuel? Idk.