Vapor Lock?!

[SebringLX]

Twice in the last 30 minutes, and once on Sunday, my engine just stopped running while I was coasting to a stop. I'm 99.9% sure it's not electrical, as all the electrical systems continue running. In fact each time this has happend, the first indication I had that my engine had stopped running was loss of power steering, then I look down at my instrument cluster to see I have 0 RPMs (I had the radio on so I didn't hear it cut off).

It really seems like vapor lock. The car will start again, but I have to wait at least 15+ minutes to get it to start again. I've never seen this happen on a fuel injected vehicle with the pump IN the tank. Have any of you? What can I do to make this stop, it's really annoying!

[karlak]

Sounds like a coil to me.

[SebringLX]

Sounds like a coil to me.

If the coil was going bad, wouldn't it not start back up? I have less than 5000 miles on this coil...

Also it's not missing at all... there's no stutter or stumble... it just shuts off without warning. The symptoms are exactly like vapor lock...

[karlak]

I have had coils that stop working when they get hot. Let them cool off and they start working again. This would be a intermittent problem. Next time it happens pop a plug wire.

[SebringLX]

I have had coils that stop working when they get hot. Let them cool off and they start working again. This would be a intermittent problem. Next time it happens pop a plug wire.

Pop it off the coil? Not sure what I'd be looking for. I know the coil gets pretty hot.

The engine shuts off just as if I had turned the key off...

[overlordsshadow]

He means pop a plug wire of the plug and crank it to check for spark, not a one man job really.

[Turbodave]

In most return type fuel systems Vapor lock is not a problem, fuel is consantly circulating back to the tank and stays cool as a result. Since you've got an external pump, I'm guessing a return line was added to the system as well.

The problem you described is also similar to a fuel pump failure, although the coil failure is very feasable as well. You said that for about 15min the car won't restart, that's 15min to troubleshoot, and I would start by looking for spark and fuel pressure when the problem occurs.

[SebringLX]

In most return type fuel systems Vapor lock is not a problem, fuel is consantly circulating back to the tank and stays cool as a result. Since you've got an external pump, I'm guessing a return line was added to the system as well.

The problem you described is also similar to a fuel pump failure, although the coil failure is very feasable as well. You said that for about 15min the car won't restart, that's 15min to troubleshoot, and I would start by looking for spark and fuel pressure when the problem occurs.

I don't have an external pump on there yet... just the stock pump in the tank still.

Fuel pump failure was actually my first though. I have had the fuel pump cut out on me at the track before, but only had it happen twice when I was playing around with boost to see where I would max out at on the stock pump. When it happend then, I got a backfire just before the 1/8 mile but the car kept running.

All 3 times that it has shut off, it's been while coasting to a stop, foot hovering over the brake but not touching it or the gas.

I haven't been able to check fuel pressure or spark when it's happend because I've been driving alone.

[overlordsshadow]

When this happened to me:

One time is it coil, other time is the was number 4 ignition wire, it got cut off by the rotor and therefore wouldn't spark.

[SebringLX]

It just happend again, this time I had a friend with me. Got him to watch my fuel pressure gauge while I tried to start it back up. Fuel pressure was fine. Couldn't get him to pull a wire to check spark... he said last time he did that he got shocked really bad, lol. I remembered that last time this happend, I opened my cut-out to see if I could hear anything when I was trying to get it to start back up, and it started up right away when the cut-out was open. Thought it was just coincidence before, but tried it again just to see what would happen. It started up!

Closed the cut-out when I got back on the road, and a few blocks later it died again, this time in traffic. :\ Put my 4 ways on, put it in nuetral, tried to start, wouldn't start. Opened the cut-out back up, tried to start it again, started right back up. Drove it the rest of the way to work with the cut-out open.

This just makes it even more confusing. :\

[overlordsshadow]

Is your cutout pre or post cat? Maybe a clogged cat or something to do with the O2?

[SebringLX]

Is your cutout pre or post cat? Maybe a clogged cat or something to do with the O2?

I don't have a cat anymore... but the cut-out is below where the cat would have been on the downpipe, if I had a downpipe with a cat on it that is.

My wideband O2 sensor sits right next to the stock rear O2 sensor, and I haven't seen anything out of the ordinary on it.

Doesn't seem like I'd be able to get very far if something in the exhaust were clogged... and it would have to be after the cut-out for it to be that. I guess I haven't gone all that far before it happens... probably only drive around for maybe 20 minutes or so before it happens.

:confused2:

[overlordsshadow]

I doubt anything could be clogged up if you don't have a cat. That cutout really make a lot of flow difference? I'm just thinking something is getting out of tune with the heat or something electrical is happening.

As you have a totally different beast, and I'm by no means an expert even on the 2.2/2.5, I not sure how much more help I could be.

One thing that did just come to mind was does the cutout, when it is open, end up grounding the dp to the chassis?

[SebringLX]

I doubt anything could be clogged up if you don't have a cat. That cutout really make a lot of flow difference? I'm just thinking something is getting out of tune with the heat or something electrical is happening.

As you have a totally different beast, and I'm by no means an expert even on the 2.2/2.5, I not sure how much more help I could be.

One thing that did just come to mind was does the cutout, when it is open, end up grounding the dp to the chassis?

Yeah it makes a difference... it's 3" to the cut-out, after the cut-out it goes into the 2.25" stock piping.

Wiring under my center console is where I'll be looking. The switch to open and close the cut-out is grounded to the chassis, along with my wideband. There's a whole mess of wires for the e-manage that I'm not even using now (it's 0'd out) under there. I was sure I capped off all the unused wires. Nothing electrical cuts out when this happens though... digital display on the wideband doesn't even flicker, neither does the Profec E-01 display.

I don't think the cut-out itself gets grounded to the chassis... it's just a butterfly valve that opens and closes... doesn't touch anything but itself.

I'm actually wondering if it may be my MSD DIS-2+ going bad. I was pretty sure that the LED on it is supposed to light whenever there's a spark. Just double checked the manual for it, and it is supposed to. Yesterday when I had my friend looking at it while trying to start it, he said he could not see it light up. After we did get it started, it was blinking very rapidly (like it's supposed to). It's a couple years old now, but only actually been used for less than 2000 miles. :\

[overlordsshadow]

Electronic cutout or manual?

[SebringLX]

Electronic cutout or manual?

Electronic.

[Aries_Turbo]

shouldnt have anything to do with the cutout.

probably the dis2 they go bad alot.

you dont need it anyway.

brian

[SebringLX]

It's still driving me nuts, happens every couple of days it seems, and on days it happens... always happens more than once in a day. Seems like I poke around at a different thing to get it to start every time, so I still haven't been able to nail it down to any 1 thing.

The only one thing that has been consistant with this problem is it always happens when I'm coming to a stop. Never happens while cruising or accelerating... always when coming to a stop.

[Speedeuphoria]

AIS?
Hows your vac at idle?

Do you have a catchcan? decelerating with high vac maybe pulls oil and fouls the plugs, maybe the pcv is sticking open? See if you got a puddle of oil in the intake

Just throwing stuff out there, if its electrical gremlins, I pray for you cuz thats the worst

[SebringLX]

AIS?
Hows your vac at idle?

Do you have a catchcan? decelerating with high vac maybe pulls oil and fouls the plugs, maybe the pcv is sticking open? See if you got a puddle of oil in the intake

Just throwing stuff out there, if its electrical gremlins, I pray for you cuz thats the worst
What's AIS?

Vac at idle is -8psi.

Haven't gotten around to getting a catchcan to put on yet.

Don't know when I'll have time to pull the intake manifold to check for oil... but now that you mention it, I did wipe some oil off the TB from around the TPS... couldn't figure out where it came from. Haven't seen any since I wiped it off though.

[overlordsshadow]

You mean 8 vac? Thats really really really bad I believe. Mine is at 18-20 vac.....

[SebringLX]

You mean 8 vac? Thats really really really bad I believe. Mine is at 18-20 vac.....

I mean at idle my boost gauge reads -8psi. I guess that would be 16Hg?
When cruising it usually reads -9psi... so 18Hg?

Er wait that's not right... -8psi is 8 psi below atmospheric pressure of 14.7psi so it would actually be 6.7psi which = 13Hg right?
So under cruise that would be 11Hg

Hg being inches of mercury of course.

I have the gauge set to psi right now, I think I can set it to read a different unit of measurement.

[overlordsshadow]

Well I'd be shitting myself if the vac on my car was 13hg, that being said, maybe motors run different vac's.....

[SebringLX]

Other than randomly shutting off when coming to a stop (which all seemed to start after I installed a front strut tower brace, but I'm sure that is just coincidence), the car as been running great.

I'm not too good with the pressure conversions here... boost gauge reads -8psi at idle, or -54kPa if I switch it to kPa. There is an Hg setting but it's m/m Hg and reads like -400 when I set it to that.

To not confuse me so much... what should it be at idle in PSI? It's a steady -8psi, doesn't fluctuate more than .2, it will go to -7.8psi but generally stays right at -8psi at idle.

[overlordsshadow]

who the hells know on that one man. Mechanical boost gauge all the way..... for now;)

[Speedeuphoria]

last I knew, -1psi is ~2.2vac for conversions, so ~16-17vac sounds right although may be slightly low but your prob Ok. My car starts up w/ 15 vac then when its warm its 18-19vac. Adjusting cams will change vac at idle(more overlap).

[SebringLX]

Well my vac may be slightly low due to my extremely conservitive timing. I'm sure I have plenty of room for more timing, a little more timing would raise the vac too. My cams are stock and untouched.

It hasn't happend for about a week now...