Car shutting off randomly. Video inside.

[GuardianLlama]

Alright so, I've searched a bit and i can't seem to figure out what's going on with this thing. It seems to frequently shut off around 3 minutes after first cold start (Video is 100% cold start) and does it randomly while driving. If i leave it in gear when it shuts off and switch the ignition switch to the off position then back to the on position it comes back to life. When the car dies the fuel pressure doesn't seem to drop at all. So i'm ruling out the pump turning off. It almost seems like the injectors just stop pulsing. Also, have tried a different ingitor chip that is in good working order and no difference.

Sr20det
Z32 MAF
Power FC
740cc Injectors
Sard FPR
Walbro Fuel Pump
OEM sending unit

You can see that i have a cold start issue with the Power FC, and it almost dies at 2:50 or so and AFR guage went lean.

Random shut off - YouTube

Let me know if anyone thinks of something to check.

Thanks,

-Ryan

[hassanbakar123]

checked for vacuum leak?
timing?

[GuardianLlama]

No vac leak that i can find, though id be surprised if that was it. Pulling -18inhg at idle too. Timing is at 15* Just re checked it when i dynoed my car a few weeks ago.

[hassanbakar123]

randomly started doing it?

[cotbu]

Get some logs, there maybe a clue in there.
I agree with you, it seems like a fueling issue the way it cuts off. So that could be many things.
How did it perform during the dyno session?
Who tuned the PFC?

[EvilRB]

try cleaning you IVAC, sounds like a vaccum problem to me...

There is some info in this thread that might give you some insight...
Good luck!

http://zilvia.net/f/engine-tech/5118...lean-iacv.html

[GuardianLlama]

Originally Posted by cotbu

Get some logs, there maybe a clue in there.
I agree with you, it seems like a fueling issue the way it cuts off. So that could be many things.
How did it perform during the dyno session?
Who tuned the PFC?

It ran great during the dyno, and drove home great. Problem was noticed a few days after. Driving down the freeway in 5th then poof! no power no throttle response what so ever. Clicked the ignition switch to off, then to back on (with the car still in gear declerating) and the motor came back to life. Electronics were still working meanwhile. Car was tuned at Churches, by Shawn. We were going to start messing with the cold start problem (i'm sure its just correction values) but this came up first.

Originally Posted by EvilRB

try cleaning you IVAC, sounds like a vaccum problem to me...

There is some info in this thread that might give you some insight...
Good luck!

http://zilvia.net/f/engine-tech/5118...lean-iacv.html

Read my above response, this is bigger than a hiccup at idle. That was just video to demonstrate the problem i'm having while driving.

[cotbu]

Have you tried going back to the base tune or something before the dyno session?

I mean if you pop the base back on, you'll know if it's tune related, maybe?
Couldn't hurt for one start up or two to confirm.

[wangan_cruiser]

check your tps

[Kingtal0n]

Id like to see you try to keep it running. When it tries to die, and you hit the gas, does that help keep it running? or will it shut off no matter what you do with the gas pedal.

Usually when a 240sx needs a complete "reset" Turn it off, turn it back on, that is related to the ECCS relay.

[idc101]

my was doing the samething till i change the fuel pump!

[army240]

I also think it's fuel related... do you have a fuel pressure gauge?

EDIT : Sorry, I just saw that you said it in your first post! Hehe

[KiLLeR2001]

How are you venting your fuel tank?

[GuardianLlama]

Been out of town so I haven't touched it for a while. But basically I drove it the other night for a while and it started doing it worse, must have died 20 times on my way home on the freeway, in gear etc. My fuel tank is vented with the OEM cap that passed pressure test a few months ago. Tps voltage doesn't drop when the car dies. I've been searching about this to no end, this is rediculous. It really seems to need a key reset to cone back to life. If I do not turn the key back to acc before cranking it doesn't want to start. It sounds relay related, but I can't see how. I've replaced changed and messed with most all of them already.

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[gostrider]

Ignition switch or check ground wire off coil pack?

[GuardianLlama]

Changed ignition switch yesterday. No difference. I've re done almost all of my grounds, but I'll take a look.

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[gostrider]

fuel filter, clog fuel lines, dirty injectors, clean iacv ?

[DJZ]

check your maf, mine had some oil on the sensor in it and car was having similar issues.

[KiLLeR2001]

Originally Posted by GuardianLlama

My fuel tank is vented with the OEM cap that passed pressure test a few months ago.

An OEM S13 gas cap is vacuum only. What did you do to the vapor line that connects to the charcoal cannister? This cannot be blocked.

I highly suggest upgrading to an S14 OEM cap and unblocking your vent if it is blocked. Make sure the fuel check valve is operating correctly as well.

[Dooley19]

Originally Posted by KiLLeR2001

An OEM S13 gas cap is vacuum only. What did you do to the vapor line that connects to the charcoal cannister? This cannot be blocked.

I highly suggest upgrading to an S14 OEM cap and unblocking your vent if it is blocked. Make sure the fuel check valve is operating correctly as well.

^This guy knows what he is talking about =)

[GuardianLlama]

Originally Posted by KiLLeR2001

An OEM S13 gas cap is vacuum only. What did you do to the vapor line that connects to the charcoal cannister? This cannot be blocked.

I highly suggest upgrading to an S14 OEM cap and unblocking your vent if it is blocked. Make sure the fuel check valve is operating correctly as well.

I like the way you think, but can you explain what would happen if my gas tank wasn't vented properly? And maybe why it doesn't seem like I'm losing any fuel pressure when it stalls? Could this possibly be tripping the eccs relay?

Sent from my HTC Rezound

[SharkMan]

For sure its a fuel or spark problem. Just as killer stated make switch to the s14 cap, make sure you filter isn't clogged(just buy a new one they are cheap), if you have an fpr with gauge monitor it and see what its reading. If not make sure you getting good fuel pressure. Check for sufficient spark, and check for vacation leaks. It may be time for a new fuel pump.

[GuardianLlama]

Originally Posted by SharkMan

For sure its a fuel or spark problem. Just as killer stated make switch to the s14 cap, make sure you filter isn't clogged(just buy a new one they are cheap), if you have an fpr with gauge monitor it and see what its reading. If not make sure you getting good fuel pressure. Check for sufficient spark, and check for vacation leaks. It may be time for a new fuel pump.

Fuel pump is less than a year old, New z32 filter 2 months ago, and my tomei fpr has a gauge on it.

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[SharkMan]

Originally Posted by GuardianLlama

I like the way you think, but can you explain what would happen if my gas tank wasn't vented properly? And maybe why it doesn't seem like I'm losing any fuel pressure when it stalls? Could this possibly be tripping the eccs relay?

Sent from my HTC Rezound

If your not vented properly or the vapor line to charcoal canister is blocked or capped, it will cas you fuel pump to fault of break due to circulation/pressure. And you said you not showing any loss in fuel pressure? Does how does the car act while under stress or revved?

Also did you check for spark issues?

[GuardianLlama]

Originally Posted by SharkMan

If your not vented properly or the vapor line to charcoal canister is blocked or capped, it will cas you fuel pump to fault of break due to circulation/pressure. And you said you not showing any loss in fuel pressure? Does how does the car act while under stress or revved?

Also did you check for spark issues?

I'm going to take a video while driving. I lose all throttle response very abruptly and will not come back until I reset ignition. Super annoying I don't have a commander for my PFC right now. Maybe I'll throw the gopro in the engine bay for a shot at the fpr while driving lol. Stand by on the ignition ground I'll go ahead and check that when I have a minute. Thanks for all the replies thus far.

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[DJZ]

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[GuardianLlama]

Originally Posted by DJZ

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Lol I'll check that too. Although this is supposed to be a refurbished maf. Only got it a month ago. I should be able to see a spike or drop in air values on my commander. I'll have to go borrow one.

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[KiLLeR2001]

Originally Posted by GuardianLlama

I like the way you think, but can you explain what would happen if my gas tank wasn't vented properly? And maybe why it doesn't seem like I'm losing any fuel pressure when it stalls? Could this possibly be tripping the eccs relay?

Pre-mature fuel pump failure. This is more apparent once the temperature rises as hot air expands. The fact that it happens AFTER a certain amount of time tells me once the tank builds up an abnormal amount of pressure, it causes the fuel pump to act funny. Although that may be another issue altogether. I would look directly at your fuel check valve as they are known to go bad (esp after 20+ years).

The fact that if you switch the IGN OFF and then back ON and the car works again leads me to believe that the contact points on one of the OEM relays are worn. Again, rise in engine bay temperature can cause this. I can't count the number of times I've dealt with relays that worked only when they wanted to, very frustrating.

[GuardianLlama]

So, i found a bad CAS connection and this seemed to go away for a while.

Then came back with a vengeance recently.

https://www.youtube.com/watch?v=fH4G...UN1BCFs9Ia2lxw

Car now starts for a second but won't stay running.

This is what my PFC is reading with ignition ON.

Something is seriously up with this now.

Ideas? Bad CAS?

[cotbu]

I see a couple funny things happening in that video, low battery voltage, mafs voltage, water temp is low, but that is normal for cold start, let it warm up before you rev the engine.