Engine shutting off after 10 seconds

[Americanitemare1]

Hey guys, I’m having an issue with the engine shutting off all of a sudden. The engine starts right up every time and sounds fine. It’ll idle like normal for about ten seconds, start to sputter, and then die. Fuel pressure stays the same throughout. Checked throttle position sensor and is all plugged in and doesn’t seem to have moved. It started while car was driving around 40-45mph down the street (didn’t have this problem before) and died all of a sudden. Now I’m having this problem. Any ideas? Thanks in advance.

 

[scgnx2]

Need more info on what you have in order to help.
What modifications do you have ?
Stock ECU or aftermarket?
What MAF ? Stock? Or no MAF (speed density)
Ignition system stock or ?
Scanmaster readings at idle ?

 

[Americanitemare1]

Stock ECU
Stock MAF
Stock Ignition System
Scanmaster Retard Reading Prior: 2.1
Scanmaster Engine Running at Idle:
O2: 398-625
AF: 09-11
L8: 60
INT: 128
BLM: 118
ATS: 85
TPS: .42-.44
IAC: 72-75
CC: Up and Down between 17-233

 

[scgnx2]

Stock ECU
Stock MAF
Stock Ignition System
Scanmaster Retard Reading Prior: 2.1
Scanmaster Engine Running at Idle:
O2: 398-625
AF: 09-11
L8: 60
INT: 128
BLM: 118
ATS: 85
TPS: .42-.44
IAC: 72-75
CC: Up and Down between 17-233

Stock MAF are highly prone to fail and cause stalling/shut off exactly how you described. IAC is high too should be closer to 20. O2 is lean as BLM is low too.

 

[Americanitemare1]

Can a bad MAF cause those numbers as well? Or Do you think they could be separate issues?

 

[scgnx2]

There is an adjustment procedure for the IAC. The O2’s and low BLM may be MAF related. What chip do you have ? Replace the MAF with a LT1 or LS1 unit and a translator box.

 

[Buick Mark]

Can a bad MAF cause those numbers as well? Or Do you think they could be separate issues?

Yes it can. Replace the MAF with an LS1 and Translator, HUGE improvement over the stock one.
DO NOT waste your time trying Cardone or other replacement MAF's

 

[Americanitemare1]

I’ll replace those items and go from there, thanks!

 

[Buick Mark]

I’ll replace those items and go from there, thanks!

Before you replace it, do the tap test.
With the engine running, tap the MAF with a screwdriver handle, if the engine faulters or shudders. its bad.

 

[Americanitemare1]

I will try that first, thanks Mark

 

[Danster]

What chip do you have?

 

[Americanitemare1]

Hey guys, I’m opening this up again as the problem hasn’t gone away. I replaced the MAF with the LT1 MAF with translator. I had adjusted the IAC to normal levels and a few days ago was able to let the car run at idle, and it sounded fine. Was able to rev it up a few times without dying. Today, I started it back up and noticed the IAC levels were once again high (90s). I once again adjusted the IAC, after it warmed up, to around 17, and then had to readjust the TPS to .42 as well. Car will always start right up and idle (although slightly rough). If I give it a few revs, it starts to stumble badly until completing dying after about ten seconds. Car has a TT chip in it. Fuel gauge showing 40lbs of pressure at idle. After the last time I let it idle, I recorded the following Scanmaster numbers:
AF: 12
L8: 76
INT: 128
BL: 123
ATS: 97
TPS: .42
IAC: 05
CC: 89
O2: 753
Any help would be greatly appreciated.

 

[Chuck Leeper]

Mileage?
Inj info?
Original coil and module?

 

[X Ray]

Original fuel pump and sock?

 

[Americanitemare1]

This engine was rebuilt last year, just broken in recently, while breaking it in it seemed to run fine. Didn’t have these issues until the last few weeks. Turbo is a TE44 with Red Armstrong pump, hot wire kit, and 60lb injectors. It is an original coil and module. Think it could possibly be a fuel issue? I know the fuel pressure at idle is 43. Hard to tell when I rev it up as it starts to stumble and then dies. O2 sensor is brand new as well.

 

[TTA308]

I would start with the TB, take it off and have a look see.. may as well rebuild while its off. Then again it could be something as dumb as a clogged fuel filter.

 

[Dylan4570]

this is going to sound dumb but humor me.

If its an oil filled gauge with a pressure relief make sure that the inside of the gauge is equal pressure to the atmosphere. when I did the cam break in the fuel trim was way off and i was confused until i pulled the rubber plug on the fuel pressure gauge and heard the air hissing.

 

[Chuck Leeper]

this is going to sound dumb but humor me.

If its an oil filled gauge with a pressure relief make sure that the inside of the gauge is equal pressure to the atmosphere. when I did the cam break in the fuel trim was way off and i was confused until i pulled the rubber plug on the fuel pressure gauge and heard the air hissing.

A common problem with the filled gauges and engine heat.

 

[Americanitemare1]

I would start with the TB, take it off and have a look see.. may as well rebuild while its off. Then again it could be something as dumb as a clogged fuel filter.

I did replace the fuel filter and now the coil and module as well. No change. I am wondering if the TB or IAC is on its way out. I can start the car and it’ll idle, although slightly rough, but stay running. IAC numbers start at around 40 and drop to zero. I’ve tried adjusting and they bounce around. If I rev it up after about 60 seconds of running, the idle kind of sticks (like it’ll come down to 1200 or 1300, and then drop to around 1000 after 5 seconds or so) and then the car sputters and dies.

 

[Americanitemare1]

this is going to sound dumb but humor me.

If its an oil filled gauge with a pressure relief make sure that the inside of the gauge is equal pressure to the atmosphere. when I did the cam break in the fuel trim was way off and i was confused until i pulled the rubber plug on the fuel pressure gauge and heard the air hissing.

Hey Dylan, the gauge is an Auto Meter pro comp fuel pressure gauge, mechanical, liquid filled. Do those have a pressure relief on them?