Car dies, then starts right back up

[GhostRiderGT]

Pretty much my issue is in the title, my 2006 Auto GT will just randomly (and I mean it can go months without doing it) die while driving. I have replaced the fuel filter about three months ago, and replaced the battery last October. The alternator was replaced late 2012 for a brand new one. I have checked all the connections coming from the battery, alternator, and starter. What kills me is it will go months without doing it and then when it does die, it will fire right back up. It is almost like someone is turnong the key off while I am driving....have data logged with MPT and they said everything looks good and they were having problems trying to help me come up with a solution since it is so random. Only other thing I can think of is the fuel pump is on its way out, but would like a few more opinions before I shell out the cash for a new one.

P.S
car has 212,240 miles on it and everything having to do with fuel is factory to my knowledge

 

[BruceH]

Is it all stock?

 

[GhostRiderGT]

No, has a JLT Series 3 CAI, MPT tune, and SSS Terminator axleback. I have done three data logs with MPT and they said on their end everything is within the right parameters, they said the only thing that looks weird was my MAF, they suggested cleaning it and doing another data log session after that and then they said everything looked fine. So I am not thinking it is in the tune....I can only think it is the CAI because with it on my car idles weird, I have idle set to 950-ish and it will fluctuate between 950 and a little over 1,000 RPM at idle and then it will surge when I go to slow down/stop...I had to replace the trans last October and we even made sure (about a month ago) that we didnt plug anything in wrong or have any lines bent/kinked so idk whats up with it. I have cleaned the TB, MAF, and ran a fuel injector cleaner through it (had the guys at my dealership verify it wouldn't mess up the car) so idk what it is...it happens so randomly too that I cant exactly let them test drive it and see what it does.

 

[BruceH]

By any chance does it happen at light cruising throttle? I'm curious because I had a similar issue with a JLT 3. I felt that it was a combination of the cai and a GT500 tb I was running. My theory was that there was enough metered air in the huge intake tube and tb to cause a failsafe issue under light throttle transitions. It only happened under specific conditions. It's the only issue I've never been able to tune for. I also theorized that it didn't happen to others because most people probably have their foot stuffed into the gas pedal, therefore no light cruise.

 

[truckman7]

Might be a shot in the dark here. But look at the wiring harness for your ignition where it connects on the under side of the steering wheel. I had a prob where the red power wire wasn't seated all the way in its slot. If I hit a big bump it would shut off. Start the car and wiggle the wires. Hope it helps.


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[GhostRiderGT]

By any chance does it happen at light cruising throttle? I'm curious because I had a similar issue with a JLT 3. I felt that it was a combination of the cai and a GT500 tb I was running. My theory was that there was enough metered air in the huge intake tube and tb to cause a failsafe issue under light throttle transitions. It only happened under specific conditions. It's the only issue I've never been able to tune for. I also theorized that it didn't happen to others because most people probably have their foot stuffed into the gas pedal, therefore no light cruise.

As a matter of fact...that is when it has happened each time....I have been told to swap my CAI and if that didn't work start at the ignition

 

[GhostRiderGT]

Might be a shot in the dark here. But look at the wiring harness for your ignition where it connects on the under side of the steering wheel. I had a prob where the red power wire wasn't seated all the way in its slot. If I hit a big bump it would shut off. Start the car and wiggle the wires. Hope it helps.


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I will try that when I get off work and get home. Thank you

 

[CJ-]

Clean your throttle body out, as the grit builds up in the throttle body, the idle will slowly but surely drop... even to the point where the idle is so low that while in Drive, the car will just sit there instead of pulling forward when you release the brake. Then as time and miles go by and mroe grit builds up in the TB, the car will start to stall.


edit: nevermind, i see you already tried cleaning the TB. If you able to view Live data on your tuner, with the ignition on but engine off... check the MAF voltage, if its between 0.00-0.03, its in good working order but if the voltage jumps higher than that... its time to replace, also, id recommend only lightly oiling your air filter on your JLT intake, if you use too much oil, the oil will make its way onto the MAF and give inaccurate readings.

If the readings are over 0.00 - 0.03, try removing the maf and spraying it with CRC MAF cleaner before buying a new one. Then check the Voltage again after you've cleaned it. If the voltage is in the 0.00 - 0.03 range afterwords, then you should be good but id keep checking it every other day to see if it gets worse or not.

 

[maz030]

Does it fire back up without you having to turn the key? If so I had this same exact issue on my DD honda civic. My issue was i didn't tighten the cables that are connected to the battery tight enough. Once I really tightened them, I never had this issue again.

 

[GhostRiderGT]

Clean your throttle body out, as the grit builds up in the throttle body, the idle will slowly but surely drop... even to the point where the idle is so low that while in Drive, the car will just sit there instead of pulling forward when you release the brake. Then as time and miles go by and mroe grit builds up in the TB, the car will start to stall.


edit: nevermind, i see you already tried cleaning the TB. If you able to view Live data on your tuner, with the ignition on but engine off... check the MAF voltage, if its between 0.00-0.03, its in good working order but if the voltage jumps higher than that... its time to replace, also, id recommend only lightly oiling your air filter on your JLT intake, if you use too much oil, the oil will make its way onto the MAF and give inaccurate readings.

If the readings are over 0.00 - 0.03, try removing the maf and spraying it with CRC MAF cleaner before buying a new one. Then check the Voltage again after you've cleaned it. If the voltage is in the 0.00 - 0.03 range afterwords, then you should be good but id keep checking it every other day to see if it gets worse or not.

Thank you I will check that when I get off work today, haven't even considered the MAF trying to die on me...it is the factory unit with well over 212,000 miles on it.

 

[GhostRiderGT]

Does it fire back up without you having to turn the key? If so I had this same exact issue on my DD honda civic. My issue was i didn't tighten the cables that are connected to the battery tight enough. Once I really tightened them, I never had this issue again.

No, I have to either put it in Neutral (if it does it wile I am driving) and turn the key or if it does it when I come to a stop I put it in Park, but it will fire back up without hesitation...I checked the battery (even though it isn't a year old yet) because I figured maybe I got a faulty one, checked to make sure the cables were tight and everything. Even checked the alternator (it got put in brand new in 2012)

 

[Wild White Pony]

Do you have to rotate the key back and then forward to start? If so that would be a shutdown in limp mode and should throw a code. If you don't then that sounds more like a terminal/wire connection problem.

If you can get a datalog up, it would be good to look at what's going on with the maf,fuel pressure and short term fuel trims. It doesn't take much to be off on the maf transfer values or have an intermittent signal to have issues.

 

[GhostRiderGT]

Do you have to rotate the key back and then forward to start? If so that would be a shutdown in limp mode and should throw a code. If you don't then that sounds more like a terminal/wire connection problem.

If you can get a datalog up, it would be good to look at what's going on with the maf,fuel pressure and short term fuel trims. It doesn't take much to be off on the maf transfer values or have an intermittent signal to have issues.

No I don't have to do that. I can put it in neutral and just turn it on without having to turn the key back and it's not throwing any codes. Can I data log with the old SCT X3? I know it has the option but doesn't let me data log with the key on engine off.

 

[Wild White Pony]

I have the SCT X3 still, I use SCT LiveLink 6.3 I'm sure they have a newer version available here for free download: https://www.sctflash.com/support
You will need to scrounge up an old printer cable to hook up to your computer.

Once you have that set you can datalog, you will get a lot of information that members can then help diagnose your problems with.

Here is an example, I had a similar problem with the car shutting down and going into limp mode as shown on the log. This is what the data log looked like when it killed, saw that loads were high and made corrections. Right away the loads are high at idle due to a change in the supercharger pulley, should be under 0.3 at idle.

With a tweak of the tune I ran the car again without any shutdowns.

 

[svtadam27]

Monitor fuel rail pressure, the sensor will take a crap at random, kill the car then fire right back up without an issue. It used to be a pretty common issue on other ford vehicles.