Failsafe back!!! 2008 gt500

[Joewee500]

After 2 years of running great the Weather got cold and instead of car running better it runs worse. Full throttle it FailSafes at top of whatever gear I go full throttle in. Seems like It happens when I let off the throttle. No hard codes or check engine lights. Torque App shows B1353,P0600,P1227,P1237,P2105,U0300,U1900,U2011. I've changed O2 sensors, both temp sensors, cleaned MAF sensor, changed battery, changed plugs, prolly lots of other stuff but too frustrated to think. Any ideas before I run this car into a deep pool of standing water? Thanks in advance.


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[VNMOUS1]

Have you checked your alternator? Half of these are electrical /connectivity issues.

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[PaxtonShelby]

Have you done any datalogging? Your tuner should be able to diagnose. You're far from stock so I'd be on the safe side. Vapor is a gorgeous color!

 

[Joewee500]

I've captured it in datalogs and can't seem to see an issue. I'd replace the alternator tomorrow if that would fix it. The no check engine light is driving me nuts. Thanks for the responses. Yes PaxtonShelby I agree, thank you...will make someone else a nice fixer upper soon if I cant get this sorted.


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[Willie]

Disconnect and reconnect both the TPS and throttle connectors. See if it makes any difference. If you have any Stabilant 22a, put a drop on each pin prior to reconnecting.

 

[Joewee500]

Disconnect and reconnect both the TPS and throttle connectors. See if it makes any difference. If you have any Stabilant 22a, put a drop on each pin prior to reconnecting.

I've unhooked them several times during the course of trying to fix this but not added Stabilant...will try anything though.


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[RedZR]

Is the car stock? After adding a TVS to my 2008 I had the same problem. It finally took a new FRPP throttle body and revised Lund tune to fix it.

I was told by my tech and Lund that failsafes are mainly a result of a bad throttle body

Good luck


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[gimmie11s]

Super frustrating. Only time my car ever failsafed was after a FRPP mono blade install. Old tuner couldn't get it figured out.

Switched to Lund along with a TVS and Whipple 68mm dual bore TB and no more fail safes.

 

[Joewee500]

Vmp twin 67 tb. 22lbs boost and e85. Never missed a beat for 2 years, 6k miles ish, now it's cold and it's a messing up.


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[RedZR]

Could the e85 be screwing something up? I have read that e85 is not very good in cold weather. FWIW I noticed my jeep was a lot more difficult to start on a cold morning after I ran e85 in it.


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[Joewee500]

Could the e85 be screwing something up? I have read that e85 is not very good in cold weather. FWIW I noticed my jeep was a lot more difficult to start on a cold morning after I ran e85 in it.


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Starting is one thing but once it gets going e85 shouldn't be the issue. Log shows constant pressure. Thanks for the response


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[gimmie11s]

Vmp twin 67 tb. 22lbs boost and e85. Never missed a beat for 2 years, 6k miles ish, now it's cold and it's a messing up.


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My DSM used to do this what youre describing.

You said you changed plugs. What about swapping out a set of coil packs for a known-working set?

On the DSMs a new set of plugs and wires always cured my misfires while under boost.

 

[gimmie11s]

Also are you monitoring AFR? Are you 100% certain fuel delivery is not the issue?

The E85 might have freed up some goo within your fuel system and it could be trapped in your filters somewhere causing a lean condition.

The car will NOT KNOCK on e85 no matter how lean it runs. You'll melt a piston (literally) before she knocks so sometimes lean conditions on e85 are a little tougher to diagnose.

 

[gimmie11s]

Also the U codes all point to throttle body issues. Swap out with a known-working TB and electronics and see what it does.

 

[Joewee500]

I'm not monitoring AFR, prolly should be with an aftermarket wideband. I guess going lean could happen except there's no loss in pressure in the logs, no lean codes either. These codes are not triggering a check engine light. These are pending codes seen on the Torque app. Having failsafed the car many many times, this list has only come up twice. Usually it's only the B1353, p01227,p01237. I don't have a spare throttle body lying around to test. I could throw money at new electronics but who knows if that'll fix. I have to do something or sale the car cheap, built engine and 10k miles on car.


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[me32]

I had a issue just like that when i installed my tvs and had lund tuned it. He said he couldnt find the issue. Even with updated tunes couldnt get it fixed. I end up getting a tune from shaun at AED and never had the problem again. Cant say for sure yours is tune related but i know for sure mine was.

Also a few others have said have the alt and battery checked. Never had a fail safe from those going bad but i did go through 3 factoy alts and 2 batterys because of the failing alts. Which cause all kinds of weird stuff

 

[RedVenom48]

Get your battery tested too.

 

[Joewee500]

I replaced the battery immediately after it failsafed the first time in October. Changed o2s, spark plugs and cleaned MAF sensor. Ran good for 2 weeks (weather warmed up). Cooled off and Failsafed again, changed both temp sensors, tightened some loose ground wires, changed some melted wires and all vacuum lines. Ran good for 50 miles then back to Failsafing.


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[HillbillyHotRod]

If you changed some melted wires that is where I would look to make doubly sure they are correct. Electrical problem can be a pain in the rear.

 

[Joewee500]

If you changed some melted wires that is where I would look to make doubly sure they are correct. Electrical problem can be a pain in the rear.

The melted wires were going to the CHT sensor at the back of the passenger cylinder head. Could the MAF be going bad and giving weird signal to he computer when it's cold? I tried to crank the car and it would start but then die...did that several times immediately following the last Failsafe pull.


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