SHO no likey cold?

[Aqua Roach]

Hi, I've got a rather peculiar problem with my 3.2 ATX. Recently with the cold, 20-30 here in SC, my SHO doesnt want to start. It will crank, run for a second, than die. For that brief second it sounds like a normal run. It will do this even when I give it gas, no matter what it dies.

With that being said after around 4 or 5 failed startups, it will run for its normal second than the rpms drop to a near stall level, lopping pretty bad then stalling, at this point I can give it gas to maintain an idle, but if I let off it will most likely die.

If I maintain an idle for awhile and it gets to near-operaring tempeture, the car runs normal, perfectly fine with no rough idle.

It's pretty strange, it's almost all new everything on this motor, and all summer long I've had no issues like this. I couldn't find any vacuum leaks, and being how it stalls if I give it gas in the begining when it's cold I don't think its the IAC. Not to sure bout this one, any advice is appreciated!

 

[SHOdded]

Has this been your DD? Could it be the switch to winter gas? How old is the battery?

 

[Aqua Roach]

Nah, I only drive it on the weekends. Brand spanking new battery, my old one would not have allowed me to crank it this many times that's for sure. Could it really be the gas?

 

[SHOdded]

I don't think so, in this case, because you at least exercise it weekly. Most times people have been working on their projects over a stretch of months, so wind up with bad gas/gummed up injectors. Still wouldn't hurt to add an ethanol stabilizer into the tank to see (Lucas/BG etc).

Def check to see if codes are set, but next culprits would be: a sick TPS, dying cam sensor, even a dirty MAF sensor. Not likely to be sticking butterflies, I think.

 

[rubydist]

when was the last time you filled with gas? typically, the refineries switch to winter gas in October, so if you have not filled it for a month, you likely still have summer gas and that is much more difficult to get started in the cold.

 

[Aqua Roach]

I put gas in it this week, it may not have mixed yet with the existing gas.

I've also discovered its running really rich while I'm.trying to start it up, if that helps figure out what it could be. I'm thinking of trying to heat up the TPS with a hairdryer to see if maybe it's just that that's sticking. (Warm, not hot lol)

 

[rubydist]

sounds like it may be flooding. try this: after trying to start and it dies, put the gas pedal to the floor and crank it again. my guess is it will fire right up.

 

[intimdatr]

Personally I think it needs 02s. Stuck in the warm engine temp range. Old vs new gas and even winter vs summer shouldn't do that from my experiences.

 

[rubydist]

oxy sensor readings are ignored during open loop engine control, and any startup is open loop for a minimum of 20 seconds (when engine is warm) and as much as 20 minutes (when its truly cold out) so whatever the oxy sensors are saying at startup is irrelevant.

 

[AREA 91]

Check for engine codes.
Check your fuel pressure.

 

[Aqua Roach]

The O2 sensors are less than a year old, and have maybe 1000miles on them at best.

I'll check fuel and codes today since its in the garage. I'll let you know!

 

[Aqua Roach]

Engine codes as follows:

KOEO:

159: MAF sensor is/was out of range – MAF

335: EGR feedback signal is/was out of range – EVR or PFE

KOER:

336: PFE sensor signal is/was was high – ">PFE


CM:

452: Vehicle Speed Sensor (VSS) problem




Think the EGR is giving me problems? If so I want to delete it altogether....

 

[itwonder]

Try the idle reset procedure.
Verify fuel pump primes and then shuts off when key is turned to ON position.
X2 check fuel pressure.
Change fuel filter

 

[rubydist]

I have never ever seen a SHO motor that runs properly with that mafs code. you need to figure out if that is a mafs sensor or wiring issue and correct it. the engine simply will not run worth a darn until you do.

 

[Aqua Roach]

Its only thrown that code once when the key was off, not while running. I checked the MAF for voltage while running and its all within range.

The DPEF was nasty to say the least. Mines of the metal kind and the body lookd normal but when I pulled the hoses it was all coroded on the outside of the stems and the insides a little as well. I cleaned it up some and put it back on and it still runs rich bad and trys to die. Its only in the 50s now, so it does crank up, runs fine for a minute, than starts acting up. (Terrible idle, rich conditions)

If it was colder, like in the 30s or 40s it would have trouble even staying running at all after I start it.

Could the DPFE be clogged internally? I don't know if air is suppose to freely pass through it, but if I blow in either tube it doesn't blow through at all.

Thanks!

 

[rubydist]

yes, but it typically clogs up in the nostrils in the intake manifold. it will only allow air to go through the dpfe when the egr is supposed to be open, which is not the default position.

whether or not the dpfe / egr works right should have no effect on cold start idle, so I would be looking elsewhere.