XP cam, new engine, Rich and studdering when hot, great otherwise

[tylerbinski]

This problem has been going on for the last week since new install... I got the intercooler on a few days ago hoping it was just heatsoaking the motor..


Everything is great, and after I boost around a lot, the car seems to run like ****, and spudder like mad... so I pull over and let it cool... then it seems better.

I also saw smoke coming into the cabin once i popped my hood after pulling over lastnight...

LTFT were at liek + 30 while it was spuddering like mad!


I was ripping around on the highway, then i slowed down for construction and was going about 5mph.. then the car started "hunting" for idle, and before long I had to limp it to the off ramp at 5mph and pull over, pop hood and wait about 10 minutes.

IAT = 59
ECT = 85


MAP values seemed high when nit ran like ****.. seeing 60@ 800rpm, TP 0%, 86kP at 950

my fuel trims were + 39 and MAP = 103 , 1180rpm, 21% tp

didn't see a single misfire.


once cooled, the car runs just fine...


Questions: 1 - where was the smoke coming from?
Question: 2 - What could be causing this problem only when hot
Question3 - Could the MAP sensor screw up when hot? and command more fuel?


mod: new engine, xp cam, stg3 blower , 3.0, fullsize IC etc.

Thanks for the help..

Exhaust is new, so I woudln't expect there to be any leaks yet, but will not rule that out, EGR is deleted and blocked, I will be checking again for a vac leak but it seems ok currently.


Thanks Guys.

[tylerbinski]

I'm going to check out the setting in the PCM for "Catalyst protection" change it from 500C to 800C since I have a hi-flow cat

[TheOtherNick]

IS that ect in ferinheight or Celsius?

[joshmith]

Sounds like a vacuum leak

[Bio248]

first off, LTFTs lock in at +16.4 at the maximum...dont know where youre getting +30.

second, if they are locked high, you have a vacuum leak or a big exhaust leak.

[TDCRacing]

I'm going to shoot for a vacume leak.

[Bio248]

wait...what? vacuum leaks means its lean. positive LTFT values are LEAN conditions.

[tylerbinski]

Temps in Celcius.. (canada)

Well, I am still tuning, Currently running without a MAF (speed density tuning), making changes to the Volume Efficiency table... making great progress.

As I said, the car is running fine most of the time, The first time I had the problem, I had been ripping around for a bit and the intercooler was not running so it was very hot (cooked some eggs on the blower...j/k)

I was misfiring, and figured there could be a spark problem, so I removed the metal heat shields around the boots and squished the snap rings a bit tighter on the boots *these are the 10mm wires from ZZP and AL103 plugs...

The car drove terrible after it cooled for only 10 mins... After it sat a while it was great, and I zipped around for a bit more and then parked the car.... 20 minutes later i started it up and zipped out of the parking lot and then the car was not happy so i pulled over n popped the hood to try cooling for 15-20 mins...

Car ran fine for the trip home.


***Added fluid to intercooler and wired up the pump/fans....***

Well I hadn't seen the problem for a few days then one night i took a 40km high speed zip down the highway, hit traffic and then the car started "hunting" for idle and started to sound like it was running on a few cylinders and i pulled over on the closest offramp..


I had the scanner hooked up and was logging all the info... At the time the fuel trims were +30....


I'm going to the exhaust shop tomorrow because I hear a small rattle at idle (sounds around the cat, but also in one of the mufflers)

Perhaps there is a leak before the 02 sensor... but as i said , exhaust is brand new 2 weeks old..

Appreciate all the help guys...

[tylerbinski]

I'm going to the exhaust shop tomorrow because I hear a small rattle at idle (sounds around the cat, but also in one of the mufflers)

Perhaps there is a leak before the 02 sensor... but as i said , exhaust is brand new 2 weeks old..


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Cat was blown apart, so the removed it and put in a "test pipe" for the duration of my tuning. no other leaks detected.

unless something is expanding and letting in a lot of air when it gets really hot...

[tylerbinski]

bumpage