Racer in need! Power loss light and no codes (Big race this weekend!)

[powermaxx]

Kinda grasping here. Was at the track tonight and in the second round in 2nd gear the engine violently cutout, power loss light came on very strong (it was dark...) and then it went out and all was back to normal for the remainder of the run. I lost as I could not make up that amount of slowdown.

Pulled into the pit and checked for codes, nothing but 55. It acted like the overboost shutdown scenario but no codes. I was going back tommorrow to fix a screw I broke on my adjustable cam sprocket but now I want to make some passes to see if it happens again. There is a big import race on Sunday and I wanted to spank alot of Honduhs, etc.. so I really need to get some ideas here.

Going to sleep now so I'll check back in the AM. I have a TU Cal but can't remember if the overboost was removed or not. I'll try to find my instuction sheet to see if that's the case (don't know if a code would be thrown if the overboost was removed).

TIA!!!!!!!

[Dave]

Well I don't know where you're from, but it has been very hot lately. Depending how soon you raced between rounds you're car could have vapor locked. Vapor lock feels just the same as overboost and is much more violent in a 5spd. I'm assuming yours is.

I'm pretty sure if your cal is set for a 3bar MAP the overboost shutdown code would still be stored. You don't completely start with a naked computer when doing a cal. You just take the memory from stock and enhance it.

Vapor lock is just my guess.

[glhs875]

A code should be thrown for overboost. Maybe the HEP in the dist. acting up? Or map sensor going bad? Or fuel pump getting weak? Or ASD relay or circuit giving problems? I don't know your car, but those are at least 4 things I would check out.

[Clay]

I would be very very suprised if it was a vapor lock problem with a circulating style fuel injection system.

[powermaxx]

Car was plenty cool so I don't think vapor lock wouild happen. (One temp cycle to bring it up to temp and the air temp was in the low 50's).

Read about the codes last night so I don't know. Heading back out so we'll check things over real good. And see what happens.

Thanks for the suggestions.

[Directconnection]

A code should be thrown for overboost. Maybe the HEP in the dist. acting up? Or map sensor going bad? Or fuel pump getting weak? Or ASD relay or circuit giving problems? I don't know your car, but those are at least 4 things I would check out.

Any issue with the map should throw a code and stay in limp mode until you reset the computer, so I would rule that one out for the most part, anyways. May it can be if an intermittent electrical issue to the map but should still throw a code I would think.

I have heard of some people in the past having weird issues with their cars if they moved it this way, or turned right, etc. Ended up being a bad ground. Maybe you have a ground issue that happened on the 1-2 shift?

Just tossing out rough ideas.

[Clay]

I had a HEP plug come loose while at the strip. It was very intermetient. Sometimes I couldnt make it out of the pits, other times I would get half way down the strip.

It ened up being the black connector up closer to the battery that was loose. So I zip-tied the connectors together so they couldnt come apart.

[puppet]

Would think too that this was ignition related considering the "right now" power loss.

[powermaxx]

Just got back from the track. Couldn't find anything amiss. It ran great, no issues at all. (Other than the driver screwed up the 2-3 shift 1st time run . Rest were 12.3's) So good to go for tommorrow.

I'll check those HEP connections in the morning too!

Thanks all!

[glhs875]

Any issue with the map should throw a code and stay in limp mode until you reset the computer, so I would rule that one out for the most part, anyways. May it can be if an intermittent electrical issue to the map but should still throw a code I would think.

I have heard of some people in the past having weird issues with their cars if they moved it this way, or turned right, etc. Ended up being a bad ground. Maybe you have a ground issue that happened on the 1-2 shift?

Just tossing out rough ideas.

I have seen map sensors be bad and NOT throw a code on more than one occasion.

[BadFastGTC]

I remember a problem that Dan Carson had at one time that was similar. He ended up determining his alternator was making contact with the rad support due to engine movement and/or bad motor mounts. Drove poor Dan crazy...

[powermaxx]

What a day ! The power loss hit me again 1st time trial, TWICE! Top of 2nd and top of 3rd. I swapped another 3bar MAP in and a backup (used) HEP for the 2nd. And then the Rev limiter switch got disconnected so had to free wheel it (but no Power loss hit like last time). No idea of what to dial 1st round and went out (wheels spun bad) but no Power Loss that run either.

I think there's a TestnTune soon so I'll try it again. I can hook up my OTC and log things then.

Thanks again!

[Gaboon]

I used to have a problem with my car hitting the cut out. Seams it would do this periodically when I had detonation from lower octane fuel or not high enough octane for the boost level and or timing .

Throw in some higher octane fuel and problem solved. This too was with a custom cal.

[powermaxx]

I used to have a problem with my car hitting the cut out. Seams it would do this periodically when I had detonation from lower octane fuel or not high enough octane for the boost level and or timing .

Throw in some higher octane fuel and problem solved. This too was with a custom cal.

I run 100octane on the track. With the G head, detonation is not an issue. I've even run 91 octane on the dyno and no detonation. (DRB II hooked up for the dyno pulls)

I've noticed that my custom cal used to run at 28psi even though it was supposedly set for 25psi (chalked it up as gage readout differences) with overboost at 27psi. Ran for 3 years that way. Now I noticed it's only going to 25psi. I'm thinking the cal is finally waking up and seeing the higher boost (spike?) and trying to control it. Hard to read the gages when you're in competition.

[powermaxx]

Update: Went to TestnTune last night and made 11 passes with no cutout at all. So it appears either the MAP of the HEP I swapped out was the culprit. (I'd really like to swap the old ones back in to verify but have no time with a race this Friday night.) Since it was intermittant I hope these were the reasons!

I even swapped a MBC in place of the wastegate solenoid and ran it up to 28psi and the custom Cal did't even flinch (still wondering about the overboost cutout that's set for 27psi.... that didn't cutout. Hmmm....) May have to test for that to see if it's real or not. Expect some difference in gauged boost vs MAP boost levels.

LTR

Thanks for the tips guys!

[BadAssPerformance]

Good to hear you got it smoothed out Steve

[powermaxx]

Well I thought it was solved. Went to testntune last Wed night and made 11 passes with no problems. So figured I was okay. Last night in our Street Sport Compact class the first 3 runs were perfect. But in round 2 the light flickered a couple of times and I ran slower but still won. Round 3 and it came on several times and slowed by .5sec off the dial in.

It wasn't like before where it came on very solid and it was VERY noticable. This time it was almost "smooth".

Again no codes thrown. Going back over this in my mind I remember the shift light coming on sooner and staying on longer than normal. I was thinking ( ) that maybe I was up against the rev limiter? Would that cause the power loss light to go on and leave no codes?

I'm thinking my clutch is starting to go and maybe slipping. I'm going to try lowering the MBC to 25psi also to see if it's just too close to overboosting. Knock sensor maybe?

I did manage to stay in longer than the points leader so I think I'm in first place (for now...).

[powermaxx]

Just wrapping the car up for winter after a head gasket change (2 of them) to a cometic type (final one). Took it out for a spin and the Power Loss light problem is back. I even disconnected the Knock Sensor plug to eliminate that as a problem (made several passes that way with no issues). Also lowered my boost by a full turn on the MBC (haven't checked the gauge yet...). I've swapped out MAP's and checked the connections of sensors and grounds. Still nothing showing up as a code after it lights up. The light comes on (flickers a bit and steadies up) at the top of the gear/rpm range.Can only do this in 2nd gear on the street (not enough room for 3rd) and it doesn't do it all of the time.

Decided to drive it to work today just to blow out the cobwebs. Smoked some guy at a light and then did a huge burnout in the parking lot (John Force would be proud of me ). Doesn't cut out just lights up.

[Mysterio]

I was having a similar problem. But I'm running an FWD-P cal and no intake temp sensor yet since I don't have my T2 intake on yet. So there's a few reasons why I would be getting a "fuel cut" type thing going on. If you figure it out definitely post up here though because it may end up being the same thing that is happening to me