2G stuck in limp mode

[tschuhly]

Hey all,

I am trying to figure out what steps I should go through to figure out what is causing my issue.

Some background is that the car has been put together and running since about mid April. Towards the middle or end of May it started to act like it had a misfire or something. I replaced the spark plugs with the higher horsepower ones but that didn't do anything.

I decided to check for codes and I got the knock detection circuit fault code. I found that my sensor was loose so I tightened it up and no luck. I then was driving it and as I took off from a light, it sputtered a little and when I gave it slightly more gas it bucked hard once and then turned off. I got it towed and later found that my ECU 20amp fuse had "blown" or broke (I'm not sure if it was just old and brittle or if it legit blew). I replaced it and my knock sensor with a new one jic and my car started up except now it won't go over 4500rpms.

It doesn't have any codes but is still running a little weird and is still in limp mode. I tried to go into my ECU pinout settings to tamper with them to see if it was because of my AEM boost sensor being pinned to my MDP pin, but it is still in limp. I will say that for a little bit I had forgot to unplug my stock MDP so there were probably 2 conflicting signals going to the ECU so maybe that did something? I haven't driven it yet because I worried it will leave me stranded again.

I attached a log of it starting, idling and revving a little. Any guidance would be appreciated!

 

[jdxnc]

Is this a stroker motor or something? LoadScale is set to 82% and usually this isn't done unless there's more than normal displacement.

I don't think these cars really have a "limp" mode per say, it's just idling stupidly rich, even though it's calling for 14.7 it's idling high 10's to low 11's, just dumping fuel.

Actually just noticed in the MAF comp tab it's not set to Speed Density, that could be the issue, all the values should be zeroed here.

 

[tschuhly]

I don't believe it's a stroker but I had it tuned prior for the setup that I have which does have a lot of aftermarket stuff including 2150cc fic, 272 hks cams, a walboro 255, and other goodies.

It's not setup for SD yet but that's what I'm working towards. The thing is, it ran fine after getting it tuned and then randomly started acting up.

Is it possible that something happened to the ECU that caused settings to get screwed up?

 

[jdxnc]

This doesn't look like an ecu issue to me.

 

[tschuhly]

An important piece of info that I forgot to mention is that my car is limiting itself to 4500rpms...

 

[1990TSIAWDTALON]

I see your launch control is set at exactly 4500, move that up to 5500, just as a test, to see if the car will rev higher.
ALSO, you have your Knock Sensor set to basically never come on. I did that ONCE and melted a piston when knock came in but the sensor didn't pull timing...... I see that as dangerous. You have yours set to come on only ABOVE 7950. Ideally, you don't want any knock but the sensor should be active starting around 3500-4000 rpm and anything more than 90% throttle (some start it even at less TPS).
Just a few things I notice.

 

[jdxnc]

I see your launch control is set at exactly 4500, move that up to 5500, just as a test, to see if the car will rev higher.

Good catch, clutch switch could be grounding out. Like I said, these cars don't really have a limp mode, it's being held back by too much fuel or a limiter like the launch limit. If I'm not mistaken you can log the clutch switch by added it to captured values.

 

[tschuhly]

Thank you guys so much!! We are currently in a heat wave so it may be a couple days before I get to it to test this stuff out, but please stay tuned because I am pretty lost at this point if I'm on my own .

 

[1990TSIAWDTALON]

If you are on here, you are NEVER alone. That's what this forum does, it tries to help. I will follow along and chip in when I think I can contribute. Hang in there, we'll figure this out.
AND, who isn't in this heat wave? We are predicted for 99 on the 4th of July.