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!

 

[tschuhly]

I just took it for a small spin and we are back to square one. It's stuttering when I drive...

 

[dwb]

It might be worth going back through some of the typical simple stuff. I haven't followed too closely so I apologize if this has been done already or if I'm completely off base.

I interpret "stuttering" like possible spark issues. So new standard plugs gapped .28 - NGK bpr6es (I once tried 7's and had issues that were better with 6's). New spark plug wires. NGK have always been my go-to. Wires are a common issue so do this if you haven't already. Inspect the plug connectors inside the coil for corrosion. Run it in the dark and look for arching from the coil or plug wires or anywhere else for that matter. Verify your grounds are tight and clean. Intake manifold to firewall is an important ground - you don't want it grounding through the throttle cable, which could cause intermittent issues.

 

[tschuhly]

It might be worth going back through some of the typical simple stuff. I haven't followed too closely so I apologize if this has been done already or if I'm completely off base.

I interpret "stuttering" like possible spark issues. So new standard plugs gapped .28 - NGK bpr6es (I once tried 7's and had issues that were better with 6's). New spark plug wires. NGK have always been my go-to. Wires are a common issue so do this if you haven't already. Inspect the plug connectors inside the coil for corrosion. Run it in the dark and look for arching from the coil or plug wires or anywhere else for that matter. Verify your grounds are tight and clean. Intake manifold to firewall is an important ground - you don't want it grounding through the throttle cable, which could cause intermittent issues.

That's a good call. Let me go back through this stuff and report back!