V1 Surging Idle Problems

[askiles]

Lonny’s is stock but Adam’s is not.

Got it. Stock tune as well?

 

[Karter2026]

I will give that a try. Though wouldn’t that give me a code?? At this point I’ll try anything. Lol

Not always. I had a bad MAF in my donor that would not idle at all and at 1500rpm sounded and acted like a dead hole. unplugged the MAF smoothed out and idled fine. Replaced it with a new sensor and no problem. Never threw a code for MAF. I had knock, misfire, o2, and cat codes but no MAF

 

[askiles]

Not always. I had a bad MAF in my donor that would not idle at all and at 1500rpm sounded and acted like a dead hole. unplugged the MAF smoothed out and idled fine. Replaced it with a new sensor and no problem. Never threw a code for MAF. I had knock, misfire, o2, and cat codes but no MAF

Understood. I will give it a try this morning. If that doesn’t work my tuner wants to mess with the tube so the PCM will be coming out and getting shipped to him. He says he can change the tube where at idle it is not trying to adjust AF to anything specific. We will see if that works.

 

[askiles]

Not always. I had a bad MAF in my donor that would not idle at all and at 1500rpm sounded and acted like a dead hole. unplugged the MAF smoothed out and idled fine. Replaced it with a new sensor and no problem. Never threw a code for MAF. I had knock, misfire, o2, and cat codes but no MAF

So I had it running, surging idle, unplugged the MAF, no change at all. Does this mean it’s more than likely a bad MAF?? How can I test that??

 

[Briann1177]

No change with the MAF unplugged means it's not a MAF issue.

 

[askiles]

No change with the MAF unplugged means it's not a MAF issue.

Got it. I swapped out the MAF real quick to confirm that and yeah, no change, still a surging idle. I drove it up to the gas station to fill it, it drives decent, but when at idle it still surges. Pulling the PCM and sending it back to Intense to fiddle with. Fingers crossed!!

 

[askiles]

So on my code reader I can monitor certain things. I was viewing the MAF and throttle position on it, and revved it a few times, and the value on the MAF doesn’t real change much. Does this look normal??? Lemme know what you guys think. Thanks.

 

[BaltimoreHokie]

I will give that a try. Though wouldn’t that give me a code?? At this point I’ll try anything. Lol

Yeah, thats a good suggestion. One thought is that you could swap the original tune on it, then swap the injectors back in. The pulley wouldnt matter unless you put it into gear as the waste gate / bypass should be open.

A lot of work to see if its the tune but may be worth it if you keep having issues.

 

[askiles]

Yeah, thats a good suggestion. One thought is that you could swap the original tune on it, then swap the injectors back in. The pulley wouldnt matter unless you put it into gear as the waste gate / bypass should be open.

A lot of work to see if its the tune but may be worth it if you keep having issues.

Right. Lol. I am sending the PCM back so he can play with the tune a bit and hopefully make idle good. Everything else seems to be fine when driving it. If that doesn’t work we will have to try something like that.

 

[ctuinstra]

Yeah, thats a good suggestion. One thought is that you could swap the original tune on it, then swap the injectors back in. The pulley wouldnt matter unless you put it into gear as the waste gate / bypass should be open.

A lot of work to see if its the tune but may be worth it if you keep having issues.

That is a good idea. He may not be able to swap tunes without HP Tuners. Swapping the injectors would tell a story but he would NOT want to really drive it since it would be tuned for the wrong injectors and would want to run lean, but it would be fine at idle just for testing.

 

[ctuinstra]

Right. Lol. I am sending the PCM back so he can play with the tune a bit and hopefully make idle good. Everything else seems to be fine when driving it. If that doesn’t work we will have to try something like that.

If they do get it sorted for you, I would love to see what they do to fix it. I'll bet they raise the idle speed among a few other things. I wish you were closer so I could at least read your tune.

 

[askiles]

If they do get it sorted for you, I would love to see what they do to fix it. I'll bet they raise the idle speed among a few other things. I wish you were closer so I could at least read your tune.

Fingers crossed the tune works. I may get HP Tuners in the near future and if I do I will send you the tune to take a look at.

 

[askiles]

UPDATE:

Intense sent me another PCM with a revised tune...car runs exactly the same. :-( Not sure what to do at this point. Waiting on them to get back to me with some suggestions.

 

[DCMoney]

Worth a shot.

https://www.cobaltss.net/forums/2-0l-lsj-performance-tech-47/idle-problem-cure-finally-116051/

 

[ctuinstra]

For a test, do you have the OEM injectors? Try the 42lbs injectors just to see what it does at idle. It will tell your sure if we are on the right page.

 

[askiles]

For a test, do you have the OEM injectors? Try the 42lbs injectors just to see what it does at idle. It will tell your sure if we are on the right page.

I do. I will go ahead and swap those in today to see if that changes anything. I’ll keep you updates.

 

[askiles]

Worth a shot.

https://www.cobaltss.net/forums/2-0l-lsj-performance-tech-47/idle-problem-cure-finally-116051/

I actually found this post as well, took the TB off and made sure it was clean. I had already cleaned it when reassembling the engine so it was, but I still “cleaned” it again. Spotless. I would eat off of it. Lol

 

[askiles]

For a test, do you have the OEM injectors? Try the 42lbs injectors just to see what it does at idle. It will tell your sure if we are on the right page.

So I swapped the injectors out for the stock ones and it still surged at idle. Completely lost now.

 

[JERMzSS]

I had this problem when I installed mtb2.8 pulley and 60s with the canned tune. The tune is the problem. You need to have someone local retune it with the goblin intake attached.

 

[George]

You can swap parts all day long. You need to find some one with knowledge of Cobalts and get ti tuned to the car.
Can tunesare always hit and miss.

Brad