Urgent Motor Help Needed After Tuneup

[Nick88]

Ahhh, I get it.

I thought maybe because the all the gas that flushed down with the misfire on cylinder 5. I cleaned thr o2 soaking it in electrical parts cleaner before I saw your post not to. Still running lean but the motor felt like it had some more pickup. BLM gotnup to 160 ish still though. I will also add and I dont know if its normal but everytime I start thr truck I get anywhere from 1-4 knock counts on start no matter how long the crank or how hot. When I did thr first start after cleaning o2 I got 9. Does o2 sensor control timing/ have to do eith knock counts at all out of curiosity?

 

[Nick88]

Hmm,maybe take Orpedcrows's advice and check for vacuum leaks. You can use carb cleaner or an unlit propane torch and go around the TB base,EGR base,vacuum hoses and intake rails. If there is a leak it will change the idle as it sucks the gas in. For $hits and giggles pull the EGR vacuum hose off and see what happens. A malfunctioning EGR control valve could be pulling the EGR open when it's not supposed to.

Ill give it a shot. Ive pulled off the hose to the EGR multiple times before whrn running to no change.

 

[PlayingWithTBI]

I start thr truck I get anywhere from 1-4 knock counts on start no matter how long the crank or how hot. When I did thr first start after cleaning o2 I got 9.

Hell don;t worry about it on startup - I used to get over 200 each time until I got the cold start dialed in better.

Does o2 sensor control timing/ have to do eith knock counts at all out of curiosity?

Not really, SA (Spark Advance) is adjusted based on MAP and RPM.

Here's an example, each cell is adjusted for best performance without too many KCs (Knock Counts). At higher MAP and RPMs you need to lower SA to avoid KCs.

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If your ICM is wigging out like mine did, the ECM will see the spike in RPMs and respond by adjusting SA and VE causing a "surge".

 

[Nick88]

Hell don;t worry about it on startup - I used to get over 200 each time until I got the cold start dialed in better.


Not really, SA (Spark Advance) is adjusted based on MAP and RPM.

Here's an example, each cell is adjusted for best performance without too many KCs (Knock Counts). At higher MAP and RPMs you need to lower SA to avoid KCs.

You must be registered for see images attach

If your ICM is wigging out like mine did, the ECM will see the spike in RPMs and respond by adjusting SA and VE causing a "surge".

The ICM is relatively new under 2000 miles on it maybe a couple months old. Tomorrow Im gonna check vacuum leaks. I also noticed thermostat housing started leaking. Could that throw off the ground on the housing??? What is that ground for could that make the truck run lean?

 

[Hipster]

The ICM is relatively new under 2000 miles on it maybe a couple months old.

One misfire can destroy it.....

A scanner is not going to tell you, an inconstant pump, fuel filter, pressure regulator, vacuum leaks, a weak cylinder, or the general overall mechanical condition of an engine.

 

[Scooterwrench]

What is that ground for could that make the truck run lean?

That is the grounds for the ECM,ESC,TPS,EGR control valve etc. Make sure is has a clean connection.
Why GM thought it was a good idea to put it in one of the most corrosive areas of the engine is beyond me. When I do my engine swap I'll be moving that ground to the rear of the intake or one of the bolt holes on the back of one of the heads.

 

[Scooterwrench]

The ICM is relatively new under 2000 miles on it maybe a couple months old.

These days new doesn't mean good or good for long and as Hipster mentioned EMF from an open secondary circuit can fry it.

 

[Nick88]

These days new doesn't mean good or good for long and as Hipster mentioned EMF from an open secondary circuit can fry it.

I havent had issues eith it yet as far as I can tell knock on wood

 

[Nick88]

That is the grounds for the ECM,ESC,TPS,EGR control valve etc. Make sure is has a clean connection.
Why GM thought it was a good idea to put it in one of the most corrosive areas of the engine is beyond me. When I do my engine swap I'll be moving that ground to the rear of the intake or one of the bolt holes on the back of one of the heads.

I think that ground is probably getting funky then. I havent gotten code 32 for egr in a long time now im getting it again, esc im getting random knock counts for no reason, and my idle is actinh all funky maybe something eith TPS- The coolant is literally leaking out from there so I wonder if its working its way down the ground stud threads and its causing weak ground.

 

[Scooterwrench]

I think that ground is probably getting funky then. I havent gotten code 32 for egr in a long time now im getting it again, esc im getting random knock counts for no reason, and my idle is actinh all funky maybe something eith TPS- The coolant is literally leaking out from there so I wonder if its working its way down the ground stud threads and its causing weak ground.

Good place to start!