The problem finally showed up
Senior Member
Joined: Jul 2012
Posts: 9,003
From: C-Town
Well did a crank relearn on the unit, was running perfect for a few days. Then I pulled up to a light and it stalled out. Started the hummer again and headed over to a friends place where it stalled again and only at idle. Did a crank relearn ran perfect for 10 km then stalled again. Will try to diag the crank sensor. Now it wont hold an idle without stalling, runs smooth over 700 rpm and has no cel or codes. Ready to dig a hole and push this in lol. Any one else have any ideas?
1st easy check "stalling at idle" >>> Disconnect the MAF and start engine. Post the results.
Thread Starter
|
Member
Joined: Jan 2022
Posts: 45
From: Alberta
Stalls at operating temperature
Alright, so i disconnected the (MASS AIR FLOW SENSOR) it idled rough bounced up and down and still getting the stall, but only when operating temp gets hot. What I did find out is that once the temperature goes up just over half is when the issue starts. From cold start to level on the temp gauge just climbing over half it idles amazing not a single hiccup. As soon as the temp climbs to over half it dies, let it cool down for 10 15 minutes and it starts perfect, idles fine. Temperature climbs a little over half again and same problem (stalls). When I installed the new cylinder head, complete gasket kits I also installed a new water pump and thermostat. So as it would seem to me it has something to do with a fail safe something. Even when the coolant temp sensor is disconnected it still idles beautiful until it hits the half way mark.
Super Moderator
Joined: Jul 2007
Posts: 13,093
From: Boat Town USA MI
You need to look at fuel trims. In cold start mode fuel is increased boosting idle to warm the engine, once temp is high enough, the fuel rich cold start strategy ends and that sound like where you are.
Last edited by Doc Olds; Mar 25, 2022 at 10:27 AM.
Thread Starter
|
Member
Joined: Jan 2022
Posts: 45
From: Alberta
My fuel trims are good. I did change my crank sensor, the interesting thing that I came across was my voltage to the crankshaft sensor is 5v on both wires. CKP 1 low ref and CKP 2 signal. I hate electrical.
Thread Starter
|
Member
Joined: Jan 2022
Posts: 45
From: Alberta
Yeah I did one with the old sensor, ran like a dream for 20km. Stalled when I got back to the drive way. Crank position code came back again. Let it cool down a little under have way temp mark and started fine again. Hits Half way and boom dead as a door nail. Changed the Crank sensor did a relearn again and still the same results. I am taking it to the dealer tomorrow to see if they can reflash the ecm and update it. I am at a standstill it feels like.
Thread Starter
|
Member
Joined: Jan 2022
Posts: 45
From: Alberta
No check engine light or codes or anything. Pre new head symptoms, were service stabiltrak system, reduced engine power. Both were intermittent with a ses on and off rarely. So I have no other assumption then it has to do with the pcm or something on the same run. Throttle body Mass air.
Senior Member
Joined: Jul 2012
Posts: 9,003
From: C-Town
No check engine light or codes or anything. Pre new head symptoms, were service stabiltrak system, reduced engine power. Both were intermittent with a ses on and off rarely. So I have no other assumption then it has to do with the pcm or something on the same run. Throttle body Mass air.
Thread Starter
|
Member
Joined: Jan 2022
Posts: 45
From: Alberta
Well no luck hummerz. I disconnected at the air box to resonator pre maf sensor and she bucks and jumps on rpms. Installed it back into place, remove filter cover and filter with no change. She still stalls around 500rpm at idle halfway temp. If I hold 1200rpm she will stay running smooth but dies as soon as I let off to return to idle. I jumped the gun and change the tb cause mine looked rough and maf cause it was cheap. No change.
