GM Drive-ability Concerns (Double Feature!)

Got two new vehicles in the shop for diagnosis in the morning.

First a 2009 Chevy Traverse with a 3.6L GDI engine

DTC's
P0336 ckp performance
P0102 MAF low frequency
p0300 random misfire

Symptoms

Died on customer while driving, start and stall, loud rattling noise under hood when running, poor idle.
CKP active counters drop out and are erractic in live data, will attach screen shot.




Also, a 2011 Cadillac SRX 3.0L

DTCs

P0011 int cam performance bank 1
p0014 exh cam performance bank 1
p0017 ckp/cmp not plausible bank 1
p0300 random misfire
p0420 catalyst bank 1

Symptoms

low power, customer states it seems tcs system is engaging in error.

this one is getting dropped off first thing in the morning, I will post back with updates to both vehicles, hopefully a diagnosis!

Looking forward to the diagnosis

I'm suspecting timing chains on the Caddy

Yup, seen a bunch of GM ohc engines needing chains latley...

So got them both diagnosed,

The Chevy, checked the ckp signal at the senor, was good. Checked at the PCM, good. Stopped my flow, checked relative compression with low amp probe and ckp signal, good. Took and oxygen sensor out on a hunch, ran better. Bank 1 converter was plugging the exhaust further downstream at the 3rd converter. The CKP performance code threw me off a little bit. Ha.

The Cadillac, customer was aware of Cmp/Ckp codes, said another shop put 4 cmp sensors in. I initially overlooked two TPS codes, and when the car was at the shop it was entering reduced power mode. The customer wanted a quick fix to get to work, and it got a throttle body and dielectric grease in throttle body connector as well as the PCM connectors per a TSB. Customer will return for further diagnosis of valve timing components.

Wow, color me surprised. :ohmy: I had the SRX pegged for chains. But, what do I know? :silly:

I still think it has bad chains. The TB was a separate issue & apparently the cause of the immediate concern. I see people all the time, when you tell them it needs chains, will run them until they die, or they have to go through emissions.

arbez wrote: I still think it has bad chains. The TB was a separate issue & apparently the cause of the immediate concern. I see people all the time, when you tell them it needs chains, will run them until they die, or they have to go through emissions.

:lol: Truth. I was blown away when an Equinox owner with a 3.0L went for a chain job last week. :ohmy:

the traverse make sense with the maf code. it isnt seeing the right amount of air flow past the maf due to the clogged cat. had an s10 with a maf coode ended up needing a converter

The garage is married to an Equinox right now with 3.6.

Came in for a used car with an engine light. I diaged it as needing chains. The mechanic disagreed until it was all apart and I measured the tensioners to show him it was out of spec.
He put cheap chains in it, (boss's call) made it a couple months.
He took it apart again and this time used factory chains. The engine seized on the test drive...
Possibly an underlying oil delivery issue causing all the trouble? I never touched it after the initial engine light diag.
They bought a used engine, installed it. Needs chains...
He's taking them out of the locked up motor.
Fingers crossed!