From bad to worse...burnt gnd wire and no start

[Renn44]

Well, sometimes a long project just ends up running away from you...

I was chasing the cause of a P1126 and P1133 codes, which had me go down a rabbit hole of replacing the upper AOS vent line. For those that haven't had the misery of replacing this line, it pretty much requires the R&R of the intake manifolds. While I was in there, I also replaced the oil fill tubes (after breaking some plastic). This required unbolting the alternator, however it connected. I reconnected everything else, and felt good about getting vacuum.

I get on the road, car feels fine, but get right back up to +20% LTFT, so whatever the actual cause of those max enrichment codes was not resolved. After the battery reset, the trim was starting to come up at speed, so I'm thinking I may need to start looking at fuel delivery as a possible culprit. Anyways, that's where I would have started until...

I come back from the 20 min test drive and idle for 5 minutes. I turn the car off, and then key back on with but no starter turn. After a few more attempts, I get the awesome smell of electrical smoke. Pop the rear trunk and a good amount of smoke is swirling around. I pull the liner and find this ground on the firewall totally toasted.



Any takers on what I messed up when putting everything back together? Feeling like that poor ground took the current when I tried to restart - but strange I had no problems on the drive or first start.

Things I removed/replaced during the top engine work:

• Both manifolds
• RH Injector and coil harness connections
• Crankcase vent valve
• The ground and harness brkt near the crankcase vent valve
• The starter cable at the starter to access the oil fill tube bolts
• Oil fill tube from crankcase to firewall

[Renn44]

Some progress; the nut on the ground cable that goes to the secondary air pump wasn't tightened! The payback from too many hours in this engine bay.

The ground circuit (off Ground Point 8) shown burnt to a crisp splits off to the LR and RR wheel carrier grounds. Will make a new Y-split for these ground lines. They disappear into the silicone tubes to go out in the wheel wells. The sheathing seemed OK once inside the silicone bundle, so will bring the new lines to the point the wires disappear into the bundle. Continuity to the wheel carriers was confirmed.

[Renn44]

Well, for those in the future that find this thread having a P1126 and P1133 code - just replace the MAF. Sometimes, it's actually the MAF...

$156 on Amazon as of writing.

[Ga 951]

Renn44

Thanks for posting, I'm sure someone will find this info helpful.

What year car was it?