High negative fuel trims and poor idle
#1
High negative fuel trims and poor idle
Hi All,
I recently completed my rebuild, 05 6sp, resurfaced housings, reused irons and new Atkins seals all around, new Intermotor coils, NGK plugs and wires. Not too much trouble starting but refused to idle (tends to hunt a LOT) until it was running for 10 mins or so. Still hunts, but no longer dies. I've put about 50 miles on so far without any change (runs pretty smooth). STFTs started at around -20, LTFT's @ 0. Over time STFTs have transitioned to be closer to +/- around 0 and LTFTs have leveled off at around -20. It's guzzling gas and I definitely smell unburnt fuel while driving. Starts easily hot and cold. Next I tried a new MAF, cleaned the TB, new injectors (verified wiring was correct), new CAT (old one was gutted), new CPP switch. No change.
I fear I've reached the limit of my troubleshooting ability and need a fresh perspective from the accumulated wisdom here! Here's a typical snap of what things look like when it idles after a drive.
I recently completed my rebuild, 05 6sp, resurfaced housings, reused irons and new Atkins seals all around, new Intermotor coils, NGK plugs and wires. Not too much trouble starting but refused to idle (tends to hunt a LOT) until it was running for 10 mins or so. Still hunts, but no longer dies. I've put about 50 miles on so far without any change (runs pretty smooth). STFTs started at around -20, LTFT's @ 0. Over time STFTs have transitioned to be closer to +/- around 0 and LTFTs have leveled off at around -20. It's guzzling gas and I definitely smell unburnt fuel while driving. Starts easily hot and cold. Next I tried a new MAF, cleaned the TB, new injectors (verified wiring was correct), new CAT (old one was gutted), new CPP switch. No change.
I fear I've reached the limit of my troubleshooting ability and need a fresh perspective from the accumulated wisdom here! Here's a typical snap of what things look like when it idles after a drive.
The following users liked this post:
DocWalt (08-27-2021)
#3
Good call, turned out to be the case. Weird thing is I had marked all the connectors before the tear down, and when I installed the new injectors I verified I had kept that sequence. I bought this as a non-runner so maybe the previous owner messed with them. Seems unlikely the previous re-builder did it, but they left out the copper washers on the oil injectors which ended up deforming the housings and taking out the apex seals, so who knows! All is good now, thanks again.
The following users liked this post:
Brettus (08-27-2021)
#4
Good call, turned out to be the case. Weird thing is I had marked all the connectors before the tear down, and when I installed the new injectors I verified I had kept that sequence. I bought this as a non-runner so maybe the previous owner messed with them. Seems unlikely the previous re-builder did it, but they left out the copper washers on the oil injectors which ended up deforming the housings and taking out the apex seals, so who knows! All is good now, thanks again.
The following users liked this post:
wcs (08-28-2021)
Thread
Thread Starter
Forum
Replies
Last Post
shawnstasiuk
Series I Trouble Shooting
7
05-13-2021 10:46 PM
SonofaMitch
New Member Forum
17
07-20-2020 01:45 PM