Am looking for help w/an issue i've been chasing since we owned the Wagoneer: rough idle/hesitationat cold start, and hesitation/backfire - when running at highway speed & letting off the throttle, coasting a bit, then getting back in it.
Jeep is a bit of a Frankenstein, with parts making quite a long-strange trip before being mated together in East Tennessee. From what ive been able to piece together, the AMC 360 engine was in a Grand Wagoneer (not sure the year), when AFI's EFI (1227747 ECM) were installed in 2006 in NJ. The engine & EFI was eventually sold to a Jeep junkyard in NC 3-4 years back (not sure what happened to the original Wagoneer), and subsequently sold to the previous owner of my Jeep, to mate with a body he'd found in Atlanta. To add to the mystery, from the high elevation sticker under the hood & the lack of rust, am thinking the body was originally out West somewhere.
With that out the way, over the last couple weeks, have dug in & fixed a myriad of issues relating to voltage drop & the ECM reading low battery voltage (~12.5V). By performing voltage drop tests on the 3 power-related ECM connections (pins A6, B1, & C16), tracing wires, removing short splices of wire & re-splicing, cleaning grounds, cleaning electrical connections with DeoxIT D100 contact cleaner, finding/fixing a cracked/corroded fuse, etc., i've seen battery voltage reported by the ECM rise from 12.5V to 14.2V, resulting in a better running, quieter engine. Overall, it's never run better.
But, i'm still chasing the:
- hesitation at cold start
- intermittent dying when going from park to drive
- backfire at speed problem,
that it's had since day one.
Over the last few days, i've noticed that when comparing voltage measured by back-probing the ECM connections w/multimeter vs. what the ECM reports, that there's a .2-.4V variance - the ECM reporting lower. Am wondering if i have a bad connection with one of the pin connectors in the ECM harness?
Here's the car we're working on:
Cracked fuse worth ~1V! Battery voltage reported by ECM jumped from 13.2 to 14.2.
ALDLdroid dashboard after the wiring cleanup effort - Battery Voltage - lower right.
Attached are the latest set of data logs, would appreciate your taking a look & see if anything jumps out. One thing i notice in the logs is voltage drops the longer the engine runs... So far, i'm only driving it in a 6-10 mile loop that includes in-town & highway driving, so am wondering how far it would continue to drop if i drove longer/further? Am planning on taking it out later on this weekend, for a longer test drive & see what happens.
Right now, the ECM is in mounted in a box under the hood, on the driver's fender where the rear window washer bottle should be. Given the hacked up nature of the EFI harness, am planning on getting a new one & moving the ECM to inside the Jeep - just wanted to get it running properly first. Am wondering, given all the trials/tribulations dealing w/the existing harness, whether i might be better off, to get a new harness & start over?
Wondering: could engine heat be affecting measured voltage? Such that, we could expect an improvement once i move the ECM into the cabin?
Thanks.
Reply With Quote
Bookmarks