1995 Jeep 4.6 Stroker

[mpgmike]

Those would be the old part that has failed. The new one has "LXH8T245" stamped on it.

[AndreyB]

I have these with molex soldered

WhatsApp Image 2025-07-31 at 13.11.13_b852feba.jpg

[mpgmike]

Perfect!

[mpgmike]

Finally got a "day off" to play with the Jeep and UAEFI. I got it running with the LS coil packs. I disabled everything else I previously controlled to focus on the ignition part. The timing table is what I had with the distributor. Earlier today I captured 2 emissions tests with the stock ECU running the show. After the install, I drove it around awhile to make sure it wouldn't die on me like the earlier versions did. I then did another emissions test. I will definitely have to do better tuning, but it seems to be running. Looks like the upgraded U103 is holding up (at least longer than the old one did).

LS_Coils1.png

I'm a bit gun shy still, so I left the factory distributor in place in case I need to do an emergency road-side swap-a-roonie. Swap ignition wires, unplug the rusEFI, and plug the stock coil back in -- back on the stock ECU.

LS_Coils2.png

Many thanks to AndreB for working with me on this one. He is truly dedicated to making this the absolute best platform of its kind.

[mpgmike]

With over a month of reliable driving, I am ready to dive deeper. That new TI U103 replacement is doing the trick for me.

[mpgmike]

It would appear my confidence level in the rusEFI surpassed my skeptical threshold. I removed the distributor and stock ignition coil and swapped in a later model Cam Position Sensor.

DistOut.png

CmsIn1.png

It wouldn't start! Found there was no 5 volt VREF to the new sensor connector. Traced it back to a bad crimp job on the UAEFI pin C1 (shame on me for sloppy work). Fixed that, and it started. It surged at idle, and died when I tried to give it throttle. I connected my dual-trace O'scope to the Crank and Cam sensors.

CmsScope1.png

Sure enough, as careful as I was to align the shutter wheel with the pick-up to match the position in the distributor, I was off. The next picture is a screen image from the scope. I added a line (Start) where it aligned initially. The Hi/Low transition must occur between the groups of 4 pulses on the Crank Sensor. It was happening after the 1st Crank pulse. I loosened the hold-down clamp, slowly twisted the new Cam Sensor until the transitions fell about midway between the 4 pulse groupings. Had I gone the wrong direction, it wouldn't run at all. With sequential individual coils, it would have tried to fire the wrong cylinder.

CmsScope2.png

On my test drive, it ran just like it did with the distributor. Next up will be to tackle fuel delivery -- including WB O2 feedback.

[mpgmike]

Spent yesterday trying to get it running long enough to start adjusting the fuel tables. I had it running the injectors Saturday night, but it would shut off after a couple seconds, then eventually wouldn't even start. Today I started checking things. The Cam Position Sensor wasn't switching (verified on a scope). Dang! Ordered a new one from RockAuto and swapped the distributor back in for now. I now have a clean Crank and Cam signal, but still no start. I checked for spark and none. Curiously, TS would go to "Offline" rather often. I'd have to shut the key off, unplug the USB cable, then start over to get communications. Checked power supply connections, all good.

Here's where it gets even better; I found an oil puddle under the engine. The engine only has <4k miles and has NEVER dripped engine oil. I checked the oil level and it was 3 quarts over full!! Apparently the rusEFI was holding injectors open constantly to get 3 quarts of gasoline into the crankcase.

I'm on my 3rd UAEFI now. When I ordered the 3rd one I saw an offer, "Buy 3, Get 1 FREE". Although I was buying my 3rd one, they were 3 separate orders. Andre was a good sport and sent me 2 for the price of 1. SOOOooo, I have a spare. I'm going to load the tune I'd been using and try again (after I change the oil).

If anyone has thoughts, I'd appreciate it.

[AndreyB]

Apparently the rusEFI was holding injectors open constantly to get 3 quarts of gasoline into the crankcase.

You would be the first person reporting that rusEFI held injectors open.

Are there any alternative explanations? Does oil in engine look diluted/smell like gas?

Do not get me wrong - you were the first one to report uaEFI damage with specific coils, and you've turned to be right about it. Just saying that so far I am not aware of reports of injectors stuck open.

[mpgmike]

I need to spend more time with it to properly diagnose, which I will. I certainly will report my findings, even if I did something stupid and there were no electronic issues. Thank you for the response, AndreB.

[mpgmike]

I removed the suspect UAEFI from the Jeep, brought it in the house, and when I connected the USB cable to the laptop, it did a rapid connect-disconnect-connect-disconnect..... Loaded the last settings & tune into the new one and the Jeep runs again. When it failed, I had the 6 LS coils, 6 injectors, IAT, CTS, TPS, MAP, Crank & Cam sensors (both Hall), and WB O2 connected. What was different was I added the Temp sensors, WB, and injectors. The Cam sensor failed about the same time as the UAEFI if that helps.

I want to diagnose the failure, anyone have a clue where to start?

[AndreyB]

Something along the lines of https://github.com/rusefi/uaefi/issues/85?

[Giobs]

Hey man!
It looks like i had a similar issue to yours with the injector stuck open (take a look at my thread), in my case I think the driver are toast, but I'm taking my time to diagnose them