Renix ECU question

Chasing a recurring stalling issue. Narrowed down to 5 volts at the TPS. I don't believe I have a honest constant 5 volts. Replaced the TPS twice, still have stalling. And I've been through everything else so far except for... The ECU.

I have a refurbished Chrysler ECU I removed from a 87 XJ. Will I have an issue running my 90 XJ off this ECU?:repair:

I'm no RENIX expert yet (but my 90 is trying its hardest to teach me) but I have been told that all RENIX ECU's are the same (87-90)

They interchange but they're not the same.
Aas years progressed, they got better fuel and advance curves, kinda like upgrades.

For testing purposes, you'll be fine, and you may not notice the running differences.

Have you performed a complete ground refreshing? SUPER important on Renix and not a stone to be left unturned. Anything you do without ground refreshing could very likely be a waste of time.

Back to the ECU:

Before swapping in a "test" ECU, I would remove the one you've got and tighten up the connectors on it with a small pick so the pins are grasped more tightly. It will be self explanatory when you see it.

As its a refurbished unit, I would hope its got all the updates. Yes, I've gone over the grounds more than a couple times. I will "refresh" the pins. Know exactly what you mean by that.

The refurb ECU came out of a 87 XJ with a rebuilt motor. Don't know the history of that XJ, as I got for free, missing parts. The thing was cutup and the rear is a trailer...

Refurb isn't a reflash. It will be fine for you.

I get 5.2 volts reference at my TPS, measured with a Fluke 88-5 and a cheapo Sunpro DVOM.

I don't think I've ever seen a TPS with 5 volts, all I've tested are 4.7 or 4.8 there abouts. They seemed to do just fine for 20 years or so. Did you measure to chassis ground or through the TPS ground when you did the volt check?

When does it stall, when you release the gas pedal? Or when you slow down for a corner?

8Mud said:

I don't think I've ever seen a TPS with 5 volts, all I've tested are 4.7 or 4.8 there abouts. They seemed to do just fine for 20 years or so. Did you measure to chassis ground or through the TPS ground when you did the volt check?

When does it stall, when you release the gas pedal? Or when you slow down for a corner?

Click to expand...

Same here, my 90 only gets 4.7 input