Engine parameters for a 1990 Jeep Wrangler

[gabe collins]

I got a snap on mt2500 scanner but I don’t know he engine parameters like the long term and short term fuel trim, all that stuff since the renix system on these old jeeps ranging from 1987-1990 can’t creat and store dtcs

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[gabe collins]

It’s the 2.5 i4 single port injected

[Gareth Randall]

I would start by getting hold of the Chrysler diagnostic manual (NOT the factory service manual) for the 1990 2.5L Wrangler. There are a few on eBay right now, like this one: 1990 Jeep Wrangler Powertrain Diagnostic Manual

The diagnostic manuals are separate items to the FSM, and go into detail about using DRB scan tools to diagnose problems. They are full of information that isn’t included in the FSMs.

I would warn that the Snap-on scanner may not be the right tool for the job and you may need to use a period Chrysler DRB2 scan tool along with the Jeep/Eagle adapter to get any meaningful data out of the system. I picked up a complete DRB2 kit including the Jeep/Eagle adapter a few years ago on eBay for about $300.

[gabe collins]

I’ll look into the diagnostic Manuel. And I’d like to have a fsm on hand as well since that would be a lot better than the Haynes Manuel

[Gareth Randall]

For sure get the FSM. It’s just a bit annoying with Chrysler that the FSM misses out a lot of diagnostic procedures, instead directing you to the relevant diagnostic manual. You really need the FSM *and* the full set of diagnostic manuals for any given vehicle from that era.

EDIT – just for my own interest I did some Googling, and came up with this info about the Renix fuel injection system, which you may find useful: Jeep Renix fuel injection

[gabe collins]

That makes a whole lot more sense now. I’ll have to clean up the 2 grounds and see what happens. The jeep runs but it’s stubborn at given moments

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