OB1 or OBD2 4.0 fuel injection?

[Zoro]

I'm gathering parts and info to get my Eagle switched over to fuel injection using the 4.0 head and cam with the 258 block. Trying to decide if I want to go with the OBD1 or OBD2 setup. I'd like to go with the 91+ systems as they don't have an EGR.

Does the 91-95 system use an EVAP system like the OBD2?

How watered down can I get the OBD2 system to run properly without throwing a million codes? IE without the dash and interior stuff.

With both systems will they run properly without the TCM(trans control module) or trans plugged in?

[max98059]

uhh i would take a look at the maga squirt

[carnuck]

Mega Squirt could be easier. I can't recall what resistance value you need to "fake" the EVAP sensor on the tanks, but they have given GM and everyone else headaches with failures causing the whole fuel pump assembly to require replacing.

[jonb8]

91 to 95 is all I would mess with, 96 is first year of obd2 and last year before the buss system so it's got alot of one year only crap going on. 87 to 90 is a renix system and it's got way to many fusable links and vac lines to mess with. If your gonna run the factory trans it would probably be better to run a after market system that doesn't need a crank sensor.

[carnuck]

Actually, aside from the axle crap, the Renix system isn't bad, but 1/2 the harness is under the hood and the other half is in the dash.

[BenM]

91-95 is the usual recommendation. 96 is a transition year, and some parts are 96 only, at least in Cherokees (I had one for a while). 97+ can work, but you need all the sensors, including one before and one after the cat.

I don't know of a car built since the early 70's that doesn't have an evaporative emissions system, but I don't know what year they started using the special sensor in cars that throws a code if the cap isn't on right, which is what I think you're asking. I suspect that's an OBDII requirement.

You need the CPS and a speed sensor, usually on the transmission but there's a CPS relocation kit. Any manual transmission computer won't care, and the early auto trans computers with the separate computer for the AW4, or from Wranglers with the 998 won't need any transmission sensors.

(I don't know if the integrated AW4 computers care or not, but you can avoid them. Maybe someone else has the answer.)

I've heard reports that auto computers have a higher idle programmed in than the manual computers. Makes sense.

I wouldn't turn down a free Renix system. EGR doesn't affect performance.

[Zoro]

Actually, aside from the axle crap, the Renix system isn't bad, but 1/2 the harness is under the hood and the other half is in the dash.

I gotta agree with ya there! I had a '90XJ and it was the most reliable thing I've ever owned aside from my current Eagle. I didn't mind the vacuum axle as I had the manual trans, shift on the fly as long as you weren't in gear.

(I don't know if the integrated AW4 computers care or not, but you can avoid them. Maybe someone else has the answer.)

I wouldn't turn down a free Renix system. EGR doesn't affect performance.

That's what I'm trying to figure out if the computer will freak out without any feedback from the trans controller. I do find XJ's with the manual trans from time to time in the boneyard but people are in such a hurry to yank the drivetrains that the wiring harnesses end up cut in 50 places. Always seems like they could care less about the autos.

My Eagle is currently automatic but in the future I'm going to swap in an AX-15 or NV3550.

I have nothing against the Renix system, I've had nothing but luck with them. Unfortunately they're getting harder and harder to find in the junkyard.

I plan on using the #7120 cylinder head(High Output) will that even work with a Renix intake?

[BenM]

That's what I'm trying to figure out if the computer will freak out without any feedback from the trans controller. I do find XJ's with the manual trans from time to time in the boneyard but people are in such a hurry to yank the drivetrains that the wiring harnesses end up cut in 50 places. Always seems like they could care less about the autos.

The computers interchange, at least for the same year, so maybe you could get the harness out of an auto rig and the computer out of the manual? Except for the transmission wiring and the TCU/computer for the AW4 it should be the same harness.

[carnuck]

I plan on using the #7120 cylinder head(High Output) will that even work with a Renix intake?

A little massaging of the intake and gasket. I just made the BBD intake fit a Renix head and header.