Esgar

So I'm getting frustrated now. I've checked fuel, getting 31 with vac. regulator hooked up, 39 disconnected. Getting plenty of air, plenty of spark, however I suspect my problem is timing.
Backstory on the swap: 1989 XJ 4.0 renix, ax15. Motor is a 1991 comanche 4.0 H.O. ax15. I've swapped dizzy, all sensors, save the TPS. I haven't found a good write up with pics for the renix/ho tps conversion. Although I don't believe I need the tps hooked up to fire the truck. The H.O. was running when pulled from the MJ, I had the crank out to put in new main gasket, everything went back together exactly to spec. Now I'm wondering if either my harmonic balancer is shot, or I have my timing chain a tooth off. Any input is greatly appreciated.

freegdr

dist back in point to no 1 on compression stroke

freegdr

timing chain gear points were toward each other

freegdr

injector pulse present

freegdr

what about knock sensor

freegdr

few articles herehttp://www.google.com/#hl=en&sugexp=...w=1318&bih=836

Esgar

I read on several forums that I didn't need the knock sensor for the truck to run. I don't have it installed as the H.O. doesn't seem to have a mounting location for the sensor. I did get the truck to run, however it's a bit shaky, it acts like it's got an aggressive cam, the idle sits at 750, which is where it's always sat, both the Comanche I pulled the motor from and the Renix from my XJ had that idle, and without warning, it'll drop to about 300Rpms, sit that low for between 5-10 seconds, then kick back up to 750 like nothing had happened.

freegdr

sounds like iac issues

Esgar

Alright, I may swap the one off my Renix, since it's known-good. Another question that forums aren't 100% clear on answering: Do the Renix injectors and H.O. injectors differ other than casing construction and spray pattern? I've seen some say no, and some say the rig will run like s**t with the H.O. injectors hooked to the Renix ECU, as mine is.

freegdr

96 and above take more pressure

Esgar

Alright, thank you. I guess I have nothing to worry about other than getting my IAC fixed for the rough idle.

I still fear I have more timing work to do though. on startup, it backfires, sometimes more severe than others, luckily it's just out the tailpipe and not back through the intake mani.

freegdr

every ho swap into renix xjs have used the ho ecms and wiring harness this is sorta uncharted ground i dont see a write up any where of this complete from start to finish to go buy ?

Esgar

I didn't even look for one to be honest, I read up on the basics for the swap, and searched for a really good TPS conversion, and I found one, but the pics were nothing but broken links so I couldn't view them. I rely almost entirely on visuals, versus written directions.

I'm kinda proud then that I've done it the way I have and made it work for the most part.

I would have used the H.O. ECU/Harness, but that wasn't an option at the time. The owner of the MJ that donated the engine to my XJ kept it to simplify his conversion. Mercedes 4 cylinder turbo diesel. Don't know what he plans on being able to use from that system, but what the hell.... With enough time, solder, and ingenuity, anything is possible.

Esgar

So, come to find out, my H.O. TPS does not have that damned bushing inside that tells the ECU my throttle position. Not sure why, not sure how. I'm going to wager that's causing a lot of my rough run problems.

Also discovered I have a coolant leak, partially if not entirely coming from my t-stat housing. Possibly the water pump too, since it's a decent (pencil-lead diameter) stream coming out.