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HO in Renix Question

kevinde1

NAXJA Forum User
Location
OKC, OK
I have a 89 Cherokee Laredo and swapped the motor with the a 91 HO that I rebuilt. I kept the Renix wiring system and used the HO intake and TB and made a TPS adaptor for it. My trouble is when I get to about 1/4 throttle it coughs, spits and sputters but will still excellerate but sounds rough. ALL MY SENSORS ARE NEW except the MAP sensor and it wasn't giving me any trouble before i did the swap. DO YOU HAVE TO HAVE A MODDED (ADJUSTABLE) MAP SENSOR TO RUN THIS THROTTLE BODY ON THE RENIX SYSTEM? I've checked my timing 3 times and its dead on, TPS is set correctly, used the renix flywheel and distributor, grounds are good, wiring harnesses are good to go, no Vaccum leaks, new cap, rotor and wires, new renix injectors, new renix fuel pressure regulator, filter and fuel pump is not that old either. I've done a lot of reading in this forum and have seen similar problems but I haven't seen any posts where they found the problem and fixed it. This is a clean jeep and would really like to get it on the road any help is appreciated. TIA
 
What spark plugs did you use? Im not sure of the years, but when I did the HO swap on mine I had to use the spark plugs for the 97' engine I put in mine and they are longer than the ones for the renix. Also, what fuel rail did you use? Does it have the fuel pressure regulator on it? Not sure if the 91 HO had one, but mine didnt and you still need it.
 
kevin, did you just fire this thing up for the first time?

If so, did you get the ground wires on at the dipstick tube stud and was the stud free of paint?

Also if so, have you doublechecked distributor indexing?
 
I started it a few days ago and just been working out all the bugs. At first I had a high idle figured that was the tps, I thought it was bad before, so i got a new from napa and that cured my high idle problem. I used the renix fuel rail and regulator it took some modding and welding a new bracket but it works. I also used plugs for the 91H.O. My grounds are clean and replaced the firewall ground w/4gauge and ran it directly to the 2 wires + battery ground. The 91 does have a fuel regulator but my book says its supposed to be 31psi and 39 w/ vacuum off, same as renix. Hard to believe my fuel pump is bad but anything is possible I guess.
 
The distributor timing was my first guess and i've pulled it out 3 times. I have a timing light but im not sure what degree it should be firing on.
 
It has nothing to do with the timing. It's injector firing. Search "distributor indexing". I'll be back in a bit. I'm installing my HD Offroad shackle relocation kit right now.
 
Ok, I think what your saying is my stator might be out of adjustment? If so I didn't know it was adjustable. But that could explain why It seems like its starving for fuel. And I do have a different cam and new timing gears. I read a post where a guy broke off the ears on the distributor and moved it to get it adjusted. But I would rather do it the correct way.
 
The correct way was to grind off the ears and index the distributor properly. Nevermind the timing light. With #1 at TDC the rotor should be .020" past the #1 terminal of the cap. The only way to see this is to cut a window into an old cap.
 
Ok, that shouldn't be a problem i have an old cap. Thanks for the information Cruiser54. Hopefully I'll get it straightened out tomorrow.
 
Ok, I had bad fuel pressure, but now its ok. But still having trouble indexing this distributor. Its lacking power and wont hold its speed, sounds great until you drive it. I dont know whether to advance it or retard it?
 
Rotate the engine to #1 TDC. The rotor should be pointing to about 4 o'clock as you're looking into the engine bay from the passenger fender area. Use the cap As explaind above to get the dizzy indexed.
 
Ok I got the distibutor indexed thanks for info on that. But I was still having problems I found a crack in the coil so I replaced it with a new one, still no change. My fuel pump ballist resistor had a piece broke off so I got one from napa and it was for chrysler vehicles with a wide range of year and model. That seemed to make the most improvement so far. Does anybody know what the Ohms should be on the ballist resistor? I would like to double check that cause the guy at the counter was unsure and so was I. Thanks
 
I have a couple questions about this indexing. With engine at TDC the rotor should be .020 past the 1# terminal. By angelfire's writeup looks like maybe .020 past 1# teminal if he was going by the center of the rotor? Or do you go by right edge of the rotor? Also what about if you have some play (back and forth) on the dizzy? Should you just try to center it, or push it all the way to one side or the other?
 
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