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XJ woes

goodburbon

goodburbon

NAXJA Forum User
Location
Westcliffe Colorado.
I have a 1997 4x4 4 door with the 4.0 and the following mods.
Open element air filter
home bored throttle body
1" throttle body spacer
3"custom cat back exhaust
Jacobs Electronics Pro street ignition (plugs gapped at .50)
Electric fans, (mechanical one eliminated)
Jet Performance stage 2 chip
180 degree thermostat
optima yellow top
and a few drivetrain and suspension mods

Here is the problem. Sometimes it doesnt want to start, and I keep getting check engine light, sometimes it dies when approaching a red light. The Jacobs kit is advertised to eliminate all of these conditions. I have changed map sensor, throttle position sensor, oxygen sensor.

It will always start if I hold the throttle wide open while starting. no blue smoke, but I will get smoke if I start it with throttle wide open, smells rich.

should I just strip it back to stock to see if everything works and jut add things one week at a time to see if its something I have done?
 
One of my buddy's has a camaro just like mine and he put a chip in it...needed o get the car tuned after that....i dont know if its the same for our jeeps but that could be the problem. Good luck.
 
Sounds like flooding to me. Have you checked the fuel injectors, fuel pressure regulator, etc? How about vacuum? That Jacobs kit won't fix a stuck injector or a hole in the manifold gasket.

If I were in your situation, especially with that much invested in modification, I'd lay out a few more bucks for some good diagnostic tools, because it's going to be hard to get regular service people to understand the thing and get it right. You could start with a vacuum gauge, which is cheap, and progress to a fuel pressure gauge and an injector tester, possibly a hundred bucks or so, but will pay for itself in ten minutes if it catches the problem.
 
I would second the thought of bypassing the Jacobs stuff and try running stock ignition. I had similar trouble with my Jacobs and it turned out that it's computer went bad. Runs fine now on stock stuff and I'll never go back to Jacobs.
 
I had a Blazer with a sb 400 in it running the Jacobs. The Jacobs would mess with the injector system causing it to either run WOT constantly or not work at all. Evidently it puts out some EMI. They sent me a filter and the thing ran awesome....until I munched the motor at least. *grin*

Sarge
 
goodburbon said:
Here is the problem. Sometimes it doesnt want to start, and I keep getting check engine light, sometimes it dies when approaching a red light. The Jacobs kit is advertised to eliminate all of these conditions. I have changed map sensor, throttle position sensor, oxygen sensor.
Click to expand...
What codes do you get with the Check Engine light? Solve that one first as it might point you in the right direction.
 
Last edited:
All advice noted and appreciated, I will start on it as soon as I get back on land. I have checked the code, dont remember what it was at this time, but it was something really odd, I didnt touch anything and it was a month before the light came back on. It seems That I am always chasing a code with that thing.
I will start with the code, move to the Jacobs , and then the chip. If I happen to replace my dummy light dash in mid stream, how will that affect my computer, I assume the codes are in the ecu and are not affected by the gauge insert, but I could be wrong, (it's happened before)?
Now the heater core is leaking too, I just bypassed it for a temp fix, from what I can see it looks like a royal pain to get to. and I have read posts about pulling the passenger seat to get to it, If I would have to evacuate the AC to change it I would just as soon pay for that one to be done. whats the estimated cost of that?

Thanks again,
 
i had the same problem ....wouldn't start at times...would die at weird moments(stop lights) etc...and i also had a Jacobs Ultra Street and a Jet stage 2...couldn't figure it out and neither could a few repair places (intermitant problem- sorry 85$). got some advice to change my Crank Position Sensor....never happened again. good luck
 
Happend to me I dont have any mods except rustys K&N and rustys exhaust system, changed my crank position sensor and it worked fine, try that... it might be a bitch to change without a air lift, when i worked at goodyear i changed mine and it was one hell of a bitch even in the air, and if you drop it in the case good luck getting it out...
 
ok, so its not the Jacobs kit, nor is it the jet stage 2 and the CPS is hard to change?!? I need to do this tomorrow, got a run coming up this weekend. No Idea what the code is, I disconnected the battery and its gone, it is now missing at high rpms inconsistently, only when warm. the CPS is not just in the distributor?, I'll be looking up posts on changing that
 
CPS changed, easy job since the t-case is dropped an inch.

that wasnt the culprit...!^%@$
as soon as I fired it up it was extraordinarily unhappy. I had disconnected the battery and now it would sputter, then surge, repeat, repeat, repeat. I turned it off, disconected the battery again and started over. it did it again, I revved the engine, and it settled down.
still hard to start. I returned to total factory ignition, changed the plugs, cap, rotor. the plugs were covered in soot.
after another battery unplug I restarted it, it is now thoroughly ****ed off at me. Once it does start, it idles high with an inconsistient miss, it actually killed and spat black smoke from the air filter, when I disconnected the MAP sensor. I pulled out a sensor from the intake manifold and it was covered in gas, I would imagine that this is an intake temp sensor, since it functioned as one when I checked the resistance.

gas in the intake manifold....stuck injector?

I was hoping to make a run this weekend, but not the way its lookin
 
easttxjeeper dropped out and it looks like your gonna have to also. that sucks, maybe next weekend since i'll have some 33's then, i was gonna try those out as it was. good luck
 
no CE light anymore, so i have no code just hard starts, and high idle with a miss, and gas in the intake manifold...

I thought that the CPS was a high altitide model since I got excellent mileage in the mountains 20+, and back in Louisiana its 15 or less so I changed it. I also had my suspicions about the hard starts.

I will try cleaning the TB when I get home
 
goodburbon said:
no CE light anymore, so i have no code just hard starts, and high idle with a miss, and gas in the intake manifold...

I thought that the CPS was a high altitide model since I got excellent mileage in the mountains 20+, and back in Louisiana its 15 or less so I changed it. I also had my suspicions about the hard starts.

I will try cleaning the TB when I get home
Click to expand...
AFAIK in the 97 there is only one type of CPS. Recently here in SoCal we had a guy whose rig was running rough and had problems starting, but he was also getting a TPS code from the PCM. Replacing that and cleaning out the TB seems to have taken care of it.
 
I found that out (no high altitude CPS available) yesterday by calling the dealership. I just replace the TPS a few months ago, because I got that code.
 
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