• NAXJA is having its 18th annual March Membership Drive!!!
    Everyone who joins or renews during March will be entered into a drawing!
    More Information - Join/Renew
  • Welcome to the new NAXJA Forum! If your password does not work, please use "Forgot your password?" link on the log-in page. Please feel free to reach out to [email protected] if we can provide any assistance.

over bumps.... it stalls?

soulslngr

NAXJA Forum User
Location
Northern NJ
sometimes my 89 LImited will stall if I go over some small jittery bumps my engine will stall, and also the other day, I accidentally let the hood slam and the engine stalled. does anyone have any idea what this could be, she runs great otherwise, but I have never seen anything like this before... thanks again for any help!
 
My guess would be a loose or bad ground wire. Check the cable between the battery to the side of the engine block. Also check the ribbon ground wire that runs from the firewall to the engine block (near the map sensor).
 
:idea:BEFORE you mess with any connections, take a medium sized hammer, preferrably rubber faced but not a rubber mallet, and TAP near these connections first, starting with the one on the firewall, while it's running. Don't tap on it, just next to them. Also try over by the coil, etc. Try to get it to quit with taps.

That way, you can isolate which one it is. Otherwise, if you're not sure which it is, and you play with a few connections (could be something other than the ground too, but probably electrical), and it doesn't quit, you dont' really know if you fixed it, or if it just isn't doing it right now...
 
I figured it was something electrical, but haven't had the time to diagnose correctly. I'll look at those first though, if anyone else had anymore ideas then I am all ears! thanks again!
 
My money's also on a loose ground connection but check that the negative battery lead isn't also loose. Another thing to check for tightness is the connection between the wiring harness and engine computer.
 
Take a look at your CPS wire. It runs really close to the exhaust manifold. Mine used to touch it. It melted the casing, and when I would hit a bump, it would ground out on the manifold, and cause my Jeep to hiccup. Just a thought. BTW, the last CPS I installed was about a foot shorter than the ond one. I guess they realized all of that extra wire could do no good.
 
under your advise I went back out and checked wires, found the battery neg that attaches to the block and found it was loose at the block. I tightened it up and we'll see how it does, but I will check all of those others too! thanks for all the help!
 
Just in case the battery cable wasn't it, I'll mention that my 87 used to do this, and stopped when I found that the harness to the fuel tank sender was dangling and hitting the rear axle on bumps. I tied it up and the problem went away. I imagine it would have been better to find the fault in the harness too, but it never showed up again over the subsequent hundred thousand or so miles.
 
If you havn't found it yet, try replacing the ballis resistor for the fuel pump on the left front fender. I have a friend that was getting intermitant stalling and it was this.
 
well, i tightened the battery ground to the block and thought it was all good, but then it stalled on me twice today, once I came to a stop at a traffic light and felt it stuble for a sec then it died, and another I was pulling into a driveway and it rocked around a little, and died........... any hints?
 
It's probably electrical, so don't just tighten the connections, clean them and tighten - block, firewall, battery, starter relay positive terminal with all the wires on it, etc. Then disconnect and reconnect sensor harnesses. It would be good to spray a little Deoxit in there and work it around too. It might also be an internal break in a wire.

While it's running, jiggle things. Dont' be rough, but try to systematically work all the harnesses and connections. You may not get it to quit, but even a change in running condition while jiggling says you're close.
 
cherokee89 said:
Take a look at your CPS wire. It runs really close to the exhaust manifold. Mine used to touch it. It melted the casing, and when I would hit a bump, it would ground out on the manifold, and cause my Jeep to hiccup. Just a thought. BTW, the last CPS I installed was about a foot shorter than the ond one. I guess they realized all of that extra wire could do no good.
did you check the cps wiring?
 
my jeep used to do the same thing...it was the plug for the CPS, one of them was no good. i could shake the harness with my hand and my jeep would stall.
i ended up cutting off the harness and soldering (sp?) the wires together. good idea or not, thats what i did. no stalling when going over bumps or up hills yet. did that a few months ago.
 
SirFrack said:
my jeep used to do the same thing...it was the plug for the CPS, one of them was no good. i could shake the harness with my hand and my jeep would stall.
i ended up cutting off the harness and soldering (sp?) the wires together. good idea or not, thats what i did.

That's a good idea. I did the same thing with my TPS last year and I've also not had any problem since I got rid of the bad connector. The only problem is that you'll have to do it all over again if the CPS itself goes bad.
 
from what I can tell the CPS wiring looks kosher, and yesterday it didnt stall all day (just as an update). I still havent figured out conclusively what it could be, but it also did its start-up high idle yesterday where it jumps to like 2500-3000 for a few seconds then falls. could the stalling be a TPS issue? it just seems so random :confused:
 
It's unlikely. A bad TPS will cause an erratic idle, hesitation, and bucking but it won't make the engine stall. Since you're getting a high idle on start-up, it's probably a good idea to clean the IAC module and inside the barrel on the TB where it's placed.
 
Back
Top