Jeep Cherokee Talk banner
21 - 32 of 32 Posts

·
Registered
Joined
·
20 Posts
Discussion Starter · #21 ·
I figured out that the problem only occurs on a COLD start and lasts until its warmed up, it will not accelerate anything above idle for the 10-15 minutes that it takes to warm up, its just bogs down and backfires but wont actually stall. I swapped pretty much every sensor from a known good running 90 xj and the problem still happens, so its either something in the wiring harness or something mechanical. its not the MAP, as running it with unplugged is just about impossible, and its got a good vacuum line, what else could cause it to run really good at idle, but bog down and with enough gas to almost kill it?
something is causing the ECM to send so much fuel that it almost kills until its warmed up.

any ideas?
 

·
Registered
Joined
·
21 Posts
When you pulled the spark plug that was wet and fouled, what made it wet? Fuel or oil?

If oil then you probably need to replace the valve seals for that cylinder.

If fuel then you need to determine why that plug is not firing (or firing on time) to burn off that fuel.
 

·
Registered
Joined
·
20 Posts
Discussion Starter · #23 ·
I'm pretty sure is oil, (although there was gas on it because it wasn't burning it) I ran a compression test a few times and got 150 on all cylinders, except #2, it got 175 first time and 160 second time, so its probably valve related. I'm not too concerned about it right now as I have a rebuilt engine to put in (when I rebuild it XD) so the current engine only has to last a few more months.

The only reason I brought up the bogging down issue is because its a PITA to have to wait ~15 minutes to be able to go anywhere, not to mention I'm only getting 5 mpg...
 

·
Super Moderator
Joined
·
11,132 Posts
Leaking injector on 2. Will cause all kinds of problems. Make sure your fuel pressure regulator is working.
 

·
Registered
Joined
·
20 Posts
Discussion Starter · #25 ·
You are absolutely right, I swapped the fuel rail and all the injectors, and it fixed the problem with #2. Also, they must have given me an ICM for the wrong year, I swapped it outand it starts and runs perfectly now, the thing probably runs better then it has in a year and a half! anyway, thanks for the help.
 

·
Registered
Joined
·
20 Posts
Discussion Starter · #29 ·
having a problem with my headlights now though, often times they will simply be super dim, and overtime (sometimes) get brighter, however recently they have started to flash on and off (dash/interior lights unaffected) so I was wondering where the headlights themselves grounded to? I think it could be a bad ground causing these issues
 

·
Registered
Joined
·
1,257 Posts
Well one thing is check the connectors, I had a similar problem, the running light bulbs stayed super dull, pulled the connector and swapped with a spare and it lit them all right up! They all have the same ground point from what I figured out and they kinda act like Christmas tree lights if a certain connector goes bad

If not that, look under the ecm and there should be a cluster of grounds on the fender well.. that was my ground point in my 01
 

·
Registered
Joined
·
2 Posts
I am having an odd problem with my 89 XJ, it was running fine but got very bad gas mileage (roughly 250k a tank) but about a year later it started doing weird things, such as bogging down to the point where you cant even accelerate and would just backfire out the intake (restart was a temp fix but replacing the ignition control module seemed to fix it) then a few weeks later, I started it up, and it ran like crap, less power then if it was running on 4 cylinders, and was really rough, and shook the whole vehicle quite a bit, but it still ran...
it was a few weeks later that it stalled after it shook more then usual, went to restart it, but it wouldn't start, it really was trying to, as it sputtered/sorta ran, but it would not actually start. The day after is when I bought a second XJ (1990) for parts, I suspected that it had something to do with the timing, so I swapped the whole distributor over and set the engine to TDC and made it so the distributor rested at 5 o'clock, (Ok yes, I messed it up and didn't put it in on the compression cycle (180 off I guess), which blew my muffler to bits after excessive cranking, fixed it and it ran) I swapped over a few other sensors afterwards (just because I knew they worked and mine were questionable, cps, iac, ait, tps, fuel sending unit) however there was so little power that I had to floor it to get it to move out of the driveway, took it around the block and it stalled 3 or 4 times, the last time is when it died, I have been unable to get it to start since, its getting 150-175 compression on all cylinders, its getting spark, good fuel pressure, injectors are pulsing properly, its getting air, the valves are moving properly and the seals looked good, the timing chain is strong and is lined up properly, yet it will not start. the wire harness seems OK, I couldn't find any broken wires, and I refreshed the grounds, so its not that, it really makes no sense whatsoever.

If anyone could shed some light on this, that would be amazing, replacing parts will not be a problem as I have the parts jeep, hell I even plan on replacing the engine and harness after I rebuild it, but that wont be till the fall, so I need this to work till then.
Thanks.
check the
02
sensors and connectors. they can cause many of the symptoms you've described.
 
21 - 32 of 32 Posts
Top