Runs Rough... Suggestions?

Voyager · 06-23-2005, 03:04 AM

Here's the deal...

1990 Pioneer, 4.0 short block installed about 6-7000 miles ago.

Starts as always. Kinda rough (like it's got a bad plug) at idle. Power loss getting up to cuising speed (still feels like a bad plug). At cruising (any gear, any speed) it feels like a couple of plug wires fell off. Let off the gas, smoothes out. Repeat...
Kick it to the floor and it runs smoother but definite power loss.

So far: New distributor cap, ignition rotor, spark plugs, plug wires, fuel filter (poured rust outta that sucker).

What next? Injectors? Could it be bad gas?

Any assistance would be appreciated.

**balloo93** · 06-23-2005, 04:00 AM

I would pull the dist and check the gear and for excessive play in the shaft. How old is the ign coil?

Voyager · 06-23-2005, 09:57 AM

Other than a short block, as I said, everything else might be original. I just got this thing a few months ago.

**balloo93** · 06-23-2005, 06:05 PM

I'd be tempted to say it's the Ign coil or ign coil module. Just for kicks, do a compression test to make sure the mech staggered the rimgs on the pistons.

Next, get a fuel pressure gauge capable of at least 40psi and check the sharder on the fuel rail.

Next get a cheapy inline spark plug tester and make sure you're getting spark on all the wires.

Voyager · 06-24-2005, 07:56 AM

I'm getting spark enough on all the wires to make me go, "Whoa!!!" I know that's not the best way to check, but it's what I know.

The mech on the short block was my uncle and he did all the compression stuff while he had it.

I'll get a fuel pressure guage and check that, but first I'm gonna pull the new fuel filter and see if there's anything nasty spilling out of it. I've got this feeling I got bad gas and it's either full of junk or destabilized. I know that destabilized gas plays hell on motorcycles, especially the plugs, but those are more sensitive than auto engines.

Nothing coming from that, I'll pull the wires from the injectors to see if there's anything there, then I'll start investing in coil parts.

Part of it is the time and money, but mostly this lil problem is driving me nuts. It's become personal!

Remind me when this is all over and I'll tell you about the Honda Magna and the carb screw. LOL

Voyager · 06-25-2005, 10:03 AM

I have a better idea what's going on now. There's apparently a bad wire somewhere. I rechecked the rotor cap, started it up... and smoke started rolling everywhere under the hood. Burned a whole bunch of wires before I got the battery cables off. Gonna have to tow it to the mechanic to get wires replaced and track down the original bad one. Something hot is hitting metal somewhere.

Voyager · 06-25-2005, 10:05 AM

Did I mention "THIS SUCKS!!!"

GenericEclipse · 06-25-2005, 10:21 AM

holy sh*t. thats no good. good luck man!

Voyager · 07-07-2005, 09:42 AM

Found out the burning wire had nothing to do with it running rough. Talked with the mechanic yesterday and it seems the lifters are shot, and so is my bank account. All the cash I was saving for my vacation this month will go to getting the Jeep back on the road.

Oh, well.

Did I mention, This sucks?"

**XJH-007** · 07-07-2005, 09:52 AM

Quote:

Originally Posted by Voyager

Found out the burning wire had nothing to do with it running rough. Talked with the mechanic yesterday and it seems the lifters are shot, and so is my bank account. All the cash I was saving for my vacation this month will go to getting the Jeep back on the road.

Oh, well.

Did I mention, This sucks?"

Dude that sucks. What kind of shade tree mechanic rebuilds a motor and doesn't throw new lifters in???? It's like $50 for ALL of them.

I'm starting to think the plugs are wired wrong or the distributor might be in upside down

Also, I'm not sure how this mechanic came to the conclusion the lifters are bad. Is it clacking real bad?? If so, do you have oil pressure??

IF you have low oil pressure with bad lifters this could be your problem...the valves aren't opening up all the way or not at all.

Note: Just because they are family doesn't mean they know what they are doing.

Voyager · 07-08-2005, 07:10 AM

I know my uncle knows what he's doing, just don't know if he did it. Dude's like, 70 years old.
As for how the mech knows it's lifters... I don't know. He's a friend and known to be one of the best in the area, and he's got so much business already I know he's not out to just get my money. He's turned me away before with a diagnosis and let me do it myself for nothing.
As for clacking, there was engine noise, but not something that made me wince driving down the road.

**XJH-007** · 07-08-2005, 10:33 AM

Right on man, well good luck.

...............I got nuthin.........................

Voyager · 07-15-2005, 02:27 PM

Just got the XJ back from the mechanic yesterday.

The lifters were bad, he found out, because the camshaft was bad. I've got the old one and the lobe for cylinder #1 is worn down almost round. His guess: The short block came from AutoZone or some place like it where they reuse original parts when they sell shorts.

There went all the cash I had earmarked for my vacation this week, so it'll be a while before I can add any accessories or playpretties to the Jeep. Guess I'll have to check around all the junk I have lying around here and see if I can make something out of nothing. Maybe a cheap light bar to start with. I've got an extra rack I picked up when I made my spare tire carrier out of the original.

06-25-2005, 10:21 AM	#8
GenericEclipse Registered User Join Date: Jun 2005 Location: Beloit, WI Posts: 87 Profile Gallery Classifieds My Jeeps	holy sht. thats no good. good luck man! __________________ [CENTER][B]1999 Cherokee Sport Black[/B] Stock 4.0L 3" 'mixed' lift. 3" skyjacker coils, JKS quicker discos, unknown shocks. AAL + blocks + factory leafs in rear. to be fixed soon*

07-08-2005, 10:33 AM	#12
XJH-007 I drank what? Join Date: Mar 2005 Location: Morrison, Colorado Posts: 4,674 Profile Gallery Classifieds My Jeeps	Right on man, well good luck. ...............I got nuthin......................... __________________ Scott-Crawlorado Native I have an addiction..... 00' XJ_T-n-T Y-Link/6" RE_OME's_33" KM2's Tera 4:1 / 4:56's_Elec. Locked D44 84' CJ7 4"BDS 33's **02 WJ Overland

06-23-2005, 09:57 AM	#3
Voyager Registered User Join Date: Apr 2005 Location: Daviess Co, KY Posts: 80 Profile Gallery Classifieds My Jeeps	Other than a short block, as I said, everything else might be original. I just got this thing a few months ago.

06-24-2005, 07:56 AM	#5
Voyager Registered User Join Date: Apr 2005 Location: Daviess Co, KY Posts: 80 Profile Gallery Classifieds My Jeeps	I'm getting spark enough on all the wires to make me go, "Whoa!!!" I know that's not the best way to check, but it's what I know. The mech on the short block was my uncle and he did all the compression stuff while he had it. I'll get a fuel pressure guage and check that, but first I'm gonna pull the new fuel filter and see if there's anything nasty spilling out of it. I've got this feeling I got bad gas and it's either full of junk or destabilized. I know that destabilized gas plays hell on motorcycles, especially the plugs, but those are more sensitive than auto engines. Nothing coming from that, I'll pull the wires from the injectors to see if there's anything there, then I'll start investing in coil parts. Part of it is the time and money, but mostly this lil problem is driving me nuts. It's become personal! Remind me when this is all over and I'll tell you about the Honda Magna and the carb screw. LOL

06-25-2005, 10:03 AM	#6
Voyager Registered User Join Date: Apr 2005 Location: Daviess Co, KY Posts: 80 Profile Gallery Classifieds My Jeeps	I have a better idea what's going on now. There's apparently a bad wire somewhere. I rechecked the rotor cap, started it up... and smoke started rolling everywhere under the hood. Burned a whole bunch of wires before I got the battery cables off. Gonna have to tow it to the mechanic to get wires replaced and track down the original bad one. Something hot is hitting metal somewhere.

06-25-2005, 10:05 AM	#7
Voyager Registered User Join Date: Apr 2005 Location: Daviess Co, KY Posts: 80 Profile Gallery Classifieds My Jeeps	Did I mention "THIS SUCKS!!!"

07-07-2005, 09:42 AM	#9
Voyager Registered User Join Date: Apr 2005 Location: Daviess Co, KY Posts: 80 Profile Gallery Classifieds My Jeeps	Found out the burning wire had nothing to do with it running rough. Talked with the mechanic yesterday and it seems the lifters are shot, and so is my bank account. All the cash I was saving for my vacation this month will go to getting the Jeep back on the road. Oh, well. Did I mention, This sucks?"

07-08-2005, 07:10 AM	#11
Voyager Registered User Join Date: Apr 2005 Location: Daviess Co, KY Posts: 80 Profile Gallery Classifieds My Jeeps	I know my uncle knows what he's doing, just don't know if he did it. Dude's like, 70 years old. As for how the mech knows it's lifters... I don't know. He's a friend and known to be one of the best in the area, and he's got so much business already I know he's not out to just get my money. He's turned me away before with a diagnosis and let me do it myself for nothing. As for clacking, there was engine noise, but not something that made me wince driving down the road.

07-15-2005, 02:27 PM	#13
Voyager Registered User Join Date: Apr 2005 Location: Daviess Co, KY Posts: 80 Profile Gallery Classifieds My Jeeps	Just got the XJ back from the mechanic yesterday. The lifters were bad, he found out, because the camshaft was bad. I've got the old one and the lobe for cylinder #1 is worn down almost round. His guess: The short block came from AutoZone or some place like it where they reuse original parts when they sell shorts. There went all the cash I had earmarked for my vacation this week, so it'll be a while before I can add any accessories or playpretties to the Jeep. Guess I'll have to check around all the junk I have lying around here and see if I can make something out of nothing. Maybe a cheap light bar to start with. I've got an extra rack I picked up when I made my spare tire carrier out of the original.