Randomly dying 99 TJ

[TSteve-O]

Howdy all,
Just a quick thread here, need some help diagnosing possible issues with my 99 tj.
Dies intermittently when driving/rolling, most often at complete random on idle. It then takes sometimes a minute or up to about 10 to want to restart. Real pain out on the road specifically.
I've changed out many many things already, including having wiring harness rechecked/repaired, replaced cps, got with wranglerfix about new ecu and replaced, new fuel pump, checked for loose grounds every which way, checked terminals on battery nothing seems amiss, not really sure what to look at now, but I've been determined to figure this sumB out.
Any help appreciated lads!

 

[macleanflood]

What's your fuel pressure at? Get a gauge you can stick out the side of the hood so you can watch the pressure through your troubles.

-Mac

 

[TSteve-O]

What's your fuel pressure at? Get a gauge you can stick out the side of the hood so you can watch the pressure through your troubles.

-Mac

Noted, I'll look into getting a gauge for that. I also believe it could be fuel related at this point

 

[TSteve-O]

If

What's your fuel pressure at? Get a gauge you can stick out the side of the hood so you can watch the pressure through your troubles.

-Mac

You've got any other good suggestions im all ears though, this has been a longtime issue and im just ready to get it resolved. There isn't anywhere really to take this thing shops-wise here in japan either up where im at.

 

[macleanflood]

If


You've got any other good suggestions im all ears though, this has been a longtime issue and im just ready to get it resolved. There isn't anywhere really to take this thing shops-wise here in japan either up where im at.

Monitoring live ODB data can really help. A simple Bluetooth ODB dongle and the free Torque Lite app will let you monitor data. Look at long and short term fuel trims, O2 voltages and timing. Unfortunately none of the TJs have a PID for fuel pressure...hence the need for an external gauge.

-Mac

 

[TSteve-O]

Monitoring live ODB data can really help. A simple Bluetooth ODB dongle and the free Torque Lite app will let you monitor data. Look at long and short term fuel trims, O2 voltages and timing. Unfortunately none of the TJs have a PID for fuel pressure...hence the need for an external gauge.

-Mac

Ah true true. Will do then, much obliged mac.

 

[GregBelleville]

I've had an intermittent issue like this with my 99 that I narrowed down to the connector at the ignition coil that goes to the main wiring harness.

 

[TSteve-O]

I've had an intermittent issue like this with my 99 that I narrowed down to the connector at the ignition coil that goes to the main wiring harness.

I'll check that. Just the connection to the coil pack? Or all the way back to the wiring harness?

 

[CharlesHS]

Many years ago I had a intermittent problem similar to yours on my '98 XJ.
Found that the coil pack would lose power caused by chafed insulation on lead touching ground.
The chafe in the wiring was out of direct sight (underneath) and was easily missed.
When your problem occurs have someone crank the engine while testing the coil leads for 12V power.
Inspect the wiring going to the coil looking for chafes or damaged wiring.

 

[TSteve-O]

W

Many years ago I had a intermittent problem similar to yours on my '98 XJ.
Found that the coil pack would lose power caused by chafed insulation on lead touching ground.
The chafe in the wiring was out of direct sight (underneath) and was easily missed.
When your problem occurs have someone crank the engine while testing the coil leads for 12V power.
Inspect the wiring going to the coil looking for chafes or damaged wiring.

Will do, im gonna a check my camshaft sensor in my distributor too, as most other common culprits are out of the way, and im waiting for other parts anyway. I've definitely got a feeling if it isn't fuel delivery its some connection somewhere.

 

[TSteve-O]

Another thing worth noting, is holding breaks at stop while applying gas to be around 1k rpms seems to keep it from dying mostly.

Howdy all,
Just a quick thread here, need some help diagnosing possible issues with my 99 tj.
Dies intermittently when driving/rolling, most often at complete random on idle. It then takes sometimes a minute or up to about 10 to want to restart. Real pain out on the road specifically.
I've changed out many many things already, including having wiring harness rechecked/repaired, replaced cps, got with wranglerfix about new ecu and replaced, new fuel pump, checked for loose grounds every which way, checked terminals on battery nothing seems amiss, not really sure what to look at now, but I've been determined to figure this sumB out.
Any help appreciated lads!

 

[MBDIAGMAN]

Chasing an intermittent problem can either drive you to start drinking or if you already do, cause you to drink even more.

Is there any pattern at all that could tie it to a circumstance, like not long after refueling, happening when you turn a corner or slow down or stop,……..??

 

[TSteve-O]

Chasing an intermittent problem can either drive you to start drinking or if you already do, cause you to drink even more.

Is there any pattern at all that could tie it to a circumstance, like not long after refueling, happening when you turn a corner or slow down or stop,……..??

It tries to die at any time at random, keeping gas on it seems to keep it from dying, but foot off gas definitely let's it die, there has been a few times driving that keeping gas on it has not stopped it though.. it seems fuel related to me so I replaced my fuel pump. Nothin. Might try fuel relay and a gauge for fuel pressure right now. I've been in the rabbithole. There just isn't any rhyme or reason to point to anything specifically in that sense. But if changing fuel related parts doesn't fix I've already replaced many other parts and will have to likely look at the connectors all over. But definitely a slow speed or idle issue.

 

[macleanflood]

Might also want to pull the plugs from the PCM behind the battery and check for corrosion.

Wiring issues most certainly can be your issue.

But I'd eliminate fuel pressure before you go delooming the entire engine harness. =)

-Mac

 

[TSteve-O]

I

It tries to die at any time at random, keeping gas on it seems to keep it from dying, but foot off gas definitely let's it die, there has been a few times driving that keeping gas on it has not stopped it though.. it seems fuel related to me so I replaced my fuel pump. Nothin. Might try fuel relay and a gauge for fuel pressure right now. I've been in the rabbithole. There just isn't any rhyme or reason to point to anything specifically in that sense. But if changing fuel related parts doesn't fix I've already replaced many other parts and will have to likely look at the connectors all over. But definitely a slow speed or idle issue.

Have also read issues of vapor lock. It does get quite hot here. But I had this issue when it was still pretty chilly so not sure.

 

[macleanflood]

Also try this...

Thread 'How to clean your IAC (Idle Air Controller) valve'

Jan 2, 2016

If you're experiencing idle issues on your Jeep Wrangler TJ the most likely culprit (and the first thing you should check) is your IAC (Idle Air Controller). Often times the IAC gets very gunked up causing the Jeep to idle improperly. A simple cleaning is usually all it takes to get it running as good as new.

If you end up needing to replace your IAC valve (they do fail on occasion), you can find the part numbers (and the links to purchase them on Amazon) below:

2005-2006 IAC Valve (Part # 4861552AC)
1997-2004 IAC Valve (Part # 4874373AB)

There is no need at all...

• Chris
• iac idle idle air controller idle valve
• Replies: 191
• Forum: TJ How-to Guides

• 

-Mac

 

[TSteve-O]

Might also want to pull the plugs from the PCM behind the battery and check for corrosion.

Wiring issues most certainly can be your issue.

But I'd eliminate fuel pressure before you go delooming the entire engine harness. =)

-Mac

Definitely attacked that maybe sooner than I SHOULD have, that doesn't seem amiss. New pcm n all.

 

[TSteve-O]

For

Also try this...

Thread 'How to clean your IAC (Idle Air Controller) valve'

Jan 2, 2016

If you're experiencing idle issues on your Jeep Wrangler TJ the most likely culprit (and the first thing you should check) is your IAC (Idle Air Controller). Often times the IAC gets very gunked up causing the Jeep to idle improperly. A simple cleaning is usually all it takes to get it running as good as new.

If you end up needing to replace your IAC valve (they do fail on occasion), you can find the part numbers (and the links to purchase them on Amazon) below:

2005-2006 IAC Valve (Part # 4861552AC)
1997-2004 IAC Valve (Part # 4874373AB)

There is no need at all...

• Chris
• iac idle idle air controller idle valve
• Replies: 191
• Forum: TJ How-to Guides

• 

-Mac

that it doesn't idle badly, but maybe dying randomly is a symptom as well. I've got a new iac on order wither way

 

[macleanflood]

[QUOTE="TSteve-O, post: 1772459, I've got a new iac on order wither way
[/QUOTE]

Right but if the passage in the throttle body is dirty or clogged...

Have you checked for vacuum leaks? Maybe a smoke test?

-Mac

 

[TSteve-O]

I

634105[/ATTACH]

-Mac

I can do a smoke test. None of my vac lines seem to be leaking though. Checked those.