Extreme Terrain
4x4Wire Trail Talk Forums: Jeep, Toyota, Mitsubishi, Pajero, Isuzu, Kia, 4WD, 4x4, SUV, Off-Road and OutdoorWire Forums


Search

Recent Posts on TrailTalk
Gen 1 Trailer Hitch and Owners Manuals
by Mudraider - 06/17/22 04:50 PM
Gen 2 UCA extended upper ball joints?
by Mudraider - 06/15/22 07:00 PM
suzi the psychic
by rascott - 06/14/22 01:47 AM
Blown Head Gasket - could use advice
by Snowtoy - 05/30/22 06:11 AM
Support 4x4Wire
New Topics on TrailTalk
Gen 1 Trailer Hitch and Owners Manuals
by Kookster97 - 06/17/22 12:37 AM
Gen 2 UCA extended upper ball joints?
by Colombia - 05/24/22 03:28 AM
Blown Head Gasket - could use advice
by Runner-Man - 05/23/22 01:58 AM
suzi the psychic
by - 03/26/10 06:59 AM
4x4 Gallery
Photos of rig
Attila
99 Monterrible Sport
Scar the Cylon Raider
Mercenary Sergeant: Code Name "Sapphire"
More News on the 'Wire

4x4Voice
4x4Wire
MUIRNet-News
OutdoorWire
Who's Online Now
0 registered members (), 75 guests, and 5 spiders.
Key: Admin, Global Mod, Mod
Forum Statistics
Forums37
Topics138,275
Posts1,081,743
Members15,265
Most Online907
Dec 28th, 2019
Previous Thread
Next Thread
Print Thread
Rate Thread
Page 2 of 3 1 2 3
Re: ISC removal? [Re: FrankR] #620801 07/02/05 02:36 AM
Anonymous
Unregistered
No it won't stay running if I use the throttle either. I replaced the fuel filter at the start of the trouble shoot. I have also checked the fuel system operation and done several other system checks. The TPS seems to be O.K. with 5.5 res. If I hold the contacts closed in the control relay it will run forever. I have tested the control relay and also tried another one the same results. Thank you for the input and would appreciate any help I can get.

Re: ISC removal? #620802 07/02/05 03:05 AM
Joined: Feb 2004
Posts: 10,238
FrankR Offline
Web Wheeler
****
That's weird - I guess you can add fuel pump and fuel pressure regulator to the list of suspects.

Do you know what ECU number you have? - Never mind - I see you have a '91. I have a good spare 6477 for an '89 I was going to suggest sending to you to swap in and see if it would run, but it's different from the '90s and '91s.

Check all of the wires and harness connectors around the distributor and coil - maybe spray inside the connectors with some electrical contact cleaner (RadioShack) just to make sure they're ok. Have you checked the coil resistance? Primary resistance should be 0.72-0.88 ohms. Secondary resistance should be 14.5K-19.5K ohms.

When were your wires replaced? Check the coil wire resistance?

Check the mounting bolts/nuts where the upper plenum attaches to the lower intake. Don't over-tighten in the aluminum, but snug 'em to 14 ft.lbs to make certain you don't have an air leak there.

Still thinkin' - this one's a head scratcher (as you've found out).

Frank


'89 [color:"white"]G-Raider[color:"white"] [color:"black"]Supercharged 3.0L, MegaSquirt 2, lockup A/T, 2.5" exhaust, 172k, Cibie H4s/Oscar SCs, Hella Micro DE fogs, Cobra CB, Superwinch hubs, LSD rear/Aussie Locker front, Bilsteins, Lifeline AGM, Rust-Oleum
Re: ISC removal? [Re: FrankR] #620803 07/02/05 04:21 AM
Anonymous
Unregistered
I have checked the fuel pressure and fuel pump and tried another pump. I have done some checks of the ignition system and found the coil and related parts to be fine. This problem happened all at once. No previous warnings. I have been told to check the oil pressure switch and I replaced it. They range from $10 to $70 so I tried the $10 switch. This engine was rebuilt about 2000 miles ago so oil pressure should be OK to. I'm glad that someone else is challenged by this to. Thanks

Re: ISC removal? #620804 07/02/05 05:12 AM
Joined: Feb 2004
Posts: 10,238
FrankR Offline
Web Wheeler
****
You can try turning the pintle tip of the ISC to different positions as the other poster suggested worked for him, but I haven't tried that and can't suggest a method that would work other than what he posted.

You might try disconnecting the MAF sensor (in the air filter can) and see if it makes any difference.

Your distributor is different from mine and I can't help you with yours - Conner is familiar with it and perhaps he'll chime in here - hope so as his diagnostic skills are excellent.

If you have spark, fuel and air enough to start it, it seems possible that an electrical component is breaking down as current begins to flow. If that is happening, it's gonna be tough to figure out.

I assume it continues to run for a few seconds after you release the ignition key? If it doesn't and quits as soon as you release to the "Run" position, the ignition switch might be faulty. Otherwise, I wouldn't condemn the switch. How about hooking up your voltmeter to the battery side of the coil and see if you have voltage as the engine dies?

The power transistor (black thing next to the coil) is what triggers the coil - if you want to check it, let me know.

One thing you need to check is fuel pressure, but without a gauge and fitting it's tough because there's no test port. If you have or can borrow a gauge, you'll need a tee fitting. You'll have to release the fuel pressure, remove the hose fitting at the fuel rail and insert the fitting for the gauge between the fuel supply hose and the rail - otherwise you'll have to cut the hose, use a barbed tee and repair afterward or replace the pressure hose.

I can't help wondering about the ECU. I have read that it's possible for the ISC to cause the ECU to blow and installation of another ECU without replacing the ISC promptly caused the next ECU to blow as well.

I'd be tempted to make friends with a junk yard owner and try to arrange some parts swaps unless someone else has an idea. If you can find a like truck and get the ECU, distributor, coil, ISC, TPS, MAF sensor to try - and pay for anything that works it might be a faster way to eliminate some suspects - particularly if they're breaking down with heat. I hate throwing parts at an engine, but if it can be done without spending a lot of money it might be worth trying.

Frank


'89 [color:"white"]G-Raider[color:"white"] [color:"black"]Supercharged 3.0L, MegaSquirt 2, lockup A/T, 2.5" exhaust, 172k, Cibie H4s/Oscar SCs, Hella Micro DE fogs, Cobra CB, Superwinch hubs, LSD rear/Aussie Locker front, Bilsteins, Lifeline AGM, Rust-Oleum
Re: ISC removal? [Re: FrankR] #620805 07/02/05 05:38 AM
Anonymous
Unregistered
Thanks again for the ideas. I have checked the fuel pressure.

The transistor has been checked but I would be willing to check it again if you would let me know what I need to do.

I'm sure that the coil has been through the check, I would be interested in your direction to check it again also.

I will unplug the AFS tomorrow and see if that changes anything.

The ISC was not plugged in after the ECU was replaced, so hopefully the ECU repair was correct and not just a partial.

I did try the ISC adjust w/out it plugged in and all it did is change the idle untill it died. Thanks again

Re: ISC removal? #620806 07/02/05 06:27 AM
Joined: Jan 2002
Posts: 457
IdahoJack Offline
Mudrunner
Your problem sounds similar to the one I had about a year ago. You might want to read these old posts to see if they might help:
http://tinyurl.com/a5l7r

Last edited by off-roader; 09/10/05 05:34 PM.

90 Montero, 2dr, AT, V6, LSD, AC, KYB shocks, bouncy seat, 182K miles, JDM engine, 87 Starion seats, tow hitch
http://www.geocities.com/idahojack03/Index
Re: ISC removal? #620807 07/02/05 01:40 PM
Joined: Feb 2004
Posts: 10,238
FrankR Offline
Web Wheeler
****
Quote
If I hold the contacts closed in the control relay it will run forever. I have tested the control relay and also tried another one the same results.


I missed that on the first run through. It does sound like IdahoJack's problem - the ECU isn't allowing the fuel pump to run.

Instructions for testing the power transistor are here . Other ideas as well.

Since you're able to keep it running by forcing the control relay, I suspect the ECU as Jack suggests.

Frank


'89 [color:"white"]G-Raider[color:"white"] [color:"black"]Supercharged 3.0L, MegaSquirt 2, lockup A/T, 2.5" exhaust, 172k, Cibie H4s/Oscar SCs, Hella Micro DE fogs, Cobra CB, Superwinch hubs, LSD rear/Aussie Locker front, Bilsteins, Lifeline AGM, Rust-Oleum
Re: ISC removal? [Re: FrankR] #620808 07/02/05 06:58 PM
Anonymous
Unregistered
Thanks Idahojack and Frankr. It does sound like a similar problem and a real positive looking solution. I will make tracks to have this checked next week since everything is closed for the 4th. AVPRO may get it back. The sites that were sent are helpful and saved.

Thanks to all for the direction and I will put the gas and flares away for now.

Happy 4th <img src="/forums/images/graemlins/cheers.gif" alt="" />

Re: ISC removal? #620809 07/02/05 07:43 PM
Joined: Feb 2004
Posts: 10,238
FrankR Offline
Web Wheeler
****
ECUs show up on ebay from time to time. There are a couple there now, but they're too expensive unless you absolutely have to have it now. Try this site and contact a few, but make sure the part number is the same as your own - and get a guarantee that it's a working unit:

carpart.com

I bought one as a spare and from what I've so far seen about these trucks it's probably the best spare part to keep on hand.

If this works, you owe Jack a <img src="/forums/images/graemlins/cheers.gif" alt="" />. Anybody who can find a bad transistor in an ECU gets my vote for at least a 6-pack.

Good luck,
Frank


'89 [color:"white"]G-Raider[color:"white"] [color:"black"]Supercharged 3.0L, MegaSquirt 2, lockup A/T, 2.5" exhaust, 172k, Cibie H4s/Oscar SCs, Hella Micro DE fogs, Cobra CB, Superwinch hubs, LSD rear/Aussie Locker front, Bilsteins, Lifeline AGM, Rust-Oleum
Re: ISC removal? [Re: FrankR] #620810 07/10/05 08:07 PM
Anonymous
Unregistered
Just to update. I checked the AFS and no change. I contacted AVPRO to recheck the computer again and was told he wants a certified tech to suggest this.

Page 2 of 3 1 2 3







4x4Wire Social:

| 4x4Wire on FaceBook |


OutdoorWire, 4x4Wire, JeepWire, TrailTalk, MUIRNet-News, and 4x4Voice are all trademarks and publications of OutdoorWire, Inc. and MUIRNet Consulting.
Copyright (c) 1999-2019 OutdoorWire, Inc and MUIRNet Consulting - All Rights Reserved, no part of this publication may be reproduced in any form without express written permission
You may link freely to this site, but no further use is allowed without the express written permission of the owner of this material.
All corporate trademarks are the property of their respective owners.

Powered by UBB.threads™ PHP Forum Software 7.7.3
(Release build 20190728)
PHP: 7.4.29 Page Time: 0.032s Queries: 16 (0.010s) Memory: 2.9146 MB (Peak: 3.1926 MB) Data Comp: Off Server Time: 2022-06-25 20:13:55 UTC
Valid HTML 5 and Valid CSS