Last post on Jul 09, 2013 at 7:15 AM
You are in the Isuzu Trooper
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Isuzu Trooper, SUV
#11291 of 11966 Re: 1998 Trooper failed smog, what to do? [wzhao68]
Jun 22, 2006 (4:35 am)
Hi, I looked and found only one technical service bulletin on converter failure. If you have an aftermarket alarm system, it may apply.Otherwise, it may help to check for any trouble codes that may have been set. Some codes remain in the ecm even after the check engine or malfunction indicator light up and then turn off. If none, then I hope this info helps you decide what to do. good luck
1998 Isuzu Truck Trooper LS V6-3.5L
Vehicle Level Powertrain Management Emission Control Systems Catalytic Converter Technical Service Bulletins All Technical Service Bulletins Emissions - Misfire DTC's/Catalytic Converter Damage
Emissions - Misfire DTC's/Catalytic Converter Damage
Misfire DTCs and Catalytic Converter Damage Due to Installation of Alarm Systems
Issue Date: February 2004
2003 - 2004 and prior Isuzu models.
It has been determined that aftermarket alarm systems incorrectly installed in vehicles have the potential to cause misfire codes and damage the catalytic converter.
These alarm systems use a circuit interrupt which utilize the ignition circuit on the vehicle, they also utilize mechanical relays and normal vehicle movement can trigger these relays to engage and disengage the ignition circuit while the vehicle is in motion. These disruptions of the ignition circuit, which occur in milliseconds, may cause more fuel to be commanded. Over time, on and off fuel dumping can cause misfire codes and ultimately damage the converter assembly.
Engineering could not identify any alarms that utilize solid-state circuitry that would eliminate this concern. Because of this, it has been determined that all alarm systems must be routed through the starter circuit in order to avoid this condition.
Dealers must be aware of this issue and take note of the wiring on vehicles with alarm systems that come in for repair, particularly for catalytic converter damage that seem to have no known root cause.
#11292 of 11966 Re: Washer fluid would not work on windshield [atfdmike]
Jun 22, 2006 (4:42 am)
Thanks for the suggestion, I will try to investigate this weekend and ley you know how it turn out.
#11293 of 11966 EGR replace, ECM reset
Jun 25, 2006 (3:38 am)
Hi All, great board. 1997 Trooper LTD, 137K. You've already helped with my first CEL for the EGR system. Initially pulled and cleaned, helped for awhile, but came back with a vengence of stalling when stopped. Yes, I checked and cleaned the tube, although it wasn't bad. Also learned to check and clean the air intake butterfly, quite skunked. Finally dropped the $135 at Autozone for a new EGR valve, pulled the ECM fuse, and off I went yesterday. Ran fine, but now the idle intermittently fluctuates, sometimes up to 2000 on start, and doesn't always drop when coming to a stop, causing the tranny to thump. About to go down and reconnect the battery from an overnight reset with hopes of a smoother day. Other issue of concern is a fluctuating voltage guage from 12 to 16, since I bought it last Sept. Local shop checked, noted proper charging, but I did opt to replace an old battery. Do these have voltage issues and would it cause a problem with the ECM ? Thanks for the help.
#11294 of 11966 Re: EGR replace, ECM reset [nytrooper]
Jun 25, 2006 (11:06 am)
Overnight reset of the ECM didn't seem help, possibly made it worse. Started and stalled several times, then ran OK, but the fluctuating idle continues, even had another CEL pop up, need to check it ASAP. How can I manually read the codes without a tester ? Praying it's not a gasket issue, runs smooth and strong, good mileage 15/19, burns about a quart every 2K, morning start up shows noticeable water vapor, later on faint white/gray smoke with foul smelling exhaust.
#11295 of 11966 Re: Trooper back [paisan]
Jun 25, 2006 (4:32 pm)
Where in Albany did you go ? Otto was a dealer, but now only German Auto Haus handles dealer service.
#11296 of 11966 Re: EGR replace, ECM reset [nytrooper]
Jun 26, 2006 (8:05 am)
Hi, I checked my manuals, and it appears that it is not possible to check your codes without a scan tool. It is a good thing if you are at least getting a CEL, as that gives you somewhere to start looking. Many auto parts stores now will read your codes for you at no charge. They will probably suggest replacing parts too, but you should first determine that there is not something else wrong before going into buying parts, especially expensive ones, until you have ruled out other causes.
I would also suggest that you do not rely on the voltage guage for checking the condition of your system. A Digital multimeter will give you precise and accurate readings. A common Isuzu service recommendation is to check harnesses and connectors for conductivity (ie: clean with contact cleaner and make sure wires and connectors are all intact. Maybe with some more info from the codes you will get more help. Good luck.
#11297 of 11966 Re: EGR replace, ECM reset [atfdmike]
Jun 26, 2006 (1:34 pm)
Thanks for the info. Just back from a 300 mile loop, no more CELs, just the idle wants to run as high as 2000 before settling down, seems to be the only issue. Switched to full syn oil and high octane, she runs strong and quietly, with almost 20mpg today. Did order an 02 sensor, $20 on ebay, to complete the EGR system overhaul. If that doesn't fix it, with another ECU reset, I'll let someone run a full diagnostic before moving on to a MAP sensor, etc.
#11298 of 11966 Re: EGR replace, ECM reset [nytrooper]
Jun 27, 2006 (12:58 pm)
Idle continues to fluctuate, and even stalled at an intersection, quite frustrating. No CEL. Brought her to my local shop, no codes, we cleaned the AIC, which certainly needed it, and replaced the PCV, pulled the ECU fuse. Overall seems to be better than ever, except for the idle issue ! Scheduled a visit to a dealer on Thursday to try and resolve once and for all. Might pull the battery connection again tonight and see if a short road trip tomorrow will help.
#11299 of 11966 Re: EGR replace, ECM reset [nytrooper]
Jun 28, 2006 (10:24 am)
140 miles, the issue seems corrected, shhhhh. Won't know if it was the AIC or PCV, but for $8, I don't really care ! Horsepower has definitely improved, I'll get back with with mileage next week.
#11300 of 11966 Re: EGR replace, ECM reset [nytrooper]
Jun 28, 2006 (6:53 pm)
Hey there, I'm a very discouraged 2001 trooper owner at the moment. It seems that we share the same problem. Has your reduced power light come on during any of this...? Mine will intermitenly come on with the Check engine light. This problem is killing me!!! She runs great and then that stuff. The light will come on (CEL)and then run great and then the light back on and is still running great. I have gone through some catalytic converters too. What did you last change to get these results today? help...