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Power-User

Join Date: Jul 2007
Location: Montana, USA
Posts: 353
Good Answers: 6

1991 Isuzu Rodeo Won't Start

04/10/2009 12:22 AM

For several weeks my 1991 Isuzu Rodeo, 3.1, tbfi, has been lurching while driving. On some days it was not so bad, and on other days it would barely keep running enough to get me home. It eventually stalled a few times, so I decided it was time to seriously troubleshoot on the driveway, since the daily temperature has warmed up, and the garage is too full of cycles to put the vehicle inside.

A couple days ago, I used a spark indicator on the coil secondary and got good spark. I removed the coil anyway, and testing showed out-of-tolerance readings with an ohm meter, so I installed a new coil. The engine started right away, so I put it in gear to see if it still lurched while driving. It rolled about 15 feet, the engine quit, and would not start, again. Spark still looked good at the coil, so I had wifey turn engine over, while I observed injectors working normally. Then, it occurred to me that the timing chain may have skipped, since fuel was being spewed up and out of the throttle body when the engine was spun.

Anybody got any other ideas?

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Join Date: Aug 2007
Location: San Diego, SoCal
Posts: 177
Good Answers: 2
#1

Re: 1991 Isuzu Rodeo Won't Start

04/11/2009 3:04 AM

Find the timing mark on the main crank pulley. When the marks are aligned, the #1 cylinder should be at top-dead-center. Pull the #1 spark plug and use a wooden dowel to check. Put a socket on the main crank pulley bolt and go on and off the mark. The raising and lowering of the dowel should match. Of course, this will only tell you if there was a big change, only one or two teeth, you won't be able to tell the difference. Just a quick check.

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Power-User

Join Date: Dec 2006
Posts: 409
Good Answers: 5
#2

Re: 1991 Isuzu Rodeo Won't Start

04/11/2009 4:32 AM

Possibilities;bad fuel- clogged injectors-mechanical fault in cyl/s inc broken v/v spring. Do compression test.

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Anonymous Poster
#3

Re: 1991 Isuzu Rodeo Won't Start

04/11/2009 9:10 AM

It also could just be a bad ECM? I had a car with similar symptoms; it would intermittently stall and/or lurch very badly. Has the "check engine" light ever come on? Is the battery voltage and the alternator output okay? Just my $0.02... good luck!!

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Power-User

Join Date: Jul 2007
Location: Montana, USA
Posts: 353
Good Answers: 6
#4

Re: 1991 Isuzu Rodeo Won't Start

04/12/2009 9:31 PM

Okay... to those few of you who responded... thanks for the suggestions. Here's what I did to fix the problem. During the afternoon, I put an induction timing light on the #1 spark plug lead, and turned the engine, but could not see the light on the timing marks, so waited until almost dark to try again. Well, once again, the timing light was too dim to illuminate the marks. In fact the timing light would not fire at all (indicating that the voltage in the spark plug lead was too weak to fire the light), but I heard a strong spark firing in the area of the new coil and when I glanced toward the sound I saw a spark jumping from the coil-to-distributor ignition lead to ground on the top of the coil. I pulled the lead off of the distributor and found massive corrosion at the terminal that was disrupting the spark, and the insulation on the lead was bad in a couple areas. A substituted lead fixed the problem. Yeah!

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