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91 LS sputtering issue

Old 07-19-18, 05:20 PM
  #31  
Michael88
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Sorry, I'm not familiar with a 91's engine layout to be of any help with this new finding, but someone will know.
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Old 07-19-18, 07:19 PM
  #32  
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So it appears to be the side coil that is causing the arc. Tracing the rubber line back it goes to the engine coolant reservoir, so my assumption is there is no electricity there. After doing some research I found quite a few diagrams on the spark plug ignition wires and I saw the one that is below the timing belt cover on the battery side.

http://www.planetsoarer.com/penski/ThePenskiFile.html

About 3/4 of the way down on the link is a diagram that shows how the wires should be laid out. The bank 1 there is a side coil with a "b" on it. That is what I am seeing that is causing the arc and causing the misfire/sputter when the vehicle is stopped while in gear. So looks like that will be my job for tomorrow. Good times.
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Old 07-20-18, 01:14 AM
  #33  
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Hey man. Thats good news. Finding the issue is the hardest part. I had some original coils with cracks in the housing that would arc from the coil body. Inspect the coil before you attack the wiring.
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Old 07-20-18, 04:48 PM
  #34  
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Well good news, I installed new spark plugs and wires and that seemed to fix the issue. I just got back from a 20 mile test drive through the city and highway and not a single issue. The electrical arc I was seeing from the side coil turned out to be the culprit. Now it is on to the belts/pulleys and brakes. Thanks everyone for help, input, and suggestions. I appreciate it.
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Old 07-20-18, 09:46 PM
  #35  
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Nice to hear,congrats.
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Old 07-21-18, 04:34 PM
  #36  
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Awesome! Be mindful not the spray water or cleaner on the engine. It can get past plug caps and cause misfires, too.
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Old 07-22-18, 04:59 AM
  #37  
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Originally Posted by 1on1 View Post
when my 91 was at normal temps with low fuel (less than half a tank), it would cause to stutter and have no power. I changed out the fuel pump and fuel filter and it worked out.
Hey guys, I have a 96 with a similar issue. Same thing - in drive, the car shakes every 10 secs or so and the idle goes up just a little and back down when that happens. I had a code 0300 and I think it's still throwing the code (I need to check it now). First I changed the coil pack which didn't do much but changing the spark plugs and a bad spark plug wire helped it to run a lot better.

It didn't completely eliminate the problem but at this point the car would only rarely shake when stopped. Also I should mention that around 40-60, when accelerating, the car would "buck" (like a stopping jerk) until I let off the gas and resumed pressing the throttle SLOWLY.

Anyway I thought fuel filter so I changed that out. NOW, it does the 40-60 bucking thing less but now it shakes more at red lights.

Is it the fuel pump? It feels like a cylinder or two just doesn't get enough gas sometimes - same with the accelerating problem.

Now I DO have one different spark plug wire. One was ripped so I replaced it. However I doubt this is the problem. What do you guys think?

Also, I think (I can't be sure... It's hard to tell) the car does drive a little better with more fuel in the tank.

Oh also, it idles around 500 but if I turn on the AC, idle jumps up to about 700 and THEN the car shakes like mad.

In neutral, no shaking. Maybe once or twice.

Now that I'm writing this out, seems like a bad fuel pump but I don't know. What do you guys think? It seems like the same problem as original poster.
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