L98 Engine Backfire
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Instructor
Joined: May 2011
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From: Miramar Florida
L98 Engine Backfire
After replacing two bad lifter in my engine, I got it reassembled and set the timing to 6*. When I drive or rev the engine to normal drive speed I get back firing in the engine. Is this do to the timing being off slightly. It seems to run good at idle. I have not set the idle air or TPS but I don't think either of these will effect the engine back firing. Am I on the right track?
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From: Miramar Florida
Le Mans Master
Joined: Aug 2000
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From: Australia
it is only thing that tells the computer how far throttle is open so it can adjust fuel and timing to suit
If you have foot @ 50% throttle but TPS is only showing throttle 25% open
then you will have problems
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From: Miramar Florida
I will be sure to set the TPS, first thing. However I did not seem to have any problems with where it was set prior to replacing the bad lifters.
Safety Car
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From: Glenbeulah Wi
After replacing two bad lifter in my engine, I got it reassembled and set the timing to 6*. When I drive or rev the engine to normal drive speed I get back firing in the engine. Is this do to the timing being off slightly. It seems to run good at idle. I have not set the idle air or TPS but I don't think either of these will effect the engine back firing. Am I on the right track?
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Instructor
Joined: May 2011
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From: Miramar Florida
OK, I set the minimum idle air and the TPS. I'm still getting the backfire, I double checked the timing and it was slightly off by one degree so I got set to 6*. I'm going to pull my valve covers and set lash on the valves again, hopefully this will correct the problem.
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Thread Starter
Instructor
Joined: May 2011
Posts: 213
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From: Miramar Florida
Success, I got the backfire issue resolved, I went back through and reset the lash on all the valves and that corrected the problem. Now the engine runs smooth, almost perfect. Only issue I have now is I'm still hearing a ticking noise as I drive. Now that I've replaced the lifter, I can rule that out, either way it's not quite the same sound as I heard with the bad lifters. I can hear the injectors fire when I have the hood open but I wouldn't think they would be loud enough to hear when driving. Any ideas, I'm thinking it is something external from the engine. I can only hear it when I drive.
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Instructor
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From: Miramar Florida
Another thought just remembered that when I was under the hood with the engine running I could feel pressure blowing at the EGR pipe when I revved the engine. Maybe the ticking sound is an exhaust leak. Would a leak at the EGR pipe cause the ticking noise when driving?
