Propane Gas Backfire

2000 TOYOTA AVALON

180,000 MILES • 3.0L • V6 • 2WD • AUTOMATIC

ALEXMESSINA

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Hi, I am trying to diagnose cause of an Propane/LPG inlet manifold backfire under load, usually when accelerating hard in top gear, does not seem to backfire when accelerating hard in a lower gear.
Any guidance/advice welcome.

Nov 27, 2016 at 2:56 AM

KASEKENNY

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This normally does not have anything to do with the fact that this is an LPG vehicle unless you have a leak in the intake and this gas is igniting in the intake.

However, the fact that you only have this at higher gears means we have a lighter load on the engine, I suspect this is just a poor ignition issue or possibly timing issue.

Here is a video that will get us started.

https://youtu.be/HiI_eeFg-2A

I am attaching the info below on how to change the timing belt. If it were me and you have not changed the belt, then it is past due, and I would suggest doing this and setting the timing correctly.

Please run through this and let us know what you find. Thanks

Images (Click to enlarge)

Oct 18, 2021 at 3:23 PM