2 back-fires at the end of a long trip
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BruceHislop
Sep 14, 2024, 7:44:11 AM9/14/24
to GMC Motorhome EFI Group
Ex Howell system with Rochester TBI, EBL, ESC
So we were coming back from a rally last weekend and the engine had 2 small back-fires (More like a muted "POP") in the last 3 miles before home.
The trip was about 4.5hrs at about 105kms/hr (about 65mph, the speed trucks are limited to in Ontario Canada). We had a decent headwind the whole way so I was pushing the gas pedal more than normal.
After a stop for gas just over an hour from home, we exited the freeway and had to stop for a set of traffic lights at the interchange. When I got the green and started to accelerate, I got a "POP" just as I hit maybe 10mph. I heard another one about a mile up the road while coasting along about 35mph (I believe). The engine then ran fine for the final 2 miles to home at about 55mph. It was an engine misfire event and sounded like it happened in the driver's side exhaust manifold.
The engine has been running fine otherwise without any such issues for several years.
So I'm wondering if I should be doing some preventive maintenance before the next trip. Maybe new plugs and fuel filters? I carry a known good ESC distributor module. I also run dual fuel pumps with a filter before each pump, so if a filter plugs or pump fails, I can switch to the other.
Or maybe it was something to do with the long run at high speed and the headwind and it was just a fluke thing...
What say yea?
So we were coming back from a rally last weekend and the engine had 2 small back-fires (More like a muted "POP") in the last 3 miles before home.
The trip was about 4.5hrs at about 105kms/hr (about 65mph, the speed trucks are limited to in Ontario Canada). We had a decent headwind the whole way so I was pushing the gas pedal more than normal.
After a stop for gas just over an hour from home, we exited the freeway and had to stop for a set of traffic lights at the interchange. When I got the green and started to accelerate, I got a "POP" just as I hit maybe 10mph. I heard another one about a mile up the road while coasting along about 35mph (I believe). The engine then ran fine for the final 2 miles to home at about 55mph. It was an engine misfire event and sounded like it happened in the driver's side exhaust manifold.
The engine has been running fine otherwise without any such issues for several years.
So I'm wondering if I should be doing some preventive maintenance before the next trip. Maybe new plugs and fuel filters? I carry a known good ESC distributor module. I also run dual fuel pumps with a filter before each pump, so if a filter plugs or pump fails, I can switch to the other.
Or maybe it was something to do with the long run at high speed and the headwind and it was just a fluke thing...
What say yea?
-- Bruce Hislop
Jon Roche
Sep 14, 2024, 7:57:58 AM9/14/24
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I would say that is a hard diagnosis without a log file.
How long have the filters been in?? Kinda same thing as anything else. Make sure fuel filters are clean, and diagnose from there.
On Sep 14, 2024, at 6:44 AM, BruceHislop <bhis...@gmail.com> wrote:
Ex Howell system with Rochester TBI, EBL, ESC
-- Bruce Hislop--
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BruceHislop
Sep 14, 2024, 8:11:03 AM9/14/24
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I was considering hooking up the laptop before
the trip home... but we had our 100lb "pup" with us. He's like a
bull in a china shop so I elected to keep the laptop safely
stored.
Yes, its been a since I installed the dual pumps in 2019. Also, the gas station we fueled a was a new station likely in the last year (name brand station). Could have been some trash in the underground tank from manufacture.
Yes, its been a since I installed the dual pumps in 2019. Also, the gas station we fueled a was a new station likely in the last year (name brand station). Could have been some trash in the underground tank from manufacture.
Bruce Hislop
To view this discussion on the web visit https://groups.google.com/d/msgid/gmcmh-efi/247BFF3D-93DE-4C04-A062-242DB76E61BA%40gmail.com.
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