Engine Trouble 2006 W-22 8.1

[Painter3066]

Left for Florida last night and about a hour into the trip engine started to backfire and hesitated while going up hills. Ran fine on flat road going back home but engine missed a lot. Coach is 10 years old and I never have changed spark plugs or wires. I have 43000 miles on it any thoughts?

[enblethen]

When my fuel filter starts to get plugged, the engine will cough through the TBI unit when under heavy load. Not much is noticed on flat or mild climbs.
Doesn't take much water or debris in fuel to plug filter.
Not sure on later models, but is the fuel filter in the correct direction for flow?

[allbrandauto]

if check engine light is blinking you have a misfire if you know someone that has a scanner you can read code and go into data and see witch one it is

[Gjac]

We are all guessing and I also would suspect the wires. Before I replaced anything I would start the engine with the dog house off at night and see if there are any sparks from the wires to ground. If so you know the wires are bad due to heat. When this happened to me I replaced them with 10.4 mm hi temp Taylor wires that are coming up to 9 years old. The std wires are 8 mm. Try this at night and report your findings, it won't cost you anything and it will help narrow down your problem. Do you see any engine codes when the backfiring occurs?

[Gale_Hawkins]

donfrump wrote:

Gale Hawkins wrote:

donfrump wrote:

Gale Hawkins wrote:
This happened twice with our 1992 454 TBI engine. First time it was the pick up coil under the distributer. Second time it was the fuel filter. Symptoms were identical both times. I do expect your much newer engine has the old style distributer.

The prior owner had the #7 or #8 spark wire fail.

there is no distributer and OP said fuel filter is new but that aside plugged fuel filter wont cause a engine misfire(backfire) underload or miss driving along flat road.But a bad injecter will misfire under load and miss like a bad plug or plug wire

Don you are correct about the injector but wrong about the fuel filter based on my personal experience.

ok no problem.I believe you no problem BUT I worked as a mechanic for 40 years and never saw a pluged FI filter that caused a engine misfire under load and a steady miss while on the flat ground
my experience with plugged FI filter would be dieing out on hard up hill throttle or surging if not forcing it(load) too hard like a bad fuel pump also does
anythings possible just something I don't remember ever happening on the ones I have worked on

Don I have only seen this fuel filter thing happen on our MH. If I remember correctly the 8.1 can generate more doghouse heat build up so the plug wires are a logical point to check. I

[ArchHoagland]

Had the exact same problem on my 2004 8.1. You need new Plugs and wires.

While you are at it have the MAF (Mass Air Flow) sensor cleaned and your air filter changed. Otherwise you will start to get P0151 and P0155 check engine light codes.

Do not change the O2 sensors if you get those codes until you have cleaned the MAF. I've been through that procedure...believe me.

[donfrump]

Gale Hawkins wrote:

donfrump wrote:

Gale Hawkins wrote:
This happened twice with our 1992 454 TBI engine. First time it was the pick up coil under the distributer. Second time it was the fuel filter. Symptoms were identical both times. I do expect your much newer engine has the old style distributer.

The prior owner had the #7 or #8 spark wire fail.

there is no distributer and OP said fuel filter is new but that aside plugged fuel filter wont cause a engine misfire(backfire) underload or miss driving along flat road.But a bad injecter will misfire under load and miss like a bad plug or plug wire

Don you are correct about the injector but wrong about the fuel filter based on my personal experience.

ok no problem.I believe you no problem BUT I worked as a mechanic for 40 years and never saw a pluged FI filter that caused a engine misfire under load and a steady miss while on the flat ground
my experience with plugged FI filter would be dieing out on hard up hill throttle or surging if not forcing it(load) too hard like a bad fuel pump also does
anythings possible just something I don't remember ever happening on the ones I have worked on

[Gale_Hawkins]

donfrump wrote:

Gale Hawkins wrote:
This happened twice with our 1992 454 TBI engine. First time it was the pick up coil under the distributer. Second time it was the fuel filter. Symptoms were identical both times. I do expect your much newer engine has the old style distributer.

The prior owner had the #7 or #8 spark wire fail.

there is no distributer and OP said fuel filter is new but that aside plugged fuel filter wont cause a engine misfire(backfire) underload or miss driving along flat road.But a bad injecter will misfire under load and miss like a bad plug or plug wire

Don you are correct about the injector but wrong about the fuel filter based on my personal experience.

[donfrump]

Gale Hawkins wrote:
This happened twice with our 1992 454 TBI engine. First time it was the pick up coil under the distributer. Second time it was the fuel filter. Symptoms were identical both times. I do expect your much newer engine has the old style distributer.

The prior owner had the #7 or #8 spark wire fail.

there is no distributer and OP said fuel filter is new but that aside plugged fuel filter wont cause a engine misfire(backfire) underload or miss driving along flat road.But a bad injecter will misfire under load and miss like a bad plug or plug wire

[Gale_Hawkins]

This happened twice with our 1992 454 TBI engine. First time it was the pick up coil under the distributer. Second time it was the fuel filter. Symptoms were identical both times. I do expect your much newer engine has the old style distributer.

The prior owner had the #7 or #8 spark wire fail.

[Bird_Freak]

Don't waste your money on the stock wires. Check Summit Racing for a set of high performance Taylor Wires. Install and forget about them for a long time. I went thru several stock plug wires before doing this and never had a problem after that. 04 8.1.

[PF_PM]

If it was wet on the road it may have been the intake system causing hesitation. If it was dry I'd say it was the plug wires. There was a replacement kit allowing for wires that were more heat tolerant.

[Southwind98]

rgatijnet1 wrote:
and it could also be water that was ingested in to the air intake and has soaked the air cleaner paper element. Did you drive in the rain?

Painter3066 wrote:
Left for Florida last night and about a hour into the trip engine started to backfire and hesitated while going up hills. Ran fine on flat road going back home but engine missed a lot.

The symptoms you described were exactly like the ones my RV experience on a trip in heavy rain and it turned out as rgatijnet1 stated. Water had went in air tuba, which faced forward, causing the air filter to collapse, starving engine of air. Replaced air filter and solution to prevent in future was to cut air tuba, spin backwards, and clamp. There are several post on the site about this problem, just something to check and cross off your diagnostic list. Of course if you haven't driven in rain recently, disregard. Good luck

[enblethen]

I have found that the high tension lead on my toads have a metal screw that rusts, not allowing for spark to get to the plug.
I have used Dremel wire brush head to clean them. I then use de-oxidation compound to keep they clean.

[donfrump]

Painter3066 wrote:
Thanks for the replies will take it in next week for plugs and wires. The fuel filter was recently changed.

rockauto.com plug wire kit with heat shields $43.00
like I also mentioned a bad injecter will cause the misfire on hills and engine miss on the flat runs!!!