Winnebago Brave 454 Chevy

[spritz]

How about full filters? That took us the first trip out.
Tim

[Patrol 65]

Have the distributor electronics checked. I had an 84 Chevy 454 motorhome that hesitated like it was out of gas and then started up again before starting to run rough. The diagnosis resulted in the coil needing to be replaced. The problem that I am having with the timing diagnosis is that I would assume that if the timing was bad, it will continuously backfire. Marie22 states that it would backfire and then run fine for about 5 miles before backfiring again.

[PCarillon]

Originally Posted by Patrol 65

Have the distributor electronics checked. I had an 84 Chevy 454 motorhome that hesitated like it was out of gas and then started up again before starting to run rough. The diagnosis resulted in the coil needing to be replaced. The problem that I am having with the timing diagnosis is that I would assume that if the timing was bad, it will continuously backfire. Marie22 states that it would backfire and then run fine for about 5 miles before backfiring again.

If the coil is going bad it will back fire under load and usually idle and cruise with no issues. When a motor is back firing through the intake its because a cylinder is firing before the intake valve is fully closed which lights the fuel in the intake as well as the cylinder

[PCarillon]

Originally Posted by mike brez

I thought if timed from bottom timing pointer you use #5 from the top #1
Could make sure firing order is correct.

I have been racing GM products for well over 25yrs and I have never ever heard of setting your timing on a GM vehicle using cylinder 5..... I mean EVER so who or where have you heard that from?

[MotorPro]

Originally Posted by PCarillon

I have been racing GM products for well over 25yrs and I have never ever heard of setting your timing on a GM vehicle using cylinder 5..... I mean EVER so who or where have you heard that from?

Some motor homes have a timing tag added underneath because you can't see the top of the damper. With this tag you time on number 5.

[whem2fish]

That is how you time them they have 2 tags you can not get to the top one on my Fleetwood that's why the bottom one

[BA-in-Mich]

What year are we looking at here? Carb, throttle body ?

[ga traveler]

Originally Posted by PCarillon

I have been racing GM products for well over 25yrs and I have never ever heard of setting your timing on a GM vehicle using cylinder 5..... I mean EVER so who or where have you heard that from?

I have probably done 50 of these in 15 years. All on # 5 cylinder. Reference Chevrolet Motor Home Chassis service guide. The publication guide number is ST-95-MH . Page 7-69 (this is just one of many.) note view with timing light from underside of vehicle use # 5 cyl.

[LVRVLUVR]

Originally Posted by ga traveler

I have probably done 50 of these in 15 years. All on # 5 cylinder. Reference Chevrolet Motor Home Chassis service guide. The publication guide number is ST-95-MH . Page 7-69 (this is just one of many.) note view with timing light from underside of vehicle use # 5 cyl.

correct...also what usally happens here is lean pop..
if its a throttle body.....the injector pulses off the distributor

you can see it skip when it's shoot'n ducks...(pop'n up through the carb)

you can start throw'n parts at it or have some one that knows fix it...

[mike brez]

Originally Posted by PCarillon

I have been racing GM products for well over 25yrs and I have never ever heard of setting your timing on a GM vehicle using cylinder 5..... I mean EVER so who or where have you heard that from?

I guess that about sums it up.

[PCarillon]

Originally Posted by ga traveler

I have probably done 50 of these in 15 years. All on # 5 cylinder. Reference Chevrolet Motor Home Chassis service guide. The publication guide number is ST-95-MH . Page 7-69 (this is just one of many.) note view with timing light from underside of vehicle use # 5 cyl.

So its motor home specific i never knew that thanks for setting me straight on it....

[BA-in-Mich]

I know when I lost power to the rear fuel pump on my '90' it would die, backfire & hesitate. But the engine fuel pump got me home as long as I kept my foot out of it's... well you know what.

[JohnRR]

Good luck with a suitable solution.