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454 Motorhome has no power

plstokes

plstokes

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My BIL just bought a 1996 motorhome with a 454 TBI engine. The previous owner has not used it for about a year, he cranked it up ever so often but has not ran it down the road.

The problem: The thing has no power, it's very sluggish on take off and spits and sputters, and when it is idling it kind of smells like it is running rich. We were thinking bad fuel so we put some fresh gas in it and some lucas fuel treatment/injector cleaner and headed home. As fast as we could get the thing on the interstate was about 60 and it only dropped in OD once or twice, but any hill would drop us back down to 45 or 50 easy. About 30 miles into the trip home we stopped to check things out and noticed from the catilytic converter down past muffler was glowing orange.

What do y'all think might be the problem??? Clogged converter maybe?? I'm sure normal maintinance needs to be done like air filter and such but I don't think that would casuse that drastic of a problem.
 
I'm thinking too lean from all the varnish in the fuel system. Usually there will be some leaks where the gaskets dried out too. That could be your gas smell.
 
What do you think would be the best method to clean it? Do you think the Lucas we put in there will get it?
 
I think that Sea Foam would work better, but it is a slow process just dumping any cleaner in the fuel tank. I believe that if you use the Sea Foam by allowing it to be drawn in through a vacuum port, i.e. the vacuum for the brake booster, it will do a much better job. Some auto garages have a machine called a Motor Vac that can clean the engines very thoroughly, but they are hard to come by.

TBI's are fairly straight forward to take down and soak in your prefered injector cleaner. If the cat has over 50K miles on it, might as well replace it with a high-flo unit. The cats that are specifically designed for your system will work better, than the universal-fit units. Good luck.
 
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To me it sounds like it was running rich, fuel started collecting in the catalytic converter and is burning up in the cat. So it sounds like a new cat will be necessary. I'd also change your fuel filters, do a tune-up, change o2 sensors, knock sensor(s) and then see how the truck feels. To me it sounds like a bad primary O2 sensor or CTS that's causing the overfueling.

There must be a diagnostic port to scan for DTC's, if there is, scan them and see if there is any stored. If the cat is that hot, the truck is sputtering and acting strange than it's got to have sent a signal somewhere.
 
Are you sure it's a 96 454? Are you sure it's a TBI? In 96 it should be a 454 VORTEC with multi-port injection. Is it a single cat or duals? If it is a TBI then I would check the fuel pressure first as the 94+ TBI's used the high pressure TBI unit. Also TBI injectors plug up pretty easily and won't mist fuel very well which causes LOTS of driveability problems. Also check to make sure it has good strong spark. And put a new fuel filter in it.
 
THEFERMANATOR said:
Are you sure it's a 96 454? Are you sure it's a TBI? In 96 it should be a 454 VORTEC with multi-port injection. Is it a single cat or duals? If it is a TBI then I would check the fuel pressure first as the 94+ TBI's used the high pressure TBI unit. Also TBI injectors plug up pretty easily and won't mist fuel very well which causes LOTS of driveability problems. Also check to make sure it has good strong spark. And put a new fuel filter in it.
Click to expand...

Based on the year it should be, but you never know what engine was chosen by the RV manufacturer anyway. It was the first year they were introduced and might not have made their way to the RV manufacturer by that point.
 
Cutting the cats off my 95 305 threw O2 codes, it required a local mechanic that knew how to manipulate the programming to reflash the PCM. I later got a chip through TBICHIPS
 
Well guys, looks like an air filter and fuel filter got it running like a new engine. I told my BIL last night that was the first thing he needed to do just to rule it out, but i never really thought it would make that much difference. We got it out on the interstate tonight and hit 65 with no problem.


THEFERMANATOR said:
Are you sure it's a 96 454? Are you sure it's a TBI? In 96 it should be a 454 VORTEC with multi-port injection. Is it a single cat or duals? If it is a TBI then I would check the fuel pressure first as the 94+ TBI's used the high pressure TBI unit. Also TBI injectors plug up pretty easily and won't mist fuel very well which causes LOTS of driveability problems. Also check to make sure it has good strong spark. And put a new fuel filter in it.
Click to expand...

It is a 96, and it is TBI, that year they offered both TBI and VORTEC in motorhomes.

I appreciate all of the help!
 
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