Hello,

First off I recently picked up a 1986 WinneBago E350 460 Big Block, well in Feburary. Everything in the cab works great and I bought it from a friends grandparents. I am 28yrs old, this is a "new" camping rig for me. I have experience working on my toyota, Duramax, boats and any other random garage or mechanical projects. However, carburetors are not exactly my forte, so I have learned quite a bit about them but, there is an art form to them which I do not have the experience!

I have been reading and reading and reading some more trying to figure this out and I am stumped, so hopefully you guys can help!

Backstory:
About 10 yrs ago the motor in this RV threw a rod and it was rebuilt. It ended up getting long tube headers, an intake manifold and the C6 was rebuilt with a shift kit. After the rebuild it was driven cross country a couple of time and then 5-6 years ago it was parked. I bought it and got it running. Surprisingly all it took was some gas in the tank and some starting fluid it get it running and drove it 1 mile to my house. Once at my house, I started working on it.

Replaced all vacuum lines and made sure the routing was correct
New plugs, wires, cap and rotor
Rebuilt carb a number of times tried different Jets, Vac Secondary spring, PV's etc. I got it running fairly well, IMO. It is a Holley 4180C, factory carb.
new fuel pump in the tank, all new rubber lines.
New fuel filters
New tires
New Brake pads, Rubber brake lines all around and flushed the whole system
Flushed coolant
Flushed PS fluid
Changed Rear diff fluid
Changed engine oil/filter

Problems I have/Had:
1. I found Timing was set to 10* advanced with the Vacuum advance connected, Once disconnected it was retarded a significant amount which was causing a back fires. Got it set to 9* advanced with the Vac Adv disconnected.
2. Lost fuel pressure, found the little rubber line from the pump in the tank blown out, obviously happened after I originally drove it home. I dropped the tank and replaced it.
3. Lost Fuel pressure again. It would start and then die within 3 seconds of getting on the throttle to drive down the street. Found the Oil pressure switch was bad and it was not turning on the fuel pump. Jumped the switch and everything was good. Replaced the switch.
4. It has a really nasty stumble off idle when fully warmed up. - more on this later.

These were really the only problems I had with it. I took it to the lake twice this year and put about 1000 miles on it. It got about 7mpg which is pretty much what I was expecting.

Problems that have me stumped for the last 2 months.
On the way back from the 2nd trip, I was about 3 miles from home and lost basically all power, I could barely give it any throttle or it would bog and almost die. 2000rpm BARELY on the gas got me 45mph on flat ground, maybe.

This last weekend I replaced the coil with the "spare" that was kept in the rig for a long time. I replaced the little ignition box on the fender well. neither of these made any difference. Checked the compression, and it was 145-160psi all the around. I started chasing fuel again, so I double checked the oil pressure and I was right around 60-70psi at idle cold and it stayed around there. Replaced the fuel filter for good measure. When I tested the oil pressure I had to take off the oil pressure switch connector and I think it had backed off. Reconnected and wrapped in in electrical tape to make sure it was not coming off again.

I took it for a couple WOT runs up the hill by my house and was hitting 65+ mph. Put some more gas in and drove about 10miles hitting 70mph for a little bit and cruising at 60mph, everything seemed great! Changed the oil again and drove it 12 miles and once it was fully warmed up, I tried to get on the freeway and had very little power, couldn't get above 45mph on the free way. I parked it for 3-4hours and then drove it the 12 miles back to my house holding 60-65mph the whole way.

What can cause serve power loss when the engine and everything is at full operating temperature but not when it cool?

Some other symptoms, which I am not sure if they are related or not:
When hot, it idles rough and then when I give it throttle it stumbles and almost dies until it gets out of the idle circuit and into the primaries, I am suspecting accelerator pump but I'm not sure. It will also diesel a little bit when I shut it off while hot.

I know this is a bit long winded and I am sure I missed some info, so please let me know what other info I can provide.


Everyone like pictures:
The caravan to the lake!

camp:

 

off the top of my head 1) choke stuck 2) EGR valve always active once activated by the PTVS (ported thermal vacuum switch)

 

Thanks for the reply!

The stuck choke is on my short list of things to look at.

The EGR is something I have not thought about, probably because I know very little about it. Do you have any more info about the EGR and how it is activated? How is it supposed to function?

 

Does your RV use an electric pump? Got a big 26ft class A on the E350 stripped chassis. Mine uses an electric, non return fuel pump mounted on the frame rail; and a canister style filter. Curious as to what headers you used, mine are cracked and need replaced. Are your brakes weak? Even after replacing most everything. Temp issues? Mine ran hot most of the way out from ohio to southern NV