1979 itasca 454 engine dying problems

[starrebel]

1979 Itasca sun cruiser Chevrolet 454. This beast has me pulling my hair out. Picked it up fairly cheap a month or two ago. It had some roof leaks that I repaired. She ran pretty good. Took a few camping trips with her close to home. Maybe 50 miles. Everything was great except for a couple of fuel line problems. Drained tanks and replaced the fuel lines on the main tank (I believe). Holds about 25 gallons. It is also the tank the generator runs off of. The auxiliary tank is a lot bigger. 60 gallons. The lines looked good so I did not replace them. fired her up to take her to get fuel back in the tanks. Got about 2 miles from home and the lights started to dim out. By the time I got home they were barely on. Bad alternator. I believe it was bad from the time I picked it up. It is possible that there was a mom switch failure while the engine was running by an ignorant operator. Replaced alternator and now the engine keeps dying. Replaced the fuel pump and changed the filter in the carb and same problem. I think there may be another fuel filter on the rail but bad weather the next few days so will not get to it til next weekend. I was wondering if anyone had any ideas about this. It runs on initial startup maybe five min and dies, A couple min she will start up and run maybe 5 more. If you spray starting fluid she will stay running. Which I think rules out an electrical issue. As soon as it dies I crack the fuel fitting at carb and there is pressure. which in my mind seems to rule out a vapor lock problem. Engine is not hot at all and carb is between cool and warm. Any ideas will be greatly appreciated.

[Elandan2]

From the symptoms you are describing, I would be looking at the carb bowl float and needle and seats.  The float may be hung up in the top position, keeping the needle valve closed or almost so.  After sitting for a while, the pressure in the fuel lines allows fuel to leak past the needle valve and partially refill the fuel bowl.  Then the engine will run until the fuel runs out.  Simply tapping on the fuel bowl with a screwdriver handle or something similar may fix it.  Otherwise, you will have to pull the carb apart to set everything right again.  Rick

[MotorPro]

Not sure about Itasca but on my Winne the 60 gal is the main and the 30 is the aux. You may be trying to run of the empty tank. ( I found this out the hard way when I got it and was told it was the other way around.)

[M & J]

I agree with motorpro. Big tank is the main tank. Also, clogged filter will build pressure but not allow for full flow, or at least ebough to keep running. Enough leaks by to fill the bowls but not enogh to keep full.

[cncsparky]

Also consider tank venting.  If the vents are plugged, the engine will run at first until too much vacuum is pulled in the fuel system then no fuel flow.  Wait a while until the vacuum dissapates then engine will run again.  Has the fuel cap been changed recently?

[DaveVA78Chieftain]

All chassis mfg's had to start using a EVAPORATIVE CONTROL SYSTEM (ECS) in the mid 70's. The Evaporative Control System is a closed system designed to prevent gasoline vapors in the fuel tank and carburetor from entering the atmosphere.  As such, they did not use a gas cap to provide normal venting.  There is supposed to be a safety relief valve in the cap in case the normal pressure relief of the ECS system fails.   The vent lines to/from the tank and engine bleed off the vacuum. 

You can check to see if vacuum is been pulled on the tank:  When the engine shuts down, immediately open the gas cap to see if hear an inrush of air.

Dave

[starrebel]

Thank all you guys for your replies. My internet has been down all day. Now its up and we are heading out the door to do the Sunday dinner and shopping ritual. I will get back to you ASAP. Thanks again

[starrebel]

Thanks Rick, that is along the same lines as I was thinking. Just fixed the alternator and the tanks at the same time so not sure if either caused it or just a new problem. I don't want to start throwing money at it until I can figure out what the problem is. Think maybe next weekend I will come up with a way to bypass the tanks and pull gas out of a gas can or hook up an electric fuel pump to rule out the tanks. Then its either carb or electrical. I went out and ran it today first ran for 20 min at an idle. as soon as I revved it a little it died. Then it ran for 5 min restarted and then 3 min and died again. had the gas caps off of both tanks to rule out pulling a vacuum on tank

[starrebel]

Guess it doesn't answer each post with a reply so Ed, Tom, and Old rock and roller thank you for the replies. I also thought the bigger tank would be the main but the previous owner said the opposite. After the dying problem surfaced I replaced the fuel pump and the carb filter and problem continued. There may be an additional filter under the frame rail. I haven't been able to get back under it to check. I have about 10 gallons of gas in each tank. Another thing I failed to mention was the electric tank selector. It showed the level in both tanks but the previous owner said it always pulled from the auxiliary tank (smaller one) Now it shows one fuel level on both tanks so perhaps the problem could be there. Going to do some checking on that next weekend weather permitting. for now its back to the rat race and I am behind lol. Thanks again for your replies and I will keep you posted. If you have any ideas on how I can narrow it down please send them my way. I don't want to start throwing money at it cause I have thrown a 100 at it and still have the problem. I tend to think it may be the carb but don't want to throw that kind of money at it til I am sure that is  the problem. Thanks again for your help I appreciate it

[Stripe]

Here is a question nobody else seems to have addressed. Have you checked the voltage at your batteries when running and when not running? I see you posted that you fixed the alternator, but there could still be no voltage going to the batteries and the only thing running the engine could be the battery.

Not to be a naysayer, but your PO isn't the brightest bulb.  The 28 Gallon Aux fuel tank was an option available on the Sun Cruiser in 1979. The main tank capacities are as follows, the 26RG and 26RT were both 45 gallons. The 26RH was equipped with a 36 gallon fuel tank.


Here is a link to the PDF Copy of the brochure for your RV if you'd like a copy.

[Thundercloud]

Id check and adjust the carberator.

[Rickf1985]

The way you are describing it dying each time in a shorter period you might want to look into replacing the ignition coil. Coil gets hot and open circuits, each time it shuts off the coil cools enough to close the circuit but then you restart and the coil is already heated up so it is a shorter time to open circuit again. Every time it does that it arcs at the bad wire so that eventually it will not close the circuit and you will have a no spark/no start condition.

[DonD]

"There may be an additional filter under the frame rail. I haven't been able to get back under it to check." Yes, replace that filter, needs it anyhow.

[Froggy1936]

starrebel FYI Throwing a hundred dollars at a Classic R/V is like swatting a lion with a noodle . Frank W%

[legomybago]

Yep

[Stripe]

Here is a link to the PDF Copy of the brochure for your RV if you'd like a copy.

Part TWO,
And now for something completely different...
The link..
Theee Link...
http://media.goitasca.com/models/globalElements/brochure/previous-models/1979/itasca/79-Suncruiser-bro.pdf

[Oz]

Oh... you meant "THEEE" link?

From right here, as usual, on CWVRV in the Member Area -> Resources - > Winnebago ->  Model Brochures... ALL Winnebago/Itasca etc...

http://www.winnebagoind.com/products/previous-models/1979/index.php

[starrebel]

Hi guys.

Thanks for all the good replies and advice. I was kind of vague in my original post. I had some starter fluid and sprayed into carburetor when she would sputter. as long as I was spraying it in she would keep running if I stopped she would die so I am 95% sure that it is a fuel issue. The alternator after initial startup after install was charging at 14.7 volts and dropped down to about 13.5 after 5 minutes. When I switched to dual it kicked back up to 15. Haven't checked it since but the ammeter on the dash is showing the same as before. Thanks Mark and Stripe for the brochure. It is the 26RH model. Frank I would think it's more like hitting a grizzly bear with a feather W%.  This weekend I am going to change the fuel filter on the rail and try to bypass the electric tank switch and see if she will run. If she doesn't I will try hooking a gas can into the fuel pump and totally bypass the tanks. If she still don't run I will attempt a carb rebuild. Do you think it may help to run a carb or fuel injection cleaner thru the system from a gas can rigged tank? I have available an electric fuel pump that pumps 2.5-4.5psi. Good idea on the coil Frank but at first I thought it could possibly be electrical but then I realized when I shot the starting fluid in it would have died anyways.

[legomybago]

Well...I think you already know the answer starrebel... W%

If you have a good supply of fuel coming out of the fuel pump flowing towards the carb, but the engine won't run unless you spray starting fluid into the carb....then you need to pull that carb and clean it out.

[starrebel]

Thanks legomybego  I kinda know that but for some reason I have a high anxiety rate about doing that. Haven't rebuilt a carb in 30 years and last time I did it didn't work  out real well   It is like I know that's a good chance the carb is the problem but I want to will it into being something easier lol

[Oz]

Nothing wrong with that.  It's honest and honestly, all the rest of us try to will things into the simplest of fixes too.

[Froggy1936]

starrbel, Just to make things worse If its the original carb its a Quadrajet The only good thing is it could just be a plugged filter That is under the big nut that the fuel line screws into  This must be replaced or if a solid fiter /cleaned Then try starting . If still no good get a rebuild kit Read the directions 3 times If you think you can handle it take it apart (after takeing pictures of the linkage on both sides )  Or take it to a person that will guarantee repairs   Most GM dealers have such a person .  Frank Hm?

[Rickf1985]

I don't think there are any dealers around with techs old enough to know what a carburetor is let alone rebuild one. That is why they are called technicians and not mechanics anymore. I used to hate that when my boss wanted me to put the letters of my certification after my name on the business cards. I said I am a master MECHANIC, Not a technician. My son in law is a Technician and when he watches me work on my old military Jeep he is totally fascinated by the carburetor and especially the distributor and points. When he first saw it he asked what the carburetor was! One of my specialties was carburetors and quadrajets were my favorites. Don't be afraid of it, just take pictures as you go, find some diagrams online to study and have handy and lay out the parts in an order that suits you as you are working.

[cncsparky]

Or you can do what I did, send it in to Sean Murphy induction.  They have the tools and expertise to do it right, quickly, and cheaper than an exchange carb at the auto parts store.  You send yours in and get your same carb back!

http://www.smicarburetor.com/products/sfID1/85/sfID2/86/sfID3/9

[Froggy1936]

He He i keep forgetting That carburators ended 30 yrs ago. Seems like , the Quadrajet just came ot a few yrs ago to me , But Im stuck in the 60,s And doing a lot of boat carbs they dont seem old . Any shop that deals in reconstruting old cars will have experience with them .  Frank