Community Forums

Sonofkong · 01-30-2023, 08:38 PM

Hello Everyone,
I own a 1990 Airstream land yacht 36’
With a P 30 chassis and 454 CID gas engine with 50,000 miles.
She has always been a great starter and runner.
We refer to her as old Nellie.

Recently I had a tragedy in my life which took my both my mother and my wife. The motorhome has sat for a year and a half and now will not start. It’s in my way and needs to be out of my life I have other priorities which I need to attend to and it’s not something I have a passion for anymore I’m sure you can understand.

I’d like to find a good home for but it will be next to impossible to sell without it running. I’m pretty mechanically inclined and have a lot of tools, but don’t know anything about fuel injection systems
Limited electrical diagnosis ability.

I am willing to learn if someone could give me some advice or hold my hand I am located near New Haven Connecticut and I’m willing to pay someone as well to get it running again. Unfortunately there’s no one around here that works on these and it would cost a fortune to have it towed.

Now she will only run when I pour fuel directly inside the fuel injection unit.

When I turn the key switch on I do hear the fuel pump running and priming

I remove the two lines going to the base of the fuel injection and crank the motor over no fuel comes out.

Should gas be coming out of the two lines when I crank the engine over and the fuel pump activates?

From little I could discern it might be a fuel pressure regulator issue or Possibly a bad fuel pump. I may be wrong.

Supposedly the fuel pump is in the tank
Is it accessible through the floor of the RV interior?

Fuel filter location?

Where is the fuel pressure regulator located on this vehicle?

Please help I would like to move on with my life and find a good home for an old Nellie so somebody can enjoy it again.

203 488 2627 you can text
Me direct or call I’m also willing to pay for
Professional consultation

Thank you in advance

MrMark52 · 01-30-2023, 08:55 PM

So sorry about your losses. I’m sure getting back into life again has been slow - and it’s good your trying to move on!

I had a ‘91 that somewhat did the same thing.

Turned out the 2” long hose that connects the fuel pump discharge to the fuel pick-up tube inside the fuel pump disintegrated - looked like a cartoon cigar that had exploded.

Dropped the tank, pulled the assembly out, went to OReilly’s and bought a new pump kit (actual pump that included a new piece of hose and 2 clamps), reassembled the coach, and drove her to my house (coach was at my sisters house).

Thought about cutting hole in floor - didn’t want to risk there being something in the way or missing the location.

60 gallon tank had about 45 gallons of fuel in it. Went to WalMart, bought 5 5 gal gas tanks, siphoned what I could into those tanks and every one’s lawnmower in the neighborhood.

Had a friend help me drop and reinstall the tank using ratchet straps.

Not hard if your handle.

Tha_Rooster · 01-31-2023, 12:57 PM

Quote:

Originally Posted by Sonofkong

Hello Everyone,

I own a 1990 Airstream land yacht 36’

With a P 30 chassis and 454 CID gas engine with 50,000 miles.

She has always been a great starter and runner.

We refer to her as old Nellie.

Recently I had a tragedy in my life which took my both my mother and my wife. The motorhome has sat for a year and a half and now will not start. It’s in my way and needs to be out of my life I have other priorities which I need to attend to and it’s not something I have a passion for anymore I’m sure you can understand.

I’d like to find a good home for but it will be next to impossible to sell without it running. I’m pretty mechanically inclined and have a lot of tools, but don’t know anything about fuel injection systems

Limited electrical diagnosis ability.

I am willing to learn if someone could give me some advice or hold my hand I am located near New Haven Connecticut and I’m willing to pay someone as well to get it running again. Unfortunately there’s no one around here that works on these and it would cost a fortune to have it towed.

Now she will only run when I pour fuel directly inside the fuel injection unit.

When I turn the key switch on I do hear the fuel pump running and priming

I remove the two lines going to the base of the fuel injection and crank the motor over no fuel comes out.

Should gas be coming out of the two lines when I crank the engine over and the fuel pump activates?

From little I could discern it might be a fuel pressure regulator issue or Possibly a bad fuel pump. I may be wrong.

Supposedly the fuel pump is in the tank

Is it accessible through the floor of the RV interior?

Fuel filter location?

Where is the fuel pressure regulator located on this vehicle?

Please help I would like to move on with my life and find a good home for an old Nellie so somebody can enjoy it again.

203 488 2627 you can text

Me direct or call I’m also willing to pay for

Professional consultation

Thank you in advance

I had a p-30 and filter was inside frame rail not hard to see I believe around halfway back.

n2zon · 01-31-2023, 03:30 PM

Instead of "easter egging it," let's take some positive steps to identify the problem.

First, check the fuel pressure. I've owned the gauge and adapters for some time but I'd guess they cost less than $100. This might most easily be done where the line exits (not enters!) the fuel filter. If the fuel pressure is normal, the problem is somewhere after that point in the system. If the fuel pressure is low, and there is no fuel dripping from anywhere, either the fuel pump or the fuel pressure regulator is bad. The regulator sits on top of the TBI unit and is easy to remove and have checked.

If the fuel pressure is normal, it's the injector or the fuel control system. I'd bet on the latter. You should be able to see fuel flow out of the injector as you try to start the engine. If you don't there are a number of candidates but a dirty MAF is pretty high on the list and very cheap to clean. Diagnosis gets more involved from there, but other things include the connections and (ugh) ECM.

HTH...

SteveJ. · 01-31-2023, 03:40 PM

Quote:

Originally Posted by n2zon

Instead of "easter egging it," let's take some positive steps to identify the problem.

First, check the fuel pressure. I've owned the gauge and adapters for some time but I'd guess they cost less than $100. This might most easily be done where the line exits (not enters!) the fuel filter. If the fuel pressure is normal, the problem is somewhere after that point in the system. If the fuel pressure is low, and there is no fuel dripping from anywhere, either the fuel pump or the fuel pressure regulator is bad. The regulator sits on top of the TBI unit and is easy to remove and have checked.

If the fuel pressure is normal, it's the injector or the fuel control system. I'd bet on the latter. You should be able to see fuel flow out of the injector as you try to start the engine. If you don't there are a number of candidates but a dirty MAF is pretty high on the list and very cheap to clean. Diagnosis gets more involved from there, but other things include the connections and (ugh) ECM.

HTH...

Iff'n ya gotta clean the MAP sensor make sure that you get the special spray for it.

cadillac_al · 01-31-2023, 04:42 PM

It does sound like a fuel issue but it would be pretty easy to check for diagnostic codes to rule out some simple sensor or something. There are a lot of writeups on the net about retrieving codes on 1988-95 GM TBI vehicles. You can also buy an adapter for checking fuel pressure on GM TBI.

donr103 · 01-31-2023, 04:50 PM

So I can't give you 100% definite answer.. but if you get your parts at AutoZone.. you can return if they don't fit.. here are my part numbers.. FG0064 or FG0061 Delphi part #.. they might let you order both and see which works.. or take your in before ordering and let them match it.. and return if not correct.. I don't work for them and don't have anything to do with them.. I just use them for most of my parts.. you can call ultra rv or brazles.com and they see what they got.. many here say Napa in store only can match it up.. many here post ... that there are so many fuel tank combinations that you may have to work to find it.. I only ask.. that you come back here and post p# and source .. so someone can find help.. oh.. you can go online and look at those part # and get the specs and see if they are close.. I believe they are adjustable for certain height.. so measure approximately the depth of tank.. then look up the numbers.. you might be able to use cellphone with flash on and record over top of tank and see your connections and match that up..
Good luck and keep us posted

1972VWbus · 01-31-2023, 09:03 PM

Quote:

"Should gas be coming out of the two lines when I crank the engine over and the fuel pump activates?"

If you are referring to the (2) injectors on the TBI...yes they should spray fuel when cranking. They will only spray fuel if the ICM (ignition control module) is functioning.

If no fuel from the TBI input/output lines then it will either be....

1. Fuel filter

2. Fuel pump

code2e · 01-31-2023, 09:59 PM

Since no fuel flow at Throttle body inlet, trouble has to be fuel supply. First, of course, be certain there is fuel in the tank sufficient for the pump to prime. Since you hear the pump running, no need to check electrical wiring or relays. Easy parts first. Fuel filter is inline along frame rail. I have attached a picture. It attaches to metal fuel line and may be tight. Recommend you use a 5/8" flare nut wrench to keep from rounding the compression nut off. Also need a crescent wrench to the filter hub still. Remove the filter and note any fuel content. If it's empty, replace it anyway, but your trouble is in the tank.

If there is fuel in the filter, leave it off and have someone crank the engine for a few seconds while you watch for fuel from the tank. You will have your answer. Fuel flow, filter is clogged. Replace and try it out.

I have also attached a picture of your pump. Note the rubber hose connection that was noted earlier. Could be rotted and pumping fuel within the tank. Also there is a filter sock on the bottom that could be clogged.

In view of the work involved dropping the tank, I personally would replace the whole pump and be done with it.

1972VWbus · 02-01-2023, 05:27 PM

The fuel pressure regulator is within the TBI unit. Fuel pressure for the 90 year is 9-13psi preferably closer to 13. The 94-95 years the pressure was 26-32psi

n2zon · 02-02-2023, 06:58 AM

Quote:

Originally Posted by 1972VWbus

The fuel pressure regulator is within the TBI unit. Fuel pressure for the 90 year is 9-13psi preferably closer to 13. The 94-95 years the pressure was 26-32psi

Right. Forgot about this. If it's bad, make sure you get the right fuel pressure regulator to replace it! The internal springs are different but they appear identical to the eye.

MrMark52 · 02-02-2023, 07:38 AM

For further clarification of the hose failure I was describing in post #2 - the fuel pump assembly in the top picture of post #9 shows that short piece of hose.

FWIW - it appeared to me that the failure I had was due to the hose dry rotting, and to my untrained eye - it dry rotted due to the hose rubber wasn’t formulated for trap days “up to 10%% ethanol” fuels.

1972VWbus · 02-03-2023, 05:10 PM

With respect to 'dry rot' of fuel hoses. I've done a lot of testing with different hose types in the ACVW community and most hose rated 30R7, 30R9 are able to withstand E-10 without issue. What 'dry rots' them is when the fuel level is left below (and or empty tank) the hose for extended periods of time.

I always prior to extended storage fill the tank full and add appropriate amount of fuel stabilizer.

If one replaces a hose use Gates Barricade hose. That is rated 30R14.

MrMark52 · 02-03-2023, 06:42 PM

Quote:

Originally Posted by 1972VWbus

With respect to 'dry rot' of fuel hoses. I've done a lot of testing with different hose types in the ACVW community and most hose rated 30R7, 30R9 are able to withstand E-10 without issue. What 'dry rots' them is when the fuel level is left below (and or empty tank) the hose for extended periods of time.

I always prior to extended storage fill the tank full and add appropriate amount of fuel stabilizer.

If one replaces a hose use Gates Barricade hose. That is rated 30R14.

All well and good with what your testing in todays world - but what about hose used on a 1990 chassis, constantly going thru cycles of fuel immersion to vapor immersion for over 30 years?