1987 Establishment P30 starts but dies in idle

[Ryan7361]

I have a 1987 Establishment P30. It will start and run, but as soon as I take my foot off the gas it stalls out. It started during a trip when I began to lose power going up a hill. Things got better after the hill, but 2 or 3 hills later we stalled on the side of the road and had to be towed home. It's a chevy 454
I've replaced all the:
-fuel filters
-and put in a new mechanical fuel pump.
-sprayed "gum out" into the carburetor


Any ideas for an Austin area mobile mechanic?
Ryan

[Born_To_Travel]

They will be the small rubber lines on top of the engine and they will run to the distributor and other areas on top of the engine... They deteriorate over time from heat and age and if the distributer advance line is leaking, It will run as you describe...

[Ryan7361]

darsben wrote:
rubber vacuum advance lines are collapsing is my first guess. Replace them. Notorious problem with them as they age. $10.00 BUCKS OF RUBBER HOSE WORTH A TRY.

Not mobile but try Fleet Maintenance of Texas
4800 E 7th Street, Austin, TX 78723

Where are the vacuum advance lines located?

[Born_To_Travel]

Sounds like a vacuum leak.. Check all vacuum lines on engine.. If they are original replace them anyway....

[Ryan7361]

Update:
I put in a new electric fuel pump and replaced ALL the rubber fuel lines(supply and return), and I even got a new gas cap and checked the vent line! I also replaced the pressure regulator. It still stalls at idle! Time to check out the carburetor? alternator???
Where would I find a diagram for my chevy 454 carburetor? I need to find these "idle air adjustment screws".

[PaulJ2]

My guess also is dirt in the idle circuit. One more thing I didn't see Wes cover. Make sure the idle-stop solenoid is working on the carb. The throttle linkage rests against this while idleing with the key on. Retracts with key off further closing the throttle to prevent dieseling.

[turbojimmy]

You probably do not have an in-tank filter. They came with the in-tank pumps and fuel injection.

My suggestion would be to bypass the electric pump and see if it will run off of the mechanical pump.

[Wes_Tausend]

Ryan,

If the engine won't idle, a common cause is that carburator idle jets are plugged. The obstruction can come from debris from deteriorating hoses, rusting fuel tanks (condensation in stored less-than-full tanks) and quite frequently, vehicles parked so long the carb dries out, leaving sand-like fuel deposits that break loose after restarting.

In 1978, automobile carbs already started using smaller idle jets to lean idle mix down and reduce raw fuel emissions during idle. Idle was one of the worst pollution offenders on older cars because idle was set very rich to assure that some fuel vapor mist made it as far as the cylinders after traveling a long path through the intake runners. Much of the fuel stuck to the walls and simply dribbled into cylinders where, unburned, it eventually pumped into exhaust and came out as stinky vapor. Unfortunately the new smaller idle jets plug up with much smaller particles. Such an engine is hard to start and will only run at medium to high speeds where the huge main jets began to supply some fuel. This is especially true of new small engines like motorcycles and lawnmowers which have the tiniest idle jets imaginable and, yes, the final mix is still a bit too lean since it is missing the idle jet contribution.

Whew. All that said, your problem is probably an idle failure after a hard pull. This can happen because the fuel bowl finally runs so low on fuel (drains) that the idle jets are uncovered. The reasoning is that the carb starts up the hill just fine at low fuel/power requirements because the marginal fuel supply system can still meet demand and the carb fuel bowl is still full. As the vehicle climbs, the fuel requirement begans to outpace the worn pump's ability to keep up. The bowl slowly loses ground, graduallly decreasing power, until the fuel mix becomes so lean the engine will not even run.

By the time you read this, it is likely you have already largely fixed an insufficient fuel supply problem. But other problems may arise from lack-of-use debris and rotted hoses, perhaps the cause of fuel pump failure.

Plugged idle jets can some times be unclogged by spraying WD-40 backwards through the idle air adjustment screws. Use the tube attachment directly into the threaded hole to gain the most pressure. Do not use aerosol brake cleaner, aerosol carb cleaner or any other harsh solvent. Gently bottom the screws out first and count the turn setting making careful note to return them to exactly the original setting where they will again work best when all is clean. Remove the screws and spray away. This is easier than disassembling the entire carb and works particularily well in small engines.

You can try simply blowing backwards through the fuel line to the tank to see if it is plugged. It should gurgle if the tank has any fuel in it.

Good luck.

Wes
...

[Ryan7361]

Time for an update! So my electric fuel pump is shot. To test it, I found the fuel pump relay and put 12v on the pump lead(i heard a noise at the tank). I took apart the fuel line at the inline filter(by right front wheel) and nothing was coming out! So either my pump is shot or the in-tank filter is totally blocked, right? I am NOT looking forward to dropping my tank..........

Ryan

[jerseyjim]

Alternator.

[1985air345]

Also check for a mid-line fuel filter. My Airstream 345 had one behind the steps in the center. It also had an electric pump in the rear and the mechanical one up front. It sounds identical to issues I had with the P-30 in my Airstream. A fuel supply issue. Mine also showed up going on hills.

[turbojimmy]

Grandpere wrote:
Check the electric fuel pump that is located by the right rear tire. It gets the fuel to the mechanical fuel pump. rubber fuel lines might be a problem, but that would show up more when you are stepping on the gas than dying at idle. Mine acted the way you are describing but that was after a complete rebuild of the carb and no fine tuning was done when it was installed.

One FYI I always add Lucas fuel treatment to our MH, 1 cup for every 10 gallons of gas. It is expensive, but not having fuel problems makes it worth it to me.

Mine was the opposite. The mechanical pump would draw through the failed electric pump up until about 45 MPH and it would run out of fuel. It would run great below that speed.

When the rubber lines failed, the fuel pump couldn't suck any fuel out of the tank at all. It would cough and sputter at idle.

EDIT: I should have emphasized Grandpere's advice. Whether it's your problem or not, make sure that fuel pump is running (behind the right rear wheels mounted on the frame). I still suspect fuel rotted fuel lines. Again, unhooking the fuel at the carb and cranking (into a coffee can or something - not letting it spray all over the place) will tell you for sure.

[Grandpere]

Check the electric fuel pump that is located by the right rear tire. It gets the fuel to the mechanical fuel pump. rubber fuel lines might be a problem, but that would show up more when you are stepping on the gas than dying at idle. Mine acted the way you are describing but that was after a complete rebuild of the carb and no fine tuning was done when it was installed.

One FYI I always add Lucas fuel treatment to our MH, 1 cup for every 10 gallons of gas. It is expensive, but not having fuel problems makes it worth it to me.

[turbojimmy]

Have you checked to see if you have fuel at the carb by cranking it with the fuel line unhooked?

The rubber lines at the tank may have rotted out and are not allowing the pump to draw fuel from the tank (it needs a vacuum). Happened to my '84 P30. I had to replace all the rubber lines.

[darsben]

rubber vacuum advance lines are collapsing is my first guess. Replace them. Notorious problem with them as they age. $10.00 BUCKS OF RUBBER HOSE WORTH A TRY.

Not mobile but try Fleet Maintenance of Texas
4800 E 7th Street, Austin, TX 78723