1998 P30 Chevy 454 - Stalling at interstate speeds

[bfrein]

Hello,

We have a 1998 Fleetwood Southwind 32V. I believe this is the P30 Chevy 454 chassis

Today while cruising about 65mph on the interstate, the RV stalled. No engine lights came on. I still had power to my guages, a/c fan, etc, but rpm dropped to 0 as did oil pressure. I coasted to the shoulder and was able to easily restart.

15-20 miles further down the road, it acted like it was going to stall again. I'd push the accelerator, but no response. RPMs were bouncing below 1500. Suddenly, the accelerator was responsive again and I was able to continue driving without pulling over.

We stopped at a truck service shop on the next exit (about 10 more miles- no issues on this leg). They tested the fuel pump pressure and it was 58. Replaced fuel filter. He was able to blow through the old filter.

We took off and make it another 15 or so miles before the engine stalled again. This time while I was coasting, I just shifted into Neutral and was able to restart.

We took the next exit and returned back to home. Of course for the entire 70 miles back, we didn't have any issues.

The RV is still fully loaded out front and we are attempted to figure out if we should risk trying again tomorrow or just cancel the week trip

Any insights or suggestions would be great

Also for reference, we just took the RV on a 350 mile trip last weekend, so the fuel is fresh. In Feb we took it on a 3300 mile trip to Texas and back without any issues. There are approx 65,000 miles on the RV

Thank you

[bfrein]

Sorry I did not reply to this earlier. It was the fuel pump.

Thank you everyone for your help and suggestions.

[udidwht]

Ignition control module in the distributor.

[rgatijnet1]

The P30's did have ignition switch problem which could cause the engine to stall if contact is lost. This was usually a failure caused by excessive heat in the switch from the headlights and eventually the switch would fail to make ignition contact while running but be OK after it was reset. Just a thought.

[Gjac]

Sometimes these things can be hard to diagnose. In the beginning stages of failure it does strange things. If you read through the next post "Engine stumble's at idle" you can see the details. In short my fuel pump had the right fuel pressure ran fine at high speeds and pulling hills but was hard to start and keep running at low speeds. Good luck hope the shop finds and fixes it for you.

[Harold_Fairbank]

jolooote wrote:
Hi, had a 454 for 14 years. Seen it all. Had simular prob. The old coach had settled down lower on the chassis. This allowed the fuel hoses atop the tank to rub on them until small holes developed. When pulling long gradual grades over time air was slowly sucked thru these holes. Engine would act like your's. Pull over, the line suction would be reduced and it sucked fuel again. Another possible...there are two electronic modules in the distributor. They get hot and begin to fail with your symptoms. Replace em.

This is good advice. Years ago I had the same problem in an old 454 P30 but for some reason mine was more pronounced at elevation and when going up hills when the engine was really sucking fuel. Took a few shops to figure it out over a few occasions (it would starve horribly then would be fine for a time), it usually happened when stranded out in the middle of nowhere. The last competent shop found the problem, ended up replacing the fuel lines that were chafed and installed a better electric fuel pump installed near the tank. The problem went away forever.

[jolooote]

Hi, had a 454 for 14 years. Seen it all. Had simular prob. The old coach had settled down lower on the chassis. This allowed the fuel hoses atop the tank to rub on them until small holes developed. When pulling long gradual grades over time air was slowly sucked thru these holes. Engine would act like your's. Pull over, the line suction would be reduced and it sucked fuel again. Another possible...there are two electronic modules in the distributor. They get hot and begin to fail with your symptoms. Replace em.

[DryCreek]

Well, if it is a 1998 model (on a 1997 chassis), you probably have the updated "Vortec" version of the venerable 454. That was the final, and best iteration of that engine. It has Sequential Fuel Injection, new piston design and improved pushrods. All that being said, 58 psig seems a little low for the SFI engines at idle.

When was the last time your distributor cap, rotor and wires were replaced? The 454 really liked to cook the rearmost wires, and the coil gets weakened after several heatsoak cycles. Those are other items to check. Since it is OBD-II, did the ECM store any codes (active/pending)?

[BrianinMichigan]

Also the ignition switch can cause problems. With it being a 1998 it will at least be throttle body injection. no carb. Mine was the very last of the carbureted 454 engines. it's a 1990.

[bfrein]

Thank you everyone for your replies. We have unpacked and dropped it off at a local shop. Without looking at it, their first suggestion was the fuel pump as well.

I'll update once they get it in and let me know for sure

[allbrandauto]

there is a test for the fuel pump even though the pump is still running its called a low amp test you need a mechanic to hook a low amp probe on the wire to the fuel pump your looking at a wave patterm that will tell you if the pump is good or bad you may go on you tube to see this test performed

[DougE]

Ditto. In-tank fuel pump gets hot and stops pumping. Especially if the fuel level is low. When it cools down it pumps normally. At 60k replacement is about due. Another (more rare) problem that comes to mind is an intermittent wiring connection to the injectors.

[ScottG]

When the fuel pump starts to go, it doesn't always get weak, it just doesn't run at times. When it does run the pressure will be fine.
So a FP test doesn't really tell you much.

[bfrein]

Thank you all for the quick responses.

The shop we stopped at did check the fuel filter. He could blow through it but since he had it off, we just replaced it as well. They mentioned that it may be the fuel pump starting to go. At the time they tested it, the pressure was in range.

Unfortunately the pumps aren't stocked anywhere local so it will take a few days to get in. We will start unpacking

1995brave - I will check the air filter and also have the shop check the vacuum lines.

Thank you

[IAMICHABOD]

I had a Class A on a P30 chassis with the 434 and had the same problems mostly in hot weather, and I tried all the fixes mentioned here.

Took it to Chevy truck mechanic and he said it was common problem,and showed me the reason. The fuel line is routed inside the frame rail next to the exhaust system and it would cause a vapor lock,he re routed the fuel line and the problem was solved.