Intermittently Dies

[MattR]

I'm a couple days into a 4200 mile trip and my 1991 Tioga Arrow motorhome (Ford E350-based with 7.5L 460i engine) is giving me some problems. I'll be driving along and it will start to lack power but only for fractions of a second at first. It will get progressively worse until the engine dies, even if I immediately pull over and put it in park. It will then refuse to start. The engine will turn over but it acts like it doesn't have any fuel/spark/something. After 10-60 minutes, I can start it back up immediately (like normal) and drive for 4-160 miles before it repeats. A mechanic replaced the fuel pump and fuel filter and it drove fine for 160 miles... but then it had been sitting for a couple hours so it might have driven fine regardless of the pump/filter. A couple times when the engine died, it threw a CEL. I tried scanning it at AutoZone but their scanner never was able to pull any codes. The CEL went out whenever it was ready for me to start driving again.

Any idea what this could be or what I could try next?

Thanks!

[gkainz]

gkainz wrote:
Buddy had similar issues, and then again after 1st fuel pump replacement. Ford got a bad batch of fuel pumps so he had his replaced twice before resolving the issue. Glad you're on the road again!

MattR wrote:
So I was able to travel to Wyoming this past weekend and bring my motorhome back. It turns out it was the in-tank fuel pump AGAIN. They said that the whole fuel sender assembly was rusted around the pump or something like that. I had them replace the whole assembly. Thank you again everyone for your ideas!

Perhaps that bad batch of fuel pumps is still in stock?

[MattR]

So I was able to travel to Wyoming this past weekend and bring my motorhome back. It turns out it was the in-tank fuel pump AGAIN. They said that the whole fuel sender assembly was rusted around the pump or something like that. I had them replace the whole assembly. Thank you again everyone for your ideas!

[maillemaker]

Last may I had an overheat problem. Put a new radiator in it. Was doing a check of the installation - did about a 40 minute drive at interstate speeds with the AC on max.

Ran fine till I pulled off the interstate, then popped and backfired and sputtered and died. Attempts to start resulted in strong cranking but sounds of sputtering as if it was out of gas. I have a relatively new fuel pump.

I checked my battery connections (I had removed the battery during radiator replacement) and discovered the negative terminal was loose. I tightened it but when I tried starting still was getting some sputtering.

While I was waiting for a tow, it fired up and ran fine.

Either I threw something for a loop by having a loose/disconnected negative battery terminal, or I may have had a thermal problem with some electronic thing. I got no CEL codes thrown.

Culprits I have been directed to are the ICM, the EEC, or the PIP. The ICM and EEC are said not to be primary culprits for heat as they are mounted on the fenders away from the engine.

The PIP is part of the distributor assembly and while it can be replaced it is hard to do so most people replace the entire distributor assembly.

I have not replaced anything yet. Taking it on a 2-hour trip next weekend so we will see how it goes.

Steve

[MattR]

As far as I can tell the CEL does not stay on... I thought initially that it was on but I think it's just lit up as it always is when you first turn the ignition on before you start the engine. I've scanned it but never got a code.

I'll try to get a fuel pressure gauge on it.

[subford]

Sounds like a bad PIP sensor or a bad PCM.
Did you say the CEL will stay on and it will only start when the cel goes out?
If so I would say bad PCM with bad caps.

Why would you think it is a fuel problem?
If you think it is a fuel problem put a fuel pressure gauge on the fuel rail and see what fuel pressure you have when it quits.
Normal fuel pressure is about 32psi at idle and 40 psi at WOT.
Very unlikely to be a fuel problem as it has nothing to do with the CEL.

Very unlikely to be a ICM problem also as it has nothing to do with the CEL.

[MattR]

j-d wrote:
So sorry. Did you reach out to the contact I pm'd to you?
Good machine, don't give up

I'll do that now. I've got to leave the rv for now... I have got to get home today. But I'll come back and get it asap.

[j-d]

So sorry. Did you reach out to the contact I pm'd to you?
Good machine, don't give up

[MattR]

Changed the coil but only made it 15 miles or so before it died again. At this point, I'm just trying to get home but I'll look for the tools you mentioned.

It's hard to say for sure but as it starts to starve for fuel, there might be a misfire or two mixed in, if that matters.

[STBRetired]

Maybe you should get some diagnostic equipment as well.
Get a spark tester. Looks like a spark plug with an alligator clip welded to the side. You pull any convenient spark plug wire, attach it to the tester and clip the clip onto any ground. Crank over the motor and watch the end for a spark. No spark means an ignition problem.
Get a fuel pressure gauge. There is a Schrader valve on the top of the motor that will allow you to measure the fuel pressure on the line that feeds the fuel injection. No pressure and it is obviously a fuel issue.
You can keep throwing parts at it if you like, but it might be cheaper to try to start narrowing down the problem to at least ignition or fuel.

[MattR]

Made it 600 miles today before it quit. Seems to do okay with 300 or so miles at a time as long as it can rest a couple hours in between. In a couple hours, I'll head over to O'Reilly's and pick up the coil.

[STBRetired]

Good to hear that you are back on the road. What you had pictured was the throttle position sensor. The coil is usually located on the front of the motor on the driver's side, but who knows where it would end up in a motorhome.

[MattR]

STBRetired wrote:
j-d, right click the broken image link and open in new tab.

MattR, what you pictured is not the ignition coil. Find the distributor and follow back the wire that is connected to the center terminal of the distributor cap.

Will do. In the meantime, I re-read the thread another time and focused in on the fuel pump regulator. I replaced it last night and have been driving ever since save for some refueling and resting stops.

[STBRetired]

j-d, right click the broken image link and open in new tab.

MattR, what you pictured is not the ignition coil. Find the distributor and follow back the wire that is connected to the center terminal of the distributor cap.

[j-d]

Want to help but I can't see the Image.