I have a 1990 E350 with the 7.5L / 460 engine, fuel injection, single tank. (Actually it is a class C motorhome) While driving at freeway speed the van will slowly start losing power until I need to pull over. The engine will idle fine for a while and then run rough and then die. Engine will sputter and die when attempting restart. After sitting for about 30 minutes it will start and run fine. I can go for another 10 to 100+ miles before it happens again. I have replace the inline fuel filter. I rented a fuel presure tester to use when it happens next. The problem is that this problem is so intermittent. Any suggestions would be greatly appreciated.

 

Did you have the module on the side of the distributor tested?

 

'Slowly Loses Power'.
Sounds like me.

OOps, wrong thread.
Sorry...

 

Does this vehicle have a catalytic converter?

 

Fuel Filter....Again

Next time open the gas tank, did it suck air? Posible blocked vent

 

What is the module? How do I test it? Will an intermittent problem be detected?

 

The cat seems fine. I did the hit it with a rubber mallot test. The engine seems to have plenty of power until it starts acting up.

 

It's the ignition module and they have a known heat failure problem, but usually they just stop working and the motor shuts off like you hit a kill switch and return to normal after cooling town a little. That's something that won't show up on a bench test so I wouldn't put much faith in that, instead pull the codes to see if you get anything related to loss of ignition. If not then your problem is fuel or exhaust related.. a clogged cat or a weak fuel pump.

 

I replaced the fuel filter this weekend after the first time this happen. I removed the gas cap and the engine would still not start.

 

Ignition module bolted to the side of the distributor. If you had a complete won't start problem, you could take the module to a parts store and get the
module tested. You got that one right, unless you get the module to the store while it is in a dead state, it probably can't be effectively tested.

Your problem doesn't sound like the typical ignition problem, ie losing power and sputtering before quitting. Usually with an ignition component being bad the engine just up and quits like you shut the switch off.

Do you have a catalytic converter?

 

I agree it sounds like the catalytic converter is plugged up. It would cause all of those symptoms, in about that very same order. How many miles are on the rig and when was the last proper tune-up done?

Proper tune-up=:
Coil
Wires
Plugs
Distributor cap
Wires
Fuel filter
Air Filter
Oil change

 

I have done a tuneup, everything except coil, about 5k mile ago. Replaced the fuel filter after the first failure.

At first i thought it was the cat but engine would run fine after about a half hour. Can a cat fail intermittently?

I have taped a fuel pressure gauge to my hood but have not been able to recreate the problem. (I dont want to wait until my next camping trip to recreate the problom.) My guess at this point is the in-tank fuel pump / filter. However, I hate to go throught the expence/work to replace it and find out it wasn't the problem.

 

I am not sure if this vehicle has ODB since it is a 1990. Didn't ODB-I start in 1991?. There are no malfunction indicator lights on the dash except for the anti-lock brake light.

 

I would be looking at something fuel related

 

OBD-I started in '87 when they introduced the EFI system. As early as '82 or '83 they had it in the cars. I had an '84 tempo with a SEFI 2.4 in it that was OBDI.