shuts down

[JR Reed]

Will not start all the time, when it does, it shuts down after 5 or 10 minutes. Then it will not start for 12 hours or more.

Can anyone advise me

2001 Dolphin with a 8.1 liter engine

 

[Gary RV_Wizard]

When is the last time the fuel filter was replaced?

Please give more clues. When you say it shuts down, describe what happens? Just suddenly cuts out, or does it stumble and slowly die? Likewise when it won't start... does it not crank, or cranks but won't fire up, or maybe fires up but won't continue to run?

 

[Isaac-1]

You can get a fuel pressure test gauge at Harbor Freight for $32 Fuel Injection Pump Tester

It will screw onto the schrader test post on the passenger side fuel rail, and should read about 54-60 psi if your fuel pump is operating correctly with the engine running, or for about 8 seconds after the key is turned to the on position.

 

[John From Detroit]

You need to read the engine computer to see if there are any codes... That's the first thing
Shut down and won't restart for 12 hours.... Not many things I can think of would cause that.

 

[JR Reed]

When is the last time the fuel filter was replaced?

Please give more clues. When you say it shuts down, describe what happens? Just suddenly cuts out, or does it stumble and slowly die? Likewise when it won't start... does it not crank, or cranks but won't fire up, or maybe fires up but won't continue to run?

Fuel filter changed about 6 months ago. Engine just cutts out, no stumble no slow die. Cranks but won't fire up.
Could it possibly be the relay for the fuel pump, because after about 8-10 hours, it will fire back up?

 

[Ex-Calif]

Will not start all the time, when it does, it shuts down after 5 or 10 minutes. Then it will not start for 12 hours or more.

Can anyone advise me

2001 Dolphin with a 8.1 liter engine

Very little to go on so let's assume it's temperature related.

Coil failure - Not sure if the 8.1 has individual coils but in 2001 I would assume one coil and distributor. If so not likely a cause.

Condensor Failure - as above. I actually replaced a failed condensor for your same symptoms, no joy. Escalated all the way up to a new computer. No joy. The replacement $5 condensor was failed out of the box. Very expensive lesson - ~$600 computer.

Cracked Distributor Cap - Not usually a cause of shut down. More likely to cause hard start and misfiring.

Vapor lock - fuel pump, fuel filter etc. suspect.

Computer failure or computer self protective shut down. Check for codes.

 

[LarsMac]

When it starts, how long will it run before dying?

 

[LarsMac]

You might want to get one of these. It may be able to offer some useful clues.
OBDII reader

 

[Isaac-1]

The 8.1L has coil near plug ignition and no distributor

 

[Ex-Calif]

The 8.1L has coil near plug ignition and no distributor

I wasn't sure - Even in 2001?

I would have thought that fancy pants stuff came later...

 

[Isaac-1]

The 8.1L was introduced in 2001, as a modern engine with coil near plug, drive by wire throttle, etc.

 

[DonTom]

Will not start all the time, when it does, it shuts down after 5 or 10 minutes. Then it will not start for 12 hours or more.

Can anyone advise me

2001 Dolphin with a 8.1 liter engine

How many miles on it? At around 100K miles it is very common for the CPS to crap out. The most common system is an engine that will start cold, and dies when it warms up.

Normally will get a check-engine light with a OBD2 code of P0320 . At 100K miles, replace it even if it works fine! This is for EVERYBODY reading!

I have had several crap out on me in various vehicles. including my Y2K RV when I was in Canada several years ago. In my case, it has always been right after 100K miles. A VERY common problem.

In fact, it happened to my Jeep in January.of this year.

From now on, I will replace my CPS in any ICE vehicle before it gets to 100K miles.

Of course, it can happen sooner, but in my case, it has always happened at above 100K miles. How much above varies. IIRC, in my Y2K RV, it was at 104K miles. Lasted a lot longer in my Jeep, almost 200 K miles. 140K miles in my Dodge Truck.

-Don- Auburn, CA

 

[John From Detroit]

Per Google that's the crankshaft sensor. That will indeed keep it from starting
Crankshaft sensor is at the rear of the engine Top. it's a 2 wire connection as I recall (might be 4)
When We put a new engine in my Workhorse (Well used) the sensor did not make good connect with the cable (We decided to use the engine's original sensor) and we had to unplug-replug a few times.. That sensor is easy to replace and there is no adjustment.

Of course if it's the toothed wheel it senses. that's a whole nutter beast.
Option 2 is bad wiring (I did have a rodent nibble a few wires once.. Ignition primary (low voltage) so it was an easy fix) and option 3 is the engine control comptuer.

But I'd start by unplugging and replugging the sensor cable a few times.

On edit.. Symptom.. that sensor drives the tachometer.

 

[Henry J Fate]

the crank sensor is a good possibility. its location makes it easy to be disturbed/stepped on if work is being done in the doghouse and it will lockout the computers ignition process if it is not sending correct info.

resetting the computer will usually restart the engine.

to reset the computer, remove the positive connection from the chassis/starting battery. turn on the headlights and let it sit for 10 minutes or about. this will drain all memory back up power for the computer resulting in a computer reset.

make sure that all pos (+) power is disconnected from the engine and there is no power making its way from house batteries. if uncertain, disconnect the house batteries and unplug from all shore power.

the engine should restart once the computer resets.

reconnect chassis/starting battery to start the engine. dont forget to turn the headlights off.

i dont know exactly how the computer responds to bad crank sensor info but i do know that there appears to be a delay in shutting down ignition and allowing a restart.

there is also a transmission switch that is mounted on the side of the transmission. i dont have hands on knowledge of that switch locking out ignition but i have heard that it will if it is not sending proper info.

 

[Kirk]

Engine just cutts out, no stumble no slow die. Cranks but won't fire up.

That does sound like it is something temperature caused. I don't have experience with that engine but modern solid state components are often subject to failures when warmed up that go away when cold. It sounds like electronics to me. I had a Dodge at one time that was much like that and it was the control module.

 

[DonTom]

Crankshaft sensor is at the rear of the engine Top.

On some engines, the CPS is on the bottom. But on the 8.1L(item 4):

-Don- Auburn, CA