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peterpete190
peterpete190, Auto Technician
Category: RV
Satisfied Customers: 26621
Experience:  Over 17 years diagnosing and repairing various model vehicles.
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It's on a 1994 motorhome with the 7.4 will not start when it

Customer Question

It's on a 1994 motorhome with the 7.4 will not start when it gets hot fine cold
JA: Have you checked the battery, particularly the terminal connections? Are they corroded?
Customer: Yes
JA: What is the model of your '94 Chevy?
Customer: It's in a motorhome
JA: Are you fixing your vehicle yourself? What have you tried so far?
Customer: Yes I'm fixing myself I've check the fuel pressure and change the fuel regulator and no change
JA: Anything else you want the mechanic to know before I connect you?
Customer: Got plenty a spark and it will turn over but will not start after It gets hot unless you pour gas in the carburetor thin it starts up and runs fine.
Submitted: 7 months ago.
Category: RV
Expert:  peterpete190 replied 7 months ago.

Hi my name is ***** ***** I will be happy to assist with this today.I apologize for any delay.

In allot of cases this issue here can be caused by a fault with the ignition module located in the distributor.I have seen this affected by heat and when it acts up this can cut the fuel injector pulse signals to allow no fuel into the throttle body.If this has not been replaced with as common as it is to fail and what is described here I suspect it needs replaced.

Let me know if you need anything else and feel free to rate my help here as this is how I receive credit for my time.A 5 star rating is appreciated.Thanks Pete

Customer: replied 7 months ago.
I already replace the ignition module and fuel pump regulator in the carburetor
Expert:  peterpete190 replied 7 months ago.

O.k. inside the distributor if you look at the metal points on the wheel that the shaft rotates around under the rotor is there any rust or green corrosion at all?

Was the pick up coil replaced (this is seperate from the external coil and is located in the distributor under the rotor area?

Customer: replied 7 months ago.
I do have a fuel pump code 54 fuel pump relay Paul
Customer: replied 7 months ago.
Fuel pump relay fault
Customer: replied 7 months ago.
Have not replaced the pick up coil yet
Customer: replied 7 months ago.
I didn't see much green or corrosion on the pick up coil but I did see some inside the cab with a pick up oil cause this problem or could it?
Customer: replied 7 months ago.
I will be more than happy to rate you when we get finished.
Expert:  peterpete190 replied 7 months ago.

I apologize for the delay.

You may have a faulty fuel pump relay or damage to the wiring or terminals/contacts at the relay.If you can locate the fuel pump relay look for any damaged wiring or connections needing repaired or replaced.If this is or was checked and found o.k. let me know so we can continue.

Thanks Pete

Customer: replied 7 months ago.
I inspected the wires and change the fuel pump relay yesterday and the oil pressure sending unit. Can the pick up coil in the distributor cause this?
Expert:  peterpete190 replied 7 months ago.

The pick up coil is a very common component that can act up/fail and cause issues like this here.I have had to replace several before.The distributor has to be removed and the shaft removed to remove and replace the pick up coil or the entire distributor replaced.It can cause injectors to stop pulsing when no signal is present from the coil and in some cases loss of spark.

Let me know if you need anything else and feel free to rate my help here as this is how I receive credit for my time.Your 5 star rating is appreciated

Thanks Pete

Customer: replied 7 months ago.
I have kind of been steering clear from the fuel pump because you can start it up cold and drive it 3000 miles with no problem but as soon as you shut it off that'swhen the issue is only when you shuts off. And try to restart it it won't start up unless you poor fuel in the carburetor and then I will run fine tell you shut it off again.
Expert:  peterpete190 replied 7 months ago.

Yeah that doesnt really sound like a fuel pump issue here.With all that has been replaced this can be the pick up coil itself at fault.I have seen this fail before needing replaced several times.In some cases I recommend replacing the entire distributor if there is any corrosion in the distributor.

Thanks Pete

Customer: replied 7 months ago.
I'm going to replace the pick up coil later this afternoon and I will let you know what happens thanks Shawn.
Expert:  peterpete190 replied 7 months ago.

O.k.,let me know how this turns out here when your ready.The only other thing I can think of that may possibly cause this is a fault in the engine computer itself needing replaced.

Customer: replied 7 months ago.
I installed a pick up coil in the distributor and I got the same thing so I got a computer on its way I'll let you know what happens.
Expert:  peterpete190 replied 7 months ago.

O.k.,let me know how this turns out here.

Thanks Pete

Customer: replied 7 months ago.
The computer came today and I installed it and I still have the same result do you have any more suggestions.
Expert:  peterpete190 replied 7 months ago.

Was the PROM chips swapped over from the old computer to the new computer when it was replaced?

Customer: replied 7 months ago.
I swapped it
Expert:  peterpete190 replied 7 months ago.

This is a tough one for me to fully diagnose from here myself.I will open your question up for others here to see if anyone else can assist further on this as someone else here may have more info on what to check or test for this fault.I hope you can get this resolved with ease.

Thanks Pete

Customer: replied 7 months ago.
Yeah please do let everybody else review it