Fuel System

[87silveradok20]

Im not getting fuel to my engine on my 1984 C30 Cummins (originally a 6.2). I have the factory fuel system up to the engine bay then a rubber line that goes to an electric fuel pump on the fender, from there it goes to the mechanical pump that is on the Cummins then to the IP. I have few questions about all this.

1) is there a fuel filter on the factory side of things?
2) Is there a fuel pump in the tank?
3) Do I need the mechanical pump on the engine block if im running an electric one?

 

[87silveradok20]

Can someone at least point me to a thread that has this information?

 

[1987 GMC Jimmy]

Im not getting fuel to my engine on my 1984 C30 Cummins (originally a 6.2). I have the factory fuel system up to the engine bay then a rubber line that goes to an electric fuel pump on the fender, from there it goes to the mechanical pump that is on the Cummins then to the IP. I have few questions about all this.

1) is there a fuel filter on the factory side of things?
2) Is there a fuel pump in the tank?
3) Do I need the mechanical pump on the engine block if im running an electric one?

Sorry. I was waiting to see if anyone else would tackle this, but I think I can help.

1. Yes. Look at where your master cylinder is/would be in the engine bay. Now look down and to the left on the driver side of the engine. There's a black plastic housing with a bolt head. You unscrew that out of the housing, and that's your filter. It's like changing the filter on a 7.3 Powerstroke, just not on top of the engine this time. You probably wanna drain the sump, too, before you change it. There should be a lever or something nearby that'll allow you to do that.

2. No. Should just be a strainer sock and sending unit.

3. I would just keep the mechanical pump if it were me. Even though the pressure parameters are likely the same or similar since the 6.2 uses a mechanical pump, too, the 6.2 is a low power, naturally aspirated animal so I'd feel better personally about using what Cummins intended. Are you running the P-Pump or the VE Pump?

Ahh, you said first gen before so VE Pump. It's a surprisingly simple fuel system. It doesn't need a fancy electric lift pump - just the mechanical pump and the IP. A lot like a tractor if you've fooled with them, which is what those engines originated from.

 

[87silveradok20]

Sorry. I was waiting to see if anyone else would tackle this, but I think I can help.

1. Yes. Look at where your master cylinder is/would be in the engine bay. Now look down and to the left on the driver side of the engine. There's a black plastic housing with a bolt head. You unscrew that out of the housing, and that's your filter. It's like changing the filter on a 7.3 Powerstroke, just not on top of the engine this time. You probably wanna drain the sump, too, before you change it. There should be a lever or something nearby that'll allow you to do that.

2. No. Should just be a strainer sock and sending unit.

3. I would just keep the mechanical pump if it were me. Even though the pressure parameters are likely the same or similar since the 6.2 uses a mechanical pump, too, the 6.2 is a low power, naturally aspirated animal so I'd feel better personally about using what Cummins intended. Are you running the P-Pump or the VE Pump?

Ahh, you said first gen before so VE Pump. It's a surprisingly simple fuel system. It doesn't need a fancy electric lift pump - just the mechanical pump and the IP. A lot like a tractor if you've fooled with them, which is what those engines originated from.

Alright so im with you on everything except the where fuel filter should be. Are you saying it is on the engine block or on the truck?

 

[1987 GMC Jimmy]

Alright so im with you on everything except the where fuel filter should be. Are you saying it is on the engine block or on the truck?

It should be to the side of the intake manifold towards the back on the driver side. Here, let me show you a picture.

 

[87silveradok20]

It should be to the side of the intake manifold towards the back on the driver side. Here, let me show you a picture.

ok so the water separator doubles as the filter then?

 

[1987 GMC Jimmy]

No, the water separator is at the bottom of the housing, and there's a little lever there to drain the fuel out of the filter housing whenever the WIF light comes on in the little information center in the Dodge truck. That's all the water separator is, but the filter is a separate piece in the same place. It screws into the top of the housing and the water separator is at the base.

 

[marks86]

those 12v mechanical fuel pumps are good up to like 500hp

 

[87silveradok20]

No, the water separator is at the bottom of the housing, and there's a little lever there to drain the fuel out of the filter housing whenever the WIF light comes on in the little information center in the Dodge truck. That's all the water separator is, but the filter is a separate piece in the same place. It screws into the top of the housing and the water separator is at the base.

ok, I replaced the filter and it seems to run better now. Havent got a lot of time on it yet but seems to be doing better.

 

[87silveradok20]

those 12v mechanical fuel pumps are good up to like 500hp

Id like to put this engine at around 350 or 400. That way it will still be driveable but will have some power too.

 

[1987 GMC Jimmy]

ok, I replaced the filter and it seems to run better now. Havent got a lot of time on it yet but seems to be doing better.

Great! A filter change can really make a difference on diesels like that. I hope my instructions helped a little. My knowledge is more towards the 7.3 Powerstrokes, but there are commonalities.

 

[87silveradok20]

Great! A filter change can really make a difference on diesels like that. I hope my instructions helped a little. My knowledge is more towards the 7.3 Powerstrokes, but there are commonalities.

Yep thanks for the help. Im trying to learn as much as I can.