Sending Unit difference- gas vs diesel

[RADustin]

On the 3 line sending units, what is the difference in the gas vs the diesel?

Was a sending unit ever made with a 1/2" supply and 3/8" return + vent?


TIA

 

[1987 GMC Jimmy]

On the 3 line sending units, what is the difference in the gas vs the diesel?

Was a sending unit ever made with a 1/2" supply and 3/8" return + vent?


TIA

Here's something to hopefully help with your first question:

http://www.gmsquarebody.com/forum/showthread.php?t=11460

As far as your second question goes, I'm pretty sure that the '80's Chevy P30 fuel sender should match that specification. The only problem is the one that does match those specifications was the factory sender on P30 based motorhomes, and from 1984.5-1989, they had a carrier for an electric fuel pump in those applications. I never had to source a new sender; I just rebuilt the old one. I RockAuto'd the replacement sender for just a P30 step van, and it looks like it has the 1/2 inch fuel outlet with a 3/8 inch vapor outlet. It's returnless. When I was working to sell my old motorhome, it used an inline filter with 1/2" nipples, and one outlet looks visibly larger in the product photo for the sender that I just saw. I'll attach it so you can see if you agree. That's the only lead I can offer from my experiences.

 

[RADustin]

OK cool. Man you know all kinds of ****! lol

I think I have an idea. I think I'll just use a standard(3/8) feed returnless style sender for now.

When I diesel swap later I will just modify the sender for a new 1/2" feed and pull the sock off the 3/8" line and make it my return.

That will work.

 

[1987 GMC Jimmy]

Ha, thanks. I'd like to think I have a few tricks up my sleeve, but some of these guys on here twice my age could really school me. So you're just gonna switch from a three outlet to a two outlet sender and modify that setup when you convert to diesel?

 

[RADustin]

yep- current I have 3 outlet senders with two of the lines plugged off. basically a feed with no return or vent.

So I'm going to put it all back together when I short bed the truck to be a single feed on each tank and a vent(2 line).

Then when I diesel swap I'll modify one sender to be a 3 line, with a large supply line. The second tank will become an aux tank with it's own jockey pump back to the main( and stay a 2 line). All controlled by the PCM. So no fuel tank switch or anything. It'll all be handled on it's own.