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Fuel pump problem

P

Paul Vallaster

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Hi new to the forum I have a 1993 chevy 3500hd with a 7.4 gas it's a cab and chassis that had a utility body on it I can't find a complete fuel pump and pickup the truck has a 40 gallon rear tank the sending unit has 2 outlets on top everywhere I ck lists 33 or 31 gallon tanks I'm sure it's a 40 gallon I have the tank out now please help if anyone has run into this thanks in advance
 
Welcome to TTS! you might check RockAuto. check out the pictures on the sending units. some might be the same design depending on the tank depth. I looked and they do list one for HD and shows "except 31 gallon" the pump is a separate part though


if you do purchase from them, they are a vendor here. look on their vendor forum and you'll find a discount code to use when ordering.
 
Thanks for cking for me my unit has 2 lines at the top and a separate 1off to the left in the top of the tankthat goes to the evap up front I looked at the link you sent that 1it has to many lines I don't know if I can use itthe tank is made by rpm tanks thanks for helping I'm kinda stuck and not sure what to do
 
maybe post up some pics of the sending unit. other may chime in that know more. look carefully on the unit to see if there are any part numbers on it to help identify it.
 
You should be able to measure the dimension of the tank, then figure how much liquid within one cubic foot and taker from there.
Also, I am i agreement with that there should be some kind of a part number stamped onto the head of the old sender unit.
It too could be possible that the sender unit/fuel pump might be from a 1987 GM truck. The SU on those was a little smaller mounting flange and different on the pipe/hose configurations.
 
yeah, measuring the tank is how I discovered I had a 34 gallon when I had been driving for a year thinking I only had a 24 gallon. the PO warned me not to drive more than 300 miles between fill ups. I was at about 300 miles when I dropped mine only to discover that was still 1/4 tank of fuel still in there!!
 
measure yours and look on Rockauto at the tanks and their measurements to compare. also like MrMarty said, look at the older year models, older body styles and see if photos and measurements may match yours. I know with your year model and being it's a cab chassis, it could have a number of things different that GM did, or someone else may have done before you.
 
That's a good idea to measure the tank dimensions the sticker in the the upper left corner says 40 gallon all the units I have seen come no where even close I did go to a gm dealer they put in the vin and what came up was wrong i can look for some kind of numbers it's pretty rusted but will definitely ck I posted some pics of unit and sticker I really appreciate all your help on this
 

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Paul, Good morning

Unfortunately that tank is not factory. with the age of the truck and fact it being an aftermarket add-on tank, the chances of finding the sender is slim. you might be better off replacing the tank with OEM style. snap some photos of the entire tank and where it mounts. others may have more info than I do.
 
not only that, but since you are dealing with a gasoline vehicle, there are safety concerns with the tank you have, the sender in your pics doesn't look like it has any vapor lines or a vent. with no way for vapor to escape the tank or vent it's self with filling, static electricity is an evil enemy! Honestly the complete new tank assemblies for these trucks are under $150. when I was pricing a tank for my rig, I found a 34 gallon replacement OEM tank was slightly over $100.

Check out Rockauto for whats available. what I do is look at other sites by application, sometimes go up n down a couple year models and find there are more "factory" options out there plus "dealer installed" options they did to these trucks back then. not all places catalog those dealer installed options, but some do. once I have a part number and other info in my hands, then I go back to places like rockauto, amazon, summit racing and others looking for the best deal and availability. sometime I have good luck and some times I hit a brick wall. just keep in mind though, for critical parts and when you want to make sure your getting GM Delco parts for other things, be very careful. there are loads of fake copies out there. if you want AC Delco stuff, go to an "authorized" dealer!

Also a good tip is to stop by your local dealer hoping they still have the info, get them to give you a build sheet for your truck. if it has "dealer installed items" they will have the info on them!
 
Cab and chassis trucks are almost always modified some how- kinda the point of it being bought that way. I used to co-own a truck equipment shop back in the 90’s and it just depended what customers needs were as to how much got modified. Replacing the tank is super common. There was literally a hundred companies we could but tanks from- most went out of business long ago. Guessing you tried contacting the company listed already?

That is definitely a gm set up. But finding a store that will let you go through inventory just looking, let alone if they have one same size - don’t count on it. Take a notepad with you and if you find one close- get it. Extending the pickup tube and float rod is easy enough in the hands of a skilled welder.

If you haven’t owned this a long time- understand things like this is why cab chassis are always for sale way less than standard trucks. When you get into things like electrical systems- it could be a complete one-off and chasing down problems there becomes a nightmare. Electrical, frame and suspension repair jibs when trucks were only a year or two old was a huge part of my business. Infact - if you are not familiar with what is ok to do and what isn’t- take many pics of yours and post them here- please choose “FULL IMAGE” not the thumbnail. If there is anything dangerous that catches my eye, I will let you know.
If you have owned it a long time and this is the first time you ran into non gm stuff- count yourself lucky. When you do get a solution, stamping a brass tag with new part number and attaching it is a good reminder for yourself and/or next owner.

oh yeah-when looking for that assembly- dont look at just your 1993 year. You might find the frame of the assembly is from many years back and the pump itself is the correct one. That was a common move- other than that, that Texas company probably made that frame assembly themselves, modifying the original.
 
OH, hey-
Something else that hit me. The rubber fuel line that was originally on that truck will not stand up to modern fuel with ethanol/methanol in it.
You need sae30r9 or higher. Use no aluminum, copper or brass in the system as you repair /replace even if that was original. Steel or stainless steel is good.
 
If your local Napa is like mine, they will let you go in the back and start comparing what you have to what they have on the shelf. You could also take it to them and let them measure it up and they should be able to get on their computer and narrow it down for you.

I built a homemade car thingy in high school and several years later the master cylinder went out. I couldn’t remember what MC I used so I took it up to Napa and they let me compare what I had to what they had on the shelf’s. Still couldn’t find it so they measured it up for me and a little while later after digging through their computer found that it was from a 1940 something dodge truck. Ordered it in and it was the exact one. A good Napa guy should be able to take the measurements that he needs and should be able to look it up I would think
 
x2 on a good counter man! our Napa here is the "go to" for stuff like that. hence where out autozone got their nickname "Vatozone" from their guys never know which end is up. lol a person can walk into our autozone here and ask for blinker fluid and they'd ask you for the year make and model!!
 
Paul Vallaster said:
it's pretty rusted
Click to expand...

You didn't say what has "failed" and what you are exactly trying to fix. If it's a bad fuel pump maybe just replace the pump itself and clean the rest of it up.

Fuel level sensor failure can be solved better by aftermarket parts like:


Yeah, it would be awesome to find the easy button replacement. But maybe you have to fix up this part.
 
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