Fuel Pump?

[Facetime]

I believe good form for asking help is to post a pic first so here it goes. First time pic poster hope it works. Finally had some nice weather here in Idaho so the top is off.

[Facetime]

So now here is the question. In warm weather my truck seems to have a problem with the fuel pump overheating and quitting. If I let it sit for about 15 mins., it will start right back up. It is an aftermarket electric pump that I had replaced at the end of last summer for the same reason. As you can see, it is located by the rear right tire and covered in some heat protective material to try and keep the heat away. Does't seem to help. Any ideas? Anybody else have a similar problem? I drove it all winter with no problem at all. I hate having a great summer vehicle that doesn't want to work in the summer.

[bouncytruck]

First, nice looking Blazer. Thanks for posting the pictures.

Why are you using an electric fuel pump and not the factory mechanical?

[lks dcvn]

[Facetime]

I should preface this with my mechanical knowledge is limited. I bought this blazer first because they have always been my favorite and second to learn with and help teach my son (only 8 ). That being said, the PO had an electric one installed and I didn't know enough to change that out and go with a mechanical one. I thought I remember hearing that the mechanical ones in the engine compartment had similar problems. Is that not the case? I assume I can find a mechanical one through LMC or a supplier of this board. Any help would be appreciated. I am tired of having to pull off to the side of the road and wait. Thanks.

[Jtrux]

Don't go to LMC to buy a fuel pump, you can get one through any auto parts store cheap, probably less than 20 bucks. My question is...is it really overheating? The reason I ask is because it almost sounds like you have a vapor lock problem rather than a fuel pump problem. When the fuel in the lines gets too hot it turns to a vapor and the fuel pump can't push it. When you sit for a minute and let it cool the temp of the fuel comes down and then the fuel pump is once again able to push the fuel.

[Burt4x4]

I have an electric pump in about the same location. I have EFI so I have to use electric to get the fule pressure up.

If you are sure heat is your root cause then I would re-locate your pump. Move it towards the tank or realy the furthest away from your exhaust pipe as you can.
OR
Install a shield, that doesn't touch the pump. get rid of that wrap. A shield in-between the pump and pipe would work better than a wrap, my opinion of coarse.
Going back to a manual pump is perrty easy once you familurize yourself with the setup. You can look at any 70s chevy truck/Blazer and see the hose routing and you can buy a pump at any parts house.
Post up some pics of your engine, the mechanical pump mounts on the passsenger side front of the engine block, you should see a block-off plate bolted there.

[bouncytruck]

I don't think you need the electric unless you're running EFI or some system that demands more pressure. I've had three blazers now and all of them had the stock mechanical fuel pump.

Are any of the fuel lines near the exhaust?

If you go back to the mechanical, you can get the pump itself at any autoparts store. They are between $15-20. You may need to replace a portion of your fuel lines to remove the electric.

The block-off plate looks something like this


The mechanical fuel pump will look something like this

[smokekiki]

The prev owner of my suburban installed an inline pump like the one pictured,but he also had the stock pump hooked up. So, you may still have the stock pump. He also said he was having "vapor lock" problems. The only problem was a dirty sock on the fuel pick up and/or really old fuel lines. I replaced the rubber lines,and replaced the sending unit. No longer needed the electric pump.

[Facetime]

Thank you to everyone for sharing your knowledge to those of us less informed. No EFI, upgraded 4Bl carb installed by PO. I thought of the vapor lock issue as well but when I open the gas cap there is no sound and on each occurrence the gas cap has play in it. Are these definitive indications of no vapor lock? I guess I am not sure if you can have vapor lock downstream of the pump or not. I have an inline filter (clear)just prior to the carb that when it won't start, I can not see fuel going into it. Normally it fills right up. For those of you who have stayed with the mechanical pump, do you have problems on hot days? By hot, I am only talking about 80 which to me should not be hot enough to cause problems.

[bouncytruck]

I've got a completely stock & original engine and I've never had any fuel delivery issues. We probably don't get quite as hot as you up here in Seattle, but I've driven it on 90+ days without any issues.

[Jtrux]

Here in San Antonio on really hot days in traffic I never had an issue with a regular ole mechanical fuel pump.

[dirty trucker]

I have a Holley Blue electric fuel pump mounted in almost the exact same spot, never a any trouble YET... In fact, my exhaust dumps in front of the rear axle, so technically, my temps should be higher than yours..
If it's not vapor-lock, I would almost wonder if that wrap is making the pump overheat?? Way up there in the frame rail, rolling down the highway, I would never guess it was a heat problem. Unless the wrap is keeping the heat IN as well...

[Facetime]

Thanks again to everyone for your inputs and advise. Finally had a minute to get under there and do some digging. Pulled the line off and realized I had no pull from the pump at all. The filter just prior to the pump seemed clean so I am guessing just a bad pump. Replaced the pump put a new filter and all seems OK...for now. Any more problems and I think I will go to a mechanical pump. Saw where the pump would go (thanks Bouncy) doesn't seem like it would be too bad to put in, thanks again!!

[Yukon Jack]

Assuming you do not have a mechanical in place right now, if you do buy one you will need to get the fuel pump push rod also.

Great looking K5 and welcome to the board.