fuel pump

[swoop]

I was wondering if a 89 suburban should have an electric fuel pump? I know that there is not a mechanical one attached to the front engine block but when I turn the key on I dont hear the pump cycle. The truck starts fine every time. Just wondering about this. Brian

[sub006]

If you have TBI, you have an electric fuel pump inside the gas tank, so you can't hear it!

Mine went out at 150,000 miles, about a $300 job to drain and remove tank, change pump, reinstall and replace fuel. Now at 386,000, still running fine, fingers crossed!

[swoop]

Originally Posted by sub006

If you have TBI, you have an electric fuel pump inside the gas tank, so you can't hear it!

Mine went out at 150,000 miles, about a $300 job to drain and remove tank, change pump, reinstall and replace fuel. Now at 386,000, still running fine, fingers crossed!

Hello, thanks for the info. I'm having a fuel related problem with my sub right now, or at least I think it is. I just recently purchased it with 122,000 miles on it. Of course when I checked it out it seemed to be in tip top shape. Very clean inside and out, engine comp. too. No leaks anywhere. But recently it has been performing different. From a stop at very low speeds it stumbles or cuts out then goes fine till it changes gears and I can feel it as soon as it shifts. Not near as bad though. It is more noticable after the engine is warmed up. It has stalled out from a stop once now, had a low tank, down to atleast 1/4. I thought mabey the gauge is off a little bit and closer to empty at a 1/4 than it shows. I'm hoping that I've got a clogged fuel filter a thats all. I have looked for cracked vacume lines or plugged pvc valve but all is good there. I dont have any diagnostic tools and autozone of course can only scan OBD11. I guess mine is a OBD1. Its not showing any check engine soon lights either. Thanks again Brian

[sub006]

Could be a lot of things, Brian. For example, I've seen intake manifolds clogged with deposits choke off an engine similarly.

Should be easy to check the gas gauge. You don't mention what year Sub you have, but the tank should be somewhere between 31 and 42 gallons. Because of the shape and mounting angle of my Sub's 37 gallon tank, when the gauge indicates the first half of a topped off tank (full down to 1/2) is used, it's actually burned at least 20 gallons. The second half (1/2 down to empty) is about 15. If it suddenly took 34 gallons to top off from a gauge reading of 1/4 I'd figure I have a sending unit problem.

I change my fuel filter annually, about 30,000 miles, and at that point I cannot blow through the used one; the pump can, but it's definitely working harder. If yours has never been changed in 122,000 (it happens), I'd be surprised if the truck runs at all. Changing the filter yourself is cheap, quick and easy so I'd recommend you go ahead and see if it helps.

A good independent garage will check out your OBD I and confirm the problem "hands on" for about $60. That's more than the cost of an OBD I scanning tool if you're a do-it-yourselfer. And Midas Muffler shops frequently do free "Cbeck Engine" light diagnosis for FREE, I recently took advantage of that on one of my BMWs. They might have a similarly good deal for your OBD.

Good luck and Happy New Year!

[swoop]

Thanks, I picked up a fuel filter last night and will replace it this weekend. It should give me something to do while I wear off my hangover I anticipate coming. My suburban is a 89. I cant remember if I posted that I had ran the tank low. It was at a quarter or lower. And the truck stalled on me from a stop and incline. I filled the tank to half that night and drove home with some of the hesitation still there. Im hoping that I did indeed clog the filter and nothing more but I still cant figure out why it would stumble more when the engine is warm though. Have a happy new year and thanks again. Brian