Fuel Pressure issue?

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TahoeInFC

TahoeInFC

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Your right long debated issue is these fuel pumps. Many many threads on these pumps everybody wants the best pump for the money but just because I got X amount of years out of my pump doesn't mean you will with that exact brand pump.
Yes, good point. Has a lot to do with environment (hot climate), letting tank run low, fuel quality, installation quality, bad day at the fuel pump factory.
Was just looking for general comments.
Thanks

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TahoeInFC

TahoeInFC

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Depends on your situation when you see the prices for an OEM pump you may consider an auto store pump. People do buy them and they get some years out of them.
Ha! Yes, definitely. $300 does make one want to look for alternatives.
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JonnyTahoe

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Hey All,
I think I'm going to have a little time to chisel on this problem this weekend.

I probably won't have enough time to drop the tank, but may have enough to pop the upper intake and have a look. Still, that's a major pain, so I'm thinking of some other tests I can run before I get extreme. I'm planning to look at the plugs, the cap and rotor, and check for vacuum leaks. I might even grab the pressure gauge and do another leak-down just to verify what I saw the first time.

I've read that a vacuum leak can cause the fuel pressure regulator to misbehave, and cause the engine to run rich. If I have a vacuum leak, it's not severe enough to make it run super bad (yet). Not throwing codes or mis-firing. Seems to run OK. Still gets around 15 mpg, so mileage hasn't suffered much. Occasionally idles a little rough if I've been driving on the highway and stop at a light, but then seems to straighten out, sometimes by the next stop light.

I'm still running rich, though. Sooty coating on the inside of my tailpipe. I can clean it out, and it's back in a few days. I can smell the richness in the exhaust, and I'm thinking I'm going to end up trashing my catalytic converter(s) if I let this continue.

I can also smell gas in the intake plenum when I remove the air intake and sniff down in the throttle. I did a quick leak-down test, but pressure stays solid when engine is killed, so is it possible that the gas smell could be a by-product of a vacuum leak somewhere? Also, is it possible for a fuel pressure regulator to 'sort of' fail? Meaning it would not leak down quickly, but could still be leaking enough fuel in the intake to cause the engine to run rich, but not rich enough to throw codes?

I'm thinking I need to attack this 'rich' issue before worrying too much about the fuel pump.
I'm in that weird no-man's-land where the truck isn't really running all that bad, but I know something is wrong.

Any more ideas?

Thanks folks!
 
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TahoeInFC

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For a job that you’d rather not repeat too soon, I’d go with an ACDelco part.


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Yeah, I'm starting to think along those lines. Fuel pumps are sort of a bummer to fix, so definitely want it to last. Going to see if I can find one around here tomorrow.

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Kelsda

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Yeah, I'm starting to think along those lines. Fuel pumps are sort of a bummer to fix, so definitely want it to last. Going to see if I can find one around here tomorrow.

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TahoeInFC

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Hi All,
I found a Delphi pump locally and snapped it up. Installed it last night (much cussing and scraped fingers), but got it in, along with a new fuel filter. Fuel pressure jumped right up to a little over 65psi on key-on, then settled in right around 60 while running. I think it runs better now...guessing my fuel pressure has been suffering a little lately, so engine efficiency may not have been where it should be.

BUT! (there's always a 'but') Of course, as some wrenching jobs go, I have a new problem. I have a fairly obvious gas smell in the driver's side rear wheel well. Naturally, I suspected a line that wasn't quite engaged, so I grabbed a flashlight and started crawling around under the Tahoe.

Tank is dry all the way around. No evidence of leaks anywhere.
Not satisfied, I grabbed a telescoping mirror and situated it so I could see the top of the tank from below. Tricky, but possible. Did this from both sides of the tank. I could see pressure sensor hookups and the top of the pump/sender assembly. All the lines were connected and dry...no signs of leakage. I made sure the high-pressure lines were fully engaged, which they are. No fuel drips or sprays on the tank, the lines, the wires, or the floor pan above the tank. All dry. I hit the key a few times to charge the pressure, and still did not find anything. I even started the truck and let it run for a few minutes while I crawled around. No sprays or drips. Hmmmm...

Oddly, I really didn't smell gas around the tank nearly as much as in the wheel well. I investigated all the fuel lines from the tank to the frame rail all the way to the newly-installed Delco fuel filter. All dry. No signs of drips or dampness.

When I had the tank out, I peeked inside. Nice and clean. No signs of anything but a little surface rust on the outside. This truck has spent nearly it's entire life in a garage in either Texas or Colorado...not any rust to speak of anywhere on the vehicle. When the new pump went in, the rubber O-ring was properly positioned and nice and tight.

Popped the hood...fuel lines and engine completely dry. No signs of leakage or smell of gas. Passenger-side rear wheel well doesn't smell like gas. It smells like...uh...tire.

The truck didn't ever smell like gas before I did this job, so it's gotta be related somehow, but hell if I can figure out where the leak is.

I did fill it up this morning, but that has never produced a gas smell before yesterday.

Is it possible that my new-found fuel pressure from the new pump has found a weak link somewhere, and is forcing vapors rather than liquid fuel out someplace? Worn out lines someplace? Ideas?


Thanks, folks!
 

east302

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I’d coat everything under there with a degreaser and drench it with a hose. Let it dry and see if the smell is back.

It could just be gas spilled when you pulled the pump, dispenser/fill line...


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TahoeInFC

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I’d coat everything under there with a degreaser and drench it with a hose. Let it dry and see if the smell is back.

It could just be gas spilled when you pulled the pump, dispenser/fill line...


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That's a fantastic idea. I may try that this weekend, unless I get a chance before.
Thanks!

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TahoeInFC

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I’d coat everything under there with a degreaser and drench it with a hose. Let it dry and see if the smell is back.

It could just be gas spilled when you pulled the pump, dispenser/fill line...


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That's a fantastic idea. I may try that this weekend, unless I get a chance before.
Thanks!

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Hey all, realized I never closed this one out.
I cleaned up the tank and surrounding area as east302 suggested and let it go.
Fuel smell has not returned. I think it's good to go.

Thanks all for your help!

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