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I'm a month into this damn fix and two matches away from solving the problem. Lol. No kidding. I have a 2000 GMC Sonoma with a 350 TPI under the hood. The entire fuel system runs on a standalone unit, and not through the factory computer. Originally, the truck was a 2.2 flex fuel truck. Fuel Pump died, not a huge deal...bought a new one (according to VIN#) a flex fuel pump. (Which I don't know the difference between the flex fuel pump and standard). The pump came in and I went to install it, only to see that the connections for the gas lines were not the same as the dead pump in the truck. Sent it back. This made me think that the pump I had wasn't the stock 'flex fuel'pump. Back to the drawing board. After TONS of head scratching, self contradicting myself, and thinking, I decided to try buying a fuel pump for a 98-99 Suburban, which is powered by a 5.7 350. The pump assembly comes in and I install it. Worked fine while I was messing with a few other things (completely unrelated to the fuel system). I put the bed back on, got the truck completely together and drove it maybe 60 miles or so, a total of maybe two hours. Came home and parked it overnight. Wen to leave early the next morning...wouldn't start. Noticed the fuel pump wasn't priming. FML! I pulled it all apart AGAIN, tested the pump, which ended up not functioning properly. Used the warranty, and exchanged it for a new one, thinking I had a defective pump.

So, the new pump comes in (same model Suburban pump). I put it in, and the truck starts right up. Before I even try to take it off the jack stands and put the bed back on, I let it run on and off for maybe a total of 2 hours or so while I polished my wheels and waxed the truck. Everything was good. Took it out for the evening. Ended up parking it in a neighborhood while I went out with some friends. Went to start it the next morning (yesterday), NOTHING AGAIN! WTF! Lol.

I don't know what to think or where to start now. I can't figure out this weird behavior. Is the truck burning up the motor in the pump? But it works fine until the next day. Bad ground maybe? Idk. Weird. Pulling it apart again tomorrow.

After going to AutoZone, then my local Chevrolet dealer, then to an AcDelco store today, I think I've figured out that the pump that originally went bad on me was the stock 2.2 flex fuel pump. However, I'm not 100% sure. AcDelco brought out the 2.2 flex pump they had and compared it with mine. All looked the same, with a few subtle differences, which they said that all of the pumps have been redesigned. After talking to them, I made the assumption that the first pump I bought (the 2.2 flex) was not labeled or boxed correctly since the one AcDelco showed me had different fuel line fittings even though it was the same model.

Pump that originally went bad:


Replacement 2.2L Flex Fuel Pump. E3967M Notice how the fuel line connectors are different and how the Return line is larger in diameter than the Feed line, as compared to the pump above...


Pump for a 98-99 Suburban. P1539M Nearly identical to the first pump.



On a separate note, I'm having issues with my fuel lines, though the truck has operated fine being this way for years. I didn't do the engine swap, so you all know how that goes. I do have the paperwork for everything that has been done, but see nothing on this topic. I feel that the fuel lines are ran backwards. From the pump, the "F" line goes up to the engine bay, though I haven't traced where it goes into the TPI. The line to the middle connection goes to this filter (charcoal?) box beside the tank and comes back out and up to the engine area. What throws me off is that it's the "R" line that's the line that runs through the fuel filter. If the "R" line is a return, and the filter has a flow direction from tank to engine, what's going on? Surely that's not right? Like I said, I didn't do the swap, so maybe there's a reason for it, but it doesn't seem logical to me. And like I said, the truck has ran fine being hooked up this way. I plan on trying to trace all the lines to see where they go tomorrow when I get it all apart again. I just didn't bother before because "if it ain't broke, don't fix it." Would the truck run with more power if I'm correct and I fixed these lines if they were backwards? On the other foot, wouldn't the engine be starving or stalling from a lack of gas if they were backwards? Someone help. Lol.
 

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Ok the line that is connected to the clear flex line under the top is your supply line. That is the one you want to hook to the fuel line with the filter. If you hook it up backwards that may be your problem. If the (F) line is your supply line and you are hooking up the (R) line to the fuel filter that is wrong. I also bet that is what is burning out the pumps trying to force fuel in the wrong direction.
 

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On my 2.2 2002 the supply F line goes to the center of the fuel filter badk. The return line R comes out the side of the fuel filter back....this is fuel back to the tank from the regulator inside the fuel filter. This is why these trucks have a high $$$$$ fuel filter....the regulator is inside them. My fuel system runs at 60 psi out the filter to the fuel rail.
Good luck
 

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Tuck,

How did you make out? The pictures of the oumps you showed are very diffrent. The E3967M pump turns in the opposite direction. If you look at the 8th digit of your vin it will tell you if it came with a flex fuel engine. send me an e-mail [email protected] with your info and I will send back the fuel diagrams and wiring configuration. you may want to check voltage during operation. Low voltage will kill a pump quick.
 

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i have a similar issue. but the photos above are now gone. this is what i have done so far. i had a p0442 i think now code the code for a general evap system failure. anyway i took the tank down and got a new pump that turned out to be the wrong pump so after messing with that for a few days and not having any luck getting it to run i dropped the tank and again and found the pump was broken at the mounts on the top. so i put the old pump back in. then that pump blew off the pressure line at the pump, so i got a new pump and some dorman repair lines 18" long and had to use some rubber gas line to make the connections at the splice lines to the filter. so i started it and found the repair line and rubber gas line splice leaning like a fire hose so i moved the splice so i could have one clamp over the kits barb and a 2nd clam on the kits barb. the 2nd new pump i got i compared it to the original pump to make sure the wires went to the same spots and the pump hose and return were the same. they were a match

so i installed the new pump and new dorman splice kits and had a leak at the spot i had to splice the dorman kits to the rubber gas line i put in years ago. started it agan and i had a leak on the filter where the center line goes into the filter body on that bulge. i was assuming that the 5/16" pressure line went into the 5/16" center port on the filter and the 3/8" return line on the pump went to the side 3/8" line on the filter.

it seems i can't find a fuel diagram that has this filter i have so that i know if i plumbed it correctly. i do not need to plum it wrong and burn out a 200$ pump and all the site i go to show the filter with 1 inlet and 1 outlet. so i have a bastard system here so i have to know for sure on my filter what is the inlet and outlet. i know on the pump the smaller port is the pressure out and the larger port is the return. i can see the hose going to the pump and to the bowl yes this photo show a bad pump i installed a new pump but di not take a photo

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Feel free to start a new thread. This one is 9 years dead. You can post a link to this thread if you like.
 
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