2001 Suburban Fuel Pump Plug?

Mattt · September 16, 2011

In the past I had an '01 2500HD truck that had it's share of fuel pump problems. I had the pump replaced once at the dealer which then quit relatively quickly with a month, so back to the dealer it went. What I came to find out was that there was a Service Bulletin that detailed how the pump connector at the top of the tank would intermittently short out. Once I knew that, all it took to get the truck running again was to reach in above the tank thru the rear fender opening and unplug the pump & then plug it back in....running again. The dealer didn't even know about this until they put the second or third pump in.

Anyway...fast forward to today....I'm now driving an 01 Suburban that is now having fuel pump issues that seem very similar to what my old truck was doing. Where on the Suburban tank is the pickup and electrical connector? I'd like to try the truck trick, but can't see where it's at. As I feel the wire loom along the top of the frame rail, it seems like it branches off to the tank right where the front tank support strap is located. Is that where the pickup, fuel pump, connector, etc is located on the Sub? Is there any way to reach it without dropping the tank?

I suspect this may be the problem as there are times I hear the pump running and other times I hear nothing. I've been messing with it this evening and have replaced the fuel filter already to rule that out. I've also banged on the tank with a rubber mallet to no avail. Sometimes it runs....sometimes it doesn't.

Is the electrical plug accessible by hand?

On a side note....I'm looking on Ebay and Craigslist for new pump modules and I see some vendors selling pumps only....without the complete pump module. Is that a new offering from GM? One of the pumps I saw on Ebay was in a GM ACDelco box(red, white, blue) so it appears to be a factory part.

Second.....do Silverado trucks use the same fuel pump module as the Suburban. I found a new in box GM fuel pump module on Craigslist for a great price, but the guy says it was bought for an '03 Silverado.

Thanks in advance for any insight to these pesky fuel pump problems.

Mattt · September 16, 2011

Well I got the tank down and see...not a chance of reaching that plug without dropping the tank.

Still looking for info on Silverado vs. Suburban fuel pump module. Also wondering about the pump only replacements....good idea or no?

Mattt · September 25, 2011

I figured I'd update this thread.....I've driven the Sub for the last few days and it has improved idle quality. I'm now thinking the fuel trim was so out of whack to compensate for the old pump being weak that it took a while for the computer to adjust to the new fuel pump. The old pump has cavitation I could feel when hooked direct to 12v battery. It still runs but there was a definite buzz, vibration coming from the pump. I also hooked the new pump direct to 12v before installing it just to compare the two pumps.....the new one has no buzz, vibration. It just had a high pitched zing sound and was smooth when running.

I'll check the fuel pressure one more time, but it appears that the system has re-adjusted and is running correctly now.

govtech · September 16, 2011

you wont get any info on sub/pick up pump assembly if it works or not unless someone has tried it .....

the dealer can see if the part numbers are the same ,not here ....

different tanks means different pumps imho,

change pump only if available and the fuel filter and screen that attaches to the pump

Mattt · September 23, 2011

Got the Sub running again today. I came to find out there was an open recall on this Suburban for the fuel pump wiring harness. When I removed the module from the tank, the power & ground wires to the pump had the insulation melted away and the plastic plug in the module head was melted in place as well. It was difficult to remove the plug from the module head.

Once I found out about the open recall, I got a local dealer involved to do the recall work and re-install the tank. Whew...thankfully no more time on the creeper under the Sub. I still ended up replacing the pump with a supposed AC Delco pump, this one.... http://cgi.ebay.com/ebaymotors/New-AC-Delc...=item53e779cf5b

I installed the pump on the module head and the dealer finished the job with the wiring harness recall and re-installing the tank. The dealer told me that pump is NOT a genuine AC Delco part......that it is a rip off, knock off Brand X pump in a copied AC Delco box. They're saying these pumps are made to look like genuine AC Delco, but are not. If you search the part #'s they do show up on an AC Delco site for Mexico. Anyone have more info on these grey market pumps?

One thing that is slightly strange since I picked up the Sub this afternoon....it is idling at a lower RPM and seems like it might almost die when idling in gear. When I kick the A/C on, and the engine is running but in Park and it loads the engine, the RPM drop is most noticable. It has only died once...but that is one time too many.

Due to this low idle and strangely low idle....I hooked up a fuel pressure gauge to the schraeder at the fuel rail. I'm seeing a solid 50 PSI with key on, not running OR once started and sitting in Park. Is 50 PSI the correct rating for a 2001 5.3?

If I blip the throttle, the PSI might jump to ~55-60 PSI but then settles back at 50. If I blip the throttle and hold it at say 2000-2500 RPM, fuel pressure might drop to 46-48 PSI at the lowest. Are those PSI's within the factory spec?

The dealer suggested a tune up when I picked the Sub up because he noticed the low idle, but I'm thinking it might be fuel pump issue? Sub does have 175k on the ticker...so it could use a tune up, but who knows what is driving this lower idle. It is idling smoother with the new pump...just at a lower RPM. I hooked up my scan tool....no codes and on the scan tool, I'm seeing a 550RPM at idle, with a swing of at most 40 RPM.

Thanks in advance.

txab · September 23, 2011

According to the SM, you should have 55-62 key on, engine off.

Mattt · September 17, 2011

I've been doing some digging today and the part #'s are different. It looks like there is a long reach pick up and a short reach pick up. Other than the length they look the same. The truck has the long one, and the Sub has a shorter one.

I've already changed the fuel filter and the pump screen/sock comes on the new pump module as far as I know.

It's funny....when I swapped the fuel filter the other day, the pump kicked back on and worked for about 1 hour....but the pump is now dead again....no fuel pressure at the fuel rail schraeder valve.