Hey folks, back after a very long absence, I've finally decided it's time to do something 'bout the 94 z28 that's been sitting in my garage all these years. I need to send it over to Tim the Tranny god for a rebuild of the 4L60e, but before doing so I thought it would be good to actually have it running. To that end, I've done the troubleshooting and have determined that I need both a fuel pump and level sending unit.

Does anyone have any recs for these? I know about the Walpro 255, but I've read that depending on the lsu you get, you might need to do some mods; I'd prefer to avoid that and go w/ an all-in-one solution, a pump/lsu config that is designed/engineered to work together. I've seen Delphi, TRQ & Spectra, and noted Jeg's has what they call an "OER" unit. There's also a lot of no-name offerings--scary. The price varies from ~$50 - $150, which is ok. I really just don't want to do this again anytime soon. Like most folks, I don't drive it much, which could lead to diaphrams going bad, etc. While I plan to drive it more in the future (assuming I ever get it back on the road), I'd like to find a pump/lsu solution that will hold up, and don't mind spending a bit more for it.

TIA for your input. Oh, and yes--I'll being doing the 'trap-door' mod.

 

In the "olde days" you had to buy a compete fuel sender unit (pump support, wire harness, float level sensor, relief valve, etc) to get a float level sensor. I think you may be able to buy just the float level sensor now. Are you after the complete fuel sender unit, or just the float level sensor?

Racetronix sells a direct replacement 255 LPH pump, along with wiring kits, install parts, etc.

https://www.racetronix.biz/search/se...=lt1+fuel+pump.

Note that they strongly recommend that you use the factory bucket when you install the replacement pump.

Buying a fuel pump online from an unknown source is a real crap shoot. There are many Chinese counterfeit products.

 

Not to mention spending a bit more money to be guaranteed the fuel pump will work, is well worth the time not spend pulling the tank out again.

 

He indicates he's doing it via the 'trap-door' mod.

 

Yep, def. doing the trap door. Much easier than yankin' the tank.

To answer your question, I'm inclined to swap out the entire assy; seems like the wise move. Did check out Racetronix, and they sure like to parse out each part, don't they? But for some of them, the strainer is separate, others have the harness separate, etc.

This is the Spectra 3908: https://www.summitracing.com/parts/sgt-sp3908h/

And the Delphi 10036: https://www.jegs.com/i/Delphi/117/HP10036/10002/-1

Seems like there should be plenty of assemblies like these, even if I do need to buy one part or another separate. Maybe my best bet is to buy it local. That way, if there's a problem, I can just drive over and get it resolved. All that shipping back-and-forth is a drag.

 

I have never needed to make a return with Jegs, but Summit is pretty awesome about working with you in the event of an issue, though I hear you about being able to talk to someone face to face.

Depending on if the car is a daily driver, I would pull the pump assembly and inspect for issues. If there were no issues, for the same cost and just the time of changing the pump in the bucket, you'll have a significant upgrade to your pump (https://www.racetronix.biz/product.asp?ic=fpa-003a). I personally installed https://www.racetronix.biz/customkit...sp?kc=rfpk-014 a ton of years ago and was happy with the solution. If you browse around, I did swap the pump and tank because of a bad gas issue that killed my tank, but I am still using the Racetronix power kit.

 

The kit you used looks good, but has parts I don't really need (like the relay), and is missing something I really do: the lsu. I jumpered the fwd connector underneath and watched my gauge drop back down like a stone, and the harness itself isn't the problem--there's power to the pump. Don't quite remember, but I think the gauge was a problem before I blew the tranny seals, so it's a holdover I never addressed. I determined the pump itself is bad by pulling the fuel filter and using the prime connector in an effort to pump out any remaining gas; I got barely a trickle. I'm assuming that letting it sit for ~5 years resulted in the diaphram drying up. Ironically, that's what led to the tranny seals going; while I was starting it a few times a month, I failed to put it in gear and force the tranny fluid to circulate. Doh!

Another irony: I used to live in Ohio, and there was both a Summit and Jeg's not far from where I lived. It's good to hear a vote of confidence for their online ability. I'd rather buy from them than, say, Amazon. Here's an oddity: both of the units I list above come up on Home Depot's site as available. Have no idea how that happens, guess they'll sell anything. While I got my compressor from HD, not too keen on buying auto parts there.

 

To do the fuel tank swap, I had to get down and dirty with the sending unit because the newer cars use a different measurement system than the LT series. The unit is really only a resistance board that will send resistances based on where a set of fingers are touching the board. If the car is not your DD, I would cut the trap door and pull the whole unit out. You can then use a multi-meter set to resistance, and measure the between the sides and look for it to change. I am not sure how something like this would go bad, and would think there is more likely a broken wire, or the fingers that ride across the board are not coming in contact.

Yes a new kit will include everything and potentially fix the issue, but you could also have something up with your gauge cluster that has nothing to do with the sending unit. I would test first and address based on what you find.

 

Depending upon how long the car has been sitting, conditions under which it has been sitting etc., it may not be a bad idea to pull the tank and inspect it. I guess you could inspect it via the trap door. My car sat for several years, unprepped, and my tank had to be replaced. It was quite rusted. You probably wouldn't want to drop a new pump into a rusted tank, which is what I did. It didn't last very long. I can't say for certain it was the rust that killed the pump, but I can't imagine it was good for it.

I've never been able to bring myself to cut a trap door and I'm not sure why. Without a lift, pulling the tank seemed like a HUGE PITA.

 

I haven’t wanted to mess with the structure of the car. The tank is a big pain in the neck, mainly because of the filler neck; but the exhaust doesn’t help either. I had one stint of 5 years where there were no issues, then another of about 3 years where the tanks was toast. I ended up swapping in a plastic tank from a newer v6, where the filler neck disconnects. That isn’t to say the swap process was easy though...

 

The filler neck is definitely the primary issue in terms of the PITA quotient. My car sat for 6-7 years unprepped and I've been working on it off & on since about 2006. The car is Ky and I'm in Michigan, so I don't get to spend a lot of time messing with it. When we replaced the gas tank, we actually cracked the welds where the filler neck goes into the tank. I wasn't aware until probably 2-3 years after the fact when I got the car out to drive it for the first time, which was maybe Thanksgiving 2017. The car had essentially been sitting since October of 2000. I went to a gas station to fill it up and gas started running out onto the ground. That was an awesome feeling. We patched the cracks with JB Weld, but I still haven't filled the tank to 100%. I want to get a borescope so I can take a closer look at the JB Weld job before doing so. I've got some posts on this site somewhere regarding the gas tank ordeal. I'll update those once I've actually had a chance to test out the JB Weld solution.

I've heard removing the tank is much easier if you have a lift, or can get the car up in the air a few feet. We we're always working with jack stands and it seemed like a nightmare. I guess we've only had to do it twice, but that was plenty. The first time we only replaced the pump, and that pump died shortly afterwards. The second time I believe we replaced the tank, pump and sending unit. I believe the exhaust may have been off my car both times we removed the tank, but I seem to recall the rear end being a bit of an obstacle when it came to maneuvering/manipulating the tank.

 

It sounds like our projects have about the same run time. My engine build finished in 04, and I have been trying to get things right since. I spend time very sporadically...

In regard to much easier with a life, I would disagree. The first time I had the tank out it was to upgrade the pump in preparation for nitrous, and the neck still made it a pain. The last time was on jack stands. The only thing I really wish I would have done is remove the rear end, as the LCA were all that held it in.

 

Gee, didn't know there were so many new replies--never got a notice. But thanks guys. To clarify a bit, this is--and has always been--a Florida car; doubt it's ever been out of the state. I've had it since 1998 and it's always been garaged. Can't remember even driving it in the rain. I did a good visual inspect of the tank and everything else underneath, and there's no rust anywhere, including the wheel wells, a rust fave. The great thing about cars down here is that they avoid rust well, unless you take them out on the beach (Daytona stills allows that). I think I'm good w/ the tank.

Pulling the tank does require a lift, according to both the factory SM (thanks to GaryDoug) and Haynes. At least if you want to do it right and save yourself a great deal of grief. Also need to drop the exhaust and loosen the rear axle to let it droop enough to get the tank out, as BTC notes. Cutting a trap door is, in comparison, an easy task. I have a good compressor and will be using a cut-off wheel; I made a template from some scraps of Hardie I had laying around. Rather than cutting the rectangle you see in most pics, I'll be cutting a jut over where the tubes connect, for ease of removal. I got some 2" zinc to reattach the panel after I complete the job. Given where it is, no one will ever know.

I'm going w/ the Spectra 3908, will prob. get it from Summit. Haven't had much time to cut the door yet, but when I do, maybe I'll post a pic. Happy Xmas to all.

 

The concern for rust with regard to the fuel tank is INTERNAL rust, not external.

 

A lift does make the process easier as you can stand and maneuver the tank, but I hardly consider is required. I have done both ways, and it sucks in either case. No matter what, you do have to remove the exhaust and the rear end to get enough angle to get the filler neck out.