Summary: Engine cranks but will not start. After driving over poorly lit road construction about a week ago and feeling like I was in a bouncy house, a few days later the fuel pump won't prime.

History:
~2009: A friend installed a Racetronix 255 kit in his driveway. Only side effects were an inaccurate gauge. Full is about 3/4, E is about 5gal remaining.
~2015: Asked dealer to look into inaccurate gauge, they installed the OEM NOS float arm I provided but no change in gauge behavior.
About 2 months ago: A local speed shop familiar with F-bodies and who was familiar with the process installed the WS6Store complete 1998 255LPH drop-in fuel kit assembly, hoping that all new parts as advertised by that vendor would resolve the gauge issue. With the exception of the gauge issue, there were not any other known issues with the pump assembly that was removed. Did not have a trap door (by choice) so the tank was dropped for the install. No change in fuel gauge behavior. Started calibrating the gauge in the PCM. Now Full is 'full' and 1/4 mark is ~4 gallons remaining. I noticed that once the fuel level got down to around the 3-4 gallon remaining level, certain movements (lefthand U-turns, graceful leaving from a stop in a straight line) would cause the engine to suddenly stall... not sputter and hesitate, but outright stall. Sometimes the engine would kick back on a few seconds later, other times I would need to pull over, key off, key on, engine started fine. I attributed that behavior to it being so long since I drove with 4 gal remaining that I simply had forgotten about that OEM behavior. They are very busy with only 1 tech (the owner), very expensive ($120/hr) and I'm not enamored with their quality of work after having them work on the car multiple times in the past.
Nov 20: I cut through the city to bypass an accident on the interstate. The GPS was not up-to-date, so I ended up taking a random route to get back on the interstate. It was dark, but the headlights showed a pattern of color changes in the pavement ahead, but they weren't painted. It turns out the lane I was in had parts of the pavement cut down due to construction, but every few feet, perhaps 6-10', there was a row of pavement that was normal height, perhaps a few inches wide... sort of like vertical rectangles. I had to turn right in about a half block and my lane was full so I ended up driving over them probably 40'ish MPH. After an unexpected drive through the bounce house, I drove home (another 15-20 miles) without issue.
Nov 21: I was driving home on a full tank of gas and the car suddenly died again, I was able to pull it into a nearby parking lot. Key off, restart, no problems restarting.
Nov 22: Car wouldn't start, got a ride to work with a coworker. Ordered replacement relays.
Nov 23: Car started in the morning without any changes. Put in new relay, car started without any issue, tried with the old again, still okay, left it with a new relay installed. Drove the car to work without any issues. When I left work, car wouldn't start. Swapped in both old and additional new relays, no change. Towed car home. Car has remained parked since then, continues to crank but not start.
Nov 24: I bit the bullet and cut a trap door above the fuel pump to attempt to ease future troubleshooting. I don't quite have the hole big enough to remove the last fuel line farthest away from the pump. Haven't done anything further with the pump assembly itself.

What I've checked so far:
* Fuel pump fuse is good.
* Tried a new fuel pump relay, no change
* The fuse at the front of the Racetronix harness is good
* Jacked up the rear of the car to look for obvious loose wires and connections on the bulkhead area, reviewed the power harness going towards the engine, etc. Nothing stood out to me as being at fault.I didn't know what I could check with a DMM at the rear bulkhead to confirm power was reaching that far, and didn't have an extra set of hands. I do have the 1998 Helms manual and have printed out the fuel pump relay diagnosis section, but don't know how to translate the Kent-Moore tool process to a shadetree level.
* I kept the old pump assembly from two months ago. The power wire was cut near the bulk head during removal, and the the yellow plastic that attaches the float arm to the assembly broke when I placed it back in the box after measuring the ohm range on the sender awhile back.
* I have not yet tried calling WS6Store support but will this morning.
* For the potential driving stalls: battery hold down bracket and battery are tight (not sliding around), battery terminal connections are tight, single ground wire attached to rear of driver head, ground bolt is tight, haven't changed the crank position sensor since the LS3 was installed in 2010.

Short of pulling out the pump assembly, what's the closest contact to the top of the fuel tank to verify power is making it as far as possible? Other diagnostic suggestions?

 

Notice the bulk connector at the top left corner of the picture? The gray wire from the plug is the power and the black is ground so you should be able to test for key on power to this point and if so then it's either trap door method or drop the tank.

 

If you can turn the key and hear both relays (very important BOTH) under the hood and on the hotwire kit, but the pump does not even make a noise, its likely the pump.

You can also use something blunt like a hammer, mallet, etc to hit near the direct center of the tank a few times then turn key on. If the pump then turns on for like 3 to 5 seconds then off, then its the pump also.

It could be the fuel pump wiring bulkhead as they are a very odd design and can burn up or melt even. Or any of the wiring inside. But it is likely the pump with what you've said.

We do offer just the pump with new install kit or an entire new drop in 98 module as well. Can work with the old hotwire harness or we can get you a new one also.

 

So simply turn key to run, and use a DMM to check voltage across the pins that match the gray and black wires?

I removed the fuel pump relay, listened, then re-installed it and listened. Definitely an extra click from the engine bay with the relay installed. In the rear, I seem to hear a click from the rear passenger side amplifier area and possibly a click from the rear driver wheel area. If I could temporarily turn off the dang ignition chimes it would help isolate the chime locations. Bottom center of tank inacccessible due to exhaust and heat shield. I placed a folded towel on the bare top section of the tank, to the left and right of the pump assembly and tapped it with hammer, no change. These are all new parts from your '98 255LPH complete drop-in assembly (which included a new hotwire harness) installed the last week of September. I know attaching the sock to the bottom of the pump was a major PITA, and I'm hoping that pain point has been resolved in an updated design.

 

Yes once you turn the key to on it should send power through the gray wire to power the pump. You most likely have a defective pump and if you went trap door then your battle is almost won!

 

The trap door part is understandable.
So you cannot hear the fuel pump prime at all then?

If you have 2 ppl you can actually have them put their hand on the relay and feel it click.

You can also jump the 2 relay terminals with the red big wire going to them, key on or off does not matter, and the pump should turn on. Usually you will want to use a short piece of wire with that you can make temporary contact with then pull away. Probing for power is the harder part there due to some of the harness being up in the tank area.

It is also likely that the in tank harness could have been disconnected somehow on accident especially with the roads. That is easy enough to determine physically, but will require removal of the pump assy. Which is obviously easier now due to the trap door. You can also assess any physical issues you can see like any burnt connection or broken tube etc.

(On the hotwire kit) You can also test voltage to the relay assy by removing it, putting red lead in the big red wire terminal spade and black to a good ground. You should have battery voltage there.

I did get your message. We are hammered with black friday stuff still, but it may be better to continue to communicate on here as you will have all the process in text to refer to, as well as any other future ppl that may have issues like this.

 

I haven't tested it yet, but want to confirm whether I need another set of hands. Should I get continuous power to that connector with a good fuse, good relay, key in run position and battery connected? Or will it only show power when it initially attempts to prime the pump?



Correct.

 

That wire only gets 12v for 3 to 5 seconds when key is on and 12v constantly while vehicle is running or cranking

 

I bought another RFPK-002 from WS6store and it's not the rear 40A relay. I've been limited to working on it on the weekends due to not much daylight after work. I'm to the point where I'm ready to disconnect the fuel lines. I'd rather work on the pump outside of the hatch, but that 4-wire fuel sender connection is permanently mounted to the pump cover. The 8-pin bulk head connector seems connected to more parts with the Racetronix setup than OEM. Looking at the prior Racetronix kit that was removed in ate September, I don't see an easy place to disconnect the harness (without disconnecting pins) and pull that harness out the top. Perhaps that would be a feature to consider on the future '98-model complete fuel pump assemblies from WS6store?

I've been trying to search for videos to see if anyone has cut those 4 fuel sender wires on top of the tank and try to use some sort of weather pack connector to make it easy to disconnect the harness at the top. What am I missing to easily R&R the harness?

 

To pull the harness off, you will unplug the big white connector from below the rear seat and then there is another inline connector with 1 or 2 terminals that you will also unplug. They are on the new hotwire harness and outlined in the instructions as well. It can and will unplug.

 

Maybe photos will help. One photo shows the newest hotwire harness that requires two terminals to be inserted to the gray 8-pin connector.

The other photo is the old Racetronix hotwire kit removed in Sep as reference. It appears I need to remove those two terminals from the gray connector (which I don't want to mess with) as well as disconnecting the other 2-pin connector with the black & red wires.

Still easier to disconnect harness at top of fuel pump assembly, just like the 99-02 models have, instead of getting under the car.

Bulkhead end of new hotwire harness

Old wiring example

 

It isnt an option with 98s to disconnect. That's just how they are. The entire module assy is so different nothing from 98 transfers to 99-02.

The pictures youre looking at are exactly the same thing. Meaning the bottom picture is just how it looks when you repin the wires. That's the finished product.
Youre literally showing a before and after picture. It also shows that in the instructions as well

 

So what prevents me from cutting the four large wires a few inches from where they connect to the top of the pump cover, and reconnecting them with Deutsch or weatherpack connectors? It appears that's what they use on 99-02, don't know why it would be less reliable?

 

GM never used Deutsch or WeathPack connectors in the 1998 fuel system.
The connectors are MetriPack.

If the bulkhead wiring is compromised you may want to consider replacing it with this wiring system:
https://www.racetronix.biz/p/univers...4-way/bcws-001

 

Like racetronix put, it does require a complete bulkhead assy with the metripak connectors. They do require a special crimp tool as well.

Youre really going to extremes for what is really a run of the mill setup. Its very easy to go off into left field with a situation like this keeping it as simple as possible is the best way to get it taken care of without spending more money and hours into it where you reach the point of diminishing returns.

So far you really do not know what was causing the issue. That doesn't mean you throw the baby out with the bath water though. I understand it is aggravating as well.

Since the hotwire harness is off, the best way to test everything is with an ohm meter/continuity tester. Remove relay. Test all the wire colors to and from connection. You have a brand new harness there to test against so its fairly straightforward.

 

1) Any tricks to getting the flexible output fuel line connected all the way on to the metal tube? I'm inferring it needs to go on dry? I haven't been able to locate ear clamp pliers locally, is it pretty safe to use wire cutters?
2) Same question on the pump dowels and rubber feet. I can't get the feet into the dowels very far when dry.I can bend the frame a little but then the dowels/feet don't line up great.The old kit we removed in September has the dowels sunken pretty far over the feet.
3) The complete WS6Store '98 kit has a different sock than what was removed in September (which was purely the Racetronix kit) and different than what was provided in the new RFPK-002 kit. The old kit seemed to have the flex return line just zip-tied in a U shape pointing up, but the WS6store complete kit has that flex tube connected to the sock. Also, the WS6Store sock connects to the pump with a metal tube that needs to be 'punched' around the circumference to increase the friction.I think I'd rather go with the new RPFK-002 sock and U-turn hose again (which is what Racetronix shows to do in their kit). I've tried to remove the drain tube from the sock without much success; can I remove it without damaging the sock? Any reason to keep one style over the other?
4) The referenced complete kit uses a different connector for the black/gray/purple wires than what was included with RFPK-002, with a different locking mechanism, so I kept the version provided with the complete kit so I didn't need to change the bulkhead connector.
5) Fuel level sender ohm range is 40-250 on both senders I removed in the past two months. I've read that '98s could have been 0-90 ohms but I don't know if V6s are different than V8s, and 99+ were 40-250. How do I know which ohm range my vehicle is expecting? Maybe I'll try the 0-90 ohm (SK1083) sender to see if that happens to be 100% compatible with my OEM fuel tank settings instead of continuing to play with the calibration for the 40-250 ohm sender.

Edit: I found some recommendations of a light coat of motor oil on the metal tube and/or heating up the metal tube AND flex hose in boiling water (or use a hair dryer) to push the flex hose on to the metal tube. Some recommended slight soapy water as lube only but others were leery about any soap in the fuel. I might try the soapy water on the rubber feet.

 

After an hour of fiddling with it, I can't get the rebuilt pump assembly all the way into the tank. It appears the bottom of the pump frame is hitting the bottom edge of the opening to the rear of the tank. The hoses do bend when the frame bends. Even trial fitting with the float arm and return valve disconnected, no joy. Is it because the bottom of the frame isn't square, as a result of not being able to get more of the rubber feet into the dowels?

 

They are all like that as far as the rubber bumpers fit into the billet legs. You can trim them down on either top or bottom to help it sit in there better without bending it too far out of shape. Likely the bottom would be the best. That should help most of the issues.

The new sock in the Racetronix kit is what is available now. The one we use is only available in a complete assembly from gm. Hence the difference. It makes no real difference otherwise though.

Its likely the bent lower section that is causing the issue OR your pump is too far in one position up or down. The hose clamp is what secures it, sometimes it can keep the module bent too much or not flexible enough at the hinge to position itself correctly.

Hope that helps.

 

So simple random thought..
Have you pressure/vacuum tested the fuel tank? It kinda sounds like a plugged tank vent/charcoal canister plumbing issue is possible?

 

I'm going to try moving the rubber bumpers from the old frame I removed in September into the new frame.

That idea has not been brought up previously. Do you think the pump not priming is related to EVAP plumbing? After I got the car back from the last pump install in September, I was getting an EVAP code (I forget the #). The all metal fill tube came back slightly bent down, rubbing against the bottom of the fuel fill door curround, and the gas cap seemed to have extra play in it. The plastic fuel fill surround is now pushed out slightly, causing the fuel door to not fit flush with the quarter panel. I replaced the cap with a new spare I had and the EVAP code had not returned. I'm pretty sure I have a new EVAP part that goes above the axle (I reseated that harness during this process), but I do not have a spare canister that is near the fuel cap.