New pump/sender combo - failed? How to test?

[jawn101]

I was driving down the road today and came to a stoplight. Went to move again after it went green and the car just shut off. The engine, I should say - all the electricals still worked fine. Tried starting - crank, no fire. Tried the plug swap and RPM relay jumper, same thing. Sigh.

Got towed home. Removed the air cleaner - no primary pressure on the flap. Ok, so no gas is getting to the motor. All the lines are new and nothing is leaking. Checked the pump area and everything looks ok. I have the new combo unit. I can see the fuel gauge moving so there is power to the "brain box" of the combo unit, but I do not hear the pump running at all - either at prime or at crank. Fuse #7 is clean as a whistle. Rpm relay is Dave's solid state one.

Hooked up my old fuel pump (dry) to the electrical pigtail and cranked the motor. It spins strong and angry at being dry. So the signal is getting that far at least. But I do not think the combo pump is working.

Does anyone know which pins are which to test that? There are 4 on the pump unit itself, 2 black a grey and a purple. How can I check if the pump is getting voltage from the brain box?

Please help! Car is stuck immobile and I have to get it moving before an upcoming trip.

[jawn101]

Another test just completed - I opened the plug where the fuel sender used to be and watched the pump while my wife cranked the motor. No evidence that it's running at all. However, if I push the float to the bottom of the tank, the fuel level light comes on. So the sender portion is working.

[Bitsyncmaster]

Your testing makes me pretty sure the pump has failed. Only thing left is the wiring on the pump. I would remove the high pressure hose and see if you can get the pump spinning.

[jawn101]

I agree... But I'm not sure what you mean about removing the hose. I mean, I know how to do that (simple on the combo as it's just clips) but what would I do next as far as getting the pump spinning?

[Morpheus]

This is exactly what happened to me. Turned out my fuel pump died. If you have the new DMCH fuel pump, they can sell you the replacement component for about $100. Replaced mine, and I'm back on the road.

[jawn101]

Really? Ugh. This is already my second one - first one had pressure issues. Thanks for the input though - I already emailed Julee (man, days like this I miss Dave.... Not that Julee isn't awesome too) to see what the deal is.

[DMCTek]

I agree that all signs point to a dead fuel pump. Only other test I would try is to feed power and ground to the two wire connector with an external 12v battery. Black is ground, white purple is power. The new pump is quiet and can be hard to hear run, pressure on the flap should verify if you have any pressure. I do NOT recommend back probing the connector on the integrated pump.

Keep me posted on what you find. We can discuss what parts you need first thing Monday.

Best,

Mike

[jawn101]

I agree that all signs point to a dead fuel pump. Only other test I would try is to feed power and ground to the two wire connector with an external 12v battery. Black is ground, white purple is power. The new pump is quiet and can be hard to hear run, pressure on the flap should verify if you have any pressure. I do NOT recommend back probing the connector on the integrated pump.

Keep me posted on what you find. We can discuss what parts you need first thing Monday.

Best,

Mike

Thanks Mike, I got your email. Not sure what you mean about the two wire connector - the one coming from the logic box? That doesn't sound right so I must be misunderstanding you. I verified the factory two wire pigtail has power by connecting my old Bosch pump, and it runs like gangbusters. I know the pump is quiet, that's why I opened the tank to physically observe the liquid. No cavitations.

[DMCTek]

Yes I meant the two wire connector coming out of the logic box.

[jawn101]

Yes I meant the two wire connector coming out of the logic box.

Gotcha. I don't have a spare 12v supply anywhere but I think I proved the power is there by the reverse approach of connecting another pump to the factory wiring. Let's talk parts! :) Thanks Mike!

[jawn101]

Hey Morpheus... did you do the pump replacement inside the unit yourself? I removed my whole kit from the car and packed it up to send to Mike, but it is really quite straightforward in design - the only potential issue I see is getting that hose on from the feed fitting to the pump nipple.

[Morpheus]

Hey Morpheus... did you do the pump replacement inside the unit yourself? I removed my whole kit from the car and packed it up to send to Mike, but it is really quite straightforward in design - the only potential issue I see is getting that hose on from the feed fitting to the pump nipple.

I did. The hardest part is getting the new hoses on. DMCH loaned me the special pliers required to do this. It's best to put a little bit of wheel bearing grease on the ends to assist with sliding the hoses on. You should also get a new pickup filter along with the new pump. All told, everything was about $100 not counting the core charge on the pliers (you need to send them back).

[jawn101]

I did. The hardest part is getting the new hoses on. DMCH loaned me the special pliers required to do this. It's best to put a little bit of wheel bearing grease on the ends to assist with sliding the hoses on. You should also get a new pickup filter along with the new pump. All told, everything was about $100 not counting the core charge on the pliers (you need to send them back).

Right on. I don't know if that's an option for me or not as I'm working with Mike at Midwest. Seems easy enough, if there's a tool to get the hoses on. But I guess I'll ship to him anyway since it's already all packed up. Just would have been nice to get the whole thing done a little quicker.

The grease is safe to use on that fitting? It won't foul up the fuel or degrade the plastic or anything?

[Morpheus]

^You only use a little bit, so no harm done to the fuel system.

[Blackie]

My pump/sender combo quit on me all of a sudden a few months ago. I found that if I picked up the spare tyre and dropped it would bump the pump through the cover plate and the pump would start running. Every time it stopped working this would fix it. The car never stalled whilst driving, it would only play up when trying to start the car. I pulled the pump out of the tank, disconnected and reconnected all of the electrical connectors, put it back in and I hasn't given me any grief since.

[todd1561]

Is DMCH/DMCMW replacing these pumps, or at least the necessary components to fix them, under warranty? Seems a little ridiculous to have to spend even $100 to fix a presumably brand new pump that cost several hundred to begin with. Then again I don't know how long the pumps in this thread have been in service, I would only expect a standard 1 year warranty.

[Morpheus]

^ I was told that, if my pump failed and was still within the warranty period, it would have been a covered repair. My pump is about 4 years old and thus no longer in warranty.

In my case, the PO installed the pump years before I bought the car, so wether or not he cleaned out the tank beforehand is unknown. The pickup filter on my failed pump was pretty gross, so I'm betting that he didn't. If you are going to go through the effort and expense to swap out your fuel pump, you should take the extra time to siphon it out and clean it properly to ensure you don't have to go back in there again anytime soon.

[steve]

Dmc Houston Combo Fuel Pump Sender. On the road today strong smell of gas car shut off. Gas puddle under car at passenger feet. Pulled cover plate off in 95 Deg. heat
to find supply line melted???????? Dmc hose supplied with unit smeared in my fingers turning them black. Could smear the covering off to expose the braided parts. Internally
the hose had deteriorated where the barbs had held it.

I cut off 2" of line and proceeded to reinstall using the old clamp that I will replace tomorrow.

The DMC line is marked Fuel in green and says BioFuel. The barbed fitting is either steel or brass that feeds into the steel line.

Any thoughts as this scared the S****T out of me smelling the gas at 65 MPH.
Steve