Won't Start

[EdR5150]

What I've done:
Pulled a plug wire, attached and grounded a spare plug, had a partner crank the engine, and conformed there is spark
Dumped some fuel down the intake, tried starting the car, and heard the car almost start
Swapped RPM relays (I use the black one, and have the green one as a spare)
Didn't hear the fuel pump prime with either relay
Jumped RPM relay, still wouldn't start
Fuel pump was making humming noise for almost a year. (bought a new one, planned to swap this winter)

Possible Next steps:
Disconnect fuel pump, put a test light on connector?
If test light lights up, swap pump?

Agree or disagree?

[DMCTek]

What I've done:
Pulled a plug wire, attached and grounded a spare plug, had a partner crank the engine, and conformed there is spark
Dumped some fuel down the intake, tried starting the car, and heard the car almost start
Swapped RPM relays (I use the black one, and have the green one as a spare)
Didn't hear the fuel pump prime with either relay
Jumped RPM relay, still wouldn't start
Fuel pump was making humming noise for almost a year. (bought a new one, planned to swap this winter)

Possible Next steps:
Disconnect fuel pump, put a test light on connector?
If test light lights up, swap pump?

Agree or disagree?

Agree.

The connector itself could also be the problem so you may want to place your test light on the power stud of the pump (this will assure you are getting power through the connector).

To make certain before you R&R the pump you could run a new power and ground wire for testing (for temporary trouble shooting of course). Moving a know good fully charged battery to the luggage compartment might make it easier.

Another possibility is a bad inertia switch.

[Bitsyncmaster]

All fuel pumps will hum when running. So did you hear the pump run when you jumpered the RPM relay socket pins?

[Elvis]

Could also be fuse #7 I think and its contacts (if the pump ist not running)
or the inertia switch.

[EdR5150]

Oh yes, I also checked #7 fuse, and intertia switch. Battery is charged. I didn't hear the pump run when I jumped the RPM switch. Should it run with the key in the 0, I, II position, or even without the key in?

The pump hardly hummed at all, but after the hot drive to and from DCS 2010 Lexington, it's been humming loudly almost constantly.

Onto the test light with the fuel pump.

[Rich]

Possible Next steps:
Disconnect fuel pump, put a test light on connector?
If test light lights up, swap pump?


A test light is a good start.

Better yet, get a VOM on it. With battery charged up and >12.0V to work with you want to see at least +11VDC on hot side of the pump and, equally important, full ground continuity at the pump connector. While you have the connection open take a minute to scrape/buff any corrosion and inspect the pump wiring in that area to be sure nothing is loose or damaged. Ideally you'll want to evaluate the voltage and ground when the pump is running but check see what's at the connector to start with.

[EdR5150]

I disconnected the fuel pump, and put a test light on it - lit up.
I put the VOM on the battery, and got 12 volts. I put the VOM on the fuel pump connector, and got between 9 and 11 volts. Is it normal for this to jump around? I chalked it up to a bad connection with the VOM leads.

I got the same voltage reading on the fuel pump side of the molex connector.
So into the tank I went. I couldn't test the voltage at the connections on the pump, since they are completely sealed by some black covering. It looks like I have to break this off:
http://www.16908.info/wp-content/uploads/2011/12/122811-0027-fuelpumpwoe5.jpg
In fact you can see I broke some of it trying to get it off. Should I make a new connector, or order one? Are these seals included?

The fuel pump is inscribed 12/06. This is right around the time the PO was doing work on the car. 5 years!

The next big surprise is there is a huge kink in the pickup hose:
http://www.16908.info/wp-content/uploads/2011/12/122811-0027-fuelpumpwoe7.jpg
Why is there so much slack in this hose? I cut out the kink, and reattached it:
http://www.16908.info/wp-content/uploads/2011/12/122811-0027-fuelpumpwoe2.jpg

I left the baffle alone. The pickup, return hoses, and boot are in great condition. The fuel pump support looks like it has seen better days. Maybe the PO replated it? Either way, I might just order a stainless one:
http://www.16908.info/wp-content/uploads/2011/12/122811-0027-fuelpumpwoe9.jpg

I've been advised to replace the red and black fuel hoses, and I have new ones waiting:
http://www.16908.info/wp-content/uploads/2011/12/122811-0027-fuelpumpwoe1.jpg

So I took out the pump, drained it, and connected it to a spare battery with some scrap wire and a spare molex connector - and it spun! So I cleaned the molex connector for the fuel pump, and made sure there is a tight connection. I put the original pump back in, put it all back together, and tried to start the car - still nothing. I can't tell if the pump is running or not. I'll charge the battery some more, but I don't think it's the battery. When this started, I even tried jump starting the car with another running car - nothing.

I've got a buddy coming over soon, so we can push the car back into the garage for the night. Ugh.

[Elvis]

Hey you're almost there.
jumper the rpm relay so you don't need to crank the engine to test the pump.
- by the way - how did you test the voltage at the pump ? while engine was cranking or
did you jumper the relay already ?


Those rubber seals on the connector of the pump are just nice to have.
Simply forget them ! take them off, break them if needed and measure at the pump directly.
And also measure with the fuel lines attached. Could be that the pump runs with no load, but when it has to build up pressure it fails.

[EdR5150]

Got the car back into the garage for the night!

I did jumper the RPM relay, and that's how I tested the voltage. Next, I'm going to compare voltage readings against the ground on the connector, and grounded right to the frame. I didn't know the pump's ground continued on into the intertia switch.

Since I don't know if the pump is working, I'm going to disconnect the fuel line coming from the pump, attach my spare line, and direct it into a coffee can.

For anyone using this as reference, I am doing all this outside my garage with plenty of ventilation. For me, working with electricity and gasoline is quite scary. The battery disconnect switch I installed helps quickly disconnect the battery for all the troubleshooting. Also, I'm always within an arms reach of a good fire extinguisher.

[Bitsyncmaster]

Your doing what I did on checking the voltage on the fuel pump. I made a long test lead for my multimeter and connected one end to the battery (-). I was able to find two bad connections. One was the fuse and the other was the two pin connector up near the pump. I also installed a new ground wire on the inerta switch to the gear shifter frame bolt. Another new wire was done on the RPM relay connector. I gained about 1.5 volts reading on the two pump terminals.

You should expect a volt or two drop over the stock wire harness. It's just the high current of the pump (about 7 or 8 amps) and the wire gauge and length of the wiring.

[Mike C.]

Got the car back into the garage for the night!

I did jumper the RPM relay, and that's how I tested the voltage. Next, I'm going to compare voltage readings against the ground on the connector, and grounded right to the frame. I didn't know the pump's ground continued on into the intertia switch.

Since I don't know if the pump is working, I'm going to disconnect the fuel line coming from the pump, attach my spare line, and direct it into a coffee can.

For anyone using this as reference, I am doing all this outside my garage with plenty of ventilation. For me, working with electricity and gasoline is quite scary. The battery disconnect switch I installed helps quickly disconnect the battery for all the troubleshooting. Also, I'm always within an arms reach of a good fire extinguisher.

I had a flaky fuel pump too. One time it would run, then stop, then one day it just gave up the ghost.

It sounds like you are checking everything. The inertia switch basically interrupts the ground in the event of a roll over, so if that little plunger has a bunch of play, it can be randomly breaking connection.

Elvis is right on about checking load on the pump as well.

[DMC5180]

Ed,

You are going to need to replace your pickup hose. The kink/twist should not have been there. That was caused by poor installation from the PO. The hose does have a molded 90deg elbow that helps it lay in the tank properly.

[EdR5150]

Last week, I visited my favorite business, DMC Midwest, and bought a new pickup hose, and a newer replated fuel pump support. I could have had it shipped, but I like picking Dave's brain, and seeing what projects they're working on in the shop. Thanks guys!

Holy crud, the fuel tank setup is a b1tch! It took me an afternoon to get everything out, cleaned, and replaced. I can see the fuel pickup hose kinks if you pull up on it, or turn the pump slightly. I can feel how gasoline made my old hose softer as well. I did my best to get it installed correctly, something the PO didn't bother doing.

I wired it, connected the battery, and I didn't hear the pump running. So today I took some scrap wire, and ran a wire from the pump ground straight to the battery. Bingo! Car started for the first time in 2 months. "This sucker's electrical!"

Next steps: trace the path of the ground and find the bad spot, and check fuel system for any leaks. More pics here (http://www.16908.info/?p=1452).

[EdR5150]

Questions
1. Pump Ground path: Pump - Inertia Switch - Ground Junction behind central AC Vent - wire harness - rear bulkhead bolt - frame - battery?
2. I don't have a torque wrench for the dome nut on the pump. I used new copper washers, snugged the dome nut, then gave it a little extra. Sound good enough?
3. I'm using the following fuel hose clamps, and tightened them until they started to fold up. How tight should they be?
http://www.16908.info/wp-content/uploads/2012/01/122811-0027-fuelpumpwoe173.jpg

[Bitsyncmaster]

Questions
1. Pump Ground path: Pump - Inertia Switch - Ground Junction behind central AC Vent - wire harness - rear bulkhead bolt - frame - battery?
2. I don't have a torque wrench for the dome nut on the pump. I used new copper washers, snugged the dome nut, then gave it a little extra. Sound good enough?
3. I'm using the following fuel hose clamps, and tightened them until they started to fold up. How tight should they be?
http://www.16908.info/wp-content/uploads/2012/01/122811-0027-fuelpumpwoe173.jpg

Sounds like you have everything correct. Fuel pump is hard to get wrenches on so as tight as you think is what most do. Your using the correct hose clamps.

[DMCMW Dave]

Questions
1. Pump Ground path: Pump - Inertia Switch - Ground Junction behind central AC Vent - wire harness - rear bulkhead bolt - frame - battery?
2. I don't have a torque wrench for the dome nut on the pump. I used new copper washers, snugged the dome nut, then gave it a little extra. Sound good enough?
3. I'm using the following fuel hose clamps, and tightened them until they started to fold up. How tight should they be?


1 - Yes. Check the inertia switch (you can jumper it out) and the connector there. There is one connector between the pump and the inertia switch cleverly hidden next to the windshield washer reservoir. It's a pretty dry area but I've seen them cause trouble.
2 - With new copper washers, you can usually feel them give a bit and then get tight. Run it once before you seal up the top and look for leaks.
3 - If you start deforming the clamp it's tight enough. Again, check for leaks.

[EdR5150]

I've decided I want to use a workaround for now, and run a new ground to the pump. Aside from the increased risk of bypassing the intertia switch, is there anything wrong with grounding the pump directly to the front crumple tube?

[DMCMW Dave]

Far be it from me to recommend defeating a safety device, but it will work fine. Recall that when killing the engine (in an accident) the RPM relay still kills the pump.