Driving down the road and engine shuts off

[Jimmycxc]

I as out for a normal Sunday drive and all seemed normal. I was stopped at a light and as the light turned green, I started to take off. Continued on the gas until about 50 mph and then the engine just shut off on me. I pulled over, tried to start it and nothing. It cranks, but will not fire.

A similar thing happened the week before also. I was out for a normal drive and as I was turning, I put pushed the clutch in to downshift into second and the car's engine turned off on me. I quickly put it in neutral and turned the key and it started right up for me.

Its not the RPM relay as I have the upgraded one. The battery charge was low, but it initially started fine. I had the alternator replaced with Harvey's about 4 years ago. Could the alternator have gone bad? I have since charged the battery, but it still will not fire. Fuel is a little over a quarter tank.

Thanks

[Morpheus]

This is almost the same thing I ran into with my car. The fuel pump died. May want to check there.

[Christian Dietrich]

Also check your connections at the inertia switch.

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[burch]

On mine, I've had this happen a couple of times. Once was the Fuel Pump fuse (#7, IIRC) and once was the Fuel Pump power connector. I'm using Hervey's "all-in-one" style pump, and I've since zip-tied the connector together.

[sdg3205]

I have had this happen as well and it turned out to be the #7 fuse not being held tight enough. To get home I had to leave the fuse area open and manually press the fuse in to keep the pump running. Once home I backed out the female spade connectors and tightened them up. Problem solved.

[Dangermouse]

In my case it was the 12V connection on top of the coil had worked loose.

[Jimmycxc]

Thank you. I went to check those things out and then tried to start her. Didn't hear the humming of the fuel pump and fuses are good. Looking like a new fuel pump is in order.

[sdg3205]

Thank you. I went to check those things out and then tried to start her. Didn't hear the humming of the fuel pump and fuses are good. Looking like a new fuel pump is in order.

Don't buy a new fuel pump yet! Measure the voltage at the harness. The fuel pump seems to have a voltage threshold around 11 volts. If you see lower than that its probably a ground issue.

[Jimmycxc]

Which color wires do I check?

[DMCMW Dave]

In my case it was the 12V connection on top of the coil had worked loose.

In my experience, the wiring on the white ballast resistors is the really bit offender on this one, but all the other things mentioned can happen.

Jump the RPM relay too, and/or replace it. New things can fail.

[Jimmycxc]

So I checked the voltage across the fuel sender unit with the key in the run position and I get 11 volts. I didn't take the pump out yet, but I believe it has been replaced by PJ Grady some time ago....well over 10 years ago.

[sdg3205]

So I checked the voltage across the fuel sender unit with the key in the run position and I get 11 volts. I didn't take the pump out yet, but I believe it has been replaced by PJ Grady some time ago....well over 10 years ago.

What was the voltage across the pump harness?

[Jimmycxc]

Just making sure I am testing the correct wires, but there are two wires going to the pump. Mine are white with a purple stripe and black with a purple stripe. I tested those and absolutely no voltage.

[Bitsyncmaster]

Just making sure I am testing the correct wires, but there are two wires going to the pump. Mine are white with a purple stripe and black with a purple stripe. I tested those and absolutely no voltage.

Those are the pump wires. You need to jumper the RPM relay to get power to the pump. The RPM relay turns pump power off when the engine is not running.

[Jimmycxc]

Those are the pump wires. You need to jumper the RPM relay to get power to the pump. The RPM relay turns pump power off when the engine is not running.

Will try that today. I do have your upgraded RPM relay. Also tried putting the stock one back in, but same result.

[Jimmycxc]

So I just jumped the RPM relay and took a reading. 7.96 volts. Does that mean I have a ground issue?

[sdg3205]

Perhaps. If when the rpm socket has a jumper you see the same voltage across the pins of the harness then yes, and it's probably in the windshield bottle harness in the front left of the tub

[Bitsyncmaster]

So I just jumped the RPM relay and took a reading. 7.96 volts. Does that mean I have a ground issue?

You have a bad connection or two. My #7 fuse had a bad connection and the two pin connector at the pump was also bad. Pump still ran but I lost about two volts over those connections.

To find where the voltage drops are, you use a test lead (mine is 15 foot long) and reference to the battery. Put that long test lead on the battery + and start checking starting with the fuse (top of fuse has little metal pins). Of course you have to do that testing with the load running (jumper in RPM relay).

Then you use the battery - side and check the drops on the other side of the pump, inerta switch, etc.

Hopefully your connections near the washer bottle are not the fault. It's a pain to access those connectors.

[sdg3205]

You have a bad connection or two. My #7 fuse had a bad connection and the two pin connector at the pump was also bad. Pump still ran but I lost about two volts over those connections.

To find where the voltage drops are, you use a test lead (mine is 15 foot long) and reference to the battery. Put that long test lead on the battery + and start checking starting with the fuse (top of fuse has little metal pins). Of course you have to do that testing with the load running (jumper in RPM relay).

Then you use the battery - side and check the drops on the other side of the pump, inerta switch, etc.

Hopefully your connections near the washer bottle are not the fault. It's a pain to access those connectors.

You can also jump the inertia switch to take that out of the equation. I don't know if they fail all in one fell swoop or if they fail gradually, if you do not have a WHITE DOT on the switch, it should be replaced anyway

[Jimmycxc]

Perhaps. If when the rpm socket has a jumper you see the same voltage across the pins of the harness then yes, and it's probably in the windshield bottle harness in the front left of the tub

Maybe I did not understand. Forgive me, I'm more of a mechanical guy and not electrical. I jumped the RPM relay, heard a little click near the fuel pump, but it did not turn on. I took the reading at the 2 pin connector at the pump and that's where it read 7.96 volts. Are you saying to take a reading at the rpm relay and as Bitsyncmaster suggested at fuse #7 as well?

[sdg3205]

Maybe I did not understand. Forgive me, I'm more of a mechanical guy and not electrical. I jumped the RPM relay, heard a little click near the fuel pump, but it did not turn on. I took the reading at the 2 pin connector at the pump and that's where it read 7.96 volts. Are you saying to take a reading at the rpm relay and as Bitsyncmaster suggested at fuse #7 as well?

I read that you took voltage at the "fuel sender" which would have been the wrong harness, so I mentioned you wanted the pump harness instead but I guess we are talking about the same thing. Yes you can measure voltage in a number of places across the system, like Dave is saying. By using the battery as a constant variable you'll find where you are getting the drop. My money is still on the washer bottle area harness.

[Jimmycxc]

4375543756

I unplugged the two wire connector to the fuel pump. With the RPM relay jumped, I took a reading of the volts coming in. 12.3. I then plugged the connectors together and took a reading on the pump side. 7.31 volts. Bad two wire connector on the pump side? Tried autozone, but they did not have a 2 wire connector.

[sdg3205]

Get some sand paper, roll it up like a doobie and sand the female ends. Then get a fresh piece and do the male ends.

[Bitsyncmaster]

4375543756

I unplugged the two wire connector to the fuel pump. With the RPM relay jumped, I took a reading of the volts coming in. 12.3. I then plugged the connectors together and took a reading on the pump side. 7.31 volts. Bad two wire connector on the pump side? Tried autozone, but they did not have a 2 wire connector.

Do you really need a connector there? I said no and just but spiced that connector out of the harness.

[Jimmycxc]

Do you really need a connector there? I said no and just but spiced that connector out of the harness.

Was wondering the same thing. Will try sand paper first, it not, it's getting cut out.

[Bitsyncmaster]

4375543756

I unplugged the two wire connector to the fuel pump. With the RPM relay jumped, I took a reading of the volts coming in. 12.3. I then plugged the connectors together and took a reading on the pump side. 7.31 volts. Bad two wire connector on the pump side? Tried autozone, but they did not have a 2 wire connector.

You just went to an open circuit with it unplugged and loaded with it plugged in. So the bad connection my be elsewhere but get rid of those two connections anyway.

[Horsebox]

I went through this circuit 18 months or so ago and was amazed how much a little cleaning improved the voltage across the pump under load.

Low hanging fruit were cleaning the fuse 7, cleaning the inertia switch connections and replacing the pump connector. Those three got me 50% of the voltage gain. The final 50% was regrounding the pump (keeping inertia switch) and cleaning the washer bottle area connectors. That last job was a soul destroying experience. Final voltage across the pump was just over 12V with a running engine system voltage of 14V.

Have fun, it's quite rewarding in a weird way!

[DMCMW Dave]

I went through this circuit 18 months or so ago and was amazed how much a little cleaning improved the voltage across the pump under load.

Low hanging fruit were cleaning the fuse 7, cleaning the inertia switch connections and replacing the pump connector. Those three got me 50% of the voltage gain. The final 50% was regrounding the pump (keeping inertia switch) and cleaning the washer bottle area connectors. That last job was a soul destroying experience. Final voltage across the pump was just over 12V with a running engine system voltage of 14V.

Have fun, it's quite rewarding in a weird way!

I've found a 1/4-1/2 volt drop in the connector next to the windshield washer reservoir. Agree on the experience!

[Jimmycxc]

43757

I got the washer fluid bottle out...yes, it was a bitch. But only 1 screw would not come out. Where is the ground? I only see a group of wires passing through the compartment.

[DMCMW Dave]

43757

I got the washer fluid bottle out...yes, it was a bitch. But only 1 screw would not come out. Where is the ground? I only see a group of wires passing through the compartment.

It's one of the connections in those plugs. There is no frame ground connection in that area. The grounds are all black, and the fuel pump wiring is white/purple. Just clean everything.

[Jimmycxc]

Thanks! Hopefully a little spring cleaning will do the trick. Will keep everyone updated.

[Horsebox]

The actual physical ground connection to the frame is buried underneath the dash somewhere. Legend has it you can just about see it if you lie on your back in the drivers footwell and shine a torch up there.

I didn't bother trying to get at it, I just ran a new wire from the inertia switch to a convenient frame bolt up front, easy to get at for r&r. I think this mod had the biggest effect on pump voltage if I remember right.

[content22207_2]

43758

Bill Robertson
#5939

[Jimmycxc]

So I check out all the grounds I could find and they actually look really good.

However, I finally took the voltage across the RPM relay while jumped and it was only 10.9. I could not get a reading across fuse #7 though. I have the ground of my multimeter on the negative side of the battery, but I don't get a reading when I touch the positive side of the multi meter to the top of the fuse. I also purchased all new fuses.

Also, how do you test the voltage across the inertia switch? I see a black wire, a black with purple stripe, and two brown w/ white strips. Thanks guys

[Bitsyncmaster]

So I check out all the grounds I could find and they actually look really good.

However, I finally took the voltage across the RPM relay while jumped and it was only 10.9. I could not get a reading across fuse #7 though. I have the ground of my multimeter on the negative side of the battery, but I don't get a reading when I touch the positive side of the multi meter to the top of the fuse. I also purchased all new fuses.

Also, how do you test the voltage across the inertia switch? I see a black wire, a black with purple stripe, and two brown w/ white strips. Thanks guys

You should have got voltage on fuse #7 all the time. Pull the fuse and see if the fuse sockets have melted the fuse block. Also check your battery voltage with the RPM jumpered.

[Jimmycxc]

With the RPM jumped,

Battery: 12.14
Fuse #7: 11.59
RPM Relay: 10.96

[Bitsyncmaster]

With the RPM jumped,

Battery: 12.14
Fuse #7: 11.59
RPM Relay: 10.96

Since your getting excessive voltage drops measured in two places, my guess is your fuel pump is bad drawing to much power. Normal fuel pump power is about 7 amps with engine running.

[Jimmycxc]

Since your getting excessive voltage drops measured in two places, my guess is your fuel pump is bad drawing to much power. Normal fuel pump power is about 7 amps with engine running.

Any suggestions on a good one to replace it with? I've seen the "Fuel Pump 909" search on ebay one for $50 and it looks fairly easy to replace. Or is it worth it to do the the DMCH one?

[Jimmycxc]

Is 12.14 Normal for the battery?

[Horsebox]

Yes, assuming engine isn't running.

I wouldn't buy anything just yet.

Check your ground side of the fuel pump circuit. Put the neg lead of voltmeter on batt neg terminal, and use the positive lead to probe the negative terminal of the fuel pump. Ideally the voltage there should be zero but in reality it will show some. How much it shows depends on the integrity of the the circuit connections between the pump negative terminal and the battery. Do this with rpm relay jumpered and pump running.

Enjoy! Not too hard...

[Bitsyncmaster]

Any suggestions on a good one to replace it with? I've seen the "Fuel Pump 909" search on ebay one for $50 and it looks fairly easy to replace. Or is it worth it to do the the DMCH one?

When your ready, the old DMCH one was $90 when I bought mine. Now their new one seems to not have the "buzz" the old type often get when the fuel tank gets hot.

[Jimmycxc]

Yes, assuming engine isn't running.

I wouldn't buy anything just yet.

Check your ground side of the fuel pump circuit. Put the neg lead of voltmeter on batt neg terminal, and use the positive lead to probe the negative terminal of the fuel pump. Ideally the voltage there should be zero but in reality it will show some. How much it shows depends on the integrity of the the circuit connections between the pump negative terminal and the battery. Do this with rpm relay jumpered and pump running.

Enjoy! Not too hard...


Did this and it read -1.42 V

[Horsebox]

Not sure why it reads negative unless the leads were swapped....

Assuming you have +1.4V at the pump negative, you should be able to harvest another volt or so by cleaning all the connectors downstream of the pump neg terminal. 1.4V is too high for such a short wire path.

Another easy test would be to reground the pump temporarily. You could do this at the inertia switch. I don't remember which colour wire does what, the circuit diagram will tell you, but essentially one of the wires on the inertia switch connector goes to frame ground. Make a connection at this point and wire it direct to the batt neg terminal. Then remeasure the voltage you have on the pump neg terminal with pump running.

The difference between your pump neg voltage with the new temp ground, and your 1.4V, will tell you how crappy your stock ground is.

Sorry if I didn't explain very well! It's much easier than it sounds...

[dhaney]

I would look hard at the white ballast resistor. We've seen 1 fire and another almost fire because of it!

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[MML]

I would look hard at the white ballast resistor. We've seen 1 fire and another almost fire because of it!

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Whoa, seriously? Can you elaborate a bit?
Mine gets really hot, as in, too hot to the touch, but I thought that was normal?

[Bitsyncmaster]

Whoa, seriously? Can you elaborate a bit?
Mine gets really hot, as in, too hot to the touch, but I thought that was normal?

To hot to touch is normal. You would not want anything laying over those resistors that could burn.

[MML]

To hot to touch is normal. You would not want anything laying over those resistors that could burn.

Ahh thank heavens for that.

Was that the cause of the aforementioned fires?

[Jimmycxc]

I would look hard at the white ballast resistor. We've seen 1 fire and another almost fire because of it!

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That's in the engine compartment, right? Would someone please provide me with a picture just so I know I'm checking the correct item?

[DMCMW Dave]

That's in the engine compartment, right? Would someone please provide me with a picture just so I know I'm checking the correct item?

The white thing in the middle


43954

[Jimmycxc]

The white thing in the middle

Sorry its been a while. I was away for business. Not much progress...I took off each adapter and took some corrosion off. Still only getting 8.3 V at the fuel pump. Is there something I can test? Here's what mine looks like.

44075




I then made a separate ground for the inertia switch and it jumped to 8.45 V at the fuel pump. I did not try temporarily grounding the pump at the inertia switch yet. Also, here is my pump.

44074

[Bitsyncmaster]

I bet your pump has jammed. When the pump has jammed it will draw a lot more current than normal. So your 8.45 volts may just be the caused by the voltage drops when the pump is drawing 20 amps.

The fuse won't blow until you draw about 23 to 25 amps and I've found the "BUSS" brand fuses don't blow reliably.

You can try reversing the power lead so the pump will run backwards and may clear a jam.

[dn010]

Take the pump out and use some alligator clips to hook the + & - directly to a fully charged battery to bench test it - it will push whatever fuel is left in it out so beware (that is, if it works). If it doesn't move, gently tapping it with a rubber hammer on the sides also clears some of the more stubborn jams that do not get fixed by the reverse method. Almost all of the pumps I've fixed that had debris in it which caused it to stop, run louder and fail soon afterwards so I usually end up replacing them anyway.

[Jimmycxc]

Took out the fuel pump over the weekend and played around with it quite a bit. Its definitely dead. Ordered a new one and should be here by Friday. Will let everyone know how it goes.

Thank you everyone for your help. I did learn a lot and even cleaned up some of my grounds at the same time.

However, I did find this unplugged. Assuming it has to do with the brakes.

44217

[Bitsyncmaster]

That electrical plug is for the low brake fluid warning light.

[Jimmycxc]

I just got my new pump and installed it. I put fresh gas in the tank, turned the key and heard the pump turn on. However, the engine would not start. I tried pumping the gas a little while turning the key, but still it would not start. Now (and this is somewhat embarrassing), I may have mixed up the fuel line and return line when re-installing. Can anyone tell by looking at it, which is which?

44262

[Rich]

I just got my new pump and installed it. ....I tried pumping the gas a little while turning the key, but still it would not start. Now (and this is somewhat embarrassing), I may have mixed up the fuel line and return line when re-installing.....

Without an answer about which line is which you can try two things:
1. With the pump on and engine not cranking push down on the air metering plate under the air cleaner. If there is any fuel pressure then there should be some resistance. With no fuel pressure the metering plate will fall away easily, suggesting you swapped the lines.
2. Try starting the engine while spraying starting fluid into the air meter. If the engine fires at all on starting fluid and not at all without then it points to a fuel problem, including swapped lines to-from the tank.

The first test won't tell you if there is sufficient pressure to open the injectors but will indicate bad plumbing or zero pump delivery.

[Jimmycxc]

If there's a 50/50 chance, 90% of the time I will choose wrong. Haha.

Had the lines reversed, but it actually did not matter at that point...I heard the pump turning on to prime, but I wanted to make sure it was actually moving fuel. Found out the suction side rubber hose was collapsed shut. I took it all out and cleaned everything. The 10mm nut holding in the baffle was like brand new. Thank you Rob Grady! Put all back, tested, fuel flowing, primed pump a few times, and eventually turned over.

Not sure what caused the old pump to stop working. The suction hose wasn't collapsed when I first took it out.

Thank you to all who offered their help! PITA? Yup. But also rewarding like some of you have mentioned.