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Posted by: 87m491 Nov 10 2017, 07:54 AM

As usual I have shot my own self in the foot and have a self inflicted "ran when parked" scenario. In the summer of 2016 I pulled a 74 2.0 with stock fuel injection out of a fairly long slumber and drove it a few hours home. After being pleasantly surprised at how well it seemed to run I proceeded to pull out the interior for sprucing up (still out) and redid wheels, brake system, wheel bearings and made my way to the fuel system.

The tank was amazingly clean so new tank sock, filter, updated style pump was already in the frunk, so new hoses, tangerine SS lines stem to stern and all new engine compartment lines, reconditioned injectors, yada, yada.

Fast forward to refire time and not so much. It's tough to confirm working FP from the drivers seat so I hard wired it and still no start. (starter is turning the engine fine) With all of the lines out at once I thought there was a better than even money chance I swapped fuel in and out. I swapped lines in the engine bay and was met with a powerful suction whoosh when I disconnected one. I hard wired the FP again and heard the fuel swirling around the tank I assume from the return so now that seems good. I also have spark from the coil and as I type this I can't believe I forgot to check from the cap out, DOH!

Short question long, is the FP supposed to run with the key on or is it keyed to engine speed etc? Also with the interior and "convenience" electricals out, might I have disconnected something that it is keeping the car from firing up?
thx
Mike

Posted by: mgphoto Nov 10 2017, 10:22 AM

QUOTE(87m491 @ Nov 10 2017, 05:54 AM)

As usual I have shot my own self in the foot and have a self inflicted "ran when parked" scenario. In the summer of 2016 I pulled a 74 2.0 with stock fuel injection out of a fairly long slumber and drove it a few hours home. After being pleasantly surprised at how well it seemed to run I proceeded to pull out the interior for sprucing up (still out) and redid wheels, brake system, wheel bearings and made my way to the fuel system.

The tank was amazingly clean so new tank sock, filter, updated style pump was already in the frunk, so new hoses, tangerine SS lines stem to stern and all new engine compartment lines, reconditioned injectors, yada, yada.

Fast forward to refire time and not so much. It's tough to confirm working FP from the drivers seat so I hard wired it and still no start. (starter is turning the engine fine) With all of the lines out at once I thought there was a better than even money chance I swapped fuel in and out. I swapped lines in the engine bay and was met with a powerful suction whoosh when I disconnected one. I hard wired the FP again and heard the fuel swirling around the tank I assume from the return so now that seems good. I also have spark from the coil and as I type this I can't believe I forgot to check from the cap out, DOH!

Short question long, is the FP supposed to run with the key on or is it keyed to engine speed etc? Also with the interior and "convenience" electricals out, might I have disconnected something that it is keeping the car from firing up?
thx
Mike

Fuel pump runs for about a second to pressurize the system, than turn off till the engine begins to rotate.

Posted by: Boomingbeetle Nov 10 2017, 10:25 AM

Pump is supposed to be on only with key in “on” position. Do you have a power probe or multi meter to verify power at the coil or a spark tester at the plug? Although unlikely, there’s no chance it is an after market pump that you reveresed the in and out flow, or left a set of vise-locks on the line someplace?

Posted by: 87m491 Nov 10 2017, 10:30 AM

Thanks, as noted power from the coil, but I didn't check to the plugs. will do this weekend. So far seems the pump only supposed to see steady power when a sensor "sees" engine RPMs, a safety feature to make sure the pump isn't working away after a cars been in an accident or similar..

QUOTE(Boomingbeetle @ Nov 10 2017, 08:25 AM)

Pump is supposed to be on only with key in “on” position. Do you have a power probe or multi meter to verify power at the coil or a spark tester at the plug? Although unlikely, there’s no chance it is an after market pump that you reveresed the in and out flow, or left a set of vise-locks on the line someplace?

Posted by: mzalanka Nov 10 2017, 11:49 AM

Can I just say that this individual's inline gauge solution has been a lifesaver for me in terms of seeing what the fuel pressure is doing:

http://www.914world.com/bbs2/index.php?showtopic=286480&hl=fuel++pressure

Very strongly recommended & cheap to boot.

Posted by: Spoke Nov 10 2017, 01:26 PM

QUOTE(87m491 @ Nov 10 2017, 11:30 AM)

Thanks, as noted power from the coil, but I didn't check to the plugs. will do this weekend. So far seems the pump only supposed to see steady power when a sensor "sees" engine RPMs, a safety feature to make sure the pump isn't working away after a cars been in an accident or similar..

The sensor which "sees" engine RPM are the extra contact switches on the distributor which also fires the injectors. Once the distributor starts rotating, full time power is applied to the fuel pump.

Posted by: Dave_Darling Nov 10 2017, 02:30 PM

Just to collect it in one post:

- The D-jetronic fuel pump does not run the whole time the key is on.
- It runs for about 1.5 seconds when the key goes from "off" to "on".
- It runs when the fuel injector trigger points in the base of the distributor open and close.

I have heard that there might be specific provision for the pump to run when the starter motor is getting power, but I don't think that's actually correct.

--DD

Posted by: 87m491 Nov 10 2017, 03:08 PM

Concise and easy to check, thanks. I knew I did not see a pulse sensor like in the late 70's early 80's cars. May never have seen it on the dizzy. Much appreciated, will report back.

QUOTE(Dave_Darling @ Nov 10 2017, 12:30 PM)

Just to collect it in one post:

- The D-jetronic fuel pump does not run the whole time the key is on.
- It runs for about 1.5 seconds when the key goes from "off" to "on".
- It runs when the fuel injector trigger points in the base of the distributor open and close.

I have heard that there might be specific provision for the pump to run when the starter motor is getting power, but I don't think that's actually correct.

--DD

Posted by: malcolm2 Nov 10 2017, 05:29 PM

QUOTE(mzalanka @ Nov 10 2017, 11:49 AM)

Can I just say that this individual's inline gauge solution has been a lifesaver for me in terms of seeing what the fuel pressure is doing:

http://www.914world.com/bbs2/index.php?showtopic=286480&hl=fuel++pressure

Very strongly recommended & cheap to boot.

YES

everytime there is a possible fuel problem, someone here will ask about the fuel pressure..... and I thank them. I installed a cheap solution as noted above. Got a fuel pressure tester kit from Harbor Freight. Used the gauge and a couple fittings.

I have L-Jet FI and installed the gauge in the hose that runs to the 5th injector (CSV) installed in the air distributor.

No, I can't see it when I am in the car, but someone else can always turn the key, or just check the gauge after trying to start. It holds at 35 psi for a long time.

Good Luck

Posted by: Mikey914 Nov 11 2017, 06:22 AM

Before you get too crazy chasing down all the possibilities, church the fuel pump relay. Swap it with a known good. You can easily check if the headlights go up and down, you can swap. If the headlight doesn't there's s smoking gun. If they do, it doesn't mean it was not faulty, as often a little bumping around can make them work at least temporarily.

Good luck, sometimes the easiest answer is what has happened.

Posted by: 87m491 Nov 13 2017, 07:51 AM

Thanks Mike. The headlights work, but alas the fuel pump does not momentarily prime with the key turned on. Will start reading through the DJet info I have downloaded recently.

QUOTE(Mikey914 @ Nov 11 2017, 04:22 AM)