Excessive Cranking on start-up, Assistance request Options

[JamesM]

Maybe I missed it but have you checked to see if your injectors are leaking under pressure?

Bottom line, you are on the right track with the FP gauge there. Your starting behavior is about what I would expect it to be based on the pressure gauge.

Car wont start without proper rail pressure AND car wont start with air in the rails. What it looks like to me is that you are building pressure, then a few more cranks to clear the air out of the lines, then it fires.

Find and fix all your pressure leaks.

Injectors, Fuel pump, pressure regulator, fuel lines. it has to be one of those.

[Van B]

James,
Injectors are fresh, flow matched, and tested. And I can confirm that there is no air leaking in or fuel leaking out of the fuel system.

You and I agree on the FP build up being a problem. And I also think the hack job wiring that is leaching off the coil wire is probably hurting both spark and fuel pump action.

I'm going to fix the wiring first and then do the whole SS fuel lines upgrade with a two port pump. Thankfully the plastic lines are still pliable everywhere, but they are 49yrs old and looking pretty discolored.

[Van B]

I didn't read the whole thread.
but I experienced the exact same symptoms with a 3 port Djet pump

I opened up the working pump
its a smart design
there is a rubber seal inside that also causes the pump to close when turned off and hold fuel pressure in the fuel lines...

I replaced the seal.
now when I crank the starter it fires right off

where as before it had to crank 5 times to build up the correct fuel pressure before starting....

these are old pumps
I did not realize they were also functioning as a pressure accumulator
not surprised a 50 year old piece of rubber was not doing its job

opening these pumps is a pain in the butt....
having a factory type crimping tool would help, but I don't have one...
so my home rebuild is not a pretty site.


I bet if you change the pump... your problem will go away


before I fixed mine... I would key on the ignition 4-5 times to build pressure...
then hit the starter and it would fire off immediately

brant

I'm gonna keep the three port and maybe attempt a rebuild when I get toward the bottom of the list for things to do on this 914... sometime around 2025 lol...
I wish that I could prime the pump, but the L-Jet pumps don't play that game unfortunately.

[emerygt350]

I'm feeling good about the spark robbing. Will it be simple to run your fudged wires over to the original?

[wonkipop]

I didn't read the whole thread.
but I experienced the exact same symptoms with a 3 port Djet pump

I opened up the working pump
its a smart design
there is a rubber seal inside that also causes the pump to close when turned off and hold fuel pressure in the fuel lines...

I replaced the seal.
now when I crank the starter it fires right off

where as before it had to crank 5 times to build up the correct fuel pressure before starting....

these are old pumps
I did not realize they were also functioning as a pressure accumulator
not surprised a 50 year old piece of rubber was not doing its job

opening these pumps is a pain in the butt....
having a factory type crimping tool would help, but I don't have one...
so my home rebuild is not a pretty site.


I bet if you change the pump... your problem will go away


before I fixed mine... I would key on the ignition 4-5 times to build pressure...
then hit the starter and it would fire off immediately

brant

I'm gonna keep the three port and maybe attempt a rebuild when I get toward the bottom of the list for things to do on this 914... sometime around 2025 lol...
I wish that I could prime the pump, but the L-Jet pumps don't play that game unfortunately.

make sure you don't store the pump dry.

flush it with kerosine or what you guys call white spirits. we call it turpentine or turps for short. (another aus slang term for turps is alcohol that you drink, ie beer, wine or spirits). the whole pump fills with fuel when its running, electrical motor and all.
so the flush has to be really good. two buckets, a car battery to run it, and backwards and forwards a few times. then run with fresh turps to fill it.

leave it full of turps, cap the hoses or ports and bag it.
that way it won't gunk up with residual fuel nor will the seals dry out.

[wonkipop]

I didn't read the whole thread.
but I experienced the exact same symptoms with a 3 port Djet pump

I opened up the working pump
its a smart design
there is a rubber seal inside that also causes the pump to close when turned off and hold fuel pressure in the fuel lines...

I replaced the seal.
now when I crank the starter it fires right off

where as before it had to crank 5 times to build up the correct fuel pressure before starting....

these are old pumps
I did not realize they were also functioning as a pressure accumulator
not surprised a 50 year old piece of rubber was not doing its job

opening these pumps is a pain in the butt....
having a factory type crimping tool would help, but I don't have one...
so my home rebuild is not a pretty site.


I bet if you change the pump... your problem will go away


before I fixed mine... I would key on the ignition 4-5 times to build pressure...
then hit the starter and it would fire off immediately

brant

@brant

can you remember where you got that little seal from?

[Van B]

I'm feeling good about the spark robbing. Will it be simple to run your fudged wires over to the original?

I ordered some high temp silly-cone wire from the amazons last night. I don’t think the wire they used was 14 AWG either btw…. (IMG:style_emoticons/default/dry.gif)
They pulled it through the tunnel and my going in plan is to do that as well. But I intend to use both wires rather than the hot lead and a chassis ground on the current setup.

[brant]

I didn't read the whole thread.
but I experienced the exact same symptoms with a 3 port Djet pump

I opened up the working pump
its a smart design
there is a rubber seal inside that also causes the pump to close when turned off and hold fuel pressure in the fuel lines...

I replaced the seal.
now when I crank the starter it fires right off

where as before it had to crank 5 times to build up the correct fuel pressure before starting....

these are old pumps
I did not realize they were also functioning as a pressure accumulator
not surprised a 50 year old piece of rubber was not doing its job

opening these pumps is a pain in the butt....
having a factory type crimping tool would help, but I don't have one...
so my home rebuild is not a pretty site.


I bet if you change the pump... your problem will go away


before I fixed mine... I would key on the ignition 4-5 times to build pressure...
then hit the starter and it would fire off immediately

brant

@brant

can you remember where you got that little seal from?

I don't recall
but I think.....

mcmark had built a few and had found the correct o rings... misc
I think he sent me a couple in an envelope at the time.
but it was a few years ago

brant

[wonkipop]

I didn't read the whole thread.
but I experienced the exact same symptoms with a 3 port Djet pump

I opened up the working pump
its a smart design
there is a rubber seal inside that also causes the pump to close when turned off and hold fuel pressure in the fuel lines...

I replaced the seal.
now when I crank the starter it fires right off

where as before it had to crank 5 times to build up the correct fuel pressure before starting....

these are old pumps
I did not realize they were also functioning as a pressure accumulator
not surprised a 50 year old piece of rubber was not doing its job

opening these pumps is a pain in the butt....
having a factory type crimping tool would help, but I don't have one...
so my home rebuild is not a pretty site.


I bet if you change the pump... your problem will go away


before I fixed mine... I would key on the ignition 4-5 times to build pressure...
then hit the starter and it would fire off immediately

brant

@brant

can you remember where you got that little seal from?

I don't recall
but I think.....

mcmark had built a few and had found the correct o rings... misc
I think he sent me a couple in an envelope at the time.
but it was a few years ago

brant

yes, if i remember right its the world's tiniest o ring that sits in a channel groove in that little needle valve. or its some kind of tit thing. would need to look at my old photos to remind myself.
be handy to know where to get hold of one --- just in case.

fortunately that was the only one in both fuel pumps that wasn't shot.
the main culprit in the pumps i rebuilt was the electrical plug o ring seal.
which required a complete drill down and full disassembly to renew.

the trick to the paper thin alum cap on the end of the spring housing of the top port assembly is to use a socket over the cap and hold it all in a vice. the socket distributes load to the stepped section of the cap and stops it distorting. which it will do at the drop of a hat. if it distorts it will screw up the operation of the relief valve. then work at it very gingerly with a screw driver. reverse for reinstall.

i totally destroyed the first one i did. and you can't buy them anywhere.
i bought two screwed pumps from a VW guy in the states for $20.00 each and had then freighted slow mail. just to get some spare caps. and perfected the technique.

[wonkipop]

found the photo.

its a tit thing.
if thats perished or thrown in the towel after 50 years your pump is farked.
won't hold pressure. and where you get one i do not know.

if you are lucky just the recess it seals against is gunked.
or as i discovered the free operation of the valve sliding is compromised by gunk in the bore it moves back and forth in.

one of the pumps i did was very troublesome getting that valve to operate freely again.
i ended up wrapping fine grit sand paper around a wooden kebab skewer and giving it a hone.

in the photo i have it orientated the wrong way in the spread out layout.
for anyone smart enough to work that out.

you have to be half mad to rebuild one of these things.
but i am getting in practice for the coming dark ages.

[Van B]

Well folks, things have definitely taken a turn here… while preparing to run the new wires to the fuel pump, I pulled out some carpets only to discover a couple were stuck together, (some of you already know where this is headed) then after a bit more exploration I discovered that my master cylinder has ruptured the seal and brake fluid was all over the floor. It didn’t take long for it to eat up the floor coating, pedal box paint, and expose bare metal in many many places.

So, with partially run wires still dangling, I’m now in the midst of an emergency clean-up, POR15 coating repair, and master cylinder replacement.

Yaaaaa….

[emerygt350]

Oh,man, that sucks.

[StarBear]

(IMG:style_emoticons/default/popcorn[1].gif) paying close attention to your adventure and the thrilling next episode.

[Van B]

(IMG:style_emoticons/default/popcorn[1].gif) paying close attention to your adventure and the thrilling next episode.

Lol… thanks (IMG:style_emoticons/default/bootyshake.gif)

So, now that I’ve concluded that drama, I’ll be installing the master cylinder I bought from @billh1963 well ahead of my anticipated timeline.
Interestingly, my car came with a 19mm master cylinder as OE. At least there’s no indication that it was ever replaced from what I can tell.

[emerygt350]

What failed on it? I am not at all familiar with these on 914s, and I saw Ian karrs video. Looks like all kinds of possible failure points...

[Superhawk996]

duplicate

[Superhawk996]

What failed on it? I am not at all familiar with these on 914s, and I saw Ian karrs video. Looks like all kinds of possible failure points...

Seals wear. Should not at all be a surprise on 50 year old cars. I had one fail on my 1st teener back in the 90's and my 73' was only about 17 years old at that point.

Back in the day you could easily buy a master cylinder seal kit. But, given that a master cylinder casting is now 49 years old and probably pitted by rust, a seal kit probably wouldn't even help depending on the specifics of how it failed.

[Van B]

What failed on it? I am not at all familiar with these on 914s, and I saw Ian karrs video. Looks like all kinds of possible failure points...

I suppose it was the same thing that ruined my childhood, abuse and neglect.
Although what @Superhawk996 said is probably more technically correct lol (IMG:style_emoticons/default/laugh.gif)

[emerygt350]

So seals on the rod. The seals on top for the reservoir seemed a bit sketch to me but I guess they shouldn't. It's just the deep location that makes it strange.

I need to bleed mine a bit more and it scares me. I want to be in the car so it doesn't over extend but I don't trust anyone else in the family with the bleeder screws either!

[Van B]

I’ve been eyeballing the motive pressure bleeder and this was finally the excuse to get it. I really like the idea of not pumping a pedal ever again lol…