'74 2.0 - 25K miles

It has been a very long journey. I, with my 17yr old son who is now 21, rebuilt nearly every system including the Engine and Transmission (a nod to Dr. Evil !! ). My son and I have learned a great deal, however, this one has me stumped.

The car runs terrific and is strong, smooth and a joy to drive, today I took it around the Lakes here in Arlington MA and at the end of the drive there is a hill with a red light - I caught the red. I waited as the button pushers jaywalked (after they hit the button) and then I waited some more with the crosswalk signs blinking and no one crossing.....sigh

OK, there is the green and I ease out the clutch and apply a little gas AND nothing...... nearly idling. I then bury the gas and the car stalls.......and since this is New England everyone starts beeping and yelling - so I get the flashers on and people go around me.

I wait another light cycle and get the cars started by pumping the gas and keeping it running over 1500, once it started moving it ran fine. It is almost
as if there was zero power below 1500, though when the car was rolling everything worked as you would expect. When the car is cold the low power is as normal as a 90HP engine can be. The temp of the car is about 2/3rds deflection of the center console temp gauge.

I am thinking all sorts of complicated thoughts.......head temp sensor is sending weird signals to the Bosch controller OR when super hot the vacuum system starts leaking, etc.

So, I thought I would start here - any ideas teeners???? Keep me sane and guide me to the light!


CTC911CTC

Do you still have the original distributor?

Advance plates sticking in distributor
Fuel pump needs replacing
Head temp sensor is toast
Check all grounds

What location did you put the fuel pump?
If it’s in the engine bay, make sure the heat exchanger is not blowing air on the fuel pump

http://www.914world.com/bbs2/index.php?showtopic=295025

read up on vapor locking.

search with google and as any question and 914world and it will bring up examples

That works for me

Bob B

Back in my dirt bike racing days, that was a sure sign that something was about to go kaputt.

They always seemed to run "better than ever" right before failing in a spectacular way.

Ain't it the way!

Vapor Lock did not occur to me - the pump is in the same place as stock - I move it a bit to make it "out of the way", will take a look at it.....

Would Vapor lock at the fuel pump result in a reduction in pressure at the rail? If so would this persist once the engine was running at higher RPMs?

I took the plates out, cleaned and rebuilt the entire assembly - tried to find a new one, however, could not find one for a stock Injector setup......

Will look within the board, Would be nice to have a spare - also, do you think it would be heat sensitive?

The advance plates once I was finished were pretty slick, the springs very taught and new

Yes,

I took it apart and cleaned it.....twice! Seems like it is all together correctly and very clean - spring plates are free and move nicely .......would this behavior be temperature sensitive?

Well, fuel and ignition
Can you reproduce the problem , near home?

I’m thinking hot coil, or hot fuel pump

Yes, I know how to reproduce - will adjust/check, adjust/check tomorrow or later this week!

If you need anything, give me a ring.

Rich

Unlikely it’s your issue, but one summer my car would run great and then stall intermittently after it warmed up. Sometimes I could drive for hours before it would happen, sometimes 30 minutes or less. I’d have to keep the RPMs up to keep it from stalling. Sometimes it would stall anyway.
Turned out the computer was bad. Likely a failing solder joint that would worsen with heat.
Intermittent issues are the worst.

Can't say enough about the 123dizzy. However it sounds like you have yours in good shape.

The fact it is low rpm really makes me lean that way. You say runs fine over 1500 but does it really? I have had bad coils on other cars behave like that, at higher rpm it was harder to notice, normally that results in bucking at low rpm cruise though.

I really don't think this is a vapor lock.

On a hill and stopped for a long time... how much gas was in the tank?

Absolutely. It's very difficult to pressurize a vapor as compared to a liquid. The vapor lock occurs in the pump or in the incoming line. I vaporized upon takeoff and almost shit in my pants. I had been on the tarmac for awhile and it was a hot day.Twenty feet off the runway it began sputtering so I had to slam the plane back down on the runway and full brakes before I ran out of runway! I was running auto gas and it vaporizes quite easily compared to AvGas.

Yes, my mind did go there - the tank was completely rebuilt with new sending unit, sock, filter and at the time of the stalling was reading over 1/2 tank.

That gets worse with load/rpm. This apparently works fine with load/rpm.

Conscious that makes Sens-ous is that the fuel pump is getting too hot and the machine is getting the vapors.......will move the fuel pump or re-route this weekend and report

That is a big pia job that may be unnecessary.

UPDATE

Got under the car today - first I started to sweep the garage, then I decided to clean it, then I was on my knees scrubbing the floor - looks good, however, took 6 hours.

FINALLY I got the car in the air and here is what I saw:

Click to view attachment

And the idea is that the heat is cooking the fuel like this.......

Click to view attachment

I took the heater hose off for the picture

So, I am planning on moving the pump but I have a few more questions:

1. I have it on the firewall, I do not want to move it up front, remove the gas tank, etc. where should it go, where is it coolest

Oh, all the welding was done by my son when he was 17, he is 21 now and is embarrassed when he see these.....I am still very proud of these ugly welds....

2. any ideas as to below the engine tin or above? Votes?

3. While the engine is running the pump is on, does the gas cool the pump? should there really be vapor lock?

4. If there is vapor lock, should there be a drop in fuel pressure?

Thank you Teeners!

You are fine there. Not an original position or pump but if you still think it's vapor lock, I don't, you can put insulation all over that and find out before you move any of it.

And it isn't the pump that will be cooking, it will be the lines.

Same day I had the trouble with the 914, my neighbor had the same thing - exact same circumstances - happen to his Model A........so I am leaning towards vapor lock

I also was thinking of putting in a heat barrier, perhaps something blocking the airflow from the engine.........

THANK YOU very much for your interest in this matter - I am trying to get this old but nearly new (25k miles) back to a reliable fun car, almost there!

When these vapor lock, they go nowhere, the engine will not start. That doesn't fit your experience. You still have fuel injection right?

That is an aftermarket 2 port pump for a 75
While I don’t agree, the filter goes after the pump on the FI side of the loop. There is no filter (aside from the tank sock) before the pump.

Start by swapping that, and move the filter further away from the heat source, that is a place for fuel to accumulate and boil….get it out of the line of fire.

See if you can find some pictures of the original placement of the pump.
It should be up in the corner above the heater hose.
Again, this location takes it out of the line of fire from the flapper box exhaust.

Lastly, make sure you have not swapped the hoses around from tank to pump.

The feed hose that goes to the pump has no stub pipe on it, just the sock ( inside the tank) and thus can suck fuel at weird angles and until the tank is empty.
The return pipe has a 1/2- 3/4 inch piece stick into the tank, so it won’t suck fuel at weird angles or when close to empty.

I think it’s an easy fix. Get some new hoses.
Flip the order….tank—pump—filter
Move it over into the corner above the heater tube..

Rich.

Notice that no air deflector flaps present .... doesn't help matters

Good catch, removed for the work - will replace - thank you!

Rich,

Good to exchange notes with you today,

I rebuilt the tank - it is in these pages somewhere - and recall getting the two sorted, one is the return the other the supply. I believe I have it correct - is there an easy way to tell? I have the Stainless steel replacement fuel lines, purchased the 9.5mm from Tangerine.

Thank you Rich!

Look for a recent thread by me on the fittings, etc.
I think i posted pics to get help figuring out the pipes and ports

Why would you put the filter after the pump? I would want to trap any crud or rust from the tank going into the fuel pump. Just asking.

I agree, BUT…

Oem the order is tank (sock or inside) pump, filter, FI

You rarely see a filter 100% full of fuel.
Thus there are air pockets

What I did was I went and got a really small re-usable racing filter, which is just a stone filter inside a very small housing.
I put that between the tank and the pump.

Honestly, I have removed that and fixed the root cause by replacing the tank and sock.

I’m not sure why some pumps work great and others don’t suck (therefore they suck at being a pump) but flow is key and I just stick with the design….

I agree…but the pump did last 40 plus years until I let the tank rust

I installed a Delphi pump from Rock Auto. My 914 is a 75. The inlet line going into the pump is 1/2". The fuel filter has a 3/8 nipple that connects the filter to the tank, and a 1/2" outlet that connects to the pump. So in my case the filter is before the pump.Click to view attachment

Location location.
The OP may have had issues with the flapper box blowing hot air at the filter.

He is moving everything around now, so he may be up and running again soon.

*****UPDATE*****

I have decided, after reading other threads on this matter,

http://www.914world.com/bbs2/index.php?sho...93742&st=20

http://www.914world.com/bbs2/index.php?sho...=10092&st=0

I will move the pump/filter to the front -

QUESTION:

This will require 2 180-degree turns in the fuel hose - I was experimenting with my pressure and n-n-pressure rated hose and if the bend is too tight it will start to kink. Any anti-kink ideas - also I experimented with bending my own stainless - could not get it with the bending tool (Brake Line Bender) I have too tight, starts to kink too.....

It will also require the cut/plug fast dance or drain the tank.......I will drain the tank........sigh......

Thank you Teeners!

Move the pump under the steering rack, so all you have to do is drop the pan to change the fuel filter.

That’s the way plan! Still need 2 180 degree bends,,,,,,,

I just had to deal with this.
Either go to the parts store and buy a pump (80 bucks ish)
Or, because my son was there, pick it up (remove tge hood) and immediately tip the passenger side up very high.
Then dad can reach in with cutters and snip the hoses.
If you remove the fill expansion tank on top you have a nice handle to grab and pull straight up.

I have the pump here is you want to use it…
I also have a 75 here if you want to look, see, measure the stock location.

Good luck.

Bent fuel hose….maybe use the pieces created to replace fuel injector hoses. I got them from 914 rubber or pelican.
It’s 5/16 ID, about maybe 4 inches total, 90 degree heat molded.

Alternate idea, Chris Foley at Tangerine Racing sells new stainless fuel lines for the tunnel and engine bay, so his pre bent tubing may solve your problem.
Rich

So assumptions.....starts with ass...


The D-jet system once set...to the stock design is pretty simple.


First: You don't wrap the pump in insulation...bad. The pump is cooled by not only the air surrounding it but also by the fuel it pumps.

Follow the stock design and use the rubberized stock isolators. That location you already have it in is almost the area I relocated my fuel pump. I ran that car in 120 amibient temps and never had a problem.

Second: You haven't ruled out.....and have only assumed...other issues. Some of those symtoms are caused by the mixture being to rich...and not lack of fuel. From your description...when it's hot. IE...the MPS diaphram is made from a Berrilium copper so if it is even slightly cracked...would leak more when warm. Ask me how I know this.

Third...looks like some one did some re-wiring for the fuel pump. The leads IIRC for that pump run through the FI harness and looks to have been bypassed. The source comes from the FI board and fuses. Electrical connections if dirty or loose connections expand when they are hot.....so has that been ruled out? Is your board clean and fuses clean...cause if they are dirty...the resisitance caused by heat will cause them to expand even more.

The worst circuit design on the 914 in my opinion was the fuel circuit becuase it is switched through the ignition and then relayed through the primitive trace board and fused as a safety feature. You need to make sure this is ALL working and clean before you start chaseing your tail.

I don't think relocating your fuel pump will solve that problem if it does then you just eliminated bypassing something you didn't check or mis-diagnosed.

Good luck.

I don't suggest wrapping it, just create a barrier for trouble shooting. His symptoms don't really match vapor lock in my opinion so I am staying out of it.

The picture showing the fuel pump the OP posted shows it that way.

I didn't post that you stated to wrap it and most likely it isn't vapor lock in my opinion.

When I moved the pump under the steering rack several years ago I had no trouble bending a U out of metal fuel line with the right bending tool. I eliminated the sock in the tank as a potential difficult service item and installed a filter before and after the new pump, no problems since.

I see that now. I bet that was for noise insulation.

What I did....couldn't find my old thread...maybe that is because now I really am old;

I installed some Rivnuts in the firewall but higher than the up and above the "cooling" flaps. Then I installed the stock isolators which stand off from the firewall surface allowing full airflow around the pump. Worked like a charm. I never liked the idea of putting the pump underneath the rack pan for a lot of reasons. The picuture of that pump looks something like the DAPO stuff I see posted. Tie wraps holding on a cheap peice of refrigeration inslulation ready made for a kindling fire. Not advisable. At least the right fuelline clamps were used.

One thing to consider, you're now pushing very high pressure through (50 year old) plastic fuel lines that were never designed for that.

If you go that route, please install stainless steel fuel lines in the center tunnel.

Here is what the fuel lines looked like - car was parked in '86 - stem to stern fuel rebuild - everything was glue.....Used the stainless lines from Tangerine!



Click to view attachment

**********UPDATE**********

First, big thanks to R_Towle, he has been sending me ideas and assisting with the troubleshooting. Got me to stop thinking about what could be wrong and focus on the basics. Thanks Rich.

We eliminated Electric and focused on fuel, this thread has some of the debate within. I then decided to move the pump away from the furnace (it was directly in the way of the heater dump valve) and moved it to the starboard side of the firewall. I used an Evil-Fuel mounting bracket and also bought an Evil fuel filter and an exchangeable filter insert.

THEN - after all of the connects were on the devices the chain of lines and size changes got to 2 feet long, I thought I could mount them side/side and it would fit,,,,,,sooo,,,,,,I decided that I would bend some soft brake line for the fuel to move from the filter to the back of the pump......I used to be pretty good at bending EMT conduit........this was harder

After a while of playing with this I thought if I ever got this done, I would not be able to write a proper note to the next owner as to why I did this........many times I think about adding notes of apologies within my barely adequate fixes......

Click to view attachment

.....SOOOOOO, I dropped back and put a new but plastic fuel filter on the low-pressure side....... hhhhmmmmm, perhaps a french horn could be.............

A few years ago I welded platypus bills on an old pair of vise-grips which is my fuel shutoff valve. I released the Platypus and let the fuel flow - had a few leaks.....sigh.....where are those nut drivers???? Got the fuel flowing nicely, no leaks now........

Rich instructed me (thanks again Rich) to put a pressure gauge on the rail (I installed a very nice brass access next to the rail and screwed the pressure gauge into the mix.

The car started right up, went to 29lbs immediately, and ran well. Next, I turned the car off to double-check for leaks and I noticed the pressure went to zero in a few seconds. Oh yea, no leaks!


There is a great deal of experience with this forum about this problem that often the fuel pump internal check valve which is in place to prevent vapor creation is the culprit.

Buying a new fuel pump - I am also buying a new regulator. Mine is 50 years old.

I also would like to buy a steel small fuel filter 5/16 to 5/16 - any ideas?

Stay Tuned!

Yummy fuel lines.

Filter, summit racing