Is it the fule pump?, Spluttering and stalling! Options

[chrispovoas]

Hi guys, Chris from New Zealand here....finally bought myself a 914! Shes a '73 2.0 with original FI. Had her about a week, after standing for 8 years.

Previous owner spent some time and money getting her on the road as part of the sale to me, but still a bit of work to be done! I'll try and attach a picture.

Took her for a shakedown run today for about 3 hours but then she started coughing and spluttering then stalled at about 60mph. Coasted to a halt, ignition on/off and away she went again for about half an hour.. Same thing again, ignition on/off and all was well for another 20 min.. This went on and on and the intervals between spluttering and stalling got more frequent until i just about made it home.

Felt like fuel rather than electrical... Could it be the fuel pump, or any other ideas?

I have a feeling I'll be using the forum quite a bit (IMG:style_emoticons/default/smile.gif)

Nice to meet everyone!

[emerygt350]

Welcome, and that's a pretty car! I would first look to vapor lock. If she runs great when you start her up cold today, that could be the problem.

There are many other possibilities but that is the first I would look at. If it runs badly cold today, then it is not the issue and we can look elsewhere.

[chrispovoas]

Welcome, and that's a pretty car! I would first look to vapor lock. If she runs great when you start her up cold today, that could be the problem.

There are many other possibilities but that is the first I would look at. If it runs badly cold today, then it is not the issue and we can look elsewhere.

Thanks dude! Well the last 3 or 4 days of cold start she coughs and splutters until thouroughly warmed up, but ok after that.. These drives have only been short distances with no issues.. The stalling etc only happened today after the 3 hour drive. Ill see how she runs tomorrow morning.

[StarBear]

Congratulations and welcome to our community!
(IMG:style_emoticons/default/welcome.png)

[BeatNavy]

Beautiful car. Welcome to the World (IMG:style_emoticons/default/beerchug.gif)

You may want to start learning about D-Jet. It's an old but reliable FI system, but like any other system the parts all have to be serviced. If the FI is 'original,' as in hasn't been maintained, you'll definitely want to go through it. Good reading: https://members.rennlist.com/pbanders/DJetParts.htm

For the issue you had specifically I'd start checking to make sure all connections are secure. That includes the ground points on the engine and the relays and connections at relay board assuming it is fuel delivery and not electrical. Could also be blocked filter or line somewhere along the fuel path.

I've never experienced vapor lock as far as I know (my fuel pump was already moved from stock location) -- can that happen while cruising? I would think the constant flow of fuel would not allow it to "boil."

[rfinegan]

Trust you instincts. The Djet is not a very complicated system compared to modern FIs and not a lot of components. Invest in a fuel pressure gauge and see what the fuel pressure is. Keep the gage installed and confirm the pressure when it acting up. I tape my gage to the back window so I can see it while test driving. You get the idea. Once you confirm your fuel delivery you can move on to another system, or fix your findings...best regards...keep us post on your findings

[emerygt350]

the attachment point on the rail for the fuel pressure guage makes Rfinegans suggestion real easy.

The rough start suggests to me your aux air valve may be misbehaving. Since it starts fine after it is warm it could be that or the FI cht sensor. If you crack the throttle on a cold start does it idle fine at 1400ish rpm? If so, likely to be the aux air valve. If it still kinda runs like crap I would check the cht sensor (it enrichens the mix when cold).

I think you are going to have to go for another long drive and see if it does the same thing. Maybe run some injector cleaner through it while you are at it.

And before you do anything else, check those plugs to see if it is running lean. If you have low fuel pressure or a pile of other issues, you want to make sure you aren't melting your engine.

[technicalninja]

Hi guys, Chris from New Zealand here....finally bought myself a 914! Shes a '73 2.0 with original FI. Had her about a week, after standing for 8 years.

What you are describing sounds like vapor lock to me as well but any car that sits that long needs a full inspection of EVERYTHING.
The first inspection I'd do is gas tank internals. 8 years is a LONG time.
I don't know what New Zealand fuel is like but here in the USA the tank would be "poisoned" and require either replacement or massive cleaning. Our fuel goes south after 6 months. 8 years would turn it into varnish...

I've got a 75 that has been dormant since 1989.
It's been "standing" for 34 years!

I'm doing what I call a "resurrection" to it. It is the longest dead time car I've ever done.
You solve all the problems you can find and drive it until something else shows up.
You fix and drive again. Lather/rinse/repeat.

One of the initial tasks is compete replacement/ restoration of the fuel system.
My car still has the hard plastic fuel lines that Porsche used 50 years ago.
It's getting all new steel lines before returning to service.

A fire extinguisher will be a passenger for the first 500+ miles, even with the new fuel system in place.
The ONLY times I've ever needed an extinguisher is when one wasn't available.
If you have it with you, you will not have a fire that requires it.

The brake hydraulic system is another system that requires full rebuild after 50 years.
ALL rubber-based parts are being replaced before road use. 8 years non-use does not kill this system like it does a fuel system, but your system is 50 years old this year and no hydraulic system lasts half a century.

Beautiful car, love the color.

[Olympic 914]

Could be blockage of the screen in the fuel tank, Debris blocks the flow when running then after it shuts off, drifts away from the screen.

You can take off the filler neck and look down in there, Not a real big deal to pull the tank and clean/replace the fuel sock.

also can check if the rubber lines have a kink in them.

[porschetub]

Hi guys, Chris from New Zealand here....finally bought myself a 914! Shes a '73 2.0 with original FI. Had her about a week, after standing for 8 years.

Previous owner spent some time and money getting her on the road as part of the sale to me, but still a bit of work to be done! I'll try and attach a picture.

Took her for a shakedown run today for about 3 hours but then she started coughing and spluttering then stalled at about 60mph. Coasted to a halt, ignition on/off and away she went again for about half an hour.. Same thing again, ignition on/off and all was well for another 20 min.. This went on and on and the intervals between spluttering and stalling got more frequent until i just about made it home.

Felt like fuel rather than electrical... Could it be the fuel pump, or any other ideas?

I have a feeling I'll be using the forum quite a bit (IMG:style_emoticons/default/smile.gif)

Nice to meet everyone!

(IMG:style_emoticons/default/welcome.png) greeting from fellow NZ 914 owner .
As beatnavy mentioned check the grounds, connections, relays etc as it could be electrical,if it all looks ok check plugs ,leads ,cap,points and plugs ,could be something simple like a dying coil or points out of adjustment/or just worn out.
Reset / check valve clearances then start it up and check timing if you have a stable idle otherwise you need to make sure your aux air valve is working,you can test this by diconnecting the power wire and if it still runs the same the valve is stuck and not opening.
See how you go ,you can email me for a chat anytime ,like to keep up with NZ owners and chat ,cheers.
Oh and forgot to mention ,real nice looking car (IMG:style_emoticons/default/beerchug.gif) .

[chrispovoas]

Hi guys, Chris from New Zealand here....finally bought myself a 914! Shes a '73 2.0 with original FI. Had her about a week, after standing for 8 years.

Previous owner spent some time and money getting her on the road as part of the sale to me, but still a bit of work to be done! I'll try and attach a picture.

Took her for a shakedown run today for about 3 hours but then she started coughing and spluttering then stalled at about 60mph. Coasted to a halt, ignition on/off and away she went again for about half an hour.. Same thing again, ignition on/off and all was well for another 20 min.. This went on and on and the intervals between spluttering and stalling got more frequent until i just about made it home.

Felt like fuel rather than electrical... Could it be the fuel pump, or any other ideas?

I have a feeling I'll be using the forum quite a bit (IMG:style_emoticons/default/smile.gif)

Nice to meet everyone!

(IMG:style_emoticons/default/welcome.png) greeting from fellow NZ 914 owner .
As beatnavy mentioned check the grounds, connections, relays etc as it could be electrical,if it all looks ok check plugs ,leads ,cap,points and plugs ,could be something simple like a dying coil or points out of adjustment/or just worn out.
Reset / check valve clearances then start it up and check timing if you have a stable idle otherwise you need to make sure your aux air valve is working,you can test this by diconnecting the power wire and if it still runs the same the valve is stuck and not opening.
See how you go ,you can email me for a chat anytime ,like to keep up with NZ owners and chat ,cheers.
Oh and forgot to mention ,real nice looking car (IMG:style_emoticons/default/beerchug.gif) .

Thanks Porschetub! where are you based?

This was Alistair Moffats car in Auckland. He's done a fair bit of work to get ot on the road, mostly what needed to be done to pass a WoF and get it drivable, so brakes, clutch, gear shift springs, bushes, some FI hoses etc etc... It drives really well. feels tight and responsive, just the stalling issue to report after a drive from Auck to Mt Maunganui and back in the same day... The usual rattles and squeeks prevail, but nothing that some online shopping at Auto Altanta cant fix! (where do you go for your parts?).

Started ok this morning.. bit of a flutter, but a boot full got it idling.. Seems to idle high at around 1200/1400 rpm.

[chrispovoas]

Congratulations and welcome to our community!
(IMG:style_emoticons/default/welcome.png)

Thanks StarBear!!!

[chrispovoas]

Welcome, and that's a pretty car! I would first look to vapor lock. If she runs great when you start her up cold today, that could be the problem.

There are many other possibilities but that is the first I would look at. If it runs badly cold today, then it is not the issue and we can look elsewhere.

Thanks emeryGT... Started ok this morning.. bit of a flutter, but a boot full got it idling.. Seems to idle high at around 1200/1400 rpm though. Havent taken it for a ride yet to confirm the same issue. A few members have suggest vapour lock, but also i think i'll start to check all of the connections first to eliminate the most obvious/easiest to check!

[chrispovoas]

Beautiful car. Welcome to the World (IMG:style_emoticons/default/beerchug.gif)

You may want to start learning about D-Jet. It's an old but reliable FI system, but like any other system the parts all have to be serviced. If the FI is 'original,' as in hasn't been maintained, you'll definitely want to go through it. Good reading: https://members.rennlist.com/pbanders/DJetParts.htm

For the issue you had specifically I'd start checking to make sure all connections are secure. That includes the ground points on the engine and the relays and connections at relay board assuming it is fuel delivery and not electrical. Could also be blocked filter or line somewhere along the fuel path.

I've never experienced vapor lock as far as I know (my fuel pump was already moved from stock location) -- can that happen while cruising? I would think the constant flow of fuel would not allow it to "boil."

Thanks BeatNavy! Yes, i think checking all of the connections that yourself and others have mentioned will be the best place to start...

[chrispovoas]

Trust you instincts. The Djet is not a very complicated system compared to modern FIs and not a lot of components. Invest in a fuel pressure gauge and see what the fuel pressure is. Keep the gage installed and confirm the pressure when it acting up. I tape my gage to the back window so I can see it while test driving. You get the idea. Once you confirm your fuel delivery you can move on to another system, or fix your findings...best regards...keep us post on your findings

Thanks rfinegan!! Thats a great idea! I think outside of checking loose connections and simple to do stuff, that might be a good place to start.

[chrispovoas]

the attachment point on the rail for the fuel pressure guage makes Rfinegans suggestion real easy.

The rough start suggests to me your aux air valve may be misbehaving. Since it starts fine after it is warm it could be that or the FI cht sensor. If you crack the throttle on a cold start does it idle fine at 1400ish rpm? If so, likely to be the aux air valve. If it still kinda runs like crap I would check the cht sensor (it enrichens the mix when cold).

I think you are going to have to go for another long drive and see if it does the same thing. Maybe run some injector cleaner through it while you are at it.

And before you do anything else, check those plugs to see if it is running lean. If you have low fuel pressure or a pile of other issues, you want to make sure you aren't melting your engine.

Yes, starts first time after the initial morning start and does seem to idle very high at around 1400rpm. Some great thoughts there.. Is there a way to actually check the aux air valve / cht sensor?

I think ill check all connections, plugs, distributor first to see if anything obvious.

Anywhere you go to get your spare parts other than Auto Atlanta?

[chrispovoas]

Hi guys, Chris from New Zealand here....finally bought myself a 914! Shes a '73 2.0 with original FI. Had her about a week, after standing for 8 years.

What you are describing sounds like vapor lock to me as well but any car that sits that long needs a full inspection of EVERYTHING.
The first inspection I'd do is gas tank internals. 8 years is a LONG time.
I don't know what New Zealand fuel is like but here in the USA the tank would be "poisoned" and require either replacement or massive cleaning. Our fuel goes south after 6 months. 8 years would turn it into varnish...

I've got a 75 that has been dormant since 1989.
It's been "standing" for 34 years!

I'm doing what I call a "resurrection" to it. It is the longest dead time car I've ever done.
You solve all the problems you can find and drive it until something else shows up.
You fix and drive again. Lather/rinse/repeat.

One of the initial tasks is compete replacement/ restoration of the fuel system.
My car still has the hard plastic fuel lines that Porsche used 50 years ago.
It's getting all new steel lines before returning to service.

A fire extinguisher will be a passenger for the first 500+ miles, even with the new fuel system in place.
The ONLY times I've ever needed an extinguisher is when one wasn't available.
If you have it with you, you will not have a fire that requires it.

The brake hydraulic system is another system that requires full rebuild after 50 years.
ALL rubber-based parts are being replaced before road use. 8 years non-use does not kill this system like it does a fuel system, but your system is 50 years old this year and no hydraulic system lasts half a century.

Beautiful car, love the color.

Thanks Technic!

The guy i bought it from did a lot of work to get it road worthy such as clutch, brakes, FI hoses etc etc etc, so it drives well apart form the spluttering and stalling.

Sounds like you've got a bigger job ahead of you than me!!!

[emerygt350]

1400 is where it should idle at cold start.

Let's take it slow and not break anything. These are 50 year old fuel injection.cars. they don't behave like today's cars.

I suspect yours is actually in really good shape.

[chrispovoas]

1400 is where it should idle at cold start.

Let's take it slow and not break anything. These are 50 year old fuel injection.cars. they don't behave like today's cars.

I suspect yours is actually in really good shape.

Cool, thanks! I'll start with checking connections etc then go from there... So far the main comments are possible CHT sensor failure or Aux Air Valve failure..

[emerygt350]

At cold start (20 c) it should jump up to 12-1400 rpm. As it warms it will rise to 1400 but shouldn't go higher. That is the aux air valve. As the filament in the aav heats it will bring the idle down. As the heads heat the sensor the ECU uses to enrich the air fuel ratio will eventually tell the ECU to knock it off. At this point the idle should be about 850. This can take a long long time in cold temps. Temps less than 20c.

The system the type 4 uses to control airflow over the oil cooler and heads is really interesting and important. Besides insuring that you are not running lean, you need to make sure that is working as intended. Do you have a Chilton's or clymers manual?