1974 911 targa Carrera will not start

[Phinneas]

We have fuel at the injector rails. At pressure
We have spark
We have pulse at injectors
If we spray starter fluid into air filter area the engine fires and runs if you keep spraying
What the heck are we missing as we cannot get it to run and know it has to be something simple

Been at this for a full week, HELP PLEASE

Peter

[fintstone]

Definitely sounds like a fuel issue. Probably need to add info. Is it a US Carrera (CIS car)? Was it a running car that suddenly would not start/run? Could be a fuel volume vs fuel pressure issue.

[Phinneas]

As far as I know a U.S. Carrera. Had I’d for 8 years just sitting and it’s delivered on a trailer. Don’t know when it last ran.

Do not have a pressure gauge to fit car

See to have plenty of fuel, has a new tank, pump, strainer, filter all working ok.
Injectors pulse as they should.

Peter

[boyt911sc]

Originally Posted by Phinneas

As far as I know a U.S. Carrera. Had I’d for 8 years just sitting and it’s delivered on a trailer. Don’t know when it last ran.

Do not have a pressure gauge to fit car

See to have plenty of fuel, has a new tank, pump, strainer, filter all working ok.
Injectors pulse as they should.

Peter

Peter,

What model/year is your car? Could you post a picture of your motor to help us understand more about it? I am not sure whether you have a MFI, EFI (Motronic), or even a CIS. My guess is a Carrera 3.2 (?). Thanks.

Tony

[Schulisco]

How old is the fuel? I suspect rust in the tank due to detoriated fuel which is also unable to ignite, also these rust particles being eaten by the pump which is blocking now. Consequence: replace the tank and fuel pump incl. fuel filter for sure. Also all fuel related / CIS components have to be inspected for rust and may require an overhaul too. Otherwise you can never rely on the car because of unforseeable issues will happen for sure and taking the fun. In general CIS is pretty robust and reliable if driven regurlarly. If not, it's getting pain in the ass...

Thomas

[Mark Salvetti]

Originally Posted by Phinneas

As far as I know a U.S. Carrera. Had I’d for 8 years just sitting and it’s delivered on a trailer. Don’t know when it last ran.

Do not have a pressure gauge to fit car

See to have plenty of fuel, has a new tank, pump, strainer, filter all working ok.
Injectors pulse as they should.

Peter

What do you mean by "injectors pulse"? They really shouldn't pulse, if this is the CIS system they should all flow continuously.

Try pulling all the injectors and insert each in a small bottle, like a baby formula bottle. You can even leave the nipple on there to help seal.

With the ignition on, lift up on the air sensor plate in the air box. Fuel should start flowing from all six injectors. They should all flow equally.

If the CIS system was sitting for 8 years, I would not be surprised if the fuel distributor is not functioning properly.

Mark

[pmax]

Injector rails .... I guess it's a 3.2 Carrera.

Originally Posted by Phinneas

Do not have a pressure gauge to fit car

Hasn't run in 8 years, I would check fuel pressures.

[porschyard]

Originally Posted by Phinneas

We have fuel at the injector rails. At pressure
We have spark
We have pulse at injectors
If we spray starter fluid into air filter area the engine fires and runs if you keep spraying
What the heck are we missing as we cannot get it to run and know it has to be something simple

Been at this for a full week, HELP PLEASE

Peter

Injector rails, injector pulse, sounds like you have a 3.2 and if that’s the case most likely the injectors themselves are gummed up and stuck.
You can try tapping on the main body of the injector with a small ball peen hammer while cranking to try and free them up or if you have access to a electric injector pulse tool they work great for getting stuck injectors freed up.
Ultimately if it is gummed up injectors even if you get them freed up and the engine running you will want to remove them and send them out to be cleaned and tested.

Richard

[fintstone]

Are you sure it is a '74 and not an '84?

[Phinneas]

Ok let me clear up my errors made through frustration and haste to ask for pointers
It is a 1984 car Carrera targa. I believe a 3.2 engine with moronic engine management

So far we have fitted a new fuel tank, with new strainer in tank. New pump and filter in engine compartment. We have good flow and pressure

Injectors pulse as they should tested with an led

We have good spark and engine spins over freely.
Injecting starter fluid in air filter housing engine will run
It has to be something simple but what defeats me.

[fintstone]

IMHO, sounds like you might need a DME relay (or possibly a speed sensor).

Start here (some reading):

https://dorkiphus.net/porsche/showthread.php?t=16859

[porschyard]

Originally Posted by Phinneas

Ok let me clear up my errors made through frustration and haste to ask for pointers
It is a 1984 car Carrera targa. I believe a 3.2 engine with moronic engine management

So far we have fitted a new fuel tank, with new strainer in tank. New pump and filter in engine compartment. We have good flow and pressure

Injectors pulse as they should tested with an led

We have good spark and engine spins over freely.
Injecting starter fluid in air filter housing engine will run
It has to be something simple but what defeats me.

Like I said injectors are stuck, just because you have a pulse signal to the injector does not mean it is spraying fuel. Read my previous comment.

Richard

[porschyard]

Originally Posted by fintstone

IMHO, sounds like you might need a DME relay (or possibly a speed sensor).

Start here (some reading):

https://dorkiphus.net/porsche/showthread.php?t=16859

He says he has fuel pressure, injector pulse checked with an LED and the car runs on starter fluid so it obviously has spark. There is nothing wrong with the DME, DME relay or crank sensors, the injectors are stuck but sometimes people just don’t want to take advice.
Richard

[pmax]

Originally Posted by porschyard

He says he has fuel pressure, injector pulse checked with an LED and the car runs on starter fluid so it obviously has spark. There is nothing wrong with the DME, DME relay or crank sensors, the injectors are stuck

Agree on the stuck injectors.

but sometimes people just don’t want to take advice.
Richard

Yep, getting the same vibes from our OP, could be working with a shop unfamiliar with these hence the "we" and the confusing statements ?

Originally Posted by Phinneas

We have good flow and pressure

You said you didn't have a FP gauge.

Now that you have one and made the measurements, post the numbers.

[Phinneas]

Happy to take advice and pulling injectors is next on the list. Limited time due to other commitments but should get to it in the next week.
The we is a friend who lives one mile away and has a lift that the car is currently on, he is more mechanical than I but not a Porsche expert in any way.
Don’t have a pressure gauge but cracked a fuel line on the right injector rail and got a good spurt of fuel which made me say good flow and pressure.

[porschyard]

Originally Posted by Phinneas

Happy to take advice and pulling injectors is next on the list. Limited time due to other commitments but should get to it in the next week.
The we is a friend who lives one mile away and has a lift that the car is currently on, he is more mechanical than I but not a Porsche expert in any way.
Don’t have a pressure gauge but cracked a fuel line on the right injector rail and got a good spurt of fuel which made me say good flow and pressure.

If you will go back and read my advice of how to free up the injectors you will probably be able to get the car running in a matter of minutes. I have used that method on 100’s of injectors over the past 45+years as it is very common for these cars to sit for extended periods of time. I have done it on an untold # of cars for customers and I have done it to dozens of cars over the years that I purchased that had been sitting for a long time. It is actually pretty simple but requires two people unless you have a remote starter button to hook up or a Electric fuel injector tester like the one in my picture.

Make sure the battery is fully charged and you have good cranking speed, Take the smallest hammer you can find and aggressively tap on the main body of the injector while cranking the engine and once you hear the engine start to fire move to the next injector until you can get it running on its own. Once it will run on its own you can one at a time disconnect the injector plug and if the cylinder is firing the rpm will drop significantly, plug that Cyl back in and move to the next one and if you find a cylinder not firing tap again on the injector and if it frees up you will immediately here the cylinder kick in. Keep going around to all injectors until you get a significant drop in rpm when you disconnect the lead.
Good luck
Richard

[Phinneas]

Richard
Thank you, I promise I was not ignoring you and will to the tapping act to see if we can get action, will let you know.
Where did you get the tester you show please?

Again thanks for your advice I can fix Morgan’s, porche is new to me
Peter

[porschyard]

Originally Posted by Phinneas

Richard
Thank you, I promise I was not ignoring you and will to the tapping act to see if we can get action, will let you know.
Where did you get the tester you show please?

Again thanks for your advice I can fix Morgan’s, porche is new to me
Peter

I have had that tester for over 40 years, IIRC I bought it off a Mac Tools truck.
A couple of months ago I pulled a 993 engine down off the racks that had been pickled and wrapped about 5 years ago to start on my test cart and I used that tester to fire off all the injectors before I put fuel pressure to it. None of them were stuck and you could here the distinct click of the injectors firing and the engine started right up.

I forgot to mention a quick way to tell if the injectors are stuck is with a stethoscope, a properly firing injector will have a distinct ping/click when it fires where the stuck injector will have a very soft/dull thud or no sound at all when firing off.

Keep us updated
Richard

[Phinneas]

Richard, you sir are the wonder kid. My helper manned a small hammer and long socket extension to reach all injectors. He tapped as I cranked.
Front cylinder on rh side fired, then the middle and finally the back cylinder and we were running on three.
Next left side rearmost cylinder and it lit off, then the middle and finally the front most which proved hardest to get at. It appears to be running but we are not 100% sure yet. Too hard to get at and pull its lead.
Non ethanol gas and injector cleaner the tank and we go
Thank you for your experience

[porschyard]

Originally Posted by Phinneas

Richard, you sir are the wonder kid. My helper manned a small hammer and long socket extension to reach all injectors. He tapped as I cranked.
Front cylinder on rh side fired, then the middle and finally the back cylinder and we were running on three.
Next left side rearmost cylinder and it lit off, then the middle and finally the front most which proved hardest to get at. It appears to be running but we are not 100% sure yet. Too hard to get at and pull its lead.
Non ethanol gas and injector cleaner the tank and we go
Thank you for your experience

Glad you got it fired up, I could feel the desperation in your post and after the week of frustration you had gone through I can see in my minds eye the amazement on both of your faces as the first cylinder fired and you both are thinking holy **** after every thing we have tried is this actually going to work and then the excitement as each cylinder fired off one by one and the big smiles when it was running on all 6.

If you go back and read your very first post the next to the last sentence you said
“it has to be something simple” well you where right it was something simple. I can see the looks on your family and friends faces when they ask, well how did you finally get it started and you say we took a hammer to it. 😄

Richard