My 83 944 has trouble starting

[FistsOfHam]

haven't started my 944 for a few weeks due to concentrating on selling another car to release some funds for getting the little Porsche roadworthy. I tried starting it last night and the engine just turned and turned and turned probably about 10 or more times (wasn't counting) but when I got fed up and let go of the key the second I did it fired up.

Once it had started it ran absolutely fine and smoothly so not really sure what the problem is, any ideas?

 

[Copperman05]

My car also does this when it hasnt been started for a while, hot weather seems to make it worse too. I would imagine its a fueling issue, Clarks garage is a good place to look. I mentioned it to my indie, he just said to let him know if/when it gets worse...

Edd

 

[FistsOfHam]

When my other car has sold I think I'll treat it to a new fuel pump as I had to pull the current one to pieces as it jammed up and replace a load of ignition parts as the car wasn't used for 8 years and no idea when it was serviced before that.

 

[peanut]

yes infrequent use allows the fuel additives to solidify into lacquer inside the injectors. This prevents the solenoids inside the injectors from activating properly and pumping sufficient fuel. This is the most common cause for non starting 944's simply lack of frequent use

To check sufficient fuel delivery remove the fuel pressure test nut from the fuel rail.

First make sure you observe the normal safety precautions as fuel is under very high pressure.Wear glasses , make sure you cover the nut from fuel spray and protect your eyes and don't do this with a hot engine . Remove the coil lead so the engine can't fire up.

Take care not to lose the ball bearing seal inside the nut

Attach a length of plastic garden hose to the fuel rail boss put other end in a 2lt plastic bottle

Remove DME relay and Jumper pin 30 and 83A under the relay with a piece of wire ie earth wire from 30 amp elec cable for 30 seconds .

Measure lts of fuel pumped using wife's best food measure jug [] and compare to spec.[]

If fuel flow is ok then you may need to get injectors cleaned and jets reset. As long as you run the engine up to temp once a week the injectors will self clean. If you want to know how to do a DIY injector clean pm me

 

[FistsOfHam]

I think I'll replace the fuel pump anyway just because I don't trust it bearing it mind it's failed once. I also have to replace the fuel lines before it gets near a road.

Once it is on the road I'll be sure to give it a good blast on a regular basis and hopefully that'll clean them out nicely.

 

[peanut]

if you replace the fuel pump you should also replace the external fuel filter at the same time. Possibly also the FPR (fuel pressure regulator)
Fuel pumps are one of the most common things replaced unnecessarily by garages when experiencing starting or running problems. followed closely by everything else they can bolt on until there is some improvement or the problem goes away.

Until you have done a fuel pressure and fuel delivery test how can you assume there is anything wrong with the pump ?
my money is on the injectors or FPR valve

I made the same mistake with my S2 recently which is why I bought a pump and filter [] filter is for sale in the classifieds

 

[FistsOfHam]

I assume something is wrong with the pump because before I completely dismantled the thing it didn't turn

Yup filter will be changed too. One of the reasons for changing the pump is for peace of mind, In my mind I can't trust such an important part that I've already had to tear apart from make it work again, especially when they're meant to be sealed unservicable items. It probably doesn't need replacing but it would just make me feel better if you know what I mean?

 

[peanut]

ORIGINAL: madrob6

I assume something is wrong with the pump because before I completely dismantled the thing it didn't turn

Yup filter will be changed too. One of the reasons for changing the pump is for peace of mind, In my mind I can't trust such an important part that I've already had to tear apart from make it work again, especially when they're meant to be sealed unservicable items. It probably doesn't need replacing but it would just make me feel better if you know what I mean?

yes I understand.
What exactly was wrong with the pump ? if your FPR is jammed your fuel pressure will rise and shut off your DME which shuts down your fuel pump. This is often overlooked by garages who do not understand how the fuel injection system on a 944 works. Easy test for over-pressure is to disconnect one injector. if the car then starts and runs its a prssure problem
If you want a half price filter I'm currently listing one in classifieds

 

[peanut]

ORIGINAL: madrob6

I tried starting it last night and the engine just turned and turned and turned but when I got fed up and let go of the key the second I did it fired up.

don't discount a problem with the ignition switch contacts especially if its an old car.

 

[FistsOfHam]

The pump seemed to get jammed up by a piece of rubbish and when I separated the plates at the bottom it span freely. It doesn't fill me with trust for it especially as it looks like the original part and was left full of stale fuel not running for around 8 years.

I've had the ignition switch out and checked the contacts previously as I thought it was the non starting issue previously which turned out to be a dead immobiliser. It does seem like it has a problem building up the pressure as once it has been started once it'll start without any problems all day after it has started once.

Still it's not very high on my list of problems at the moment, just something I was pondering.

 

[peanut]

if the fuel is leaking back to the tank you might check your fuel line damper and the non return valve in your fuel pump. Not that you would want to remove that again in a hurry []
Alternatively leave the car overnight then remove the fuel rail pressure release nut . If you have fuel pressure then the pump non return valve is working ok.
Your fuel pressure regulator could be letting by ? it should maintain pressure and only let by when over -pressured. Still sounds like sticky injector solenoids to me. Do they all click nice and loudly whilst you start her up ?

 

[FistsOfHam]

Not sure about the injector ticking noise, not really listened for it before. I'll have a look next time I'm tinkering.

Thanks for the advice.

 

[peanut]

each injector has a SS solenoid and return spring inside it. Every time the injector is pulsed the solenoid is energised and slams down the other end squirting some fuel into the cyclinder as it does so. Thats basically how they work.
Not sure how many times each injector gets pulsed a second but you should hear a definite click as the solenoid plunger hits each end of the injector many times a second.
http://auto.howstuffworks.com/fuel-injection3.htm

 

[FistsOfHam]

You learn something every day

This will give me something to think about whilst diagnosing the electrical fault in the other car and doing other boring stuff.

 

[peanut]

what is your electrical problem ?

 

[FistsOfHam]

That's on a VW Passat. It has an electrical leak somewhere which is draining the battery faster than I can charge it so I'm going to sit there pulling fuses until a lamp I connected to it goes out then I'll have found the circuit which is causing the problem, then I just have to pull the car apart to fix the problem.

It's all go.

 

[peanut]

sounds like you got that one licked. Bear in mind though when using a bulb to indicate a live circuit it only indicates voltage not amount of current drawn.
If you have an alarm or immobiliser they both draw a residue current when the ignition is off because they are on standbye but it should be a negligable amount.

Whenever I test for this I usually remove the earth strap from the battery and all the fuses and then just lightly touch the battery earth strap back onto the battery terminal. Any current that is being drawn will show as a tiny arching or crackle as the connection is made.There should be none with ignition off.
If you then re-introduce each fuse one by one until you get the sparking on the battery terminal you will have found the culpret circuit.
Favourites are the glove compartment light and one of the courtesy light door pillar switches.Usually you'll get a fluttering relay when you open the car doors
good luck