944 starts then cuts out

[JuvUK]

Hi all,

I really need some help, my 944 1986 2.5 lux has suddenly stopped working

it fires 1st time everytime from the key, but cuts out almost instantly, i've changed the DME relay, and i must be getting fuel and spark as the car keeps starting, but why does it keep cutting out straight away?

any help will be gratefully recieved.

thanks in advance, Justin

 

[jwindwood]

I'm thinking (If it's not an immobiliser problem) that you may have a knackered fuel pump, which just isn't moving enough fuel. I think that would be my first port of call.

 

[JuvUK]

thank you for the reply (i guess i'll need a way to check the flow rate)

i don't have an immobiliser

 

[pauljmcnulty]

Moved to the general 944 forum for you. []

 

[JuvUK]

ooops sorry about that, i did put it in the wrong section[]

 

[robwright]

In the same vane as Mike I was thinking could be Fuel Pressure Regulator. Enough to start but not to keep it running.

 

[George Elliott]

Justin, I had this symptom with a failed Air flow meter.

(reason being the 0v-5v electrical wiper had gone up the creek)

...and once the engine was running, the airflow pulls the flap open slightly (to allow a feed of air) and moves the wiper onto the area of the resistor rheostat which is worn (because that is where it spent most of its life / passed over to get to every other position), or corroded because it is polished by the continual wiping action and vulnerable to corrosion.

I could suggest starting at full open throttle, but only to get onto another area of the wiper, I don't know if you know what I am on about - but don't post back to say you put a rod thru the block of a cold engine[8|]

otherwise get the resistance values off clarks garage website, and check the unit with a meter

In regular use this is rare, if doing 500 miles per annum its not unusual.

keep us posted, good luck

George
944t

 

[Mike_Pollock]

It is quite easy to move the contact track on the AFM if that is the case.

 

[JuvUK]

well i got some time to look at the 944 this morning and i seem to have got it running, not sure which bit got it running though

i opened up the DME relay and held the contact closed and could hear the fuel pump running and i could hear fuel flowing, i used some contact cleaner on the relay and gave the fuel pressure regulator a "tap" turned the ignition and hey presto it fired up and ran fine

trouble is i don't know if it was the DME or the "tap" that fixed it, guess i'll have to wait for it to fail again to find out which one was the cure! lol

@George Elliott, i use the car every day as my daily runner to work and back (approx 20 miles each way) but i certainly will take a look at the AFM while i'm under the hood

thanks again for all the help guys[]