Diagnose my rough running symptoms please

[Asiangunner]

Evening guys,

My 944 is running unusually rough, its a 83' LUX. Earlier this year I had the head gasket done with oil seals and engine mounts etc.

Its was running really well for a few months but then I started noticing the car seemed to feel lumpy as it pulled at low revs.

I then got married and went away on honeymoon, When i got back the battery was down as expected but I got it running, I checked the oil but not the water before taking it on a longish drive...

Started driving and the fans weren't blowing hot and car started getting hot..... some how the car was mega low on water. luckily got to a petrol station and waited for it to cool before topping the water/coolant up (it was pretty low)

Now that problem seems to be sorted but not sure where the water went......[8|]

The main issue is that when i drive the car it feels mega lumpy and jaulty at low revs now and even when i try and put my foot down to try push the car through the rev range the car holds back big time. I though it might be crap fuel but i filled her up with some decent s.unleaded but no change.

It feels like the the fuels not coming through when i need it, the cars smooth when keeping it at a constant rev and stable speed.

I've bought a fuel damper and looking for a fuel pressure regulator as they might be a good bet from what i've read but wondering if anyones come up with similar symptoms.....

Ranj

 

[alwigley]

Early 944's (especially mine) seem to be plagued by similar problems...... The only way to crack it is going to be patience and elbow grease

Under/over fuelling is basically caused by wrong signals being given to the dme - you need to start by checking the various sensors and related wiring using a multimeter where necessary following the guide in the factory manual. You can check most things quite easily. The dme temp sensor seems to be a prime culprit, and a lot of people seem to mention afm problems. I am going to take a look at my own arm on the bench one night due to similar issues as I spent all day tracking down a rough idle problem with only some degree of success !

Beware of just replacing parts.... You can spend a small fortune and get nowhere - best bet is find a mate with same car running ok and try swapping out the bigger items.

Try searching the forum as you will find a plethora of posts on similar matters.

Hope you have some success !

 

[peanut]

ORIGINAL: Asiangunner






Started driving and the fans weren't blowing hot and car started getting hot..... some how the car was mega low on water. luckily got to a petrol station and waited for it to cool before topping the water/coolant up (it was pretty low)

Now that problem seems to be sorted but not sure where the water went......[8|]





Ranj

not sure if this problem is sorted or not but its often a problem bleeding all the air from the coolant system on 944 . Sounds like you had air in the system causing an airlock preventing proper coolant circulation .
Keep a check on the water level to make sure the system is fully bled.

Oh congrats on getting married by the way.[]

 

[peanut]

re the rough running might be worth checking the vacuum system as a lot will have been disturbed when the head gasket got replaced

 

[Asiangunner]

Thanks for the replies guys, been busy with work so not had time to check bits out on the car. sorry for not posting an update...

The coolant situation seems to be sorted now, I jacked the front of the car up and got out all the air and the heaters and temp gauge are all working fine.

I will check the vacum system first as that seems less scary than checking relays etc on the fueling system, i have driven the car a few times and its not started to cut out completely when the revs drop really low and ive had to flick the ignition off and restart it on the go.

thanks for the comment about not just changing odd parts without diagnosing the issue properly, that is normally my way of going about things but your right, it can be costly and a game of luck lol

 

[Asiangunner]

Guys,

The cars finally sorted, it turned out to be the Number 3 ignition lead was failing and that caused the car not to fire properly.

I went for a set of Magnecor 8mm leads and they are brilliant(£70 delivered) , I called the company direct and they were super helpful.

Ranj

 

[944 man]

Cool. The next problems will probably be the vacuum lines, the fuel pressure regulator and the fuel filter. None are expensive, fortunately.

Dont forget a new genuine 993 prefix DME relay either -although Im sure that you already have a new spare in your glovebox?


Simon