Hi guys,

I have a Porsche 944 S 2.5 16Valve 87' with suposably 35k it's done.
Well I got this one as a non runner thinking that a few minutes and I would have it running, but a few minutes turned into a few hours and the hours became days and so here I am in need of some advice from you Porsche Pros.

What I know is this: [ol][*]Engine compression good[*]Fuel pump good[*]Fuel pressure good[*]Injectors firing good[*]Ignition HT spark on all 4 plugs good[*]Dme realy good[*]All fuses and realys good[*]All known grounds cleaned good[*]Vaccum pipes seam good tested with vac gauge pump[*]DME module not sure(smells funny) it's from an 88' 944 the same I think[*]Air mass sensor not sure(clean, change in resistance when move the flap)[*]Starter turning over and engine back fires.[*]Seams to be flooding itself resisting cranking speed[*]Exhaust system? (maybe blocked?)[/ol]Also noting that the car had a complete respray at some point.
According to the last owner the car had been sitting in a garage all winter and had not ran since. Also having only 400 miles since it's MOT last year.

The car seams to have 3 of the 4 main things to start the engine:
Compression
Fuel
Spark

But I'm not sure about AIR or Exhaush?

If anyone could post me some advice or have any ideas please let me know as I am desperate at this point and I don't have the money to just start changing random parts and hope for the best...
And thank all of you who has bothered to read this

Kind Regards

Anthony

 

The DME computer smells funny, that is probably not a good thing. You may want to verify that it came from a 944S. What is the part number? if it is an S, Id want to open it up and see if it is OK. This is just a guess, but with a computer controlled ignition, back fires are not expected due to tuning problems.

 

The Bosch no. is 0 261 200 080
Porsche no. is 944.618.124.00
I am waiting for another DME I got on ebay for £36 not bad I think, if it works...

 

I've changed the DME but still no start, I'm wondering about the fuel pressure regulator, would a faulty one prevent starting. I don't have a fuel pressure gauge but I suspect that the pressure may be too high, as when cranking the engine gets flooded, dose this sound right.

 

What is your fuel pressure? What is your compression?

Go back to the basics, if you have fuel (injectors firing), and you have spark at the plugs, then the only thing you can't have is air.

 

The compression on all cylinders is about 170psi +,- 10 so this is not a problem.
The air flow meter is working perfictly as I tested it and adjusted it.
I am trying to get my hands on a fuel pressure gauge.
I tryid to test the opperation of the fuel pressure reg with a vaccum/ pressure pump by applying over 3.8bar to the fuel rail side of the regulator but it did not relese the pressure out the return.

 

Does the tach move at all when you are cranking the car? It should have very slightly movement up and down.

 

Yes the tachometer is moving, and I've removed the sensors and tested them, there good.
Since the car dose not have a cat I would rule out a blockage of the exhaust system, nun the less I will try starting it with the flange of the header open to be sure.
Is there any other sensor I need to check such as manifold pressure sensor etc?

Cheers

 

The movement of the tach is more than slightly...

 

Did the car come without a cat, or was it removed? If it was removed the o2 sensor needs a resistor as a replacement.