1987 944 S 2.5 16 Valve N/A will not start
 

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

RE: 1987 944 S 2.5 16 Valve N/A will not start
 

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.

RE: 1987 944 S 2.5 16 Valve N/A will not start
 

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...

RE: 1987 944 S 2.5 16 Valve N/A will not start
 

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.

RE: 1987 944 S 2.5 16 Valve N/A will not start
 

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.

RE: 1987 944 S 2.5 16 Valve N/A will not start
 

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.

RE: 1987 944 S 2.5 16 Valve N/A will not start
 

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

RE: 1987 944 S 2.5 16 Valve N/A will not start
 

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

RE: 1987 944 S 2.5 16 Valve N/A will not start
 

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

RE: 1987 944 S 2.5 16 Valve N/A will not start
 

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

RE: 1987 944 S 2.5 16 Valve N/A will not start
 

It never had a cat.

RE: 1987 944 S 2.5 16 Valve N/A will not start
 

Now I've checked the fuel pressure and it is going up to over 3.5 Bar so this is not the problem.
I also have spark at the plugs.
Air flow meter is working.
Crank sensors working.
Exhaust not blocked.
Compression good.
I've changed the DME.
But it still refuses to fire up, juts the odd back fire.
I have no clue as to why this heap of sh1t wont start...
HELP!!!

RE: 1987 944 S 2.5 16 Valve N/A will not start
 

Just to get this clear there is only one refference sensor on the flywleel of the 87' 944S nonturbo as far as I know and a hall generator on the camshaft pully. If you think I may be wrong let me know.

RE: 1987 944 S 2.5 16 Valve N/A will not start
 

This may be way off the mark, but have you checked the cam alignment. I think that engine has the chain driven cam system. Check the timming belt and the cam chains to see if they are aligned, not just close to being right. Or have you already done this?

RE: 1987 944 S 2.5 16 Valve N/A will not start
 

Yes that's correct there is a chain between the centre of the cam shafts running over plastic guides, it looked ok, not looked liked any thing moved but I can't say for sure. I checked the timing belt which is alined properly.
Since I can't say what the history of the car I wonder if the ignition is firing in the right time i.e. is the HT roter in it's right position as today I noticed it can be in any of three positions as there is three bolts holding it in place and could fit in any of these positions.if I rotate it.
I'll move it around tomorrow and let you know and I'll check the cam position again, Thanks Kinderrick

RE: 1987 944 S 2.5 16 Valve N/A will not start
 

Yes, Line up all the timing marks and set the rotor position for #1. Its really hard to find when you get a non runner that some one has done something unexpected to make it not run. Let us know what you find.

RE: 1987 944 S 2.5 16 Valve N/A will not start
 

Also Check the J boot closely for cracks, if it is leaking air it will give you the back fire problem with no start.

RE: 1987 944 S 2.5 16 Valve N/A will not start
 

The J boot you refer to is this the intake pipe from the air flow sensor to the manifold?

RE: 1987 944 S 2.5 16 Valve N/A will not start
 

yes, thats it

RE: 1987 944 S 2.5 16 Valve N/A will not start
 

Ok, I've checked all the timing and it's spot on, not the problem.
Then I removed the J boot inspected it and it's good no cracks or holes.
I then decided to remove the manifold so I could have a better look around the engine, this is when I noticed a hole where a sensor should possibly be infact 2 holes.....??? The car only has one sensor over the flywheel is this correct or am I missing something. I could not find any other free connections around the engine bay to indicate that there is something missing.

The wiring diagram shows a number of different sensors for the 944 S 87'

Hallgeber I assume this is the Hall generator at the cam

Klopfsensor 1 ?

Klopfsensor 2 ?

Speed mark sensor

I need to know if this is the correct information for this model?

This is the only tangable explanation that there is something missing in this area....

[IMG]local://upfiles/3736/07093234182F4EBCB11E0F720B5D5DEE.jpg[/IMG]

RE: 1987 944 S 2.5 16 Valve N/A will not start
 

I dont have the books on the Euro model, but you should have the hall sensor up front, not back there, could the sensor be in the wrong hole?

RE: 1987 944 S 2.5 16 Valve N/A will not start
 

No, no the hall sensor is up front, thats ok. The sensor you see ther is the reference sensor, I think.

I got this pic from clark's garage but it did not specify what model it reffers to, look like anything?


[IMG]local://upfiles/3736/86D22C670BF04C6693C206A18D142050.jpg[/IMG]

RE: 1987 944 S 2.5 16 Valve N/A will not start
 

Wiring diagram shows a couple of knock sensors, but I dont know where they go, or what happens when one is missing.

RE: 1987 944 S 2.5 16 Valve N/A will not start
 

That looks like the typical 8V setup.

RE: 1987 944 S 2.5 16 Valve N/A will not start
 

The Knock sensors are both on the side of the engine block, intact ok.

Oh that is KLOPFSENSOR's Knock sensor in German.

RE: 1987 944 S 2.5 16 Valve N/A will not start
 

If I wasnt so stubern I'd give up now and go back to my Toyota!

RE: 1987 944 S 2.5 16 Valve N/A will not start
 

Did you check the balast resistors for your fuel injectors?

RE: 1987 944 S 2.5 16 Valve N/A will not start
 

Hmm' no where are they and what will happen if they don't work or arn't there?

RE: 1987 944 S 2.5 16 Valve N/A will not start
 

Your injectors wont fire, or wont fire at the right time. would have a bad return side.

RE: 1987 944 S 2.5 16 Valve N/A will not start
 

Injectors are firing. Where are the resistors?

I can see them on the wiring diagram but I don't know where they are on the car.

RE: 1987 944 S 2.5 16 Valve N/A will not start
 

item 31

[IMG]local://upfiles/1568/5A9AFA51BA054DA7AD3EECA7ADFF1760.jpg[/IMG]

RE: 1987 944 S 2.5 16 Valve N/A will not start
 

wiring diagram

[IMG]local://upfiles/1568/8BE66340DF64465086B82E1EC00E97F5.jpg[/IMG]

RE: 1987 944 S 2.5 16 Valve N/A will not start
 

Jes' thanks dude if you wernt so far away I'd buy ya a beer!

RE: 1987 944 S 2.5 16 Valve N/A will not start
 

I found the spec's for the Ballast resistors which is 6ohms. I got the same result when I tested mine so its ok.

I also have power to the Ballast and have continuity betweem the ballast plug and the injectors, so I am ruling this out as a problem.

RE: 1987 944 S 2.5 16 Valve N/A will not start
 

It is a speed sensor on the bellhousing, not a reference sensor. The hall sensor takes place of the reference sensor on the S

RE: 1987 944 S 2.5 16 Valve N/A will not start
 

Did you replace the DME with an S dme or an 8v dme?

RE: 1987 944 S 2.5 16 Valve N/A will not start
 

I replaced with the correct DME for the 16Valve with matching part no. for this spec. according to the Porsche 944 S spec. & parts manual.
As you probably know there are only two part numbers that match the 'S' which are: 944.618.124.00 & 944.618.124.01. I have both.

RE: 1987 944 S 2.5 16 Valve N/A will not start
 

Well since nothing has seemed to work, Have you tried bypassing the alarm. Checkout http://www.clarks-garage.com/ ELECT-23, Alarm System - Bypassing. That may be the Problem.

RE: 1987 944 S 2.5 16 Valve N/A will not start
 

I would do only there is no alarm fitted, just a bridging connector where the alarm module would be on the loomb.

RE: 1987 944 S 2.5 16 Valve N/A will not start
 

did you verify the bridge is shorting the correct pins together, also does your wiring harness have a resistor in place where the 02 sensor would be?