Hello everyone!
Maybe somebody can help me with my 944 s2 89? The engine is not starting at all. Here is the video: I replaced ignition module with a new one (Bosch 0 227 100 124), fuel pressure is about 4bar, spark is very good, marks on camshaft and crankshaft is ok.
Everything looks good, but the engine is not running.
What is the reason? Where else can I look at?
Thanks a lot in advance.

 

in the context of electronic ignitions evolution, the '80s/Bosch stuff wasn't very good and rotted in just a few years.

*to offer some objectivity, the harnesses on the 968 are dramatically better.


after observing 7000 no start threads with dubious resolution,

I ask; would you run an '80s laptop? or exposed to time, heat cycling, corrosive gasses, a million bumps, bruises and weather, would you expect anything less than for everything to be mostly fried by now?

don't take it to an indy shop. take it to your local PORSCHE dealer with a straight face. not that they will take it (they know better).... but, they built it. they've been building and tuning their endless Bosch embedded garbage for 60 years.

they should be held accountable for any ignition issue - instead of do-it-yourselfers endlessly covering for them, (and almost throwing up their hands before issues are solved)...

hell, they might even learn themselves a thing or two for the next guy who comes along.

you also have the option of ringing up a *top-to-bottom engine harness replacement.


*the moment when some people discover they're stuck running 30 year-old 944 ignitions.

 

You need to do a little investigative work before anyone here can [effectively] assist you.

In order to run, an engine requires three things: fuel, spark, and timing/compression. Ascertain what you do/do not have and report back...

 

If you have spark and fuel pressure, it seems like the injectors are not pulsing. That could be a bad DME, or maybe a bad VR signal from the reference sensors, maybe some more experienced people can chime in. Are you able to test the actual injector pulses? These aging fuel injection systems are a roll of the dice sometimes...

 

odurandina, thank you for your answer.
To my regret I have in the city / country has no Porsche dealer serving these cars. This is the harsh reality: no one cares. I, against the advice do not want to throw away this beautiful car, I believe in this car.

 

I already checked fuel pressure, it about 4bar, spark. Now I think, that the problem with timing, but no sure. I have already replaced ignition module, and speed sensor(on clutch bell). Also I have tried my Hall sensor(just emitate) - it worked as I see.

 

Probably somebody have or know where I can find scheme of DME connector with wires colors? I will try to check wires to sensors from DME.

 

The DME relay jumper is always a good test. It might not be related but it's a common issue that should be eliminated as a distraction f nothing else.

clarks-garage.com shop manual is helpful here.

Checking to see if it will catch with a squirt of gas or starting fluid is also a very good basic test.

Testing spark should be done with a spark checker or other means to see if the spark can jump 10mm, not just by looking for a very small spark. A weak coil or module issue can lead to a spark that looks OK but will not fire in the head at over 10bar / 160psi. 10x the spark gap simulates 10x the air pressure.

-Joel.

 

If you have good fuel pressure, that indicates that the DME relay is working. You only seem to get tach bounce for the first second or so of cranking, I suspect your reference sensors need replacement, those and DME relays end up causing the vast majority of difficult no-starts. Make sure to get Bosch, others have had some crazy issues trying to use alternative brands.

If you would like to do more debug first, you can try making sure that you don't have a short between the two wires in one of the injector plugs. If you can verify that you don't have spark and the injectors aren't firing that will definitely point towards the reference sensors, or far less likely a bad DME.

 

Thanks a lot to everyone for your answers, I will use this information and make some tests. Now I have checked most of the wires from DME connector to sensors. I have found missed connect 17 and 30 — it is ground from fuel injectors and knock sensor. They refer to "welding point 2". Where is this point? It must be constantly ground? There is no ground on connectors 17 and 30 — should it be?

 

At this scheme 17 and 30 wires refuse to ground(welding point 2). Is it correct? May I try to connect this contacts to ground? Will it be a good test?

https://rennlist.com/forums/attachme...ge-24_28_8.jpg

 

After watching your video I see that the car started to "catch" a couple of times, meaning it almost started. What I really noticed was that there was no tach bounce. It made a slight movement when you first turned the key, but didn't move after that. My guess on this is that your reference sensors are either bad, not set properly or have bad or broken wiring. I would look there if I were you.

 

Thank you for answer. I tried to use another one reference sensor, but no original - all the same. I couldn't test DME, but I have checked wires from DME to reference sensor - it good, but I have no signal from 17 wire from DME to ground fuel injectors. May it be a problem with ground of engine? Where I can find it? Or should not be the constantly ground on this connector?

 

Thank you for your answer.
I tested DME relay (http://www.clarks-garage.com/shop-manual/fuel-05.htm) - all seems regularly, I mean, relay is good.
On the coil spark is very strong. I have tested spark wires and have replaced distributor cover. It is no result. I also have tested wires to Hall sensor - it is good.

 

Mine did a similar thing - I started out doing the DME bypass - - I could hear my fuel pump buzz - but no start. Then I bypassed my factory alarm and it started right up. DO NOT USE the procedure on Clark's Garage - the 1989 S2 is different. Us the version for the Turbo I'll see if I can post a link