heeltoe914

Good day all. I have a 1986 944 N/A car has been fun and very reliable the last five mouths I have owned it until last week.
After a nice detail job on the car and a little cleaning on the motor It just wont start;
I do not have spark coming from the coil to any plug wires nor when I put a plug on the end of the wire coming from the center of the coil. Here is what has been looked at or tested.
Timing belt is spinning
Swapped out know good DME relay
Swapped out know good coil.
Put my ECU in another car his car started great.
Power from battery is good

Checked reference sensor by pulling it and passing a screwdriver pass it to make sure it is getting a reading. numbers jumped up and down so I think its working.

Motor cranks and dash lights come on.
Swapped thee two wires for I think speed sensor and reference sensor still no spark
Checked fuel pressure by pulling a line and fuel pressure is good when motor is cranked.
injectors show like 1.4Mv solid. Arent thay suppose to turn on and off??
For grins jumped the coolant temp.

So after all that still no spark, What parts control the spark to the engine? I have power at the + side of coil when key is on and when cranked the - neg, side of the coil show hot as well, is that normal. I am out of ideas, So No comment is a bad comment ideas gladly welcomed. Thanks

Dougs951

So you introduced water to the engine bay?

Let it dry and try again later.

JimV8

More problems are caused by interfering with stuff. You've dislodged something. Check the ref/speed sensor connectors at the back of the engine, just over the heater valve.

F18Rep

You're right to want to eliminate the injectors. I'm thinking the test is to pull one injector and with key to on, you should see 12v (either pin, measured to a ground point). When it starts cranking, one (not both) injector pin will get grounded (on and off) by the DME.

If you are missing both spark and injectors, but do have fuel pressure, then I think you're down to the DME or maybe a harness.

Normally I would pull the distributor cap and look for water in there but that damn thing is so hard to get back on, I dread pulling it....Bruce

944_FUnRUn

I've had my car idle for several months actually a little more than that. I've used the trickle charger over the winter and put fuel stabilizer in the tank. I've started the car through the winter to keep the engine going. Recently I've started the car and it ran quick and smooth. The idle seemed a little low and bounced a bit before settling down. A few days later I moved the car out to wash. The car gave me some trouble to start. Placed the car back on the trickle charge and then I had to pump the gas peddle and leave it half way to start the car. But after turning the engine off and after the car wash, there was no hope for a restart. So I'm gonna siphon the fuel and put new gas. I was thinking about also changing the oil even though it's before the due oil change. What other recommended fluids should I flush?

pnbell

After you put the DME in your friend's car, and it worked, I assume you put it right back in your car and it didn't?

I just ask because my car had these same symptoms, but if i would SLAP or move the DME the car would start..Turned out to be a Cracked Solder Joint in the DME... Resoldered, and it's all good now.

As someone else mentioned the Ref Connectors need to be tight, or the same symptoms will occur.

good luck

TexasRider

I saw this on the other thread. I DONT have this problem as my 951 starts and runs very well but came up with a bit of rough idel (ICV likely) but it is one that I want to get out of the way before it ever gets there.

Is this solder on the DME board, the socket receptacle, the relay, the legs, or the relay and/or chip itself ? The curious are curious to know. Before we go looking .

Then again there is always the dont mess with it if it nots broken thing .

Thanks.

pnbell

i mean everything on the board is soldered; from what i've read the most common fail points are this Transistor (cause it gets very hot during use, then cools; eventually causing cracks ) and the Ribbon cable.

But: "Then again there is always the dont mess with it if it nots broken thing" however unless you 100% positive it is not a problem, it might be worth investigating...

TexasRider

Thanks.

I cant be sure that anything is not a problem, or a potential problem, on a 25 year old Porsche. Unless I have checked it and most likely re-newedit, replaced it, or rebuilt it. Recently, that is. LOL. Thanks again.

heeltoe914

As you all know the speed and reference sensors is always suspect when no pulse comes from injectors along with no spark,

Well even if you do the wave screwdriver test and you get a reading that is not good enough. I did and had to go back to steps 1 2 3 only to just pull both sensors replace them and car started right up.

Save yourself the time get a scope I am buying one today. Thanks for all the tips learned allot about my car today.

Landseer

Just replace those two sensors. Use the BMW equivalent part number of Bosch , cost is $60 each. 928sRUS (Rog100) stocks them (both 944 sensors are same as the 928 ref sensor). Use clarks garage to ensure you get the correct sensor to the correct harness plug (the triggers differ, not the sensors. (Don't laugh, 928sRUS has very sophisticated parts supply situation, including direct supply from Porsche and worldpac. They just don't have all the parts listed on website )

Also clean critical grounds. Injectors will have 12v on both sides until computer, using timing dictated by sensor signals, switches one side of each injector to ground. So the sensors have to work. And ground has to be unimpeded.

If you washed, also, pull battery and ensure no holes leading water onto the critical electricals beneath passenger feet. That's another ballgame.

Replace the sensors, though, premptively.

944Ross

Just don't compound the problems by dropping the bolt(s) down into the clutch!! Cover the timing hole!!

TexasRider

This sounds like trouble from the Devil !