Another Newbie with a no start condition
 

Hello all, Here is the story. A buddy of mine got me into the 944 realm and I bought one, a 1985.5 with a no start condition thats been sitting for a few years. Lack of money to buy a running one blah blah. Now to the car... the car cranks but will not turn over... So far I checked the coil using the clark's garage procedure and its ok. But when I used the green wire I had no spark. I did the resistance check on the speed and reference sensor and the resistance between 8-23 and 25-78 respectively was not open (it was 0). So I bought two new sensors (the Bosch BMW sensors with the longer cable), had a bear of a time because the old ones were glued in and had to take the bracket out. Now I believe I gapped the sensors properly, however my mounting bracket was a little different than expected being it had one bolt ( the pivot bolt) and a bushing on the other end (Not sure if someone messed with it before). But cranking now I have no tach bounce (not sure if I did before). I haven't even attacked fuel yet but any assistance in getting this thing to start. This is a first for me and will take the newbie busts, but please help...I hate for you guys to be a broken record and repeat from other posts but I am unsure where to go. I don't have an oscilloscope so if someone in the area wants to shoot by and have a few cervezas and take a look that would be great too.
Thanks.

Lets get the simple things out of the way first.

Check for spark and fuel first before it gets too crazy.
Do you have spark when cranking? Pull a wire and check while cranking.
How do the spark plugs look? It's been sitting around for a while so I would check all four of them, not just one.

Did you dump the old gas and put in new gas?
If so then good! If not then do it. :)

Are you getting fuel to the fuel rail?
If so good. The fuel pressure should be around 44 PSI at the fuel rail if you have a gauge to measure.

Are your fuel injectors firing (spraying fuel)?
If not are they clogged? Are they getting the electrical signal to fire?

Once you know you have good spark and good fuel then you can work on the other things.

The DME relay can cause problems. Clark's has a jumper set up there. A bad relay will cause problems with the fuel pump. So if you're not getting fuel to the fuel rail try the jumper for the DME relay first. From what I have read, both the DME relay and the DME itself are full of cold solder joints. They can be repairded.

If you're getting spark when you crank you could try some starting fluid. That might get it to fire but it may not run. At least that way you can rule out the ignition system and start looking at other things.

There are a lot of different reasons as to why it will not start. Try and get the easy things out of the way first.

Get a good look at that timing belt!!! The timing belt, the balance belt, and the water pump are a MUST change for your car! If you do the work yourself it's not too expensive. The cheapest water pump you're going to get is around $150 for a rebuilt. It will prob have a $100 core on it. If you pay someone to do it you're looking at paying at least $1K.

^ Do what he said then let us know.

Takes about ten minutes and can save a lot of time.
-Make a "Y" out of a wire splice and some wire.
-Open the fuse box and remove the DME relay (relay G5 IIRC)
-On the bottom of the relay, there are some numbers stamped
-place the two wires that are spliced into 1 into slots 87 and 87B, then the single wire end into slot 30.
-This will bypass the relay and kick on the fuel pump and DME
-listen for fuel pump near passenger-rear wheel
-Try to start the car
For More detailed instructions and photos, re-visit the clark's garage manual under the topic "DME relay"

Thanks for the wisdom Icey. I will try some of that this weekend. On a few responses. I am going to have to pick up a pressure gauge (and ideas?). I have checked the DME relay in my buddy's 944 and it cranked right up. I have to rig up some sort of fuel dissipation contraption (I have heard by running power directly to the fuel pump. I am getting a spark when I bypass the computer but not using the computer. I do want to change the plugs, and fuel filter and perhaps better ignition wires. I did put a jumper across the fuel sender fuse and the pump does run when the key is in the run position. I also noticed that what I believe to be a vacuum line that connects the pressure regulator to the MAF sensor has been melted by the intake manifold. I wasn't sure this would prevent startup but rather it would run rich. What do you think?
Thanks
P.S. Before the car moves from my driveway the timing belt and waterpump WILL be changed. Also, I need to get a windshield. Anyone have any ideas where I can find one cheap?

Maybe things are different on your car. My fuel pump does not come on untill I am cranking the car. The fuel pump comes on in the run position on every other car I own. Maybe my car has some real issues. :)

I wouldn't waste money on a fuel pressure gauge unless you will have more use for it. I bought one for $50 from Lindsey Racing. You don't need to spend that much money, but I needed one for the range I will be using. I would just take the cap off the end of the fuel rail once you know for sure the fuel pump is pumping and the fuel system is charged.

Sounds like you ruled out your DME relay. So that is good. :) Can you take your DME out of your car and try it in your friend's car? That would also rule out a bad DME.

I have read about that vac line in other posts. I don't remember what the end result was. I think that was one of SoCal's pet peevs. I think that vac line, if I remember correctly has something to do with the engine warming up.

If you are getting spark then try some starting fluid in the throttle body. It may not keep running, but at least you will know your ignition system is working properly.

No real ideas on the windshield. Try a post for "WTB: Windshield" in the classified section here. I got a good clock from there. :)

When you say "computer" do you mean the DME?

I am not clear exactly how you determined you have spark. "...bypassed the computer..." How exactly did you do that? While cranking the engine or by tapping a ground wire on the coil (-) with the ignition on? Like John said, the car WILL NOT start with fuel that's "a few years" old. The tach not bouncing while cranking usually means a newly installed reference sensor is not gapped correctly. If the reference sensor is wrong, the speed sensor is too since they are mounted on the same bracket. I do have a cheap way of checking those sensors. Read this thread:

http://forums.pelicanparts.com/showthread.php?s=&threadid=343212&highlight=LED+se nsor

When checking the reference sensor while cranking, you will see a pulse every second or two. When checking the speed sensor while cranking, you will see a bunch of pulses per second.

Sorry for the confusion....(Just as you predicted Edek) What I did to test the coil was disconnect the green wire (which runs to the DME) and grounded the negative terminal to the block and read from the coil output to ensure I had a good coil (giving spark). I believe that I did not gap the sensors properly and therefore is not giving the signal to the coil. I would love some help in gapping properly, but like I said above my bracket was a bit different because I think someone messed with it before.

I am getting fuel out of the rail even after the car is off, and am not sure if that means anything without a pressure gauge. I do have to check the injectors and then ask for further expertise. Thank you guys for all your ideas....I am open to anything and will try things as I can (have a newborn)...

We are looking into testing my DME in my friends car and what potential damage it could do. I know we have ruled out testing his DME in my car in case my car fries his DME (I would hate to have to buy two)

Yes when I say computer I mean DME..again sorry....used to american cars but enthused about getting this mess sorted out.

Glad to hear I'm not the only 944 owner with baby duty. At this point I'm probobly not much help, good luck!

Are you getting spark ONLY when you ground the green wire? Or do you ALSO get spark when it is running through the DME? If it's not sparking through the DME it could be a bad DME, bad input to the DME, or a bad wire coming from the DME.

You will get fuel out of the rail after the car is off. The fule system is pressurized to about 44 PSI. So you will lose some fuel, if it is charging the fuel system correctly, if you open the fuel system when the car is off.

I don't think a bad DME could cause any harm to any car. If it doesn't work then it doesn't work. :) The bad DME all seem to have cold solder joints.

Have you tried starting fluid yet? :)

Look though some of these old posts. Someone asked about using different MY fuel injectors in their car. Sid had some good numbers to check the fuel injectors with on a volt meter.

Sounds like reference sensors to me with the tach not bouncing. There is nothing sending a break in the signal. Look on clarks for testing and gapping.

I would drain the fuel and run a bit of new through the system by removing the end cap on the rail with a hose clamped on it using the jumper on for the relay. If you keep runing the old junk fuel through it you will have bigger issues when you do get it runing ie: clogged injectors, and that could cause a burned piston very easily. I would then pull the injectors have them cleaned and replace caps and orings. Maybe the fuel lines as well as these cars a notorious for engine fires

The vacuum line you are talking about is nothing to worry about it just gives a small vacuum and pulls a little fuel pressure at idle and cruise.

I am going to use Hugh's tagline of "please put the year of your car in your profile".

Be careful swithching the dme into other cars as the early ones use a 12v AFM signal vs the late 5v. They will work if the matching AFM is used however.

You're finally back Sid! Good info...

Don't waste your time with anything else until you get the speed and reference sensors squared away!

FIRST. Follow this link on how to gap them:
http://www.clarks-garage.com/shop-manual/ign-02.htm

SECOND. Follow this link on how to test them:
http://forums.pelicanparts.com/show...ight=LED+sensor

THIRD. With fuel that is "a few years" old, THE CAR WILL NOT START! Drain the old gas out of your tank, then flush and refill it with fresh fuel. Change the fuel filter. (You never stated that you actually did any of this.)

THEN we can start troubleshooting the no start issue. I don't want to sound like a broken record either, but to solve this problem, you have to attack it in a systematic fashion. Otherwise you will be darting around like an ant!

Ok....I created the sensor light and it lit as I believe it should which means the sensors are gapped properly. I do not have any tach bounce.
On the fuel issue, I spoke with the mechanic who tried to get the car started for the guy I bought it from and he told me he drained the fuel, changed the fuel filter, put in new fuel with stabilizer and checked for fuel in the rail (which I did but not formally with a pressure gauge) and he unplugged the injectors and checked for them spitting. For now I think I should ASSUME (which I know will end up biting me in the butt) that he is being honest since I own the car and he is not trying to sell it to me. DO you guys agree?

I believe the next step for me is to check continuity of the sensor wires to the DME and check the DME in my friends car? Is this where you guys would go? Any other ideas?

I appreciate the perseverance.

Thanks.
Brian

Pure and simple...tach not moving the sensors are out of spec. Whether it is gap or electrical. How did you(methods) determine the gap?

Dal

I used the procedure listed in clarks garage. With Edek's 2 Volt light, wouldn't that prove the gap and signal are correct? I read somewhere that the tach not bouncing could either be the sensors or the DME. Is this not the case? Do you know what pins on the DME connector receive the signal from the sensors so I could check them for the 2 volt signal?

Bottom line is you changed the sensors. It could be the DME but very unlikely, try your DME on a running car to verify. But if the sensors are not up to par the DME will get nothing to read, no start. As far as a noid light goes I cannot comment. They are new so they should be ok electrically spec wise but not if they are not able to signal, all it is, is a magnetic pickup. Double check the gap at 8mm iirc. Could it be you are using a BMW sensor? They say VW door handles work but they do not!

Tach bounce..Yes either one, if the DME is not talking to the sensors visa versa, nada happens. This provided the tach drive is ok.

Dal

Ok....here is where I got today....Checked my DME and Coil in my friend's car. Fired right up...924Sman, I believe you are correct that the problem still lies within the sensors....I started playing with the gap to try and get something and wierdly enough, when I moved the bracket up, I started to feel a tapping which I am guessing is the flywheel. Any ideas on why? then I got a little tach bounce and the mpg gauge was moving all over the place. I started to wiggle the connector and got a bit more,,,then for one cranking session the mpg locked up and the tach was the best it was...I pulled back the boot and one of the wires is exposed. Does anyone know where I can get a new wire to the DME and/or the procedure to install it, or should I try to fix the one I have...Got dark so no more I could do tonight.

At least you are making some progress!

If you are hearing tapping noises, the stubs on the flywheel are physically hitting the sensors and this would normally happen when you lower the bracket, not by raising it. This is not a guessing game as there needs to be a 0.8mm gap and any physical contact will damage the sensors. If you have problems removing them out of the bracket, that would be a good indication the "head" of the sensor made contact and is deformed. Also, there should be 2 6mm allen bolts holding the bracket. The second allen bolt goes into the sleeved hole and is identical in size as the other one.