dek944

Alright here is the scenario...I was working with my friend on his '88 944. He had just replaced his clutch and today we were in the process of putting the car back together...transaxle, transmission...etc. His clutch has been out of the car for the past 2 months...taking forever for the shop to build his new one to spec. Anyways, my friend noticed that for the past 2 months the fuel lines at the fuel filter have been pinched off the whole time while he was waiting on the clutch.

Basically put, we put everything back together and he goes to start the engine, and it doesnt fire up. The battery is fine plus we tried jumpstarting it incase it was the battery too. The spark plugs are fine. The gas tank is pretty much full. Any clue of what can be the problem???

Another thought he had is that at the front somewhere, I wasnt present when he did this, but there are some electrical connections near the clutch/starter area, could that be the problem? And also in the rear at the transmission I believe we saw two or 3 electrical wires of which one or two of them we connected, but we saw no place to attach the final wire. If anyone has any suggestions we would be very thankful, this kind of job is very frustrating especially when other side problems occur like this, I guess that is why it costs over $1000 for labor alone at some shops.

Once again, thank you all,

Declan

special tool

Dude - Cal Poly? "some electrical connectons"????


It is most likely that your friend has discombobulated the crank triggers which reside in an aluminum extension on the back of the top of the block, overhanging the flywheel/pp. Ask him how he dealt with these in removing the clutch.

dek944

Dude - Cal Poly? "some electrical connectons"??? - special tool

yea, randomly enough I am studying Electrical Engineering too....but I have no idea what he worked on in those areas of the car, I basically just held the transmission up for him while he was installing it, and seeing that it was 3am, and we both have to be up in a few hours, we really didn't get into it that much...

But yes, he did mention something about potentially putting something in the wrong order, whether or not what he mentioned were the "crank triggers" I have no clue...but tomorrow we will look into it. Thanks for the help.

Matt H

Likely an issue with the crank and position sensors on top of the bellhousing. Check grounds near the back of the crossmember as well.
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pete944

There are 2 senors at the top of the bellhousing. If he's lucky he may have connected them wrong. Try swapping connectors and see what happens.

Predator

Those, who, randomly disconnect, remove, relocate, in haste, pay the price, later, upon reassembly, says "Confussion". Especially when then do not consult the Bible (Hanes mannual). Its probably the flywheel position sensors per earlier lister. The wires an the tranny are back-up lights and speedo. Shouldn't impact the car starting. Good luck.

Wachuko

Just cross your fingers that they did not lower them... or at the first spin it will eat them away... and they are expensive...

dek944

Wachuko, it seems that it did eat away at one of the sensors. We did end up replacing both, just as a test, from good sensors from another 944 and put them in the right position, and it still does not fire up. You can hear it going, but theres no spark being made it seems.

BTW, Predator, I wouldn't call the HANES manual the bible, seeing that it doesn't help at all with explaining those flywheel position sensors.

So yea, if anyone has any other ideas, I would be much obliged.

Dec

SoCal Driver

"Haynes" like in leg hose. Not Hanes or Haines or Hains.

While the electricals in the Haynes are darn close for the early 944's (pre 86) there are some discrepencies for the later cars. But not enough concerning the speed and reference sensors to make any difference.

The trouble shooting guides are still 99% good for the 86 DME/ECU logic.

Try www.clarks-garage.com and www.frwilk.com.

Electrical engineering? First year?

dek944

3rd year.

I understand the schematics are good in the manual, but that still doesnt solve the problem of getting this thing started. We do have the sensors in the right spots now and its still not igniting. He checked the fuel lines, and fuel is being sent through, except he thinks there is not enough pressure through the lines. I really cannot think of any other solution anymore, this thing did start fine before we took out the clutch, and after going over every step twice to make sure everything is connected, we cannot come to a solution to the problem.

Der Cupmeister

Are the reference senders set for the proper gap of .08 mm ? If they are too far away from the flywheel and ring gear the car will not start.

hth,

Der Cupmeister

Opps....I meant .8mm NOT .08

SoCal Driver

3rd year...

Check the coil for 12 VDC with the key on: Check any one of the injector terminals for 12 VDC to ground. If the coil has voltage but not the injectors it's the first stage contacts in the DME relay. If the coil doesn't have voltage it's the ignition switch. If both have voltage check the sensors.

Get an o-silly-scope and check the pulses coming from the sensors. From center pin to one of the outside pins. When cranking you should see at least two volts in pulses from both. The front sensor (speed) is one pulse per revolution. The rear sensor (reference) is 132 per rev.

Should have about 2k ohms across them if the windings and cables are still good.

Other wise get a spare spark plug and pull #1 wire. Stick the spark plug in the wire and lay it on the intake. Crank the car and see if there is spark. If there is no spark and the coil and sensors checked out then it could be a loose rotor or a bad coil to dist wire. The wire ends like to corrode and pull loose inside the weather boots. In one case a persistent owner found that his headlight arm had pulled the cable loose. This was after he replaced $400 in parts that he didn't have to.

The factory testing procedure has 16 check points; twelve of these are for no start! You have to approach this systematically. Usually a decent volt/ohm meter will find the problem.

As the clutch has just been replaced I keep thinking it's the sensors. Hopefully they were removed before the clutch job otherwise they could be bent.

dek944

Well I get a call today from my friend, and I guess he got it going last night. First point, he said the Haynes was absolutely useless for this type of procedure. Der Cupmeister hit the nail on the head with stating that these reference sensors had to be set specifically to a certain height, of which was 0.8mm. My friend found that out on the Clarks Garage site.

The other part, which got the car going basically, was that one extra plug that I stated wasn't plugged in. It was not for the tranny at all, I guess it is used to power the fuel pump, or something related to that, once he plugged that in and set the sensors to the right height, he said it started up right away.

SoCal Driver - LMFAO, Oscilloscope, oh man what the unnecessary overkill. One: I dont have one, dont have the $$$ to buy one, so I guess I would have to try and jack one from school. Two: since he got it running, I guess I dont need to worry about the DME relay then.

Now the car is going after just sitting there for the past year and a half. Thanks everyone for your help on this, we really appreciate it, especially with doing from what I am told is one of the most time consuming jobs on these 944's, every input was useful. Now its my turn I guess to pick up another 944 for myself soon.

Declan

SoCal Driver

Used o-silly-scopes are about $50 to $100. You can even get volt/ohm meters with scope displays that will show the spark and the volt pulse from the sensors. Nice to have but a simple doide and resistor setup would have shown you the two volt pulses. Same with the injector pulses. Called noid lights if you go to a decent auto parts store and ask for one.

Haynes isn't the best but it's definately a repair manual that most can buy. Can't say that for the factory manuals.

If you don't have the mechanical aptitude then the Haynes and the factory manuals will not help.

P.S. You are welcome for the reference to Clarks web site.