1983 944 won't start

[rrwebster]

My car hasn't been running for several weeks due to the clutch going out... waiting on parts... and the time to do it.

I just finished up and went to start it up and no go.

I did pull the gas tank while doing this.... however I didn't touch the fuel pump.

When I first turned the key on I didn't hear the fuel pump running (still don't).

Did I maybe not put enough gas back in it to have the fuel pump run? (just added more and the light went out)

I marked the wires for the sending unit so I know they are back on there correctly.

Did I perhaps mess up a ground when I pulled the tank?

Those two sensors on the clutch housing... not certain they are put back correctly but I think they are... would that cause it to not start or the fuel pump to not run?

Any thoughts or prior experiences?

Thanks in advance,

Robert

[968 GUY]

Fuel pump relay? Fuse, broken wire? I believe there is a set distance from the sensors to the flywheel that needs to be followed, otherwise they send errant signals to the computer.

[rrwebster]

Thanks 968guy... I was beat when I got to that step so wasn't thinking... will start with fuses and relay... then if still no action out of the fuel pump I'll head down there with the multmeter. just doesn't make sense though that it's not working... it was when the clutch went and it's only been maybe 5 weeks that it's been sitting...

[kfray]

Information dealing with checking and adjusting the speed and reference sensors
http://www.clarks-garage.com/pdf-manual/ign-02.pdf

[rrwebster]

Ya know I had a horrible time getting those sensors out... they just wouldn't come out... I had to pry them out.

also in the clarks garage instructions it says to disconnect them which i did... but the PO must have had some problems with the connections because one of them the connection end is actually gone (the leads are loose) and electrical taped together and the other one had been melted so when I unplugged it it fell partically apart... so both may be toast...

I looked them up on our sponsor and they only list one sensor... are they both the same and just pulg into the different ends?

According to clarks garage it appears that they are supposed to be different but on the site here in the parts section it says you need two of the reference sensor.


are they both the same or are they different?

Thanks again,

Robert

[John_AZ]

Originally Posted by kfray

Information dealing with checking and adjusting the speed and reference sensors
http://www.clarks-garage.com/pdf-manual/ign-02.pdf

When in doubt---------------read Clarks.
Sensor closest to the firewall is the speed sensor. Connect it to the "D" wire at the rear top of the engine.
The other sensor-reference, gets connected to the "B" wire.

Originally Posted by rrwebster

Ya know I had a horrible time getting those sensors out... they just wouldn't come out... I had to pry them out.

also in the clarks garage instructions it says to disconnect them which i did... but the PO must have had some problems with the connections because one of them the connection end is actually gone (the leads are loose) and electrical taped together and the other one had been melted so when I unplugged it it fell partically apart... so both may be toast...

I looked them up on our sponsor and they only list one sensor... are they both the same and just pulg into the different ends?

According to clarks garage it appears that they are supposed to be different but on the site here in the parts section it says you need two of the reference sensor.


are they both the same or are they different?

Thanks again,

Robert

Yup, If you had to pry them out and were able to get them out you were lucky. They could have broken in half and then your work triples.

You can check to see if the sensors are good with the Clarks resistance check.

You can get new connections---male/female at a couple of shops.

The sensors, speed and reference are the same. You need 2.

You can get cheaper reference sensors if you use the BMW cross reference sensor. Pelican sells these as well.

Put some antiseize on the sensors before installing and they come our easy.
Gap the sensors per Clarks

Check your negative ground cable on the flywheel and the small ground wire next to it.
Put a piece of tape over the TDC hole to avoid dropping a nut in the clutch

GL
John

[rrwebster]

John,

1. How do you tell which is "B" and which is "D" mine are just hanging there... no bracket.

2. If I hook them up wrong will it damage them?

3. The resistance test if this is checking the male plug of the sensor I got no reading on either sensor.

Also, when I crank the engine the tach does nothing.

Thanks for your input!!!!

Robert

[John_AZ]

Sensor connection passenger side ----Porsche put heavy duty bands around the wire, check to see if yours are there. Follow screwdriver tip.



OK, your sensor connections are missing. here is my sensor wire color chart to check the resistance using the correct color.



You will not damage sensors if hooked up backwards---your car will not start tho.

GL
John

[968 GUY]

I have also heard of a mod for the bellhousing. I believe that a piece is cut out where the sensors sit which allows the sensors to stay in place. I have only seen a post where it was mentioned, don't know much about it.

[rrwebster]

Okay... those pictures will help.. I do still have a band on one... it's on the sensor side though.


the resistance test is what I need to know about. it this done at the sensor side on the male part of the connector?

or is it done on the female side?

if it's the male side I need new sensors.

[kfray]

The resistance test is for the sensors.

[rrwebster]

Originally Posted by kfray

The resistance test is for the sensors.

Thank you... logically this is what I thought... but since the car ran fine before I replaced the clutch... testing the sensors I had no results from both of them I wasn't sure I was doing it right. (I hoped I was doing it wrong they aren't cheap!)

thanks again to every one for their input.

Robert

[pk386]

have you by passed the DME fuel pump relay? Just as a sanity check to see if the fuel pump turns on?

If you still suspect the sensors I found a good method that uses an LED (most LEDS are 1.5-2V so if it blinks when you are cranking it should work...)
http://www.944time.com/porsche/dme/dme07.jpg

[rrwebster]

Originally Posted by pk386

have you by passed the DME fuel pump relay? Just as a sanity check to see if the fuel pump turns on?

not sure how to do that.... Would be nice to know... I'll certainly not be a happy camper if new sensors don't fix it!

okay I found the bypass in Clarks... will try that this morning... thanks for the tip!

[rrwebster]

Fuel pump is fine when I bypass the relay.

thanks again!

[jpk]

A lot of people expect to hear the fuel pump run with the ignition on; that's not the case. The fuel pump will run when the key is turned to the start position (engine cranking) and will continue to run as long as the DME sees at least 300 rpm from the engine speed sensor.

[rrwebster]

I had pulled the tank and emptied it... so it should run until there is enough pressure built up even with no RPM's That's all part of the software within the DME. Mine always runs for a little bit when I first turn the key.

it's also how the systems work in my 305 and 350 TPI's and my LT1.

Actually if you look closely at the 944 NA engine it's exactly half of the TPI's same components and everything (not same as interchangeable) but same parts in the same places... kinda cool for me since I was already familiar with TPI's.

[fmartenies]

Originally Posted by rrwebster

Mine always runs for a little bit when I first turn the key.

I searched high and low for that clip from Family Vacation but its no where to be found on YouTube. Yeah, you know which one I am talking about.

"You may hate it now, but wait until you drive it."