joster86turbo

**Data finding and update in post 8**

So I did some searching, but now I need help putting it all together. So first a back story that led to this post. If you don't care to read it, feel free to jump to links and questions. Thanks guys

For a while now I've had a intermittent no-hot-start on my '86 951, so I tried wiggling the sensors while someone cranked the car and sure enough, every time it would work.
Now a couple of days ago, I went to go leave and it wouldn't start. so without even thinking about it I went to go shake the sensors especially knowing it reached 100 degrees outside that day. so after a few times of wiggling and cranking I started to look for other things.

I did a DME relay jump, fuel pump kicks on and the rail fills but didn't actually check the individual injectors to see if they fired though. but I assume thats enough to say I'm getting fuel.

So then I checked for spark, nothing at the the plug wires end or out the coil to distributor wire end. so I check the coil and it checks out and it's getting power.

I figure it has to be the speed and reference sensors finally went out.

I ordered new ones and decided to take out the old ones while I waited for them to come in. I read about it before I got started and sure enough the reference sensor came out no problem but the speed sensor was dead stuck, just like I read generally happens.
I let PB blaster sit on it over night and the next day I was able to twist the top half of the sensor but would not pull up at all, tried leverage still nothing. so the bracket had to come out.
With the guide sleeve and speed sensor still in there the bracket ended up breaking trying to get it out.


So I went back to the search and found a lot of info but now I need help to wrap my head around what I actually need to get and the proper way to do it.

here is a picture of the bracket and shim I had on my car.
http://img268.imageshack.us/img268/7162/dsc1244v.jpg

I found this bracket on paragon
http://www.paragon-products.com/Refe...101.321.07.htm
but is this the one i need? it's the updated version that uses the sleeve and sells it separately http://www.paragon-products.com/Refe...101.320.00.htm
so if i get this i need both of them, right?
what other options are there?

As far as reassembly, I just planned on following Clarks garage and the shop manual and glueing the 0.8mm washer to an old sensor. Do i do this for both sensor holes or just the speed sensor hole?

I see that people use the Sharky? tool as an alternative? could someone enlighten me to what that is exactly? if I should use that instead or any other suggestions.

and I notice both the replacements sensors are the same. I guess i thought that the sensors themselves were different but is it just that they are the same and just need to be in the correct bracket hole and have the correct harness connection.

I know it's pretty long, but I really appreciate any help you guys can give me to put this all together.

TIA
Jonathan

Grandpa#3

Both Sensors are the same, but you have to be sure to plug them in to the proper harness plug.

As far as reassembly, I just planned on following Clarks garage and the shop manual and glueing the 0.8mm washer to an old sensor. Do i do this for just the speed sensor hole?

Tighten the bracket pivot bolt and then remove the old Sensor used for measurement.

Cheers,
Larry

joster86turbo

Thanks Larry.

Any recommendations on which bracket to get? updated or original I guess are the only two options.
It looks like the only difference is the updated version has a sleeve. Is it needed?

what's this about starter kick back?

joster86turbo

does anybody have a mounting bracket they're looking to get rid of?

Grandpa#3

I would put in another bracket just like the one you broke. Normally one can be found on ebay rather cheap. I keep a spare as we have 3 944's. On modern cars I have never heard the term "starter kick back" used except when a cylinder gets liquid locked.

http://cgi.ebay.com/Porsche-944-Flyw...item2a116daff4

Cheers,
Larry

joster86turbo

well the speed and reference sensors are gapped and changed but it still won't start. the reference sensor had a mark to identify it but I switched the connections and tried it anyway just so I could cross it off the list of things I tried.

so where to go next?

Is there like a "NO Spark Mega Thread"?

what do you guys check first when you have a no spark situation?

Grandpa#3

A No Start it could be the Ignition Switch Module forward of the key. I'm old, so I had to remove the steering wheel, trim, gage surround, and gages just to see where the module was located and how to remove it. I got the inspection mirror out and looked at the back side of the electrical switch module. There is a plug with all the wires that has to be pulled off the module, got that pulled (careful you don't pull out the wires) and there are two screws holding the module to the ignition assembly. Long story short. I broke off the handle on my shortest stubby screw driver, used a SHORT long nose vise grip and was able to turn out the screw next to the steering shaft. The other screw was a snap. I plugged in the new ignition module, used a cross point screw driver to turn to start and WOW the engine started. Installed the module to the ignition assembly. While the gage cluster was out I replaced all the light bulbs. The gage cluster trim has two hidden screws, one above and one below the trip reset button at the vent edge. I hope this helps if you have to use it. The link below gives the module wire lay out for the plug. The second link will show what the Ignition Assembly looks like.

http://www.clarks-garage.com/shop-manual/body-24.htm

http://forums.pelicanparts.com/porsc...87-944-na.html

http://nasaforums.com/viewtopic.php?f=40&r=(d20345

Cheers,
Larry

joster86turbo

where to go next? here's a run down of where I'm at....

The car is pretty much stock.
I have the cat cut out, LBE, cycle valve delete, and vitesse AFM chip.
Just to cancel it out, I put the stock DME chip back in and the cycle valve.
same result. engine cranks but no start.

So I was able to get a hold of and oscilloscope and both the speed and reference sensors at the DME are good with their voltage; 2.5v peak-to-peak .

The coil itself will get 12v as a supply, but is getting nothing as a trigger while cranking on DME terminal 1 (output to coil).

I verified with the DME relay jumper that the fuel pump comes one and fills the fuel rail, but with a check for 10v at the injector harness end when cranking it's not getting any voltage.

We used Alldata for all the ohm and voltage reading at the DME. here's what we got:

Grounds:
key off: | resistance-ohms: | result:

(pin 5 to G1) | Continuity | Continuity
(pin 5 to 16) | Continuity |Continuity
(pin 5 to 17) |Continuity |Continuity
(pin 5 to 19) |Continuity |Continuity
(pin 5 to 28) |Continuity | 20.57k


Magnetic Coil Sensor:
sensor type| resistance-ohms: | result:

Mark (pin 8 to 27) | 900-1050| 164.8k
Speed (pin 25 to 26) | 900-1050 |31,120


Coolant Temperature Sensor:
temperature F | resistance-ohms: | result:

68 degree (pin 5 to 13) | 2200-2700| 1175
176-194 degree (pin 5 to 13) | 210-350|1175
*outside temp ~ 95 F


Air Temperature Sensor:
temperature F | resistance-ohms: | result:

68 degree (pin 6 to 22) | 2200-2700| 1178
104-122 degree (pin 6 to 22) | 700-1000| 1178


Throttle Switch:
position | resistance-ohms: | result:

Closed (pin 5 to 2) | Continuity | 47500
Full Load (pin 5 to 3) | Continuity | 47400


Altitude Sensor:
change with alt. | resistance-ohms: | result:

(pin 5 to 30) below 3000' | infinity |1401
(pin 5 to 30) above 3000' | 0-2 |1401
*located at sea level


Air Flow Sensor:
at rest | resistance-ohms | result:

supply (pin 6 to 9) | 200-600 | 79,600
load (closed) (pin 6 to 7) | 70-140 | 37,400
load (flap opened to max.) (pin 6 to 7) | 150-450 | not tested




All voltage checks at the DME resulted within range. including:

-Grounds
-Start Signal
-Main Relay Supply
-Coolant Temperature Sensor
-Throttle Switch
-Oxygen Sensor
-Air Flow Sensor
-Fuel Pump Relay

So this is for all the DME guru's out there. where do you go from here with this data?
Any other check you guys think are worth checking just shout it out. I've either done it and can tell you the results I got, or would be glad to try it out if I haven't.

Thanks
Jonathan

joster86turbo

Thanks for all your help Larry.

I looked over the schematics of the ignition system and it appears that the problem I am having is coming after the ignition switch.

fast951

If you are not getting a signal out of DME #1 (it gets pulled to ground); Have you bypassed the KLR?
To bypass KLR: disconnect KLR connector and jumper pins #9 and #16 on the connector itself.

If it causes DME #1 to fire, your problem is in the KLR (either KLR chip or KLR box). If after bypassing KLR, you are still not getting a signal off of DME #1 to coil, then your DME box is bad...

You can also put the scope on both terminals to see where the signal is getting dropped...