william_b_noble

no, peanut, I guess I am not prepared to work with you - from now on, only Marius will post, if at all. Thanks for your help.

Jimmy586

did you get this car to start ? It would be useful to have some closure ....or not

peanut

this should give you a clue !

First of all you said it happened after a car wash then you said it happened after your starter got stuck ?????

You need to ascertain the cause of your starter issue and check the incidental damage caused. The starter issue may have been caused by a faulty ignition switch which may be affecting the DME relay and ECU supply when cranking


This is telling you why the car isn't starting! The ECU is not receiving an output from the CPS crank position sensor.
Until the ECU receives the CPS output it cannot initialise your DME relay .

If the DME relay coil isn't being grounded by the ECU you'll get no fuel pump, no injector pulse, no ECU power supply ,no 5v sensor supply and no ignition pulse for the ignition amplifier.

mhariush

Hi peanut,

After working on the car for a year I started it up and it fired tight up without hesitation. I drove car from downtown la to santa monica, where we thought the engine had a strange noise, but it was running fine. Drove it back to hollywood, with a couple of stops, and it stopped and started perfectly each time. Before I got home I drove through a car wash, car started perfectly, drove it home about 2 minutes and when I parked it in the garage, I tried to shut it down, but it didn't because the starter had gotten stuck engaged. The car stopped after a metallic clank from mid car somewhere and the starter stopped spinning. After that it didn't start up again.
I swapped the ingition switch with a working one from my running na, and that car is now driving around with the ignition switch from the S. So I take that as a sign that the switch is fine.

So if the crank signal (is this the same as the reference signal?) Isn't seen, what would be the next step? When reading the speed/ref plug in the engine comp with a scope as per the manual we see what looks like the speed signal but not the reference signal (the higher peak) as per the manual.

I'm really stumped and don't know what to do next.

peanut

I run a 944S2 which is a 16 valve and has a single crank sensor on the flywheel. has your car got the same single sensor ?

The crank speed sensor is a magnet which creates a variable DC voltage which is converted into a digital signal by the ECU.
Your sensor may be working fine but it must communicate with the ECU before the ECU will ground the DME relay.

Usually if you can see a tiny bounce of the tach needle it means that the ECU is seeing the sensor signal ok.

If you cannot see that bounce on the tach needle when cranking the engine you need to either check the cable from the crank sensor to the ECU connector for shorts or breaks or you need to bypass that cable .

from what you have described it sounds like water must have caused a temporary short circuit somewhere which forced the starter motor to crank the engine whilst the engine was running.
That would suggest a fault with either the ignition switch or the associated wiring running from the ignition switch and the battery to the starter motor.

I suppose it is possible that you have a faulty immobilisr ? if there is one fitted. You may have a disused immobiliser that has been left in place but disconnected.

Please appreciate that it is very difficult to diagnose a non start problem over 1000's of miles by internet messages . I'm trying to keep explanations as simple as possible as it is clear that you haven't even the most basic understanding of your car's injection and ignition system which makes this all the more difficult

mhariush

Hi Peanut,

Yes it has the single sensor (and the short one that i learned is only used by Porsche for some diagnostics, i assume).

I have checked the wires, and all appear (visual inspection) to be in working order and not broken.

You mention an immobiliser, what and where is this located?

And no, i don't know anything about the fuel injection system, nor have i claimed to know anything about it. I'm trying to the best of my ability to explain what I have done, what I have found when checking/looking up suggested solutions.

mhariush

My car has an alarm system, and I've bypassed it as per "Clark's Garage" but the car still didn't start.

peanut

I wouldn't just rely on the Clarkes bypass guide. You must make certain from first principles and not assume anything.

If the ECU receives an imput from the speed sensor with the engine cranking over 225rpm then it grounds the primary coil of the DME relay which then supplies the fuel pump and the ECU with power .

One way of bypassing the DME relay is to install the 3x way bypass cable in place of the DME relay and then try start the car. Have you done this yet ?

mhariush

Im in bed with a cold now, but later this week I will try that tree way bypass. I did bypass and get the fuel pump running, with 30 and 87b(?) so at least that's working.

C ANDERSON

Have you pulled the reference sensor to look at it ? since it was being driven with the starter engaged , you did say you turned key off and kept turning engine . There may be enough metal from the starter drive and the flywheel stuck on the bottom of the sensors to not let it pickup the allen when it comes around. Had a simular problem after repairing the battery box area when metal grinding chips from cleaning the area up found there way to the sensors.

Clifton

mhariush

Hi cliffton,
I pulled the sensor (but didn't move the bracket) and looked at it, no marks or scratches and no dirty or metal shavings on it.

peanut

ok well you need to try with the 3x way bypass 30- 87b- 87 which will supply 12v to the pump ,ECU, sensors and coil etc .
Hope you are feeling better soon

mhariush

Hi
I tried jumpering 30-87-87b today. No start. I measured that terminal 30 has 12v+ even with ignition off. I tired jumpering two different ways, a three-way spade connector and connecting a wire between the three pins on the dme relay. No start on either.
Also, the fuel pump itself did not start when connecting 30-87b, which it has done previously.

peanut

ok if you have jumpered DME relay terminals 30 & 87b and the pump doesn't run continuously there are only 5x possible reasons for that.

1. you didn't get good electrical connections on the DME socket terminals with the bypass cable. (did you solder or crimp male spade connectors on the cable or just push bare wires in the socket ?)
2. The fuel pump fuse is blown ( did you check ?)
3. the earth to the fuel pump has a bad connection ( check the pump earth connection just below the number plate light in the rear hatch area behind the carpet )

4. the fuel pump is fubar! It could just be jammed. Try putting the bypass in and then banging the pump with a rubber mallet or something similar

5. there is a break in the wiring between terminal 87b on the DME relay and the pump fuse or..... between the pump fuse and the fuel pump......or between the fuel pump and the pump earthing point.

mhariush

Peanut,
I need to try the 3-way jump again with some better connectors i think.

But my other car, 87 NA, stopped yesterday. There's no spark. The coil appears to work. We did pull the computer though and Pin 5 had been burned.

I also found that the battery's negative ground, that connects to the chassis under the Pressure Relief Valve, dumbest place to have this, had split because of the brittle plastic and had lots of corrosion (green on the brass wires).

We're soldiering the computer and hopefully that fixes it and that nothing else on it got damaged. What do you recon made Pin 5 burn out? Could it be the battery ground?
The car was acting funny for about a week, but worked again after i disconnected/reconnected the battery. After I did it last time, and cleaned the connectors and tightened them properly the car seemed fine for days until it suddenly just died on my, puttered out in an intersection, but the battery still held a charge.