87 900 Turbo no start

[grego]

Hi, I'm new here, but not new to Saabs. I'm on my fourth 900T and third 9000T, but I have an issue with my 900 that is new to me. I appreciate this forum and all the help on it. I've looked through the archives, but it's confusing me, so here's my plea for help:

87 900 Turbo convertible ran great on thirty mile drive, parked it and hasn't started since. The fuel pump does not charge when the ignition is turned on, but does run when I jump fuses 27 and 30, but the car still will not start. I've replaced the fuel pump relay and I can feel/hear it click when the ignition turns on. My f/p relay is on the fender well by the fuse box, but a few folks have said there is another in the footwell? Is there more than one relay?
Now I'm looking at the Hall Sensor, and here is the source of some of my confusion. Someone had previously soldered the wires into the connector on the outside of the distributor, Bingo, I thought. So I got another harness with connector from a wrecking yard (and then another), but my car's wiring has three wires, green, brown and black. Every harness I've looked at or bought has two wires, green and brown, wth a bare wire wrapped around them, coaxial style. How do I/can I wire this in? Is the 87 Hall wiring unique to this year? Both harnesses I bought are from '88 900T. Haven't found an '87 donor yet.

Any help or referall to help is appreciated. Apologies for such a long post first time out!

grego

[9008v]

Is the sensor in the distributor or on the crank shaft?

If the original wire had three wires, the two outside ones should be a live and negative supply, and the middle wire should be the signal wire.

Pull out one of the spark plugs to determine if the problem is ignition or fuel.
A wet plug with no spark is an ignition problem.
A dry sparking plug is a fuel problem.

[grego]

Thanks for the info. The hall sensor is on/in the distributor. I get spark at the plug, and if I spray starting fuel into the intake, she starts and runs like a champ for a few seconds, so I'm pretty certain it's a no-fuel problem.

I will check my wiring on the sensor and hopefully find a problem there. At the risk of sounding stupid, but to be thorough, the coax style wire that's wrapped around the other two has to be ground, right?

Thanks!
G

[Jim Mesthene]

A wet plug with no spark is an ignition problem.
A dry sparking plug is a fuel problem.

On a US model 1987 900t, that's not so.
Without spark, you can get no fuel.

The fuel pump does not charge when the ignition is turned on...

It's not supposed to. It should only be powered when the Fuel Injection ECU sees that there is spark (engine cranking).

My f/p relay is on the fender well by the fuse box...

It's not supposed to be. Are you sure you're testing the right stuff?

Is the 87 Hall wiring unique to this year? Both harnesses I bought are from '88 900T.

No, they should be the same.

The Hall Effect sensor in the distributor has the signal wire shielded by a Ground Braid; thus you have power, ground and signal as 9008v said.
If you have a Test Light, touch the center signal wire momentarily while it's connected and powered. This should cause a spark; if it doesn't, try an Amplifier.
Fuel Pump Relays hardly ever fail unless some misguided person replaced it with one of the cheap, common Fog Light relay replacements.


Welcome, and I hope that helps.

[grego]

Thanks Jim,

The relay I'm seeing is marked 'Fuel Pump' and is located in the fuse box/relay panel in the left side fender. It's just like my previous 86 900T if I recall correctly. It's a small silver Bosch, and is the same as in my 89 9000T (which does power the f/p on when the igniton is just turned to ON - that's why I assumed the 900T should power on with ignition ON as well).

I think, from reading archives etc, that either the Hall or ecu is not signaling the injectors perhaps, since the f/p doesn't power until spark is signaled. I'm still focusing on the Hall Sensor and its wiring pigtail.

I will try the test you suggested with the test light. I just sprayed starting fluid in again, and she started right up. What a tease...

Thanks!
Greg

[Jim Mesthene]

Originally Posted by grego

It's just like my previous 86 900T if I recall correctly. It's a small silver Bosch, and is the same as in my 89 9000T (which does power the f/p on when the igniton is just turned to ON - that's why I assumed the 900T should power on with ignition ON as well).

Only 8 valve engines have a Fuel Pump relay in the relay box, and those aren't supposed to power the fuel pump with the ignition only either. The Fuel Pump relay in all 16 valve cars is above the ECU in the right footwell.

I will try the test you suggested with the test light. I just sprayed starting fluid in again, and she started right up. What a tease...

If that's happening, you have spark so the Hall Effect sensor is working.

[9008v]

I read the 1987 wiring diagram;

If you jump pins 30 and 87 of the fuel pump relay, the fuel pump should run.

To test if the engine running signal is working, go to the TSI socket located in the main fuse/relay panel. It’s a circular connector with six terminals. Terminal 1 is battery live, terminal 2 is ground, .... , terminal 5 is ‘engine running’ signal. Test the voltage of pin number 5. (Test the voltage between pins 2 and 5)

This will verify if both the hall sensor and ignition pulse amplifier relay are functioning. (Correct me if I’m wrong)