OldSchool AG

It's been a while since I did any CIS-E troubleshooting. Girlfriend's '85 4000Q, stock Bosch CIS-E (KE Jetronic) system. When the key is turned to the "ON" position (one click before "START" position) the fuel pump should energize for a couple seconds, correct? If not, either the fuel pump, fuel pump relay, or the ignition switch are defective, correct? If replacing the fuel pump relay with a jumper causes the pump to run continuously but the car will still not start (confirmed fuel is being delivered to injectors when airflow plate is raised) likely cause is the ignition switch, correct?

More dumb ?s: When should I see 12V at the coil? Only when hall sensor detects rotation or anytime key is "on?" If the answer is the former, could the problem also be with the hall sensor? Or does the fact that the fuel pump not run when key is turned to on make the likely cause the ignition switch?

Planning to replace the switch as it's cheap, but thought I'd query the forum first.

Thanks,
Chris

mt6127

when you jumper the two large spades of the FP relay, you should hear the pump kick on with the key. if not, you either have no 12v going to the pump (ie switch or perhaps a fuse) or a dead pump. To test out if the switch is given power to the relay you should be able to see 12v across the large spades when the key is on. the relay will only connect when the engine is turning over to avoid running with the key in the on position while the engine is off.

OldSchool AG

As I mentioned the pump is AUDIBLY energized with the relay jumpered, furthermore, there is evidence fuel is being delivered to the fuel distributor and subsequently to the injectors when the air flow plate is raised by hand. Additionally, the car still refuses to start even wit gasoline poured into the intake manifold. Not a fuel delivery issue. My question is more as to whether the key switch energizes the coil thru a separate circuit from the one by which the fuel pump relay is energized.

I have a Bentley, so if anyone can provide references there, I'd appreciate it.

AudiSport4000

And since you are getting fuel to the injectors, start checking the ignition components, check for spark first. Im assuming you have none. Check the coil, plug wires, hall sensor, hall sensor control unit.
I went through a problem like you had, fuel pump WOULD kick on with relay, but car wouldnt start, but with the relay out and a jumper wire in place, car started. Sounds like a faulty hall sender control unit to me, or something similar.

Mike

OldSchool AG

Yes that is the next step. Just wanted to query the forum and see if anyone had any ideas before I start reinventing the wheel. Maybe it's fun to you guys, but guess what # on my list of things I want to do this week troubleshooting a goofy CIS problem is? ;-)

By the way, car won't start with a jumper in place of the relay. I tested the specs on the coil with a multimeter and they seemed reasonable compared to what the Bentley said.

Thx.

AudiSport4000

Then its gotta be the hall sensor, hall sensor control unit, or something along those lines.

Mike