What is an impulse wire???

[Garageaholic]

What is it? what does it do? Where exactly is it? and why is it so much more expensive than non-impulse?

[arsevader]

What is it? what does it do? Where exactly is it? and why is it so much more expensive than non-impulse?

I assume you are talking about the inductive pickup wire that is attached to the #6 wire on 325i spark plug wires as opposed to the ETA wires which have no extra wire.

It's used by the Motronic ECU help fire the injectors. The ETA has no inductive wire and fires all of the injectors at once, the 325i fires the injectors in 2 batches using this cable for timing.

The other wires are identical. The 325i can run just fine without this wire too, it'll just fire the injectors in one batch. The only side effects being slightly lower fuel economy.

[cunninglinguist]

I think it does more than create batch timing for the injectors. Consider that the Motronic 1.1+ has no flywheel sensors, but does have a toothed crank wheel. Speed/position are read from the crank wheel.

Maybe I'll try to disconnect the sensor before start-up, and do another test when the engine is already running.

[lordofthewaters]

I assume you are talking about the inductive pickup wire that is attached to the #6 wire on 325i spark plug wires as opposed to the ETA wires which have no extra wire.

My Bentley manual has the impulse generator as being on the 4 cylinder engines only. No mention or diagram of it being on either version of the M20 6 cylinder..................

Plus my 325i has nothing like this that I've seen...........

[arsevader]

I think it does more than create batch timing for the injectors. Consider that the Motronic 1.1+ has no flywheel sensors, but does have a toothed crank wheel. Speed/position are read from the crank wheel.

Maybe I'll try to disconnect the sensor before start-up, and do another test when the engine is already running.

The crank position sensor is a different sensor than the inductive pickup sensor. Without the crank sensor, the car won't start, without the inductive pickup the car will run just fine.

The pickup just reads when the #6 cylinder is at TDC.

Plus my 325i has nothing like this that I've seen...........

Do you have aftermarket spark plug wires? It's an extra wire that is attached to the #6 wire close to the Distributor cap.

Impulse generator is something different and I don't think that's what he's talking about.

[lordofthewaters]

Do you have aftermarket spark plug wires? It's an extra wire that is attached to the #6 wire close to the Distributor cap.

Yes it had aftermarket wires on it when i got it way back.............Where does the other end of the wire go?

Impulse generator is something different and I don't think that's what he's talking about.

Think maybe he means the pulse sensor wire?

[arsevader]

Yes it had aftermarket wires on it when i got it way back.............Where does the other end of the wire go?

It attaches to a connector in the same bracket as the crank position sensor connector.

[Garageaholic]

i wonder if it's long enough to reach. I have to check my car

[mikeedler]

doesnt the tach read off the wire you all are saying he doesnt need?

[arsevader]

doesnt the tach read off the wire you all are saying he doesnt need?

No. The tach reads off the crank sensor. If you read the Bosch engine management book, all the inductive pickup is used for is to sequence the injectors into 2 batches.

[arsevader]

i wonder if it's long enough to reach. I have to check my car

Not sure I understand what you are asking.

It's long enough to reach because it was designed that way. Which wire are you wondering about?

[Garageaholic]

NO IMPULSE SENSOR WIRE
THE ATTACHED FILE DOES HAVE THE IMPULSE SENSOR ATTACHED AT THE FRONT OF THE #6 WIRE. THE LITTLE STRANGALY WIRE WITH THE 3 PRONG CONNECTOR. JUST LET ME KNOW IF I'M CORRECT IN ASSUMING THIS.

Thanx guys, hopefully this clears things up

[arsevader]

THE LITTLE STRANGALY WIRE WITH THE 3 PRONG CONNECTOR. JUST LET ME KNOW IF I'M CORRECT IN ASSUMING THIS.

Thanx guys, hopefully this clears things up

Yes, that's the one. Obviously the top set isn't from the M20 though.

[Garageaholic]

yes, you are correct,

I'm doing the M30 conversion from an E32 735i, so that's where it came from, but as long as the idea's the same, i can move on

Thanx alot for all of your help guys

[Jordan]

Thats not M30 either.

Looks like S38 to me.