Vauxhall Owners Forum banner

L3 Jetronic > Motronic Possible??

3K views 13 replies 7 participants last post by  envoy cdx 
#1 ·
I can get hold of a MK3 Cavalier SRi with a buggered engine.
All Fuel Injection stuff is OK though.
Would it be theoretically possible to fit the Motronic Fuel injection onto my 18SE engine, replacing the Jetronic Sytem.

Obviously I would need to use:

Throttle Body
Throttle Switch
Throttle Linkage
ECU
Air Flow Meter
Maybe Crank Sensor?
Maybe Intake Manifold
Fuel Injection Rail
All Wiring Looms
Idle Control Valve

I know that this conversion has been carried out with BMW's running L3 Jetronic, so I was wondering if it would be possible with Vauxhall's.
And more to the point, would it actually be worth doing?
Any thoughts and Ideas much appreciated.
 
See less See more
#3 ·
as long as the crank ring has the same amount of teeth all you need is the loom, ecu, idle control valve and airflow meter. if donor car is m1.5 then the throttle body but if ml4.1 you just use your own. the crank sensor, temp sensor, manifold and all that is the same. dunno if its worth it though.
 
#8 ·
Very interested to know more about this aswell. Are you guys saying that If I wanted to convert my L3 jetronic system to motronic ML4.1 then I'd need the following from the motronic ML4.1 donor;

ISCV
ECU
full loom
and airflow meter.


Anybody know the mods needed to the fuel pump relay/wiring????

Thanks
 
#9 ·
Steve,

check how the motronic 2.5 system works with regard to the knock sensor. You've not listed it, so your not going to use it?

If that's the case, the motronic will just keep advancing, expecting a knock signal to get it's timing. :eek: I haven't run a M2.5 without a knock sensor. I could try my engine to see, but it may have dire concequenses.

Anyone else got info about running with no knock sensor, or can you fit it?
 
#10 ·
The knock sensor bolts on the back of block between cylinders 2 and 3, it is located just below the inlet manifold.

If you run the car without the knock sensor it will give out a fault code, and the ECU will switch to "limp home" mode.

I don't think it would be possible to run it out of limp home mode without a knock sensor, or without remapping the ECU.
 
#11 ·
OK, so maybe it could be fitted then. But will the harmonics generated by knock in the 8V block be the same as that in the 16V block? As the 16V block is a lot larger and heavier, I would have expected the knocking frequency to be found at a lower frequency.

I know that BM's have done this too, however the BMW software will be different, and therefore, may account for the loss of a knock sensor. Or they have a knock sensor on their L3/Jetronic system (Which I doubt)
 
#12 ·
Whoa, this is an old post!

Actually I wasn't planning on using the Motronic 2.5, but was intending on using the Motronic ML4.1 as fitted to early (before 1990) 8V GTE's and Cav SRi's. This does not have a knock sensor.

The only major hassle is that the crank pick up rings would need to be changed to run with this system.

List of parts needed:

Throttle Body
Throttle Switch
Throttle Linkage
ECU
Air Flow Meter
Crank Sensor and Crank Sensor pick-up ring
Intake Manifold (Maybe)
Fuel Injection Rail (Maybe)
All Wiring Looms
Idle Control Valve
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top