Need abit of help,
I've got a high compression engine 325i m20,
I'm removing in within the next few weeks to swap for the lower compression 325i m20.
is the wiring that i've got at the moment going to be the same to use? (i know the ECUs are different?) so would i just have to swap over ECUs? or not even have to swap?
Bit of help!
M20 high compression swap low compression?
Moderator: martauto
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Brianmoooore
- E30 Zone Team Member
- Posts: 49359
- Joined: Mon Jan 10, 2005 11:00 pm
A low compression 325i fitted with the management from a high compression engine would work (complete loom swap), but would give you the worst of both worlds.
The drop in compression ratio was compensated for by the improvements in engine management made at the same time.
ECUs have a different number of pins in their plugs, so have to stay with their respective looms.
The drop in compression ratio was compensated for by the improvements in engine management made at the same time.
ECUs have a different number of pins in their plugs, so have to stay with their respective looms.
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DanTheMannn
- E30 Zone Newbie
- Posts: 169
- Joined: Tue May 14, 2013 11:00 pm
Right, so you think best bet is to probably change loom aswell?
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Brianmoooore
- E30 Zone Team Member
- Posts: 49359
- Joined: Mon Jan 10, 2005 11:00 pm
Definitely, if you're fitting the later engine. The old engine should be removed complete with its loom, and similarly, the loom for the later engine should stay fitted to it while it's installed.
Check out the condition of the round plug and socket under the inlet manifold, where the injector loom joins the rest of the engine loom. Check for corrosion under the rubber boots, and make a small nick in the rubber of the lower boot at the lowest point, as per BMW TIS, to provide a water drain.
Check out the condition of the round plug and socket under the inlet manifold, where the injector loom joins the rest of the engine loom. Check for corrosion under the rubber boots, and make a small nick in the rubber of the lower boot at the lowest point, as per BMW TIS, to provide a water drain.