Author Topic: injector change (Read 3173 times)

redhead · « **on:** December 17, 2006, 05:36:19 PM »

Has anyone changed the injectors in their m42 engine? What do I have to do other than remove the intake manifold and re/re the injectors, and what gaskets do I need to buy ahead of time? Fuel lines?

TIA,
Gene

bmwman91 · « **Reply #1 on:** December 17, 2006, 06:32:43 PM »

It is a good idea to replace the fuel softlines. Get the high-pressure stuff from most local parts stores for ~$1/foot. I cannot remember the exact inside diamter.

Pull the intake stuff and unbolt the fuel fail. Also disconnect the injector wiring harness from the big black box that sits under the lower manifold, near the firewall. Unless you damage some gaskets in the process, you can reuse them.

kowalski · « **Reply #2 on:** December 18, 2006, 12:35:43 AM »

there is also 2 orings on each injector, and a plastic pintle on each one that you can replace if you feel like it.

ak96ss · « **Reply #3 on:** December 18, 2006, 05:17:58 AM »

Definitely replace the fuel lines under the upper intake manifold - one of mine sprang a leak and was dumping raw fuel onto the starter. Made for a fun drive home!

It's 8mm high-pressure hose, and I would recommend replacing the worm-drive clamps as well. There are two lines under the manifold, a couple of inches each, and four worm-drive clamps.

Injector o-rings have been mentioned, and should definitely be replaced. IIRC, the Bentley calls for (and I think BMW recommends, but don't quote me) replacing the clips that hold the injectors to the fuel rail.

I would replace the gaskets when you do this, no sense taking it all apart and not replacing them, they are cheap. There is a gasket between the upper and lower intake manifolds, as well as one between the lower manifold and the head.

Also, take a look at all the rubber lines underneath the upper manifold - now is the time to replace them, you are already going in and will have to take some of them off anyway! Fuel pressure regulator, throttle body coolant, the line to the ICV, etc.

Are you putting new injectors in, or rebuilding the existing ones? For rebuilding, Rich at http://www.cruzinperformance.com charges $14/ea plus return shipping, and does a very good job. New o-rings, pintles, flowtested.

redhead · « **Reply #4 on:** December 18, 2006, 05:18:43 AM »

It lists 8 o-rings but I only see one o-ring per injector in the picture at realoem.com, where does the other one go?

Gunni · « **Reply #5 on:** December 18, 2006, 05:29:15 AM »

one on top and one on bottom, the top one sits in the fuel rail, and the injector trough it, the other one sits in the lower intake manifold and the injector trough it,

kowalski · « **Reply #6 on:** December 22, 2006, 04:06:36 AM »

and there is a little plastic washer on each of the bottom o-rings.