'90 740 wagon fuel injector questions

e777 · Post by **e777** » 03 Nov 2007, 19:34

Hello,

I have removed the 4 fuel injectors and I have a couple of questions.

1. The O-ring pack I ordered (from eeuroparts.com) for each injector has three o-rings plus one yellow "protective sleeve" and one gray "support ring." As I look at the injector, all I can see that could be replaced is an O-ring at the top (where it meets the rail) and one at the bottom (where it is inserted into the manifold). Are those the only two items that would need replacing? What about those extra parts?

2. The injector tips are black and crusty. Is there a particular chemical I should use to clean them?

'90 740 wagon
215k miles

Thanks!

Eric

Post by **billofdurham** » 05 Nov 2007, 13:03

I can't see where the third O ring would go but the spacer fits above the lower O ring and the yellow protective sleeve goes on the business end of the injector.

Is it the injector tips that are black and crusty or is it the part that the yellow bits replace?

Bill.

wojeepster · Post by **wojeepster** » 05 Nov 2007, 15:21

like he said above you remove the plastic cap on the end, replace both orings and replace the plastic cap on the end, mine (88 740 did not have spacers)

e777 · Post by **e777** » 06 Nov 2007, 17:12

Thanks, Bill and Wojeepster. It happens that my injectors (which are apparently Bendix brand) did not have the plastic caps on them when I removed them (given my luck, the caps probably fell off during removal and are bouncing around in the engine somewhere...). Nor did the injectors have a spacer ring. They just had two O-rings. I'm thinking that the O-ring pack is made for a variety of injectors and that all parts may not be used in some cases. Anyway I replaced the two o-rings on each injector (one on the manifold side and one on the fuel rail side) but was disappointed to find that the one ring (in the manifold side) which I knew was bad was not fixed by replacing the ring. I tested the new ring's seal by spraying starter fluid around the manifold-injector union and was disappointed to find that the rough idle went away as it slurped up the starter fluid and came back again seconds later, which is exactly how things were before the fix. Oh well. Back to the drawing board.