Author Topic: K-Jetronic: Anybody replace fuel injectors "on principle"?  (Read 942 times)

raueda1

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Re: K-Jetronic: Anybody replace fuel injectors "on principle"?
« Reply #15 on: 01 May 2019, 11:27 AM »
The time has come to revive this project.  The consensus seems to be that, at a minimum, I'll be no worse off and more probably see an improvement, ranging from minor to substantial. 

One question is:  is there any merit to testing new injectors?  I guess this really means, has anybody ever heard of a new injector being bad out of the box?   I don't have any way to test or I would.  Any other last minute comments before I begin?  I'll certainly report back on the outcome.  Thanks and cheers,
-Dave
Now:  '76 6.9 Euro
Before that:  1966 230S, 1964 220SE coupe, 1977 Carrera 3.0

raueda1

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It's done.  As others have said, this is one of the easiest jobs imaginable.  The old injector tips looked clean though the shafts were pretty dirty from carbon and sludge deposits.  All the sealing gaskets had compression set and were pretty hard.  I noted that the seals on 2 adjacent injectors were significantly degraded where the holder plate compresses the seal.  On those seals the bulge between the manifold and the plate had actually broken off and the injectors were pretty wobbly.  Vacuum leak?  Probably.
 
The result:  Well worth doing, it definitely helped.  Idle is substantially smoother, especially when cold.  SSOTPP (Subjective Seat Of The Pants Performance) seems subjectively improved as well.  I'll do more evaluation in due course and report if there's anything especially noteworthy.
-Dave
Now:  '76 6.9 Euro
Before that:  1966 230S, 1964 220SE coupe, 1977 Carrera 3.0

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Re: K-Jetronic: Anybody replace fuel injectors "on principle"?
« Reply #17 on: 09 May 2019, 11:31 PM »
Here in South Africa, I specialise in the diagnostics and repair of K-jet systems, including rebuild and bench calibration of WURs and FDs.  In general, with an 'unknown' client's car, any time I do major WUR or FD work, I replace the injectors as a matter of course.  It represents a small % of the total bill, and often saves me a lot of time and comebacks chasing down silly issues.

So, push to shove, I could send you my WUR's and you could rebuild them and invoice me?

Correct Stan. 

'76 6.9 Euro, '78 6.9 AMG, '80 280SE, '74 350SE, '82 500SEL euro full hydro, '83 500SEL euro full hydro , '81 500SL