Cleaning fuel injectors

1965 Mercedes 250SE

Sat for a few years, bad fuel pump, would not start.

Fixed fuel pump, drained 1/2 tank of the most stale gas ever seen, and started car. Bad gas made it run horrible for a bit, but cleared out. Put in full tank of good gas. Ran well

Driving, car died. Will start, run rough, die.

Confirmed fuel pump still working, gas pressure into & out of injection pump, at single injector, will squirt gas from steel line, but will NOT come thru mechanical fuel injector.

Priced out a set of six injectors for just under $500.

Any way to just clean the old ones? Any other ideas?

Reply to
iNet
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Conceptually, there's no downside to attempting to clean the old mechanical injectors - $500 will replace them if you fail. Choose the ugliest among them and take it apart - carefully, make notes how it comes apart so you can reverse the process after the muck is cleaned out of it.

BUT FIRST, before you attack the fuel injectors change the fuel filter(s). There may be enough fuel getting through for you to check a single injector but not sufficient fuel to run the engine. The fuel filter(s) is highly suspect given the recent fuel problems. Of course if the fuel pump delivers a great gush of fuel to the engine the filters must be OK.

Reply to
T.G. Lambach

A 65 250SE? wow.

There's a good chance they're just gummed up with crud. If you pull them and have them ultrasonically cleaned and tested you might get out ok if they were ok beforehand and are just funky now because of sitting so long and the bad gas.

I want pics!

Reply to
Richard Sexton

Excellent points - If I wreck the injectors, I have to get new ones anyway.

I have NOT opened / changed the filter. The feed line was taken off the injector pump, and it spews gas. This is mechanical injection, does the big filter on the engine come in to play before or after the injector pump? If after, then there is my problem.

Is the tip of these bosch injectors spring loaded (tip opens/closes)?

Note to others - DO NOT put a q-tip in the feed end of this injector - tips check in, they don't check out.

Reply to
iNet

Ah. Nothing kills an SE fasster than clogged fuel filters. You definitly want to change these before you go any further. God knows what manner of rust, crud, gum and varnish is in there.

Hemostats.

Reply to
Richard Sexton

I would hope the filter comes in the sequence before the injection pump, otherwise the pump would be the recipient of all the dirt etc.

Suggest you first replace the filters then you'll know positively that the filters are OK and not causing the problem. THEN it will be on to the injectors, not the other way around.

Reply to
T.G. Lambach

Look at:

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They clean both electronic and CIS injectors for $12 each. I have no experience with them but someone here recommended them a while back. Let us know if you give them a try.

Reply to
M. Davis

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