free hit
counters
Can not adjust mixture on Bosch injected car - Fuel System/Carbs - The Lotus Forums #ForTheOwners Jump to content


Can not adjust mixture on Bosch injected car


Recommended Posts

So my car (1987 HCi) is running quite rich. Smoke machine has been used, and no vacuum leaks found. This is a federal car with Bosch K-Jet.

Tonight, I hooked up a Gunson exhaust analyzer. Hoooo boy. Factory range for acceptable CO is 0.3 up to 1.3.

My car was averaging a reading of 3.5! And yes, that's some eye burning exhaust.

So I took the airbox off to perform the adjustment. Done this many times before on DeLoreans which are also K-Jet.

Somebody has been in there before, as the factory metal plug had been drilled out, and there was a properly fitting stopper in place.

I pulled out the stopper, put my 3 mm Allen wrench in, and went to turn the screw to lean it out. It seemed to turn a little, but then the wrench slipped. Thought maybe I didn't have it into the screw quite right, but after feeling around with the wrench, I did.

At this point, I became suspicious. I got a magnifying glass, and a flashlight, and looked into the adjustment hole. Whatever clown drilled out the factory metal plug also managed to drill into and mangle the adjustment screw. No size Allen wrench (and I tried a few) will fit into and be able to turn it.

So, I literally can not adjust the mixture because the screw is mangled.

Considering how rich the car is running, I really have no intention of leaving it more than double the acceptable C/O.

My thought process is this: Disconnect all of the fuel hoses from the mixture unit, unbolt the top half from the bottom half (so I don't have to pull the whole thing), remove the mangled adjustment screw, and replace it with a good one. Provided I can find one of these screw, I understand they're a bizarre shape and thread.

Thoughts? What would you do in this situation?

Link to post
Share on other sites

Upgrade today to remove Google ads and support TLF.
  • Replies 2
  • Created
  • Last Reply

Top Posters In This Topic

Top Posters In This Topic

Posted Images

I guess you won't have the choice, you'll need to pull it out. You could unscrew the whole distributor from the pressure plate assy.

Cheapo option would be to grind a slot across the allen head to use a flat screwdriver.

If you are able to remove the adjusting screw and you need to re-use (and if there is enough space) you could drill in the head, tap and fit another small allen screw on top. I know...sounds crazy. Gluing it in could also be enough, you probably already know there is not a lot of running torque on this screw.

Take pictures, I'm interested in seeing the exact setup.

Luc

Something I learned about cars or planes, it all works until it doesn't anymore...sometime there is no way around it!

Link to post
Share on other sites
  • 4 years later...

i also need to adjust my mixture but the manuel does not say how to remove the plug. my k-jet guy in Australia said drill it out

does anyone know if this is removable?

or do i have no choice but to drill it out? 

20210121_145818.jpg

Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.




×
×
  • Create New...