Mixture - Part 3 a stripped screw!
12-05-2004, 08:23 PM
#1
Pro
Thread Starter
Join Date: May 2003
Location: SF Bay Area
Posts: 601
Likes: 0
Received 0 Likes
on
0 Posts
Mixture - Part 3 a stripped screw!
I finally got off my butt and started to do the mixture adjustment using the new Gunson's Gastester. Those of you following the saga may recall that I thought the car was running a bit rich, and it was a good excuse to buy a new tool.
Step 1 - Calibrate the gastester by letting it run in clear air for 10 minutes. It turns out that air has 2% CO. Who knew?
Step 2 - Take the shark for a spirited drive to bring the oil temp up. This was the fun part
Step 3 - Set the park brake, chock the wheels and leave the car running in neutral. Unplug the O2 sensor and insert special tool US 8023 (or reasonable facimile) into the exhaust stream. Let the Gunson stabilize for a couple of minutes. This gave me a reading of around 1.8% which is rich. The spec is 0.4% to 0.8%. So far so good.
Step 4 - Use special tool 9187 (or homemade facimile - see previous thread) to adjust mixture. I inserted the special tool and gave it a few cranks. No change on the reading. Pulling out a large flashlight which is needed to peer into the deepest depths of the L-jetronic housing where some of the worlds finest automotive engineers decided to put the adjustment screw, I find that in all my messing around. I have apparently stripped the screw. I can't back the screw out at all.
Step 5 - Go grab a cold beer and consult the Rennlist crew
At this point I need to fix the screw so I can turn it. It is way to far into the housing to dremel a slot in it, and I'd need to take the whole top of the air plenem to get to it. The only thing I have come up with is that I could probably JB weld a phillips head machine screw into the 3mm allen wrench hole. that would make the thing easier to adjust in the future.
Anyone got any bright ideas
?
Step 1 - Calibrate the gastester by letting it run in clear air for 10 minutes. It turns out that air has 2% CO. Who knew?
Step 2 - Take the shark for a spirited drive to bring the oil temp up. This was the fun part
Step 3 - Set the park brake, chock the wheels and leave the car running in neutral. Unplug the O2 sensor and insert special tool US 8023 (or reasonable facimile) into the exhaust stream. Let the Gunson stabilize for a couple of minutes. This gave me a reading of around 1.8% which is rich. The spec is 0.4% to 0.8%. So far so good.
Step 4 - Use special tool 9187 (or homemade facimile - see previous thread) to adjust mixture. I inserted the special tool and gave it a few cranks. No change on the reading. Pulling out a large flashlight which is needed to peer into the deepest depths of the L-jetronic housing where some of the worlds finest automotive engineers decided to put the adjustment screw, I find that in all my messing around. I have apparently stripped the screw. I can't back the screw out at all.
Step 5 - Go grab a cold beer and consult the Rennlist crew
At this point I need to fix the screw so I can turn it. It is way to far into the housing to dremel a slot in it, and I'd need to take the whole top of the air plenem to get to it. The only thing I have come up with is that I could probably JB weld a phillips head machine screw into the 3mm allen wrench hole. that would make the thing easier to adjust in the future.
Anyone got any bright ideas
?
12-05-2004, 08:27 PM
#2
Rennlist Member
i THINK i DID SOMEthing similar on a LR I had. The head is plastic IIRC. I think I finished up using a flat blade driver tapped lightly into the cavity to turn it...
jp 83 Euro S AT 48k
jp 83 Euro S AT 48k
12-05-2004, 11:05 PM
#3
Rennlist Member
Marc,
So how's the new toy?
Does the adjustment screw turn inwards? - or has the 3mm key on the end of the 'special tool' come loose in its extension shaft?
I have a spare AFM sitting here, and the female 3mm hex is centered in a 12mm conically dished round head steel adjuster - 35mm down in a 12mm bore well! The hex key engages 4mm - so it would be very difficult to strip the adjuster. However, it would be easy for a little corrosion to seize the steel adjuster to the aluminium bore.
The one I have here refuses to turn easily, and it does not appear to be a spring loaded adjuster (push in & turn) - so for the fun of it, I'll give it a shot of kroil penetrant.
It is far easier to lift the AFM out with the lower air box if you need to play with it - it takes far less time to do that going for another cold one .... and you can actually see the critter, which is next to impossible when installed.
EDIT: 2 min of soak time, and the adjuster came free - hope that works for you!
So how's the new toy?
Does the adjustment screw turn inwards? - or has the 3mm key on the end of the 'special tool' come loose in its extension shaft?
I have a spare AFM sitting here, and the female 3mm hex is centered in a 12mm conically dished round head steel adjuster - 35mm down in a 12mm bore well! The hex key engages 4mm - so it would be very difficult to strip the adjuster. However, it would be easy for a little corrosion to seize the steel adjuster to the aluminium bore.
The one I have here refuses to turn easily, and it does not appear to be a spring loaded adjuster (push in & turn) - so for the fun of it, I'll give it a shot of kroil penetrant.
It is far easier to lift the AFM out with the lower air box if you need to play with it - it takes far less time to do that going for another cold one .... and you can actually see the critter, which is next to impossible when installed.
EDIT: 2 min of soak time, and the adjuster came free - hope that works for you!
12-06-2004, 01:24 AM
#4
Pro
Thread Starter
Join Date: May 2003
Location: SF Bay Area
Posts: 601
Likes: 0
Received 0 Likes
on
0 Posts
Thanks, that worked great. It didn't occur to me that this thing was actually attached to the bottom of the MAF and that I could yank it out and work on it on the bench! 
I pulled it out and hit is wth a squirt of penetrating oil. It now works great, but that was only half the problem. The other problem was with special homemade tool 9187. The spare allen key that I used to make it with wasn't a 3mm! It was slightly larger (probably a 1/8) and wasn't seating in the hole properly. That is now fixed and I will get back to it.
Life is tough, but it's tougher when you're stupid.
I pulled it out and hit is wth a squirt of penetrating oil. It now works great, but that was only half the problem. The other problem was with special homemade tool 9187. The spare allen key that I used to make it with wasn't a 3mm! It was slightly larger (probably a 1/8) and wasn't seating in the hole properly. That is now fixed and I will get back to it.
Life is tough, but it's tougher when you're stupid.