milwaukeeshark

I have narrowed my K-Jetronic (79 US 5-speed) problem to the WUR. (Normal system pressure, high cold control pressure and high warm control pressure). Using an open-ended hose to can for the return from the WUR, still high. It would appear that the screen is plugged up pretty good. It has been suggested by several here to remove it. I have the WUR out and disassembled, but cannot see how to remove the screen. Any tips from those that have BTDT? Any help is appreciated. It was running great before this!

UPDATE:

Although I didn't remove the screen, I was able to clean it up and reassembled the WUR. Now all values look good to me. They are as follows:

Cold control pressure @ 30-32 psi
Cold system pressure @ 75 psi
Warm control pressure @ 46-47 psi and steady after 5 min.
Rest pressure drops to ~23 psi after 20 min.

Although somewhat better, symptoms persist. Flat, breaking up when throttle opened quickly especially above 2500 rpm.
Checked timing at 3K and is 31-32 BTDC and right at TDC at idle (~900 rpm).

What am I missing? Idle seems smooth without any hunting. It seems to be running out of something as rev's increase. Any thoughts? Dist. cap, rotor, wires, coil all new within the last year or so.

milwaukeeshark

Bump for Update

Dennis Wilson

The screens are normally cylindrical and inserted into the male hose fittings. When they start to deteriorate a lot of particles can migrate through the system. Try blowing both WUR lines out with air. If the change in control or system pressures is significant, you should reset the air/fuel mixture. It sounds like you may be running a little rich which will hurt high rpm performance more than low end.

Dennis

Sean79 5spd

I'm with Dennis. If you have your control pressures correct then the next likely thing would be mixture. You can go to a shop or search the archives for a procedure for setting by ear.

This of course assumes you have renewed hoses, gaskets and injector seals, always the first thing to do.

Also, if the screens are now clean and they appear to be intact, leave them alone. They do serve a purpose.

Sean

milwaukeeshark

Thanks for the suggestion Dennis. I don't seem to be getting any black smoke or fuel smell.
I have readjusted mixture and idle adjustment after any major change or reassembly. I haven't looked at the filter screens that are in each injector line at the fuel distributor.
I have blown out the WUR lines.
Again, all pressures seem to be in tolerance. How can I check the Fuel distributor control plunger without total disassembly? Would a sticking plunger cause this? Thanks for the help!

928BC

The screen is a three part assembly coarse, fine, and extra fine cloth type screen. It will be totally destroyed upon removal, I would'nt go there unless your sure that is the culprit.

milwaukeeshark

Thanks Sean, as all pressures seem to be correct, I will leave the flat screen in place in the WUR. I have adjusted the mixture as you say "by ear" using the peak of rpm change and then backing off a quarter turn to lean. Readjusting idle if necessary afterwards.
I've pulled the main vacuum line from the plenum (y-to booster) and plugged with no change. Doesn't seem to be vacuum but ?
Any other thoughts?

milwaukeeshark

Thanks, Robbie. Are you referring to the screen in the WUR? I didn't realize it had multiple layers. Using carb cleaner and shop air, I think I've got it cleaned up. But symptoms persist.

Dennis Wilson

A sticking plunger would cause a lean mixture at higher rpms. Checking it can be done insitu but it requires very small arms and nimble fingers. I would remove the fuel distributor (requires removal of all fuel lines and three screws). Then bend back the tab(s) that hold the plunger in place. DO NOT drop the plunger. BTW the teat on the plunger goes toward the bottom of the distributor. Once the plunger is out, use brake or throttlebody cleaner to remove any gum in the bore. Look for scratches/grooves in the plunger and bore. If not smooth, fuel can leak past the plunger into the intake which will cause rich running and low control pressure (even richer running). Reassemble and pray to the CIS gods. Also sacraficing two bloody knuckles worked for me.

Dennis

Lizard928

have you checked the fuel dizzy arm for free movement, as a sticky arm will cause those symptoms.

Dennis Wilson

BTW adjusting the A/F mixture by ear isn't very accurate. What sounds good at idle may not be good at mid and high rpms. There have been a couple good techniques discussed that doesn't require an exhaust analyzer.

Dennis

928BC

Yes I was referring to the screen in the wur. Of coarse Dennis's method of checking the plunger is the most accurate way to check for defects, I do know of a very genral check if it is sticking bad.
Push down the sensor plate full travel gently, and then let it swing up and quickly push it back down. If you feel a "gap" before you feel the piston contact the sensor plate arm it is sticking.

928BC

MJ did you happen to notice a change in color on your spark plug tips before and after your cleaning of the wur?

milwaukeeshark

Dennis,
I'm leaning towards a sticking plunger. I think I will pull the center line(to WUR) at the fuel distributor and try to work some carb cleaner magic overnight. If that doesn't help, a couple of busted knuckles will be on the agenda for tomorrow.

As far as the A/F mixture, I've turn the adjustment CCW until I can't hear the injectors the back CW until I just hear them flow. Continue CW until rev's fall off and then back a 1/4 turn or so. Any suggestions as to method are welcome.

Robbie,

I think the plunger is definitely sticking as there is a distict "gap" before hearing contact with the plunger.

milwaukeeshark

After pulling and verifying the control plunger was not sticking, I was scratching my head trying to figure out my next step. Although my earlier vacuum leak checks were negative, because I had replaced injector seals and runner gaskets a few years ago, I hadn't checked them. Sean had suggested they be renewed so I checked them. Sure enough, one gasket (runner to head) is leaking. Spraying with carb cleaner while blipping the throttle and low and behold.........Bwaaaaaaahhhhhh!!!!

Thanks to all that helped, RENNLIST is the best tool in the box!