New WUR new problems

[Scott R]

Received a new WUR on Friday and installed it, reason being is that due to a wiring issue on my SC the old WUR was melted internally. In short the cold control pressure would never change since the wiring was to the element was melted, however I could drive it and it ran well once warm.

With the new WUR however I have two issues, the idle is around 2000 when the CO is set, and that's with the bypass screw turned all the way down, and as a result it runs like crap. Lots of popping out of the tailpipe when the mix is leaned out to where the idle is below a 1000. On the other hand I have great top end power now.

I would check the control pressure, however I dropped and as a result cracked my tester this weekend, so that's not going to happen for a while.

Why would it run better with a dead WUR? Does this indicate that something else is messed up?

Oh and to add the following have been replaced in the last few months:

WUR
Freq Valve
AAV
Injectors
Air box
Manifold gaslets
Runner boots

I am one step away from ordering a Tbitz kit, this is getting to be a joke, three local wrenches now and not a one has been able to get this system running right.

[anh911]

Have you checked the throttle plate adjustment? With all the problems/parts replaced, someone may have messed with it. I'd start from scratch and baseline all adjustments (timing, idle bypass screw etc) static - not running - then start tweeking.

[Scott R]

Originally posted by anh911
Have you checked the throttle plate adjustment? With all the problems/parts replaced, someone may have messed with it. I'd start from scratch and baseline all adjustments (timing, idle bypass screw etc) static - not running - then start tweeking.

I had removed/cleaned/adjusted the thorttle plate a few months ago, I will pull it and check the switch position again tomorrow, I did check timing today, and it's spot on even when it's stuttering during idle. About the only part that I can confirm is working correctly right now is the cold start valve, since it never fails to start even below freezing.

[ianc]

This is basically a dead issue until you can either repair\replace your pressure gauge. Until you know your SP, CCP and WCP, you won't have any idea what's going on. I've read lots of stories of factory-fresh WUR's being out of whack.

I'm a big proponent of modifying your WUR to be adjustable. It's not extremely difficult to do, and you will get the ability to tweak the system for best performance according to desire\season, etc.

Let us know what you find when your gauge is fixed.

ianc

[Scott R]

Guage will be fixed in the AM with a bit of luck, thanks for the advice, in reading through the archives I am also suprised in the amount of failed WUR's right out of the box. I hope it's just the lack of warm control pressure that's at fault here. I will re-post after a trip to Napa tomorrow.

[Jim Williams]

Scott,

From your description of the idle being at 2000 with the proper CO (you didn't mention the CO reading), and not being able to bring the idle down with the idle air screw on the throttle body, it sounds as if you are either bypassing air around the throttle body somewhere, or have an air leak after the throttle body.

Not being able to adjust the idle down to 900 RPM or even lower with a closed idle air screw suggests that either the throttle plate needs adjusting, or the other three usual suspects, the Decel valve, the aux air valve or the aux air regulator are not doing their job. These are the only official components (including the bypass screw) to bypass air around the throttle plate. At idle (cold or hot), the decel valve and the aux air valve should be closed. At warm idle, the aux air regulator should be closed or nearly so.

You can do a quick check on these three by removing the hose at the rubber boot connecting the air flow meter and the throttle body. This is the manifold hose that connects to all three of these units on your '80 SC. Plug both ends, that is, the hose end, and the opening in the boot the hose was attached to. The engine should be warm, not cold for this test. Start the engine and observe if the RPM has dropped. If it has, one of these three units is the culprit. If not, you may have an air leak after the throttle body.

Let know what happens.

[Scott R]

Ok Jim, I'm off to go try that. In the mean time I have taken a pressure reading on the new WUR and it looks good:

Garage temperature 60 F

Cold control pressure 29-30PSI or 2.0 BAR
Warm Pressure was 50PSI or 3.45 BAR after 2 min.
System Pressure is 73PSI

OK, so after the WUR warmed up the idle started to drop and the then the rough running condition started. I shut it down to take a look at the gate on the AAR with a mirror and it was about 25% open at that point, the AAR is showing about 11 ohms of resistance.

[Scott R]

Ok, issue solved. Jim was correct in that the throttle plate was not entirely closed, it was not however the plate adjustment, it was in fact the the throttle linkage. When I had the motor out last summer I had removed to the CIS system to clean the engine up and I had adjusted the link rod after it was re-installed, however.... I had neglected to tighten the lock nuts and over time it appears that the arm turned and adjusted the idle up. A condition that a broken WUR masked as the CO was off due to incorrect warmcontrol pressure.


So thanks Jim!

And BTW the WUR is a rebuilt from "Fuel Injection Corporation" in California, excellent customer service and an affordable $76.00 for the part.

[anh911]

Originally posted by anh911
[U]Have you checked the throttle plate adjustment? With all the problems/parts replaced, someone may have messed with it. [U] I'd start from scratch and baseline all adjustments (timing, idle bypass screw etc) static - not running - then start tweeking.

[Scott R]

Originally posted by anh911

Damn, sorry about that. Credit where credit is due, I checked the plate the first time around when you suggested it, and while I had it out of the car, was just pure dumb luck that I noticed the plate move when I snapped the link rod back on.

[anh911]

Thanks. Had a similar thing happen to my 3.2. Different solution but noticed the throttle moved when I snapped the linkage back on.
Time to go for a ride yet?

[anh911]

Thanks. Had a similar thing happen to my 3.2. Different solution but noticed the throttle moved when I snapped the linkage back on.
Time to go for a ride yet?