Should I wait? Or do it myself?

makaio · 01-28-2002, 01:12 PM

I have my new WUR siting next to me, and my car is scedualed to go to the doctor Friday for installation and mixture settings.

My question is, should I install it myself, or wait for the shop to do it Friday? At first I was leary, but after reading my Bentley manual, it seams within my scope of practice. Except I don't have a exhaust gas analyzer to check my mixture settings afterwards. Or do I even need to worry about that?

Thanks in advance!

Superman · 01-28-2002, 01:33 PM

Good question. Normally, I'd say that yes, you will have to re-set your mixture. But I think the WUR allows control pressure to equal system pressure once it is all warmed up. That being the case, pressures will be the same (after full warm-up) after the installation as they were before. Still, I'd check mixture when I'm done.

It is not a difficult job to remove and replace the WUR.

wckrause · wckrause's Garage

You can do the replacement yourself. There's not much too it. But to test it afterwords, you need a CIS pressure tester. There are specs in the Bentley manual for system pressure, and a spec for control pressure vs. temp.

makaio · 01-28-2002, 02:15 PM

Your both right, changing it out is pretty simple. Just save myself an hours worth of labor at the shop.

Now, do I need to bleed the system before starting the car? I imagine so.

Superman · 01-28-2002, 02:17 PM

Bill, does control pressure equal system pressure at full operating temperature? It seems to me I asked this question once and got a 'yes.' Of course the real world and the theoretical one are different, but in theory, if control pressure = system pressure, then the two WURs would be indistingushable at operating temp, which is the temp at which you set mixture. Still, I suggest re-setting the mixture afterwards.

wckrause · wckrause's Garage

No, control pressure is always lower than system pressure. In other words, the WUR is always doing some pressure regulation.

There are some charts and specs in the Bentley book that show this. I thought there was one of the charts in the archive, but I wasn't able to find it.

makaio · 01-28-2002, 02:29 PM

i got installed and started the car. Still doesn't idle. But I am assuming that's because the mixture is not set. Am i right?

makaio · 01-28-2002, 04:09 PM

I went ahead and leaned out the mixture. (like 1/16 of a turn) I didn't drive the car but 1 mile, but just in that short distance throttle response and torque seemed much better. After I have the CO adjusted on the tester, I think I might have a rocket ship on my hands!

wckrause · wckrause's Garage

Get the mixture set with a CO meter when the engine is good and warm. If you still have a cold start problem, then you'll need to have your fuel pressures checked, and possibly your WUR adjusted.

There was an earlier thread where a guy ruled out the WUR as his problem with cold starts because he had just replaced it. It turned out to be out of spec and only required an easy adjustment.

Getting on my soapbox--------

If you own a CIS car get a CIS pressure tester. You wouldn't try to work on ignition timing problems without a timing light, would you????? Or electrical problems without a multi-meter (or at least a test light)???

-----------Off of my soapbox