David0514

Hi, I put a 78 SC warmup regulator on my 77 Carrera (Euro), could that be the cause of my poor warmup issues? They looked idenitcal but the #'s were slightly off. Any suggestions. Thanks.

1980SC

Do you have a CIS fuel pressure testor? They are very helpful diagnosing CIS problems. If so, check that your control pressure with and without the lower vaccum line attached are to spec. I don't know the specs for a '77 3.0, but someone here should. I'd assume they would be the same as the '78-'79 3.0's which are :

46-53psi with vac line on
39-45psi with vac line off

This is with the engine fully warm.

The mixture that the WUR creates during warmup can be adjusted by raising or lower the pin on the top of the WUR. I believe there is a tech article here on this.

I've done LOTS of WUR adjusting lately, and can provide more help if needed.

Rob
1980SC euro

David0514

Thanks Rob, where is this pin on the warm up regulator?

1980SC

The pin is about 1/4" diameter, and located on top of the WUR near the electrical connection. The opposite side from where the fuel lines attach. It requires quite a bit of force to knock the plug down. It doesn't need to go down very far, so it's easy to overdo it. If so, the WUR will need to be removed and disassembled to reset the plug.

Down will richen warmup mixture
Up will lean warmup mixture

If it's too lean, it usually starts then dies a few times before it runs. When it's too rich, it will start and run, but the idle will oscillate up down for a while.

I drilled and tapped a small hole down the center of the pin, and installed a stud with a nut on it. This way, when you beat it down too far, you can turn the nut to raise the plug back up.

It's best to make this adjustment after you have verified that the warm control pressure is correct with a CIS fuel pressure tester. There is an O-ring on the inside of the WUR, underneath where the two fuel lines attach, which gets old and throws the control pressure all out of whack.

Rob
1980SC

Jeff Curtis

<img src="graemlins/roflmao.gif" border="0" alt="[hiha]" /> Rob, you're the man...beat me to it! I was reading down the post and thinking this would be a good time to reveal an old secret of mine...wallah!

...guess it's not such a "secret" eh?

David, Rob's advice is just plain stellar...there's NO way to top it. PLEASE, do have your control pressures verified BEFORE messing with the plug in your WUR.

The only difference between the SC and "Euro" WURs were the different control pressures. Have your local P-Car mechanic look up the different values for you...I know they're out there somewhere, I just don't have them handy!

David0514

Thanks everyone. Any idea what one would have to pay to have the pressure tested or does it make more sense to buy a tester?
Thanks again.

1980SC

Not sure what it would cost to have yours checked, but you can buy a nice CIS tester from JC Whitney for $70 including the shipping. The Bentley manual has instructions for using the gauge, or we can tell you how.

Rob
1980SC

David0514

Goog morning, I was able to locate the pin on the WUR. I will not do anything until I have my pressures tested. But any way, from what you have written, I believe I will need to raise the pin up. The car takes like three or four times to start on its own and then backfires (airbox) for about a minute or two. It also idles around 7 and then as the car warms goes to 9500. Would it be normal to start by raising the pin if it has never been moved. The WUR is brand new. If so, approx. how far can I drill into that pin to put another bolt and nut on it for easier adjusting? Thanks again.

1980SC

Actually, the starting characteristics which you described are of a lean warmup mixture. Not rich. The 3-4 starts before running at low rpm, and the airbox popping is what happens when it's too lean.

Before drilling, I would first try and tap the pin down, you may get lucky. It only needs to go down a mm or less. If you go too far the car will start on the first try, but the idle will oscillate a bit. If so, remove the WUR and put it in a vice.

I had a 4-40 sized tap, nut, and allen head bolt handy, so that is what I used. I'd use a larger size next time. Perhaps 6-32 threads. 10mm is a good depth. You can disassemble the unit to see what the pin looks like inside. It's not very complex. I wish I had a digital camera because I have a spare WUR disassembled at home.

If you've never tapped threads before, you may want to practice on some spare metal. I broke off quite a few taps as I learned to use them years ago.

After tapping a hole, you can place a washer over the pin. One that is slightly larger than the pin itself. Spin a nut on the bolt, then tighten the bolt into the pin. Turning the nut now will raise the pin. I like the allen head bolt I used because a socket the size of the nut fits down over the head of the bolt.

Now the pin can be raised and lowered as often as you like, with the WUR remaining in the car !


Rob
1980SC

David0514

Greta stuff. Thanks.

David0514

I tapped the pin down last night. I tapped it down to far so it is doing exactly what you said it would do. The RPM's jumped up and down, but no backfiring at all which is a huge plus. Anyway, I took the WUR apart twice last night and tried pounding the pin upward. I am assuming that where I pound the pin back upward is on a nut that is on a bolt that runs through the strip that heats up and moves up and down (depending on tempature)and then goes into the pin. I can not see that the nut and bolt connect to the pin because that piece mentioned above blocks the view, but it seems like that is how it must be. Is that the correct place to be hitting it back upward? Also, I was not expecting all these pieces to come falling out when I opened it up. 2 springs, one pin and a small metal cap. I am pretty sure I reassembled correctly. Does the small spring just go inside the larger spring? I am almost positive that it does but I figure I would ask. Thanks.

1980SC

I had always removed the nut, bimetallic strip, and the wiring to keep from damaging them. You can just pull it all out and let it dangle over the side. I'd put the nut back on when you hammer it to keep from damaging the threads of the plug.

Yes, the smaller spring sits inside the larger one. I should have warned you it was spring loaded. Be sure the thin 2mm pin stays in the little 'cup' when you put it back together. Underneath this small 'cup' is a very thin diaphragm that I would tell you to be sure was clean, but this is a new WUR.

The height of the large plug we've been discussing changes the amount that this thin 2mm pin presses on the diaphragm, thus changing the warmup control fuel pressure. Once the bimetallic strip heats up, the pressure of the thin 2mm pin is removed from the 'cup', and no longer effects control fuel pressure.

If you beat the large plug down way too far, then the thin 2mm pin will still place pressure on the diaphragm once the bimetallic strip is fully heated, and this will cause the engine to run overly rich and accelerate like crap. Been there, done that...


Rob
1980SC

David0514

I have been busy with other things lately so I have not been able to fine tune the Warmup regulator pin. The CIS is now slightly rich. The car, unless I slow down in gear has a tough reaching an idle. If I am driving at say 3,000 rpms and just drop the car into neutral and take my foot off the gas, the rpm's bounce up and down. Also, sometimes when I start it the rpm's will bounce until I help it out or it dies. Anyway, I went to take the Warmup regulator apart last night to push the pin back up. I removed the nut that holds the Bimetal spring down, but there are two wires that loop up from the side under the BS and then over the BS that block the spring from coming off . Where they loop over the BS, they do not connect to anything. What do I do with those to get the BS off. The two wires seem rigid also. Can I just bend them or would that throw off some exact setting. Thanks for your help on this. The car does start great now. No more backfiring, but does have a tough time reaching idle.
Thanks again.

1980SC

You can bend those wires out of the way. I've done it many times on my own two WUR's. The only thing you don't want to bend is the bimetallic strip.

What do you mean when you say those two wires don't connect to anything? They should run from the electrical connection on the WUR's case, to the heating element on the bimetallic strip.

Rob
1980SC

David0514

They might connect. I found someone at work to tap a bolt in for me so hopefully I should be all set. Thanks for all your help. It's funny the stuff you can learn on this website. I've read thr Jame Weber Solving Bosch CIS Problems about the WUR a dozen times and it does notmention this trick. Thanks again.