Warm up regulator

landyman96 · 01-03-2022, 01:18 AM

Hello Pelican members,

Again I am having trouble with my fuel injection. Engine is a 1983 3.0 US spec. I cleaned the fine mesh on my warm up regulator in acetone and the cold control pressures seem fine. Problem is i cannot make the warm control pressures go down. Can someone confirm what ohm reading my heating resistor element should be please? Pic below. Also, Ive since modified my WUR to be adjustable. Problem is warm control pressures after 1 hour keep going up. My heater element seems to be lethargic. Thank you in advance.

landyman96 · 01-03-2022, 01:20 AM

Also, could someone confirm this in fact is the correct WUR for a 1983 US spec engine? I know the base on this particular WUR is not orginal given that it had a hole and it was sucking air from there so perhaps the entire WUR is from a different vehicle.

Marwil · Marwil's Garage

I may be mistaken, but the 83 shouldn’t have a vacuum port on it. Yours looks like it has a port. Post the WUR model number and someone here should be able to confirm it for you.

boyt911sc · boyt911sc's Garage

The (WUR) in the picture looks like -072 designated for ‘80 SC CIS but will work too with your late SC (WUR-090). Without seeing the side and bottom views of the WUR, it would be difficult to tell whether you got the right components.

First, it would help if you post the value of the heater resistance (Ohms) when cold (50°~80°F). Are you the fellow from UK? Keep us posted. Thanks.

Tony

ahh911 · 09:22 AM

Landyman,
The bimetallic strip should not be in contact with the spring loaded plunger above ~ 45degC.

I set the point at which the metal strip no longer made contact with the spring plate at around 42C. This was done on a bench, the idea is to isolate the spring and plate from the common, or the case of the wur. The bimetallic strip is also at common, so if you attach a wire to the spring, reassemble and measure for continuity between the case and the spring, when the circuit goes open (at 40-45 degrees) you know that above this temperature the heating element has no effect. I knocked my pin in another 0.1mm from where it was previously set with pressure by a shop. There may be other causes for what you're seeing, but this may be of interest to you. Oh, should mention that the teflon strips are very thin and should not affect the results, measure them for yourselves and see, you'll need one below the spring and one in the area where the pin goes into the plate.

Phil

ahh911 · 09:54 AM

Just to finish up, this is how I did the adjustment that saw the pin knocked in another 0.1mm from where the shop had set it. You may not be at this point, but might as well finish up on what I did as it may prove interesting/useful to others as well.

What was done, applied 12V to self warm with the heating element till above 45C, then let it cool down, it would take around 5min or more to cool back down, so not the quickest, but this way the temperature would stabilize within the housing. I used a small food temp gauge and shoved it into the vent hole and inuslated it with plastic tubing. If I had a thermocouple I would have put one inside the case. Obviously this won't work to correct warm pressure issues and is not a substitute for fuel pressure testing.
Phil

landyman96 · 01-03-2022, 10:10 AM

Hi Tony, yes I am the fella from the UK. Had to take a break from that car as it has given me way to much grief but back at it again this new year. My WUR is still in the car so I can't photograph it at the moment but my WUR is exactly like the one pictured above. The bottom plate doesn't have any ports or anything. Should this work on a 1983 3.0 motor?

AHH911- what you just wrote seems very interesting and I shall do that. Problem in my car arises after about a 45 minute drive. The fuel pressure seems to just continue rising. I usually just park the car and poor some water on the WUR to cool it down and it runs perfect. Once, I also disconnected the wire that plugs in the WUR and got home that way.

ahh911 · 11:22 AM

landyman,
The warm control pressure has to be correct firstly, which once you've taken it apart is pretty obvious how to achieve, shimming the base of the spring or reducing/making a new pin of different height would be pretty good starting points, though I didn't need to do that. THere may be more going on with that as well, maybe someone rebuilt it and didn't calibrate the warm pressure setting, haven't any experience with different scenarios. But, once warm pressure is set and tested in the car, then the stuff I've shown above has a very good chance at working.

Maybe it is from your description that the bimetal strip is for some reason contacting the spring plate even when warmed. But how cool did you make the wur by pouring water on it..

While you are there, make sure to check the spring height. May be someone swapped or manipulated it to compensate for relaxed bi-met strip losing radius over the years. I don't have the spring height, should've measured it.

Phil

landyman96 · 01-03-2022, 11:31 AM

Phil, I think you might be on to something with the spring plate touching the bimetallic strip. I have a second WUR that I bought from a VW. This second WUR did the exact same thing, the warm control pressure just kept on rising. I will test on this WUR as my other WUR is in my car and my car is stored far from where I live.

ahh911 · 11:57 AM

landyman,
I doubt both wur's have the same obscure problem unless the vw one has a different setup internally. The control pressure should not keep rising. As noted by others, is there a restriction on the fuel return side or backpressure for some reason that is heat dependent, not too probable either. You did check the primary pressure over temp too, right? Since you measure controlled pressure, you would have checked this too?

Anyhow, you can check the current flow through the wur when plugged in the car. The expected current flow for ~12 V would indicate a good power feed. Is there intermittent or heat sensitive contact issues or worn connectors, then your amps would be low. So measure the wur resistance (for the 090 they can fold into parallel as it warms up so be aware) and then I=v/r. So for the 090, when warmed up it was 10 Ohms roughly (by memory). So I expected was = 12.3v/10 A. If it was much lower then contact connector issue. I have extra connectors that i can add in series making this test easy. Otherwise check for additional resistance of the wur to the fuse box and local to the wur. The delta is the R drop. Be aware that one terminal of the wur for me was common. You can even bring the multimeter into the car and observe the current draw as you drive, but the setup has to be clean.
Phil

boyt911sc · boyt911sc's Garage

Quote:

Originally Posted by landyman96

Hi Tony, yes I am the fella from the UK. Had to take a break from that car as it has given me way to much grief but back at it again this new year. My WUR is still in the car so I can't photograph it at the moment but my WUR is exactly like the one pictured above. The bottom plate doesn't have any ports or anything. Should this work on a 1983 3.0 motor?

AHH911- what you just wrote seems very interesting and I shall do that. Problem in my car arises after about a 45 minute drive. The fuel pressure seems to just continue rising. I usually just park the car and poor some water on the WUR to cool it down and it runs perfect. Once, I also disconnected the wire that plugs in the WUR and got home that way.

Edric,

You need the correct CIS components that are good and working. Without knowing they are all working properly, it would be difficult to diagnose any of your problem/s. Every CIS components in your engine could be bench tested conveniently using common tools. The big question is do you know how to test them?

You have shown determination and tenacity in over coming most of your problems rebuilding your motor. I have not encountered anyone that had achieved so much considering what you accomplished with your particular situation and you should be proud of it. Personally, I don’t think I could do what you did rebuilding this beloved motor of yours.

You are now at a different stage of your project, which troubleshooting. Hard work and commitment to over come your problem now would only frustrate you to a point of giving up. It is not how hard you worked, but how smart you did the job.

The problem is right in front of your nose but you do not see it. So how do you locate or identify it? Simple. Name your problem or it’s symptoms and start the troubleshooting.

Tony

boyt911sc · boyt911sc's Garage

Quote:

Originally Posted by ahh911

landyman,
I doubt both wur's have the same obscure problem unless the vw one has a different setup internally. The control pressure should not keep rising. As noted by others, is there a restriction on the fuel return side or backpressure for some reason that is heat dependent, not too probable either. You did check the primary pressure over temp too, right? Since you measure controlled pressure, you would have checked this too?

Anyhow, you can check the current flow through the wur when plugged in the car. The expected current flow for ~12 V would indicate a good power feed. Is there intermittent or heat sensitive contact issues or worn connectors, then your amps would be low. So measure the wur resistance (for the 090 they can fold into parallel as it warms up so be aware) and then I=v/r. So for the 090, when warmed up it was 10 Ohms roughly (by memory). So I expected was = 12.3v/10 A. If it was much lower then contact connector issue. I have extra connectors that i can add in series making this test easy. Otherwise check for additional resistance of the wur to the fuse box and local to the wur. The delta is the R drop. Be aware that one terminal of the wur for me was common. You can even bring the multimeter into the car and observe the current draw as you drive, but the setup has to be clean.
Phil

Phil,

The system pressure is not a function of temperature. The system fuel pressure remains the same when engine is cold or warm. Have you measured the SP at different operating temperatures and obtained different values? Keep us posted. Thanks.

Tony

ahh911 · 09:24 AM

Quote:

Originally Posted by boyt911sc

Phil,

The system pressure is not a function of temperature. The system fuel pressure remains the same when engine is cold or warm. Have you measured the SP at different operating temperatures and obtained different values? Keep us posted. Thanks.

Tony

Hi Tony,
Ya, I know it's not supposed to. Without knowing the extent of the debug done to this point, I was reaching out for an obscure scenario where the fuel pump is for some reason building more pressure as it warmed over a long time interval and someone had set the system pressure at a point when the pump wasn't up to max pressure but below system regulated pressure, really a far reaching thought, but who knows, in rare cases maybe there is a resistive or a connector that expands as it warms up improving contact and the fuel pump get more current as time goes on, again obscure and really a 1/100000 type of scenario as a fuel pump running that low a pressure would have terrible throttle response at all temperatures. Also, in my head I was thinking of a sticking system pressure valve that relaxes over temperature, again a 1/10000 scenario. I'm sure it's not as complicated as that, but it would be on my lists of tests after checking power feeds are good to the device, heating element is okay, the wur screen is clean, then system and control pressure over temperature just for good measure.
Phil