WUR wiring connector

[deguitars]

Reading through a recent thread on WUR values I decided to check mine (it's low for an '82 SC, around 10 ohms) and in the process the plastic plug on the harness sort of crumbled and the wire spring clip fell off. So while the plug will still plug in it's not the most secure thing in the world. Does anyone know where I can get just a new plug which I can graft on? Dealer?

cheers

[Gretz]

Send Timmy2 a PM. He will get you a new connector quickly for a reasonable price. If you need a new 090 WUR, contact Tony.

I’m working through potential WUR issues myself right now. Make sure you do a fuel pressure test. There is some discussion of proper WUR resistance. My current WUR 090 has about a 10 ohm resistance in 86F ambient (Florida). Some folks say that might not be an issue. Tony said the car will likely not run correctly at initial cold start with my current WUR 090.

A fuel pressure test will tell you a lot. Supposedly. I’ll be doing mine this weekend. When you get the pressure testing kit, make sure it has the correct included adapters. My kit should have had all the right stuff but one of the adapters was incorrect and I’m waiting for Tool Aid to send me the correct one now.

[Gretz]

Just wanted to add that Timmy2 has been great. Purchased a replacement connector from him and it was quick to arrive. When I was installing it, I had a couple questions and he provided great support. I would certainly recommend him.

[Bob Kontak]

Originally Posted by Gretz

There is some discussion of proper WUR resistance.

+1

26-ish ohms when ambient is cold. 10-ish when above a warmer threshold (still cold start mode, tho)

That said, it's 80F in my garage. I am going to check my 090 right now and will revert.

Edit: 9.98 ohms. Also, it's 88F in here.

[Gretz]

I just checked my 090 in my 82 SC. It's 85F here in FL. I also have a newly rebuilt/calibrated 090 unit sitting about 5 feet away from the car. The one in the car reads right about 10 ohms. The rebuilt one reads 27.4 ohms.

Just finished my fuel pressure test, the results of which I'll post in another thread, but I think my current 090 WUR is the (a?) problem in my car.

[pmax]

Originally Posted by Gretz

I just checked my 090 in my 82 SC. It's 85F here in FL. I also have a newly rebuilt/calibrated 090 unit sitting about 5 feet away from the car. The one in the car reads right about 10 ohms. The rebuilt one reads 27.4 ohms.

The 27.4 Ohms at 85F doesn't sound right.

What was rebuilt ?

[Gretz]

I purchased the rebuilt 090 from Tony and it certainly looks like it’s in great shape. Based on Tony’s excellent reputation and the support he’s provided to me, I have every reason to believe it’s a high quality part which has been rebuilt and correctly re-calibrated. My current 090 appears to be the problem causing cold control pressure issues so I may soon swap out my current 090 and install the rebuilt one. If so, I’ll re-run the fuel pressure tests to ensure my problem has been solved.

[gazzerr]

I have one of Tonys rebuilt WURs and it's been working great for me the last 2 years.

[tirwin]

The resistance has been discussed before. There is an old post in the CIS for Dummies thread where I stated something either backwards or it wasn't clear. The problem is it won't allow me to edit the old post.

I can't remember the details of the conversation.

The basic principle is that the heater element attached to the bi-metallic arm causes the arm to deflect. One would think that higher resistance means greater heat. Therefore, higher resistance would cause the arm to move faster.

The WUR and the AAR emulate a choke like a carbureted motor uses on cold start. If the heater element heats up faster than the engine comes up to operating temp, then the mixture will be prematurely lean.

It's never been clear to me if the 10 vs 25 Ohm resistance is a sign of a failure mode or if, perhaps, the resistance changes depending on ambient air temperature.

[Gretz]

I guess this could just turn into a discussion of the proper resistance for a 090 WUR. I’ve read through many threads but never found a definitive answer. I have heard several people with failing 090’s report that their resistance was around 10 ohms, but that’s far from a reliable controlled study with resulting data.

Edit: Tim, you ninja responded while I was typing. The only thing I’ll add is that I checked the resistance on two 090s in my garage at the same time, one in the car and one on the bench. They had both been there overnight and it was then 85F. The rebuilt one was 27.4 ohms and the one in the car was 10 ohms. As you know from my other thread, the 090 in the car has issues. Not sure if that’s related to the resistance.

[tirwin]

Originally Posted by Gretz

Edit: Tim, you ninja responded while I was typing. The only thing I’ll add is that I checked the resistance on two 090s in my garage at the same time, one in the car and one on the bench. They had both been there overnight and it was then 85F. The rebuilt one was 27.4 ohms and the one in the car was 10 ohms. As you know from my other thread, the 090 in the car has issues. Not sure if that’s related to the resistance.

That would seem to rule out the possibility that temperature affects resistance.

I believe my WUR had a resistance of ~10 Ohms and it originally was closing too quickly. It went from CCP to WCP in around 30 seconds. That seems to be backwards of the theory that greater resistance = greater heat = faster ccp->wcp transition. Edit: I'll have to look through my old posts and try to find where I recorded it. If I am mis-remembering it and the Ohm value was more like 25, that would seem to be consistent with the idea that greater resistance = heating too fast.

It would be nice to nail this down once and for all.

FYI... the factory service manual makes no mention of checking the resistance value. It only mentions that if there is no continuity, the WUR should be replaced.

[boyt911sc]

Originally Posted by pmax

The 27.4 Ohms at 85F doesn't sound right.

What was rebuilt ?

Sean,

Do you remember selling a burned out WUR to Mark Epstein a few years ago for $170? Mark sent it to me and I replaced the heater and calibrated it too. You claimed it to be working when removed from the car. Really?

Tony

[pmax]

Originally Posted by boyt911sc

Sean,

Do you remember selling a burned out WUR to Mark Epstein a few years ago for $170? Mark sent it to me and I replaced the heater and calibrated it too.

Based on the info I found here from past threads, I have come to realize that 090 WUR I sold wasn't burnt out. 10 Ohms at that temperature is not symptomatic of a bad WUR.

I have an engineering question if you don't mind answering for the benefit of the forum ... exactly which heating component (given it's a relatively simple device with only a handful of parts if anyone has ever taken them apart) did you replace in that WUR or Gretz's 090 and what is the resistance characteristic of the WUR after ? I have a followup but those will do for now.

You claimed it to be working when removed from the car. Really?

Tony

This has no relevance to the burning technical questions everyone is asking here but ... looking back at my for sale thread, this is what I wrote word for word ... "From a working low mileage CIS system bought here, according to the previous owner." Fair enough ?

[boyt911sc]

Originally Posted by pmax

Based on the info I found here from past threads, I have come to realize that 090 WUR I sold wasn't burnt out. 10 Ohms at that temperature is not symptomatic of a bad WUR.

I have an engineering question if you don't mind answering for the benefit of the forum ... exactly which heating component (given it's a relatively simple device with only a handful of parts if anyone has ever taken them apart) did you replace in that WUR or Gretz's 090 and what is the resistance characteristic of the WUR after ? I have a followup but those will do for now.



This has no relevance to the burning technical questions everyone is asking here but ... looking back at my for sale thread, this is what I wrote word for word ... "From a working low mileage CIS system bought here, according to the previous owner." Fair enough ?

Sean,

This is the heater that came out from WUR you sold to Mark.





If this is fair you tell me. Thanks.

Tony

[timmy2]

090 WUR is 2 stage heating as you can see from Tony’s pic. (3 wires to resistor element)
27 ohms or so is overall, 10 is partial only.

[tirwin]

Originally Posted by timmy2

090 WUR is 2 stage heating as you can see from Tony’s pic. (3 wires to resistor element)
27 ohms or so is overall, 10 is partial only.

So, is the basic idea that you take a single 12v source in and split it to 3 resistive elements? So each is roughly 1/3 or ~9 Ohms each?

[Bob Kontak]

Originally Posted by tirwin

So, is the basic idea that you take a single 12v source in and split it to 3 resistive elements? So each is roughly 1/3 or ~9 Ohms each?

I am guessing two not three given Timmy's 2 stage statement.

The is all new to me. Pretty cool.

[tirwin]

Originally Posted by Bob Kontak

I am guessing two not three given Timmy's 2 stage statement.

The is all new to me. Pretty cool.

Oh, 3rd wire is ground. Got it. I didn’t pay enough attention to the picture. I thought it was 3 power on the element at first.

[Gretz]

This is a ton of knowledge about WURs- I’m learning a lot. Thanks for sharing, folks.

[pmax]

Originally Posted by Gretz

I guess this could just turn into a discussion of the proper resistance for a 090 WUR. I’ve read through many threads but never found a definitive answer. I have heard several people with failing 090’s report that their resistance was around 10 ohms, but that’s far from a reliable controlled study with resulting data.

Edit: Tim, you ninja responded while I was typing. The only thing I’ll add is that I checked the resistance on two 090s in my garage at the same time, one in the car and one on the bench. They had both been there overnight and it was then 85F. The rebuilt one was 27.4 ohms and the one in the car was 10 ohms. As you know from my other thread, the 090 in the car has issues. Not sure if that’s related to the resistance.

If you get a chance, please measure the resistance of the rebuilt unit at warmer than room temperatures e.g. after a drive but before the engine has cooled down completely.