[Autocross7]

So, my 88' Esprit has been running rather crappy. Getting worse gradually got me into the garage and in the trouble shooting mind set. As I have a number of spares, I used this as a "test" to confirm spares were good... but that is the longer version.

The short version is that the frequency valve was not operating correctly. So, popped in the spare. No change...

Changed out the lambda sensor. No change...

Blue based RPM relay swapped. No change. Hmmm...

Swapped out the ECU (known working spare). No change.

And so it was that I unplugged the WUR (the electrical connector). Problem instantly corrected!

Odd I thought... 2 yellow wires. One black wire... I assume this is the ground even though the wire diagrams all show the ground to be within the WUR. At any rate, yellow wires - one brings in electrical current and the other takes that current off to the Auxiliary Air Valve. As this 'connection' to the AUX Air Valve does not run through the bi-metallic strip, but rather connects at the blade terminal... the AUX Air Valve would be unaffected.

Now, unplugged I can only assume that the bi-metallic strip will not "warm up fast" and that is about it. The natural heat sink should eventually allow the WUR to correctly function...

But the thought I have is that the ground has indeed somehow failed in the WUR and that this created some sort of feed back into the frequency valve and thus cause the frequency valve to operate incorrectly (intermittent, weak, and not at all). Anyway... if the WUR is plugged in the frequency valve fails. Unplug the WUR and the car runs like a top once warm. WTH??? The wire diagram in no way seems to account for this.


Anyone have a different thought?


Thanks,
Cameron

 

[Autocross7]

http://www.ferrari400parts.com/Warmupregulatorrepair.php

Thought I add this just for kicks...

 

[MRDANGERUS]

If your bimetallic strip heater element is fried or not getting any juice, the WUR does not raise Warm Control Pressure and your engine is running pig-rich, even after the warm up.

If you use a white thermo-conductive paste between the base of the WUR and the intake manifold, it will eventually get warm enough to adjust the WCP to prescribed 3.5-4.0 bar, but it will take long time.

Check continuity across the WUR plug with an analog VOM (look for 15-30 Ohm). If =infinity-> replace strip heater or get a new WUR. They are the same as on VW.

 

[Autocross7]

Okay, I'll def check out the resistance.

I'm still stumped on how the WUR being plugged in would kill the frequency valve (and then the frequency valve seems to correctly operate when the WUR is unplugged)...

Seems to be electrical and not fuel pressure related... ?

 

[Autocross7]

Everything appears super clean on the WUR... but with an analog multi meter set at 10K I'm showing 10 ohms. On the digital multi meter set at 200... I'm reading 10 ohms.

So... 10 ohms it is.

Mr Dangerus... do you know what VW make and model this WUR matches? Or the last 3 numbers frm Bosch? Mine looks a bit like my bro in law's 911 WUR on the inside... "096". There are a couple of threads I have reviewed, and it seems a number of different WURs are in use. However, not a lot about any real difference in cold driving... which really does not last long in Alabama! LOL


Cameron

 

[Beerman]

If you need a new WUR then I would seek out the original WUR (not the VW one). As I recall the original WUR is a -096. The VW rough equivalent is a -026 if I'm remembering right.

The VW WUR works well when the car is warmed up, but the cold operating pressure isn't right and the car runs poorly. The original -096 is much better in this regard.

These guys do a good job of rebuilding WUR's: http://www.specialtauto.com/warm-up-regulators.html

 

[Autocross7]

If you need a new WUR then I would seek out the original WUR (not the VW one). As I recall the original WUR is a -096. The VW rough equivalent is a -026 if I'm remembering right.

The VW WUR works well when the car is warmed up, but the cold operating pressure isn't right and the car runs poorly. The original -096 is much better in this regard.

These guys do a good job of rebuilding WUR's: Warm up regulator-Special T Auto has the correct warm up regulator and warm up regulators for all cars - The De Lorean Parts Specialists

Thanks for the reply... I am sourcing a new from Special T Auto. They seem to def know their stuff. The Bosch unit for the Esprit is a 096... and the turbo cars are actually 096T apparently. At any rate, they seemed pretty nice and prices were very good IMO. I was just curious as to the different units that seem to have been used and what the differences were found to be...


Cameron

 

[sleekgt]

[snip]The Bosch unit for the Esprit is a 096... and the turbo cars are actually 096T apparently. [snip]

I don't believe my 88 Turbo has '096T'; only 096 - here's the info I recorded a few years ago.

Lotus Esprit 2.2 Turbo
Warm up regulator
Control pressure regulator

0 438 140 096
2/1980 to 7/92

 

[holmz]

One can also measure current with a modern VOM.

 

[Autocross7]

I don't believe my 88 Turbo has '096T'; only 096 - here's the info I recorded a few years ago.

Lotus Esprit 2.2 Turbo
Warm up regulator
Control pressure regulator

0 438 140 096
2/1980 to 7/92

Mine did not have a T either... and it is factory original. Special T Auto list a "T" and "no a T". It is my understanding (correct or not??) that they may have done a bit of tweeking. Either works...

Cameron