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Discussion Starter · #1 ·
Okay, on an 88' Federal car...Bosh K-Jetronic...

Anyone have any damn idea at all as to how plugging in a WUR can cause the Frequency valve to fail to operate correctly???

Below is a list of what is new. Not particularly because of this issue... but new. Some of the parts I had on the shelf and did put in to see if there was going to be a difference in operation... the WUR is new from the Special T Auto.


WUR
Frequency Valve
Lambda (O2) Sensor
Fuel Filter (no abnormal sounds in the pumps)
Alternator
RPM Relay (blue base)
Engine Control Module
RPM Relay (black base)

The frequency valve is very intermittent... and sometimes not operational at all... then unplugging the WUR it kicks right in and the car revs appropriately. It does not seem to be all that rich without the WUR plugged in either...

The wire diagram shows a very simple connection point with power coming to the WUR from the frequency valve to ground with a split to the AUX Air Valve to ground.

There is nothing else running to this damn thing! 2 wires in a series...

Cameron
 

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Integrator
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Cameron,

Check the resistance between the blades of the WUR connector, should be 15-30 ohm. Then, between each blade and WUR body, should be O.L.

If there is a short to the ground in WUR circuit (the same effect if heater element impedance is too low)-it will affect FV, see below.

Also, check the hi-temp (coolant) switch, N.C., should open at 70C.
 

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Integrator
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Also,as a precaution,
check this:

-open the ECU and verify that R331 is still alive. This resistor is underrated (0.25 W) and often turns to charcoal.

Replace with 1/2 W rated part (verify the bar code, I think it is a 28 ohm resistor, but it could be 280 ohm - don't remember for sure)
 

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Wow! Awesome pic and as usual extremely helpful advice. Mrdangerus' "Extreme" Esprit spirit is again reflected in his on-target information and really detailed posts meant to keep our K-jetronic cars running as well as they can.

Cheers,

Scott
 

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Super Moderator
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Wow! Awesome pic and as usual extremely helpful advice. Mrdangerus' "Extreme" Esprit spirit is again reflected in his on-target information and really detailed posts meant to keep our K-jetronic cars running as well as they can.

Cheers,

Scott
I knew MRDANGERUS/John was meticulous and knowledgeable about reading the Esprit Bosch CIS diagrams down to the component level and interaction.

But down to the PCB board and individual resistors?

That's amazing and hard core beyond belief - great benefit to the Bosch CIS folks out there - Many thanks to John! :clap:
 

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Wingless Wonder
1988 Esprit Turbo
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6,327 Posts
I feel for you, Cameron. :(


As Mr D said, you might have a short in the wires going to the WUR. Or even an open circuit...with any voltage you measure "backfeeding" through other circuits.

I'd look carefully at the round connector (that supplies the intake) located just forward of the rear engine bay wall...I had some problems with the connections there, after my engine rebuild. Clean with DeOxit or another contact cleaner, and verify that the plug is fully seated with none of the connectors backing out.

But first, verify that, with that connector and the one at the WUR unplugged, you have infinite resistance to ground.



+++++++++++++

You aren't the only person PI**ED at their car, I spent all day Sunday trying to align my hatchback. For several hours, it was hung up on the latch BRACKETS. (Not the latch itself) :facepalm

Finally had to tear my interior apart so I could move the hinge mount bolts to get it unstuck. :mad: :mad: :mad: :mad: :mad: :mad: :mad: :mad: :mad:

:panic:
 

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Cal H
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982 Posts
Mr D is pretty good at the CIS. He is someone I would pose a question if the opportunity came up. I think I 1st ran into him in the mid 2000's on PH or maybe earlier. He has been around a while
 

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Integrator
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Thank you for your kind words.

I'm not an Oracle, just your humble disambiguator.

Constantly learning new tricks...
 

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Discussion Starter · #11 ·
Update... the car now seems to be running as it should. Why... dunno.

What I did: treat like a PC. I unplugged everything new and plugged it all back in. ECON light seems a bit twitchy... but the bulb is good so it goes to a bit of a squirrel in the TPS or by pass relay. Not any real issue. The Fuel by pass valve operates as it should consistently.

Now... off to vacuum out the AC and re-charge it. The heater core is on the to do list... but so is the radiator. So.. it will wait until it is does not feel like 120F with 100% humidity and damn summertime has gone to the other side of the planet where it can stay! LOL

Thanks for all the input. Mr. Dangerous... I do believe my RPM relay, blue base, is no longer good. If you would like to take a crack at finding the bad component and correcting it I will happily send it to you. Over my head and patients. Just let me know if you want it.


Cameron
 
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