1981 3.0 sc ROW CIS Low idle & dies off throttle

[pmax]

Just one observation about yout test setup, not sure if anyone has mentioned this, you shouldn't plug that ...
... since the seat cover should be a tight seal unless it's at fault.

[brentrussell]

Hmmm, now you got me questioning myself
I might head over to car and swap it around to go direct into FD so we can eliminate that possibility.... will report back in a few hours.

Originally Posted by Vereeken

I think you set-up is OK but I do not see the connection in the back. The simplest way is to take off from the line at the fuel distributor to the wur.
The way you have it now I believe you could have hooked up to the return line and that would give you a false reading.

[Vereeken]

Originally Posted by pmax

Just one observation about yout test setup, not sure if anyone has mentioned this, you shouldn't plug that ...
... since the seat cover should be a tight seal unless it's at fault.

He did that for the smoke test. It seals well when pulled by vac less when you push air in through other holes. But clearly it should not leak ....

[brentrussell]

Hey Michel,

At car now, plumbed direct into Fuel Distributor and have same result. The line I had used was the correct one.
Still no increase in WCP… will remove WUR and open up.
Will report again.

Brent

Originally Posted by Vereeken

So you have good CCP, 12 Volt, good resistance and it holds vacuum. I say your WUR is almost perfect.

But you have no WCP.

1. you have the fuel line to test wired incorrectly.
2. the pin inside the WUR fell out. Not a big deal but it means opening up the WUR.

If you hook up the test kit as I described we will no soon enough.

Do that first.

[pmax]

Originally Posted by Vereeken

He did that for the smoke test. It seals well when pulled by vac less when you push air in through other holes. But clearly it should not leak ....

... and should be tested so as part of the methodical troubleshooting process.

[brentrussell]

Opened up WUR, not sure what I’m looking at… but pin is still located on top of springs.
I applied 12v to plug for 6mins and the bimetallic strip definitely warms up.

Now what? 😉

[Vereeken]

Picture?
If the pin is still holding up when you split the halves something is wrong.

[brentrussell]

Hi Michel,

Picture below.
Hmmm, yeah... I'm out of ideas.
I had thought to connect it back to car with actual WUR plug connected, bypass the WUR fuel lines and straight from FD to fuel return and then run fuel pump which should heat WUR... remote possibility its the plug connection?

Brent

Originally Posted by Vereeken

Picture?
If the pin is still holding up when you split the halves something is wrong.

[brentrussell]

[Vereeken]

I think your WUR is fine. If the bimetal gets hot when connected to the plug all is well.
So why does your WCP not rise?

Is it the picture or does your wur inlet screen full of junk?

If the plug to bimetal connection would be broken you would not be reading 32 Ohms at teh plug.

[Vereeken]

If you disconnect the bimetal from the wur and take it out, next close the wur and connect you have immediate Warm CP. Your pressure reading should be 2.8/3.2 no vac.

[brentrussell]

Morning Michel,

I thought the same with the WUR inlet screen.. not sure how clear it should look... but wouldn't that issue promote a high control pressure?

Originally Posted by Vereeken

I think your WUR is fine. If the bimetal gets hot when connected to the plug all is well.
So why does your WCP not rise?

Is it the picture or does your wur inlet screen full of junk?

If the plug to bimetal connection would be broken you would not be reading 32 Ohms at teh plug.

[brentrussell]

Ok, will go there after work tonight and do this then report.

Fingers crossed I can collect another WUR from my friends Porsche shop today so I can run pressures with that.

Originally Posted by Vereeken

If you disconnect the bimetal from the wur and take it out, next close the wur and connect you have immediate Warm CP. Your pressure reading should be 2.8/3.2 no vac.

[boyt911sc]

Brent,

I helped and guided a fellow PP member from UK rebuilt his motor using Face Time. If you have an IPhone, PM me your country code and your phone #. I will walk you through the procedures. Don’t forget we have 16 hours time differential.

For the meantime, measure the resistance (Ohms) of the heater. Hope it is not burned or defective. The good news is that there is a local supplier of CIS parts in NZ. That is where I get some of my parts.

Tony

[brentrussell]

Yeh! So cool… sent pm..

Ohms of the heater inside WUR is 31
Temp is 10deg Celsius here.

Brent

Originally Posted by boyt911sc

Brent,

I helped and guided a fellow PP member from UK rebuilt his motor using Face Time. If you have an IPhone, PM me your country code and your phone #. I will walk you through the procedures. Don’t forget we have 16 hours time differential.

For the meantime, measure the resistance (Ohms) of the heater. Hope it is not burned or defective. The good news is that there is a local supplier of CIS parts in NZ. That is where I get some of my parts.

Tony

[Vereeken]

Originally Posted by brentrussell

Morning Michel,

I thought the same with the WUR inlet screen.. not sure how clear it should look... but wouldn't that issue promote a high control pressure?

The screen should look super clean. Zero debris. This screen is after the fuel filter and after a screen in the FD. It can clog up with tarnish but also rust coming from fuel tank.

You should be able to blow though the inlet outlet of the wur with a can of brake cleaner.

You are right that this should normally increase fp . it is the part I do not get myself.

But if I read your original problem it feels as if you get fuel starvation the longer your run and that makes sense with a clogged inlet screen.

But if you re-install the WUR minus the bimetal (but with the pin and hat and springs) you have a WUR with only WCP. This can be difficult to start and keep running the first 2 minutes but it will tell you a lot. It will probably also tell TOny a lot.

For me the WUR (aside from the inlet screen) looks perfect. Good OHM, bimetall not skewed to left or right, 12 V, good CCP.......

Let us know what Tony thinks.

M.

[brentrussell]

Well this gets worse and more puzzling now.

Tried 072 WUR and it made no difference… still no increase in WCP.
I ran it for 6mins, was just about to shut it off and could hear fuel pump struggling, pressure started dropping until I’m the pump almost stopped.

So I removed the 072.

Got my 089, removed the bi-metal plate and plug from the WUR. Tried spraying Brake cleaner in either hole and nothing coming out but I didn’t have the stalk to give it a good shot.
I tried blowing air from my mouth and that wouldn’t pass through either (maybe not enough air pressure)?
Hooked it up to car ran for SP started at 70psi /4.7 bar and very soon dropped down to 40-45psi /3 bar.

Now I’m wondering if there is something blocking the fuel flow in the WUR if that’s even possible.?

I’ve just bypassed the WUR with the gauges and now only getting 40-45psi fuel pressure.. so don’t think the WUR is the fuel block issue?

Back to you team

Originally Posted by Vereeken

The screen should look super clean. Zero debris. This screen is after the fuel filter and after a screen in the FD. It can clog up with tarnish but also rust coming from fuel tank.

You should be able to blow though the inlet outlet of the wur with a can of brake cleaner.

You are right that this should normally increase fp . it is the part I do not get myself.

But if I read your original problem it feels as if you get fuel starvation the longer your run and that makes sense with a clogged inlet screen.

But if you re-install the WUR minus the bimetal (but with the pin and hat and springs) you have a WUR with only WCP. This can be difficult to start and keep running the first 2 minutes but it will tell you a lot. It will probably also tell TOny a lot.

For me the WUR (aside from the inlet screen) looks perfect. Good OHM, bimetall not skewed to left or right, 12 V, good CCP.......

Let us know what Tony thinks.

M.

[Vereeken]

Also time to test fuel delivery from pump.

[brentrussell]

Yeah I tried to do that tonight also but couldn't find a fitting to connect on the return fuel line at back left of engine..
Will try to source something tomorrow if I can.

Any other suggestions of where to take it from?

Originally Posted by Vereeken

Also time to test fuel delivery from pump.

[Vereeken]

top of fuel filter or accumulator.
Can you measure amps at the fuel pump when running? If this is +9A FP is toast. In that case no need to bother measuring fuel delivery.