| Author |
Message |
Greg Rodgers (Joechristmas)
Member
Username: Joechristmas
Post Number: 413
Registered: 3-2001
| | Posted on Monday, July 29, 2002 - 5:52 pm: | |
WURs are rebuildable. 2 or 3 companies rebuild them. |
Jeff Edison (Euro308guy)
New member
Username: Euro308guy
Post Number: 9
Registered: 7-2002
| | Posted on Monday, July 29, 2002 - 5:19 pm: | |
Great Post, David.
I've replaced the warm-up regulator on my '85 Euro 308, (BTW, $359 from Roy Rodgers import Auto Parts). Car runs like a champ. I don't believe this particular part is rebuildable.
Jeff |
David Feinberg (Fastradio2)
Junior Member
Username: Fastradio2
Post Number: 110
Registered: 4-2002
| | Posted on Saturday, July 27, 2002 - 11:14 am: | |
The warmup regulator is responsible for controlling the amount of fuel delivered to the engine during it's warm-up period. The pressure acting upon the top of the control plunger varies depending on the engine temperature and provides an effective method of enrichment.
The control pressure is tapped off from the primary pressure circuit in the metering head's lower chamber through a tiny restrictive hole which gives it the ability to differentiate between the two pressures. A flexible pipe then connects the control plunger gallery to the warm-up-regulator and returns back to the metering head to a connection next to the primary pressure regulator's transfer valve. This valve is in the circuit to close the fuel from the control circuit when the engine is off, avoiding the total loss of system pressure while the engine is stationary.
The internals of the warm-up-regulator are quite simple comprising an inlet and outlet port, a stainless steel shim, a bi-metalic heated strip and a spring.
The input to the warm-up-regulator flows into a small chamber in the top of the unit, its return is through a small drilling and back to the metering head. By controlling this return flow it will cause a change in pressure acting on the top of the control plunger. With a cold engine the flow must be fairly free giving it a lower pressure. This will allow a higher lift of the plunger which in turn will enrich the mixture under these conditions. The free flow is obtained by the internal bi-metalic strip exerting a downward pressure on the spring which decreases the pressure acting upon the shim, this lower force allows the fuel to flow almost uninterrupted.
As the bi-metalic strip is heated, by either it's heater element or natural heat soak from the engine, the downward pressure acting on the spring is gradually decreased, increasing the force of the spring, which in turn increases the control pressure.
Typical cold engine control pressure will be as low as 1.0 bar increasing over approx. 10 minutes to around 3.5 bar. Some warm-up-regulators have a vacuum connection that will sense a drop in vacuum and lower the control pressure during these acceleration periods.
The voltage supply to the regulator is from the fuel pump relay, because if the ignition was on without the engine running, all enrichment would be removed as the bi-metalic strip would be heated prematurely and the driver would not benefit from the cold engine enrichment.
The two pipes that connect to the warm-up-regulator have different sized 'banjo unions' to avoid them being connected incorrectly. The control pressures quoted are as an example only and reference should be made to the technical data as these pressures can be specific to the part number located on the unit's housing.
This unit will have a resistance value of approximately 20 to 26 Ohms.
So...by using the incorrect regulator, several things happen:
1)The mixture during the warm up phase may be too lean, or rich.
2)Driveability during warm-up may suffer.
3)Only fully warmed up, the volume of fuel may be lower (hence leaner) than the Euro regulator.
4)One can be deceived in thinking that the mixture is correct, as it will be possible to set the idle C.O. and HC levels to the correct Euro or USA specs.
However...if you have the control pressure graphs for both regulators, you may find that the differences are minor.
Hope this helps,
David |
Christian (Christiank)
Member
Username: Christiank
Post Number: 352
Registered: 1-2001
| | Posted on Saturday, July 27, 2002 - 10:29 am: | |
ctk, please xplain. Maximum performance, the WUR is there to warm up as the name says. More technical details please, its not an exlectronic device. |
ctk (Ctk)
Junior Member
Username: Ctk
Post Number: 58
Registered: 7-2001
| | Posted on Saturday, July 27, 2002 - 8:05 am: | |
The WUR is important. If you have the wrong model fitted the engine will not start well or run at maximum performance. The WUR on a Euro version is different. They usually never ever breakdown. They are adjusted at the factory and fine tuning can be done for the engine it is fitted to. A wrong WUR will also cause poor warm up and max. power runs. |
Christian (Christiank)
Member
Username: Christiank
Post Number: 351
Registered: 1-2001
| | Posted on Saturday, July 27, 2002 - 1:35 am: | |
Can't be that different. What do they do? Pumping in some gas in an old engine. Take one from a Volkswagen or an Audi and the thing is fine. |
Matt Boyd (Mattboyd)
New member
Username: Mattboyd
Post Number: 21
Registered: 1-2002
| | Posted on Friday, July 26, 2002 - 11:48 pm: | |
James,
Can you ask your shop why/how the Euro ones are different, and what implications there are for using a USA one on a Euro car?
I have records on my car that indicate that the original warm up regulator was replaced with a USA one (I have a Euro car).
Thanks,
-Matt |
Greg Rodgers (Joechristmas)
Member
Username: Joechristmas
Post Number: 394
Registered: 3-2001
| | Posted on Saturday, July 20, 2002 - 3:05 pm: | |
You can get them rebuilt to spec for around $100. I haven't had this done before so I cannot comment on the outcome but there is a company that can rebuilt them. |
James H. (Jamesh)
Junior Member
Username: Jamesh
Post Number: 122
Registered: 5-2001
| | Posted on Saturday, July 20, 2002 - 12:53 pm: | |
The shop I have my car in told me the warm up regulator is bad in my 308. He said the Euro model uses a different regulator than the US version and is having trouble locating one locally. He did say he can order one from a place in Europe. He also said they are around 400.00. Does anyone know where I can pick one up or do anyone know if the one used in a US version 308 would work. |