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Below are the "official" parts lists by model and region from the Bosch database. The excerpt you included is taken from ROW 4.5L list. Numbers were different for USA cars, and there does appears to be some duplication between porsche and bosch part numbers (ie. some porsche parts changed bosch #'s over time, and some bosch #'s were used for more than one porsche part #). The part is the "warmlaufregler". I put some other translations on the 4.7L list (the car I have).
ROW 4.5L used .036, replaced by .087 in 7/80 (both porsche p/n .04)
USA 4.5L Kjet used .023 (9/77-2/78), .053 (9/77-8/78), and .063 (9/78-7/79). Looks like .023 was only on very early 5 speeds, but the others had overlapping production. My best guess is that the porsche .02 part is the .023 initially, replaced by the .053 and later then .063, but the automatics (porsche part .03) probably used the .053 the whole time? USA CIS owners can help confirm this.
ROW 4.5L Kjet used .036, replaced by .086 in 7/80 (both porsche p/n .05)
One difference between the. 036 and. 086 seems to be a more elaborate double heating element on the later bimetallic strips which would change the way the mix leans out on a cold start. My 036 moved roughly linearly from cold to warm pressure over about 6-7 minutes when I measured control pressure with fuel pump relay jumpered and engine off. Not sure if the later setup is faster, slower, or nonlinear. The WSM shows the same pressures and temp curves for all S cis cars, so I suspect that may be the only difference between those two parts. Different springs and/or different strips would change the slope of the cold pressure vs ambient temp curve. The springs should also affect warm temp.
as far as I know, yes, only one vacuum port for all CIS 928's, the top port always to "atmospheric" attaching to the throttle body well below the throttle plate.
Revision 12/7/11: See post#23, it looks like there was one version with only a top port
Last edited by Luis_M; 12-08-2011 at 01:19 AM.
Reason: to add revision
interesting, since -00 and -01 are not in the PET catalog.
I did find an old german Bosch company reference document today listing the details of all of the 0.438.140.xxx family of WUR's. The .023 WUR was a different case with only a top connection (Type 4 - mit hoehenkorrektur translates to "with altitude correction") so that was probably the 928-606-109-00 "for high altitude areas". Not sure which would have been the -01. All the others bosch #'s (.036, .053, .063, .086, .087) had the same case (Type 3) with the top and side connections. The .053 is listed as the replacement for the .023. As an aside, it would appear that having the extra port to atmospheric allows automatic altitude correction in the later WUR versions, since the membrane would experience the difference between manifold and atmospheric pressures, as opposed to the earlier WUR design with a single sealed box connected to manifold only. I guess we need more details on the internals of the .023 to know how "altitude correction" was achieved in that design.
Below are the "official" parts lists by model and region from the Bosch database. The excerpt you included is taken from ROW 4.5L list. Numbers were different for USA cars, and there does appears to be some duplication between porsche and bosch part numbers (ie. some porsche parts changed bosch #'s over time, and some bosch #'s were used for more than one porsche part #). The part is the "warmlaufregler". I put some other translations on the 4.7L list (the car I have). The dates quoted seem to be production dates for Bosch. My 1981 4.7, early production, has a .036 WUR, for example, not the .086.
ROW 4.5L used .036, replaced by .087 in 7/80 (both porsche p/n .04)
ROW 4.7L Kjet used .036, replaced by .086 in 7/80 (both porsche p/n .05)
USA 4.5L Kjet used .023 (9/77-2/78), .053 (9/77-7/79), and .063 (9/78-7/79). Looks like .023 was only on very early 5 speeds, but the others had overlapping production. My best guess is that the USA manuals (porsche .02 part) used the .023 initially, replaced by the .053 and probably later by the .063, but the automatics (porsche part .03) used the .053 for sure in the later cars but possibly for the entire auto-trans production. USA CIS owners can help confirm this.
Check the WSM for the pressure curves of the two different WUR, but my brain says that a WUR for the 4.5 with smaller inlet pipes, and less power would need less fuel than the 4.7 S.
I suggest you do the fundamental checks on fuel pressure at the WUR to see if its behaving before worrying about model differences too much. If its running rich when fully hot that would imply that EITHER the mixture adjuster on the air flow body has been adjusted rich, OR the WUR is giving LOW back pressure, which would be pretty unusual IMHO - mostly they fail high due to crud in the unit.
Here's a comparison between WUR rates. Fairly significant between the two engines. My 80 EuroS had a WUR from the PO's Mercedes SEL. Took couple of years to figure out the problem, so it can be a big deal.
Eventually, I drew up the charts below sending the one on the right to a Delorean shop in Texas to re-calibrate my "Mercedes" unit. Everything worked great after the rebuild and calibration.
From those charts (out of WSM?) I would expect a 4.7S fitted with an 063 WUR to run a little lean, but not much. When I last had gauges on my -086 WUR I saw a fully hot through pressure of 45psi (3.06bar), and it ran (and runs) very well, and cold starts fine down to 45F . OP says he has an -036 WUR, but that version is not listed in the WSM - what are the pressures for that model?
My WSM only lists -053, 063, 087 and 086 WUR.
What pressures is the OP seeing?
Changes in control pressure change the position of the arm for a given airflow. That pushes the piston up a different amount. The position of the piston is further affected by the adjusting screw.
What you need to do is tune the A/F with the adjuster screw for the new system.
Luis thanks for the information. Do you know what the other two terms correspond to? (The first four numbers - 0 438 and the second three numbers - 140)
12-03-2011, 01:21 PM
