82 SC RoW - Possible bad WUR

[yahh]

Originally Posted by boyt911sc

Yahh,

The reason I asked about the markings on your WUR was to determine if you have "Germany @ 30 Ohms" or "France @ 36 Ohms". These are the average resistance values I find between these WUR's (G or F).

Next, is to gather the data for same test but with engine running. This initial data shows your WUR is working but out of calibration. Your next data would be totally different so do not be alarmed. Just collect and record data without prejudice. Thanks.

Tony

Here is the test from today 15*c, almost exactly 24 hours since the last test.

BAR Seconds
- 0
.75 30
1.4 60
1.7 90
1.9 120
2.1 150
2.3 180
2.5 210
2.6 240
2.75 270
2.95 300
3 330
3.1 360
3.2 390
3.25 420
3.3 450
3.4 480
3.4 510
3.4 540
3.4 570

A small blip of the throttle and the car idled pretty consistent at 1k. Large throttle blip ~5k RPM, it was idling from 600 to 1000rpm and felt like it wanted to stall.

[yahh]

Originally Posted by SkiVT

Just to confirm: are you applying vacuum to the wur for your pressure readings? The chart posted shows results with vacuum, I believe. Tony will help you solve it but the little details like this can make all the difference in troubleshooting.

That was without vacuum as the car wasn't running. Most recent one is with the car running.

[boyt911sc]

Originally Posted by SkiVT

Just to confirm: are you applying vacuum to the wur for your pressure readings? The chart posted shows results with vacuum, I believe. Tony will help you solve it but the little details like this can make all the difference in troubleshooting.

SkiVT,

I simplified the test procedure because I have the profiles for the WUR's without vacuum applied. A quick glance at his data tells me that the WUR is working but out of spec. I will get into the details after tabulating the fuel pressure data in psi.

Tony

[SkiVT]

Got it. I recall seeing the no vacuum pressures being .6 to .8 lower for the 089 wur which roughly agrees with the path Tony is on for you (wur working but out of spec).

[yahh]

I really appreciate the help everyone has given so far. You guys have been awesome!


Picture of the car!

[boyt911sc]

Originally Posted by yahh

I'm having an issue with my 911sc. Ever since I've owned it (last few months) I've had surging idle on startup that evened out when the vehicle got warm. It shut off on me once during startup a few months ago. A few days ago, I went to start it and it wouldn't hold idle. When I hold the throttle it will stay running. We ran a few tests and here is what we have so far:

Smoke Test through airbox = Passed
CIS Fuel pressure = 5.3 Bar
WUR cold pressure = 1.3 bar 22c
Resistance on the heating element = 37 ohms

We are suspecting a bad WUR, does that sound correct?

Thanks!

Yahh,

Went over the fuel pressure data you collected and are these are my observation:
a). CCP (cold control pressure) is too low.
b). Is the CIS fuel pressure @ 5.3 bar the system pressure? If yes, this is out of spec. It should be between 4.5~5.2 bar.
c). WCP @ 3.4 bar is at the low end. Range is 3.4-~3.8 bar.

Recommendation:
a). The measured CCP is too low. Set it higher 1.8~ 2.0 bar @ 22°F.
b). Set system pressure within spec. (4.5~5.2 bar) or @ 4.9 bar.
c). Adjust the WCP between (3.4~3.8 bar) or @ 3.6 bar with vacuum applied.

The WUR is working just needs some minor calibration. System pressure is set at the fuel distributor. Keep us posted.

Tony

[yahh]

Originally Posted by boyt911sc

Yahh,

Went over the fuel pressure data you collected and are these are my observation:
a). CCP (cold control pressure) is too low.
b). Is the CIS fuel pressure @ 5.3 bar the system pressure? If yes, this is out of spec. It should be between 4.5~5.2 bar.
c). WCP @ 3.4 bar is at the low end. Range is 3.4-~3.8 bar.

Recommendation:
a). The measured CCP is too low. Set it higher 1.8~ 2.0 bar @ 22°F.
b). Set system pressure within spec. (4.5~5.2 bar) or @ 4.9 bar.
c). Adjust the WCP between (3.4~3.8 bar) or @ 3.6 bar with vacuum applied.

The WUR is working just needs some minor calibration. System pressure is set at the fuel distributor. Keep us posted.

Tony

Tony,

We removed a shim from the fuel distributor and now the pressure is perfect at 4.8, however, our CCP fell to .6 with the WUR unplugged. We adjusted the pressure to about 1.8-1.9 and shes running like a champ! Back to DD duty for her! Thanks guys.

[yahh]

Curse this car and its problems! I'm having an issue when I'm sitting at the light the cars rpm starts to rise slowly. Goes from the set idle and climbs. If I force it down by letting off the clutch and holding the brake it will go right back down. Any ideas?

[SkiVT]

AAR? My idle behaves a little like that until AAR fully warms to close off the extra air.

[Vereeken]

I am assuming your 089 WUR is still connected as it should and you have a thermal valve and euro type decel valve still connected to the vac system.

The AAR being still open is a possibility. Easy to test. Mind you they all allow a little air through even when fully closed.

But my guess is your decel valve is ruptured or the vac line for the brake booster has a hole in it.

I am going with the last option first. Usually it leaks at a connector at the underside of the car.

[DanielDudley]

Originally Posted by Reiver

CIS Flowtech...give Larry a call. The only Bosch authorized WUR/Fuel head rebuilder in the US and gets the fine little parts no one sells.
If you buy a rebuilt one 99% chance he did it.

He rebuilt my 89 Euro WUR and now the CIS works as it should (euro AFR controlled by the wur).

No affiliation with Larry but he does great work.....the indy shop I go to in Phx send all of their Bosch stuff to him....never had a return.

If you sent it to him, he will test and calibrate it on the bench.