Please confirm my O2 Relay
 

Hi everyone. I am going through trouble shooting my cold start problem (with much reading from this site), and as part of the process I ordered a O2 relay as a just in case. I ordered this from our host, but what I got is different based on the BOSH part no. and other info. I have attached pictures of both my existing relay and the one I purchased (on the yellow sticky note).
Can any of you good folks confirm which is correct. Based on my readings, the one I have currently seems to the the correct one. It also has an integral "flange" on the body with a clip to secure it next to the Lambda ECU. The one I bought from our host does not have this.

At this time all indication points to having to test the K-Jetronic system pressures methodically and go from there. I was hoping for a quick fix; my current relay looks pristine and shows 87.5 ohms between the 85-86 pins of the relay. I have no problem running warm once I coax the engine to over 950 RPM after cold start; which is terrible. This is the first time she is doing this, and I have had the car for 2 years. 1982 911SC.

Thanks in advance.http://forums.pelicanparts.com/suppo...ys/men_ani.gif

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Hi, I think if you remove the relay when the car is warm and it starts to run like crap then you can confirm the relay is working fine. You can test the old one that way.

I'm going through cold start issues (low idle, grumpy) and it's air leaks around the injector seals and a WUR that's out of spec for cold control pressure because the WUR's heater element resistance is too low.

Basically you have to measure fuel pressures first, fix all the air leaks, check the ignition timing and go from there. Don't touch the mixture until you know everything is in spec and you have no air leaks.

Search on posts from tirwin, boyt911sc, Bob Kontak. Lots and lots to go on there.

Great place to start:

http://forums.pelicanparts.com/porsche-911-technical-forum/758788-cis-troubleshooting-dummies.html

Here's a pic of my relay known to be good, seems to be the same one you bought. Note the diode in the circuit diagram on the side show. I know a lot of the relays supplied seem to be missing this diode and it's referenced in the 911 electrical diagram. The relay I had before is also the one you had and didn't have this diode but it doesn't *seem* to make a difference. I replaced it so it's the same as the factory spec. The Gurus here should be able to explain it's use.

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Hope that helps.

To test the relay:

1) Car in neutral, parking brake set to ON.
2) Right hand grabs relay under passengers seat with the fingers.
3) Left hand starts car.
4) During 3 above fingers in 2 above should feel relay make a single "click" if it is working, and after driving for a bit the relay will become warm to the touch.

With this warmer weather my 82SC was becoming more "cold natured" to start cold with no light accelerator help. So I remember what I did last summer, which was to disconnect the vacuum retard line (blue or black small rubber hose) from the distributor vacuum pod and plug it with a golf tee. Then I put a small rubber cap over the port on the pod from whence the line connected. Cold starts much better now.

The 019 019 relay is the one you want. It does not have the structural part that holds it to the Lambda box. I replaced the original with the 019 019.

Gazerr noted the diode. I never even saw the diagram embossed on the side. Does the original have a diode?

I know that there is a diode in the red fuel pump relay. The expensive one. The diode prevents current from going in the wrong direction. Where it would go is beyond me but it must have some importance. I have seen a later 80's 930 with all red relays vs. just red(s) and black.

If the original is without perhaps this is an upgrade. No functionality improvement, just higher integrity (built in traffic cop) so it works like it should.

Thank you Gazzer, Scadddle and Bob. Yes, Bob and boyt911SC and others seem to be the SME's here (Sorry, my work is creeping in here. That stands for Subject Matter Experts) and have read their posts and advice on more than fuel injection.

Gazzer: I did your test and confirmed yes relay is fine. My car not only idled bad but it didn't start without the relay. My new Relay doesn't have the etched sketch on the side but right on top as seen in the picture, and it has a diode.

Thanks Bob for confirming that either relay will work (019 019). So the one with diode diagram is an "upgrade", but if my old one works I don't have to swap, right?

Now, on to more fun stuff that I was hoping I could avoid, but have to restrain from doing "while you are there" work while I address this cold start problem. Last year my clutch cable replacement ended up being a clutch pedal cluster upgrade, and left me with a sever crick in the neck.

NOTE: My 911SC does not have a CAT. Thought I should put it out there. The PO had put some nice headers and brought the HP to about 200, and removed the Cat-Converter.

Cool - I think your relay is good. I switched it out to satisfy my OCD that's about it.

No cat is fine if you are in a "too old to smog state" like me. The O2 sensor probe is before the cat anyway.

I have a new pedal cluster ready to go in. I just need the courage to try to install it :).

Do a fuel pressure test and test the resistance on your WUR. That's a good start. Pressures will tell you what's going on.

gazzerr confirmed. I just backed him up.

The relays get tired. Contacts inside get a little crusty, a little corroded, etc. and it makes a difference with a new one.

However, I suggest getting your cold start issue nailed THEN drive your car with the old relay for a while. Stop and go around town after full warm up. Stop back at your garage and change to the new relay, get out there again and see if it makes a difference. I am certain you will notice.

This is not your cold start problem.

If you need any tips on the pedal cluster let me know, I can share what I have learnt. I compiled a whole Powerpoint detailing my work, and saved it in case I need to get there again. I basically dismantled everything, sand blasted, painted, etc, etc..I think I do have some OCD tendencies ha ha ha.

Bob, absolutely. I am meeting my friend who tinkers with 914's, and 911's tomorrow bright and early plus he has all the neat gizmos to test stuff with - lucky me. As you suggest I do want to test out the old and new relays once the cold start problem is fixed.

Good deal.

Gizmos are good. :D

Also, if you have an O2 bung in your exhaust and the O2 is in there and connected you are fine.

KKothand thanks! I have a rebuilt cluster ready to go in so it's really just a matter of R&R the old one but I'd love to hear your experience with that. I've heard it's a bit of a rabbit hole but not too nasty. I'm 1/6 of the way through my injector seals and seats now ... I'm slow.

Gazzer,you are smart to do the way you are doing. It took me over a month, rebuilding it on my own, not to mention then PITA steps I had to do. Keep me posted on your fuel injection project.

As of now, my cold system pressure is low at 4.3 bar. Supposed to be 4.5 - 5.2 per Bentley Manual. My friend thought this is not too bad, and may be I should replace the fuel filter first. We checked for leaks around the hoses, and no issues. So I am starting with replacing the fuel filter. Any input or other ideas on next steps is much appreciated.

Tony needs to help here. Shims in fuel distributor allow tweaking of system pressure.

I seldom see filter changes alter pressure.

Bob, I am thinking the same thing since it seems related to the primary pressure regulator in distributor which is adjusted by shims. Means this would be above my capability and may have to take to a mechanic (?). I will also read up on Tony's posts.

I have to replace the fuel filter anyway, which at this time the fitting nuts on the fuel line are refusing to budge. The filter is over 3 yrs old.

Yep you'll need to talk to Tony there. Possible WUR issue too maybe.

I got my pedal cluster from Bruce Stone. Going slowly on the injectors. Working on #2 now.

Those fitting nuts are a b*tch. I've had the best success with a bit of PB Blaster (clean it up because you don't want that in your fuel system), then use 2 wrenches, one to hold the line on the lower fitting and one to turn on the top fitting that comes off then "squeeze" the wrenches toward each other in the right directions. Seems to work for me.

I am trying the two wrench system,yes. I don't think there is another option there. Will try the PB blaster, if it remains stubborn. The nuts to be loosened are the ones on the fuel lines, as the others are "part" of the fuel filter, correct?

Yep - it's the nut around the line itself that you loosen. The nut on the adapter that's screwed into the "device" - in your case the accumulator is the one that you counter hold. Grab a set of flare nut wrenches for the top nut as it wraps right around the nut and gives you more torque on the nut. They don't seem to slip either.

WD40 doesn't seem to work anywhere as good as PB Blaster or Kroil. I don't think WD40 is really that good as a penetrating fluid.

Just drag your feet for a couple of days before taking to a pro. There is a recent post where Tony helped a guy put shims in.

If you did the pedal cluster there is little risk you cannot handle the shims.

Money saved will buy you two sets of pressure gauges.

Thanks Bob, I think you make a solid case on both counts. Will keep you all posted...

Sorry it took so long
 

Hello all. Work has kept me busy but finally managed to do the pressure tests recommended. Here is what I am getting. Looks like fuel system side of things are good. Tests ran without engine running; jumpered 87A & 30 in relay in fuse box.

System pressure = 5.1 bar @ 73 F
Cold control pressure = 2.1 bar @ 73 F (WUR connection unplugged)
Warm control pressure (PEAK) = 3.7 bar; reached in a little over 2 mins, and stayed there past 4 mins. Ended test after 5 mins.

Residual pressures after shutting off ignition switch. Temp 73 F; all values in bar.
After 5 min 2.3 bar
10 min 2.0
20 min 1.75
30 min 1.65
60 min 1.60

Is my Control pr regulator aka WUR is the suspect now? I should note that I got no resistance value at the WUR electrical connection. Please let me know what next.
Thanks,

I don't see how you could get the results you got with zero resistance across the WUR terminals. It seems to be behaving properly.

Your cold control pressure is just on the low end of normal. Everything else looks fine per the Bentley.

At this point I would move on to other possible problem sources.

Good reference for narrowing down potential problem areas:

911 CIS Primer - Troubleshooting

Look at the far left column in the table.

The one thing I'd add to this list is to make sure poor spark isn't an issue. Old plugs, plug wires, cap, rotor, etc can be a contributing factor. You said you've owned the car for two years. Do you have service records that indicate when those things were addressed last? If not, you might want to consider putting those things on the maintenance "catch up" list.

Tim, yes I do have the PO records and will go through that. But for the cold start idle, she runs beautifully. That is what is so annoying. Guess I have to go through the rest of the possible causes. Hope I nail this down before Oct-Nov, otherwise it has to wait till next spring..

Trying to check the AAR valve (closed or open), and looks like I have to remove the whole top end of the Air box. Is there a better way to take a look at this? Is the rubber hose towards the engine on the AAR is flexible enough that I can push it out of the way to use a mirror, after loosening the c-clamp?

Hi KKothand,

You can get it out but like everything else it's a bit of a PITA.

Remove the electrical plug - if it has a metal spring clip you have to remove that first - massive PITA, (lots of swearing - I used a small pick - careful it will spring off into the depths of the engine compartment) then the plug comes off. Then there's 2 capped 5mm(?) allen screws - one under the electrical plug and one opposite on the other side. The AAR is actually attached to the number 5 runner.

Then remove the right side hose - unscrew the clip and lever the hose off with a screw driver (be gentle). It's difficult because the air line is metal and doesn't want to move. Then loosen the hose clip on the left side under the air box and wiggle the whole unit out. This hose is flexible. It actually runs up behind the airbox to the air intake on the rear right of the CIS hat.

I'd also unbolt and move the ac compressor to the right rear fender with a thick towel to one side. I beat the crap out of my forearms with it in.

I've been traveling for work so I've paused on my injectors. I've got 5/6 done. Working on the really hard one on #6. Easy out method didn't work for me (wouldn't budge at all with the easy out in and I'm just destroying the seat) so I'm going to try an improvised neoprene expansion nut puller and see if I can pull it that way ...

Hope that helps.

Thank you Gazzerr, this kind of info is exactly what I was looking for before I start tearing into things.
I was going to start with the CSV, but reading other experts here decided to go after the AAR first.

Don't know if I will get to find out the root cause of my cold start problem before Nov, but have to keep working one at a time...process of elimination and all.

No worries - you can test the resistance across the electrical prongs and it's supposed to be 33 ohms.

If you stick the unit in the oven and heat it to engine temps then the valve should close in about 5 minutes.

My problem was the WUR being out of spec when it's cold. And assorted air leaks that I'm trying to address now.