CIS trouble shooting

[Jk369]

To start I suspected the WUR or possibly the AAR.

The other morning it was on the cool side, I started off no problem but within a 1/4 mile it began popping the pop off valve with loss of power. As soon as it warmed up it was fine. The next day it began with the loss of power and pop off valve and never improved.

Here is where I am at with it so far:

Cold Control Pressure about 40 PSI @ 80 Deg F
System Pressure 70 PSI
Warm control Pressure 54 PSI
Rest Pressure 28 to 35 PSI
WUR has resistance across the terminals and voltage

I can not get to the AAR because of the air box - does it come apart?
There does not seem to be any gross vacuum leaks
I have not yet checked the injectors for flow but it dos not sound like it is missing

What next?

[john walker's workshop]

the cold control pressure is pretty high, almost 3 bar. 3.4 to 3.8 is all it should get hot. way too lean w/cold in that case. search adjustable WUR.

[Jk369]

John,

according to one book i have it gives different pressures for different temperatures. It appeared to be in the range. I understand the regulator can be cleaned and adjusted, is this correct?

[ossiblue]

Originally Posted by Jk369

To start I suspected the WUR or possibly the AAR.

The other morning it was on the cool side, I started off no problem but within a 1/4 mile it began popping the pop off valve with loss of power. As soon as it warmed up it was fine. The next day it began with the loss of power and pop off valve and never improved.

Here is where I am at with it so far:

Cold Control Pressure about 40 PSI @ 80 Deg F
System Pressure 70 PSI
Warm control Pressure 54 PSI
Rest Pressure 28 to 35 PSI
WUR has resistance across the terminals and voltage

I can not get to the AAR because of the air box - does it come apart?
There does not seem to be any gross vacuum leaks
I have not yet checked the injectors for flow but it dos not sound like it is missing

What next?

Unless you've done the tests, I would not make the assumption on vacuum leaks quite yet.
Your car has classic symptoms (for a CIS) of lean running. If the WUR checks out, you will need to follow-up on any component, fitting and hose that carries vacuum, many of which are not visible. This is where I suggest you start. Lots of threads on this board about your exact problem, use the search function and spend some time reading.
Try this site: http://members.rennlist.com/jimwms/CIS/CIShome.html for some ideas on where to look.
You appear to be on the right track, it's just a matter of persistence. Keep us up to date, and good luck.

[Bobboloo]

Did this problem start suddenly or has the car gradually been getting worse? If this problem started suddenly like after a fill up then gas contamination might be suspect.

[Jk369]

I think if there is a vac leak it is small, I did not mention, but I sprayed carb cleaner around with no change in idle. The idle is also stable. The problem has come and gone but was not ever as severe as it is now. In fact the feul tank has been near E the past few times this has happend. I dont think that is it but it is easy to eliminate.

[Bobboloo]

Try adding gas and see if the problem goes away.

When was the last time you changed the fuel filter? Now might be a good time.

Sometimes when gas tanks get near empty they tend to suck in debris that sits at the bottom of the tank.

[Paulporsche]

I'm beginning to not trust those charts for control pressures. I recently tried starting my engine w/ the prescribed cold cp for an ambient temp of 21C. From memory, it should have been about 2 to 2.5 bar. The engine wouldn't start unless I had the WUR set to produce 1 to 1.2 bar, which is down @ the bottom of the graph.

[Bobboloo]

Originally Posted by Paulporsche

I'm beginning to not trust those charts for control pressures. I recently tried starting my engine w/ the prescribed cold cp for an ambient temp of 21C. From memory, it should have been about 2 to 2.5 bar. The engine wouldn't start unless I had the WUR set to produce 1 to 1.2 bar, which is down @ the bottom of the graph.

If the WUR is performing to spec for it's chart and the car doesn't doesn't start well when cold then I'd be inclined to suspect some other component not performing correctly. Possibly an air leak or the cold start valve.

[ossiblue]

Originally Posted by Bobboloo

Try adding gas and see if the problem goes away.

When was the last time you changed the fuel filter? Now might be a good time.

Sometimes when gas tanks get near empty they tend to suck in debris that sits at the bottom of the tank.

+1

Now that you mentioned the low fuel situation when the symptoms happened, why not go with the easy (possible) soultion first--fuel starvation. Follow Bobboloo's suggestion and report back. Could be as simple as that.

[Jk369]

Update #1

Filled with gas and some Lucas fuel injector cleaner; I figure this could not hurt. When cold no change, when warm it is better but it is still rather flat and definitely running lean. I checked the chart in my Bentley book and it looks like I am in the range cold and at the top of the range hot. I am not convinced the charts are accurate. I surmise that the more pressure the leaner the mixture. I can not reach the AAR to test it or the electrical connection so I started looking for air leaks, I have the o-rings for the injectors so I wanted to eliminate this and check the flow. I can wiggle the injector and I thought this was clearance and compression of the o-ring. I pulled the first one, the ring was not that hard and a good pattern on the injector, replaced it with a new ring. I pulled the second one and to my surprise it came out with a larger plastic part. This has an o-ring that is hard and I don’t have this o-ring. If I do have an air leak this is definitely suspect.

The question: Is there a tool for pulling out this part or a trick?

Jeff

[Bobboloo]

Originally Posted by Jk369

Update #1

Filled with gas and some Lucas fuel injector cleaner; I figure this could not hurt. When cold no change, when warm it is better but it is still rather flat and definitely running lean. I checked the chart in my Bentley book and it looks like I am in the range cold and at the top of the range hot. I am not convinced the charts are accurate. I surmise that the more pressure the leaner the mixture. I can not reach the AAR to test it or the electrical connection so I started looking for air leaks, I have the o-rings for the injectors so I wanted to eliminate this and check the flow. I can wiggle the injector and I thought this was clearance and compression of the o-ring. I pulled the first one, the ring was not that hard and a good pattern on the injector, replaced it with a new ring. I pulled the second one and to my surprise it came out with a larger plastic part. This has an o-ring that is hard and I don’t have this o-ring. If I do have an air leak this is definitely suspect.

The question: Is there a tool for pulling out this part or a trick?

Jeff

There is a special tool. It's basically a cable that has a T handle on one end and the other end has the same type of 14mm nut on the end as the injection line. I've never used one though. It would be fairly easy to make the tool if you wanted.

I usually just take a 13mm open end wrench and insert it under the 14mm nut on the injector and lever the injector out using a piece of wood as a fulcrum.

You are correct on the pressures. The higher the control pressure the leaner the mixture and vice versa.

If your WUR is in spec according to the graph then I would look elsewhere for the problem. Even if the control pressure is a little out of spec the system will still perform.

The O-rings are a good place to look at. If air is entering at that point then your mixture will be lean.

What's the number on the WUR? I can check it against the factory manual specs.

[Bobboloo]

Here's the factory graph for an 80' WUR Bosch no. 0438 140 072

[Jk369]

Update #2

Got the injectors out; the easy side the insulators came out with injectors, the other side they all stayed in. It turned out be relatively ease to get out, I took a long ¼- bolt turned the head about 0.005” less then the injector. Slid the head down in to catch the inside bottom edge and pried it out the same way as the injector. I got the o-rings from a local shop that can get most parts in about 4 hours if it is not in stock. Yea, I can’t believe either. The injectors all have a good pattern and I put it all back in with a new fuel filter. Started it and it was the same. I then took out the WUR, and the actuator was rusted to the diaphragm cover plate. I disassembled it cleaned it and put I back in. There is an adjustment screw inside, (good place for it) but it needs to be opened to get to it and it looks like it changes the time to open the contact to switch to the other part of the coil. It ran better but not great, I will need to check the pressures and lower it some.

[Jk369]

Update #3

I think I got it! I hooked the pressure gauge up and it looked on the high side and was still popping. I removed the WUR and decided to remove the tube fitting that I did not do before. I saw a picture without one and there is a screen in there. It had some dirt but not sufficient to cause a problem, but now I could start my compressor (wife not sleeping) and blow it out. I also blew thru the passage. I did not remember the pressure it was at so I put it back in and forgot to replace the electrical connector. I started and it ran good at 3.7 bar @ 38 deg C. With the gauge still in place I took it for a spin. I got it up to 200F and checked the pressure, it was 50 bar. I plugged in the connector and it went to 52 bar. I am now going to let it cool down and see what happens.

[Bobboloo]

You're still a bit high for cold pressure. You can adjust the WUR.

Take a punch and and lightly tap the post that the bi-metal strip is fastened to. Knock it downward to lower the control pressure. Do this with the pressure gauges hooked up and the fuel pump running.

[Jk369]

I adjusted the WUR low temp and of course it went too low, about 1 bar. Rather than do the modification I pressed the pin up. It is now about 2.2 bars. It is still a little low but it ran great for about a minute. I then got it fully warm and adjusted the fuel mixture to where it seems the best. Tomorrow I will see if it runs ok cold.

Not to close the thread out but the advice here has been very helpful; thanks to all who have posted.

Jeff