I finally got Watson's book; an excellent explanation for the novice. I still have some things that I'm not clear on and am hoping those with more experience will chime in to help with my first time doing this on my 79.

1. Watson talks about a cold start injector (aka "fifth injector"). Does the 928 have this and, if so, where is it?

2. Watson's procedure begins with three steps that I don't see talked about by others:

(a) adjust minimum air--needs a tachometer; is he referring to the tach in the dash or something else?
(b) adjust curb idle speed
(c) adjust co--needs a CO exhaust gas analyzer--don't have one of these.

So, my question is, given that people don't mention this and I don't have an exhaust gas analyzer, how important are these steps? I'm trying to hunt the cause of cold and hot start issues, otherwise the car runs great. In my case, am I okay to skip this step?

3. Where exactly is the auxiliary air valve? I haven't taken the air cover off yet to look at the FD, but is it the only thing on the FD that has an electrical plug on it? Need to know where it is because the electrical to it and the WUR need to be unplugged for some tests.

4. For the jumper wire for the fuel pump relay, Watson says it should be an 8 amp fused jumper. All of the pics I've seen of peoples' jumpers are just a wire without a fuse. Should the wire ideally have an 8 amp fuse in it? Does the wire need to be a particular gauge?

5. (probably the silliest question, but I'm a newbie) When you get to the part of the testing where you turn on the motor, do you put the air box and filter back on (my guess is YES, but just want to confirm).

6. I bought my gauge set from Roger. It has a button under the gauge. Is that button a "release valve" for bleeding air?

TIA
Doug

 

I know that I'm not the most qualified person to say, but here we go anyway.

1. Cold start injector is on the front of the upper intake plenum, should have a harness that looks just like a regular elec injector, there will be an injector base, usually reddish in color.

2. I have not gotten that far on my car yet so I can't say what is needed and I am not required by my state to do smog.

3. Aux air valve is located near the cold start injector towards the front left side as you are looking at the front of the engine if I am remembering right, there will also be an arrow of flow on the valve. It will be going to the cold start injector base.

4. I have seen the same "regular wire" jumper, but I have a harness that I made up with a switch and a fuse for my diag.

5. I have heard that in some instances when you don't put the airbox and filter back on it will suck more air in [ no restriction from the filter and airbox]. I put mine back on anyway...keep it clean and no debris in the engine that way.

6. The button is a manual relief incase you have quick disconnects or the like, I suppose it could be used as an air bleed too, haven't needed to bleed air on mine.

hope it helps...sure the OBWan will chime in sometime [jadz]

best of luck,
Josh

 

Thank you! Can you describe/post pic of the harness you made with a switch for testing. That sounds like a good idea.

 

I just used a 3 position switch. one way is on, the other is momentary, center position is off. Just ran enough wire to go through the window to the front of the car. wired in an inline fuse on the 12v power side to the pump. I just followed the "instructions" to jumper the FP and found which side was 12v and which was the switched power. I am not at home, but if you want to pm me your e-mail, I'll dig it out and send you a pic.

 

PM sent

 

I bought an air/fuel meter from Summit Racing. Welded the O2 sensor up stream of the cat. Installed the gauge to the right of the clock.

 

Interesting. I'm not looking to add an O2 sensor. Is that why one needs to check (c)? I assumed it was to get the mixture to a baseline.

 

I adjust my idle mixture by ear. Not very satisfactory, to be honest, but you can kinda do it. Need to get around to buying an exhaust analyzer at some point.

 

If you plan on having a CIS car and 'tuning' it you should pick up one of these. I can't begin to tell you how much easier it is to do with this. Called "Colortune" but can't give you any clues on where to find one.

 

Hey Doug I hve 6 CIS cars here when your ready to start working on yours pm me and I can give you my number and can explain most everything to you

 

Does the colortune work all the way into the deep 928 plug wells?

 

With the A/F meter, I get feedback on mixture whenever the engine is running under any condition. Good value.

The CO gas analyzer was probably made redundant by the O2 sensor.

 

@Karl--probably what I'll have to do. Thing is, the idle is good, but the exhaust is a little on the gas fumey side, so I'm guessing it's probably a little rich. But, as indicated in my first post, I'm hoping I can skip this step, at least for now (of course, I'll visually inspect the air inlet thingie as per Watson).

@ sean--interesting, I'll keep my eye out for one of those. Did some reading on it... tune to blue spark at idle and good to go, sounds simple.

@tailpipe--Excellent! I will definitely PM you.

 

Ahh, I get it. Cool solution!

 

Absolutely, used it on many CIS cars, a majority of them were 928's.