Brevity, per your first post, is the absolute last thing you want with this kind of problem. I would not do anything else until you check your CIS fuel pressures (system pressure, then cold control and warm control pressures).

Then, it does sound like a lean condition. Is your airbox sound? Do you have a pop-off valve? Is that epoxied in well, and is it sealing well?

Brett

 

I realize that, sorry. Family issues and other personal things come before cars, so I admittedly am trying to piece things together and this process is much too long as I tend to it piecemeal between other obligations. It's not fair to you folks, but just trying to get it running right since I love driving it.

 

Frankly, I've been afraid to drive it like this!

 

Thanks Brett, the fuel pressures are up next. Bought the car without a pop off valve, and it's been just a fantastic car so I never got to it. The order was placed last Friday and should be here tomorrow.

 

You might hold off on the pop-off valve. There are those experts that say they're not necessary and argue against them (Peter Zimmerman, for example). The argument going something like... A well-maintained and properly tuned CIS engine simply doesn't need a pop-off valve since the intake backfire should be a non-occurrence if maintained properly. And, the installation of the pop-off valve has its own issues: foreign material possibly being introduced into the intake and eventually the cylinders (i.e. shavings from drilling the hole), then the possibility of a vacuum leak due to a poorly executed epoxy job, and also a vacuum leak from a poorly sealing rubber seat on the valve itself. On the other hand, it would appear that there have been thousands of successful pop-off valve installations. So, your call whether to actually install it or not. My 1978 911SC had one when I bought it. I did a valve adjustment and had the timing and mixture adjustment done afterward, and I was under the impression that it was well-maintained and well-tuned after that. It ran beautifully; started immediately everytime. But, one morning, Boom, intake backfire. The pop-off valve had become fully dislodged during the explosion. It's possible that it saved my airbox. I had to epoxy it back in place, but afterward all was well... until I found the broken head stud, but that's another story.

Anyway, I'd get it running and tuned well, then revisit the pop-off valve. No need to introduce another factor at this point.

Brett

 

I think fuel pressure is up next. I dont kniw squat about cis systems, but a clogged fuel filter or check valve would not surprise me. Try tapping on the fuel pump with a plastic mallet. There is also a cold start enrichment valve that opens while cold. It raises the idle until the motor is warm.

 

my car doesnt have a pop off valve and runs flawlessly .. putting one in will NOT fix your problem .. however you could have a blown airbox or some other massive unregulated air leak ..

 

just wondering how old the fuel is in the tank?

 

I think I mentioned it's old, but there was very little, I've filled it, stabilized it, injector cleaned it so I'd be suprised if that's it. After it's warmed up a good long time it runs pretty normal.

 

Haven't done the fuel pressure test yet, need to get a jumper and will hit that tomorrow. But I need some help with an electrical issue that MAY be related. Reading the Bentley manual, it sure sounds like it MIGHT be a control pressure regulator issue. ? Per the manual I checked the connection, but am NOT sure I'm doing it right. The manual reads as follows:

If the control pressure does not increase as the engine is warmed up, the heating element within the regulator may not be functioning. Check that the heating element in the regulator is receiving voltage. If battery voltage is not present at the connector, check for ground at the brown wire in the connector. Check red/white wire for positive voltage coming from terminal 30 of the fuel pump relay. If no faults are found, the heating element in the regulator may be faulty

Well here's my findings, there is NO voltage at the connector at the regulator, flickered like .02 volts. I assume I do this with ignition on (car not started)? I kept the ignition on and tried to get voltage at terminal 30 in the socket where the relay plugs in, no voltage there. I cannot find the brown or red/white wires since they're wound tightly, buried and hidden in the bowels of the car. Might this be an issue? Don't want to start tearing into the electrics if I'm way off base here, but I'm pretty darn positive I find no voltage coming and wondering if a corroded wire or faulty ground is to blame.

 

If it were me I'd just go ahead and order a new control regulator. Given the age of it I'd replace it. I was working on my ac in my 89 the other day, it was upgraded by previous owner but the vent temps were terrible. I got in the smugglers box and checking things the ac blower relay was hot hot hot, so I ordered a new one. Just installed yesterday went for a 10 minute drive with ac on pulled back in the drive way and vent temps were 30 degrees........a simple relay was all it needed go figure.

 

Seeing as I'm not sure I'm getting voltage to it, and the cost of one of these, I'd rather not just buy one. Anyone here chime in on the voltage issue?

 

Try again with a test light to be sure. Sometimes a volt meter is hard to get a reading with.

 

The heater should just be a coil of wire, no? Does it have continuity or is it open circuit? It's not uncommon for the heater coil in the auxiliary air regulator to go open circuit.

Although voltage supply is a separate issue. I don't know how the air sensor plate switch is wired, but the fuel pump does not run unless the engine is turning (drawing air into the intake to raise the sensor plate and trip the switch). Does this mean that all circuits going through the fuel pump relay also have no power unless the engine is running? I don't know, but if that is the case, you'll need to have the engine running, not just ignition turned to on. It stands to reason that this heater would not operate unless the engine is running. It's supposed to warm the regulator control mechanism to simulate engine warm up. You wouldn't want it acting like the engine is getting warm with just the ignition switch in the on position when the engine isn't actually warming up. I'd check for voltage at the connector again with the engine running. You could just lift the sensor plate at the same time as checking the voltage

Brett

 

Rusnak, I didn't get a light with the low voltage test LED. Brett, those are good points. I will try it with th engine running. I want to be sure I'm on the right thing. As I'm facing my engine, the control pressure regulator (same as the warm up regulator?) is on the left between the first and second cylinder. I disconnect the harness on top to check voltage. Was not sure if I should do this with the car running, but will try.