throttle switch issues

[yousaidpoo]

Car is a stock 1974 1.8 L-jet

I was having some issues with my engine starting, and then idling rough and not revving at all when i gave it gas. I am in the process of going through the whole fuel injection system and troubleshooting more or less everything. I got to the throttle body and took it out of the car and cleaned it up. I then tested it using an ohm meter. I read (in the haynes manual) that the resistance is supposed to go from infinity (throttle closed) to zero (throttle open).
That having been said, there are 2 things:
1) The resistance doesnt go all the way down to zero. It will go down to about 1.5 ohms.
2) It doesnt go down gradually. Its more or less an on/off situation.

Does it need to be replaced?

Also, when I was cleaning the throttle i noticed there was a fair amount of what looked like oil on the throttle plate as well as the bottom of the throttle body and intake air distributor. What would cause that, and how do i fix it?

[yousaidpoo]

btw, are there any 914 clubs around the southeast (north carolina area)?

[silver2.0]

Does it need replaced? NOt necessarily. You will see "steps" in the continutiy by checking it that way. Please use this useful diagram to properly set up your throttle position sensor.
About the oil. Don't worry about it. CHange your pcv valve, it's probably just a little bit of blow by from extra cankcase pressures.

[Dave at Pelican Parts]

The 1.8 throttle switch really is a switch. It won't go gradually, the resistance falls all at once. 1.5 ohms is probably OK, but you can try popping the plastic cover off the switch and using some contact cleaner (e.g., Radio Shack TV Tuner Cleaner, or Wurth contact cleaner which we sell) to clean up the traces and contacts inside.

--DD

[yousaidpoo]

I took the cover off and cleaned the contacts, then put it back in the car, and I still have the same problem. What happens is the car will start, but it will only run (rough) for a few seconds and then it will cut off again. I have tried giving it some throttle, but it has no effect (hence i checked the throttle switch). To save me the pain of going through and checking every single component of the injection system, does anybody know what is the most likely cause(s), so I can check those first?

Also, I was going to check the temp sensor for the intake air (the one next to the oil filler neck) and the haynes manual's way of checking it is a little "hazy" on the explaination. Any help with that would also be appreciated.

[Dave at Pelican Parts]

In a 74 1.8, the intake air temp sensor does not exist. In a 75 1.8, it's a part of the air flow meter.

I'm not sure what is next to the oil filler neck that you want to check...

Any idea if you're getting a reasonable amount of fuel pressure?

Any vacuum leaks? What kind of shape is the ignition system in?

--DD

[yousaidpoo]

Ignition system is in perfect shape. There should be no vacuum leaks since i just replaced every inch of hose in the car (both fuel and vacuum). I have checked the fuel pressure and its right at 37 psi.

Dave, I mean auxilary air regulator. I figured it out tested it by blowing air through it and it closed like it was supposed to as it heated up. Then I put the regulator in the refrigerator for about a minute to check and see if it opened back up, and it did. The unit also reads exactly 30 ohms resistance. One thing though, when I am looking through the hole the air goes through, the opening is relatively small compared to the overall size of the hole. The opening is maybe 25% of the overall size of the hole. Also, when the unit is out of the car, I can twist the plug and it will open and close the sensor.

Also, silver2.0 that diagram and procedure must be for a D-jet, because the plug on mine only has 3 contacts, not 5, and you cant twist the throttle body on the plate (without breaking it )

[silver2.0]

ok, I have a djet, but I pulled the diagram off this site for the 1.8 ljet. I have no way of confirming it's accuracy, but you can look it up in the tech section if you wish.

As for your current problem, the first thing I would check is as Dave stated, the fuel pressure. It sounds like a dead on case for fuel pressure problems. Put a guage on it, and check it FIRST. Good luck!!

[yousaidpoo]

fuel pressure is 37 psi all the way around. I tested before and after both of the fuel rails, and right after the pump

[yousaidpoo]

dont know if this is the problem, but it needs to be replaced anyways.

The thermoswitch is bad. Gonna order a new one, which begs the question, where can i get one for a '74 1.8 L-jet?