72 square running rough @ neutral throttle position

[Dyscord]

This is my first experience with the fuel injection system, and I was wondering if anyone had any suggestions as to where to look to correct this problem.

I have just finished installing a rebuilt longblock. Initially got everything together, and it started up just fine. (after turning it over a bunch of times to get the oil moving) It ran like hell though, couldnt get the timing close. I checked the movement on the dist and then pulled it to move the drive gear back one tooth. After that I was able to get the timing on the money.

Now the engine runs pretty good, except when the throttle is in a neutral position (not accelerating or decelerating) When the throttle is held steady the engine runs rough, its hesitant. When you step on the gas it smooths out. The hesitation is more noticable at low speeds. At idle the engine seems to miss ocasionally.

If slowly pulling away from a stop the hesitation is pretty bad, causing the car to buck a little. If you step on it though its fine.

Also the idle, I had to unscrew the idle speed screw on the throttle body a long way (there is about 1/2 in of thread visible above the locknut) just to get the engine to idle, its even still a little slow I think.

Any suggestions would be appreciated.
Thanks

[Dyscord]

The saga continues. I checked everything out yesterday, by pullin plug wires off one at a time when it was running. The went to fuel injector plugs. Looks like #1 injector is plugged. I checked the continuity in the injector coil and thats fine 2.9 ohms (#2 injector is 3 ohms) took the #2 injector plug and put it in one, no difference to being unplugged. Took #1 plug and put it in #2 and that worked ok.

So I am looking at either the fuel pressure being low, or I have a plugged injector, possibly 2. #4 doesnt seem to be working at full potential either.

I dumped some injector cleaner in the tank, perhaps that will work. Either that or perhaps I can take them out and soak them in some chemtool? Anyone have any experience with this type of thing?

Does anyone happen to know which way you turn the pressure regulator to increase pressure? None of my manuals say, they just say to adjust it to 28psi. Also how sensitive is the regulator? i.e. how much psi would you increase if you turned it 1/2 turn?

[JDogg]

I've found this and all other problems anywhere on this post to be symptomatic of driving a post 69 type 3. Get an older one and watch your troubles be much more rewarding to deal with.
JDogg

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Dyscord:

Some advice to the D-Jetronic fuel injection:

While it may be more serious of a problem, I would start at the Throttle Position Sensor. It's mounted on the throttle body/air distributor and I have found it to be a well hidden problem in the later (69 on ) T3's with the D-Jetronic Fuel Injection. Sounds like the contacts need to be cleaned. Mine did this and it took me a great while to find the problem. Now I'm happy and sailing smooth. The Fuel Injection system on these cars is very simple. As long as the wiring is in decent shape and connections are clean, they are usually pretty easy to maintain. My engine started after sitting for 15 years, All I had to do was clean out the gas tank and the pump and boom, so the system is very durable. Pre-69 (68 actually, the first year for the FI system) systems with the dual carbs work well too, but with my experience the FI system is much more precise and better on gas.

Its entirely up to you what to do, a lot of people scrap out the system in favor or carb'ed options, but that throttle switch is worth checking out, carbon can do some wierd things to electrical contact over the years.

Keep Trying!

Tim Schell