Long ride home, Engine kept cutting out Options

[dralf]

Yesterday I went from Dayton to Columbus Ohio to visit an old friend. I was excited for this was the first big trip for my Teener. What a day, the sun was out, my top was off, the radio was playing some great oldies, all the stoplights to the interstate were green, and I even had an attractive woman smile at me as I passed her car on I 70. (IMG:http://www.914world.com/bbs2/html/emoticons/cool.gif)
This is the good part of my story. Now when I come home this morning the car does not want to run right. The first few miles it was merely a hesitation at about 3000 RPM. I had checked my timing and idle before the trip for I was always suspicious of my throttle position sensor, and or CHT may be off. I have a CHT on order to change out since it is only a few bucks. Well as my 80 mile trip continues the follow symptoms start to surface. There is a noise coming from the engine compartment. I is not a grinding sound, nor is it a squeak. It sounds more like a “squall” like dogs sound off in the distance when they are upset. I have heard sounds like that from my woman’s German Shepards on occasions, I have not hear that sound from her pussy – her cat only moans (sorry, I had to add a bit of levity to this story so that I do not stress about the car). Ok, sounds seems to be coming from the passenger side, and I do not want to bet my lunch money on it but the source appears to be near the distributor (which from now one in the story will be referred to as the “dizzy”). The sound is not truly in sync with the engine RPMs and at low RPMs is almost non-existent. As for the engine, it runs and cuts out, runs and cuts out. When I say cut out I mean drops to idle and if you do not hit the accelerator hard it will actually stop. By now you are wondering how did I drive it home? Well, I would get up to about 75 mph, it would cut out and I would coast and at about 50 MPH the engine would catch and I could accelerate back to about 70 only to repeat the process. I think the constant jerking has loosened all my fillings and my hands are cramped from gripping the steering wheel as I tried to avoid getting killed on the highway. (IMG:http://www.914world.com/bbs2/html/emoticons/blink.gif)

OK, in-between thoughts of death, tow-trucks, and wishing I could have sex one more time, I was mentally diagnosing what the problem was and how to find and fix it. My Teener is a 1975, FI 2.0. The dizzy has new points, cap and rotor and the spark plug wires
appear to be new. The engine was rebuilt by the PO about 6,000 miles ago. I had cleaned most of the FI connectors before the trip, and they all appear to be OK now. I first was thinking FI trigger points are bad, however, I do not think that would cause what I was seeing as I drove into town on city streets. I had black smoke billowing out the back when the engine cut out, and my gas mileage for the trip was terrible! I would think that means I have a sparking problem for if the injectors were not firing I would not be using or loosing gas. How would I test that or check the dizzy? (IMG:http://www.914world.com/bbs2/html/emoticons/idea.gif)

I now plan on making a stiff drink, and looking for any thing loose and wait for some help from you experts who perhaps have been down this road before (no pun intended).

Signed,
ALL SHOOK UP
(IMG:http://www.914world.com/bbs2/html/emoticons/wacko.gif)
PS, I have got to say the Teener did not leave me stranded or hanging which is not always the case with my woman. It did get me home.

[Dr Evil]

I would have to say that it sounds as if you are going extreme rich when it cuts out. Does your tach go to zero when it cuts out? This could indicate a spark issue as its signal is taken from the coil which is triggered by the points. The rich condition will happen with a bad TPS, a bad CHT, or if your fuel pressure is too high. Your pressure should be at 39psi. You can measure it at the nipple on the drivers side fuel rail withw cheap gauge purchased at Harbor Freight or some other inexpensive FLAPS like Auto Zone. I find that hte best approach is to rule out the obvious conspirators. Here is a check list for you (mind you, this is jsut off of the top of my head):
-take an ohm meter and check your CHT. Wiggle the wires and see if you can get it to short or open.
-Turn your key on and check fuel pressure before the engine is started. It should br dead nuts 39psi.
--start car and see if the pressure drops or surges.
-Take hose of of MPS and check that it will hold vaccume by either sucking on it (shade tree) or using a vaccume gauge. The values that you should be shooting for are on this site, just do a search.
-Fuel points are easy to check if you can get to them. Remove and look for excessive pitting or any broken springs (?) I am not sure if there are springs as it has been a while, but look for anything out of the ordinary.
-TPS, remove the cover and check the runs in it. See if they are still existant or if they are significantly grooved.


Are you seeing black smoke during the cut out, or directly after the cut out? During would possibly be one of the top problems, after sounds more like you are still getting fuel while your ignition system is cutting out and you get the smoke at the end of the lag because your ig system comes back on line and burns all of the fuel that was continuing to be dumped into your cylinders.

It is quite likely that you have more than one problem. Hey, it happens. The 3000 rpm number sounds like a TPS, but if it were the only faulty component you would be going lean not rich.

After you check these things out, which should not take very long at all, let us know the results and this will help us to diagnose the problem further.