Wiggle test

[grummph]

I have an '87 ranger with a 2.3 engine. For about five months it has been running fine until it warms up. Then it starts running real rough and blows black smoke out the exhaust. No codes pop up. I have been searching the archives and have learned a lot about the 2.3 engine. Being basically cheap, I have been determined to properly trouble shoot this problem and not spend a lot of money randomly replacing expensive parts. My voltmeter and this Ranger have become quite familiar with each other! I was just about ready to junk this thing when I thought I would start wiggling wires while the engine was running roughly. To my surprise, when I started wiggling wires around the rear of the engine near the egr valve -- the engine suddenly started running smoothly. So, I started poking around the general area and a connector came apart in my hand. The engine started running rough again. When I seated the connector properly again, all was smooth. The problem connector was the one which connects to the air bypass valve which is fastened to the side of the air throttle body assembly. After disconnecting the battery for awhile to reset the Keep-Alive Memory, I re-connected the battery and took off for a drive on some back roads and the freeway. The Ranger has been running great ever since. Thought this might be of interest to some of you who have been having trouble with rough running engines and black smoke. The air bypass valve can cause a lot of problems if it is not working correctly. The moral of the story is: If you are at the end of your rope and have tried everything, try the wiggle test.

 

[Mark_88]

Well, I'd have to say that is my most scientific test of all...lol...

I've solved a few problems just by wiggling wires, tracing them back to their source, and checking the connections...

When I saw the heading on your post I thought you were referring to the piston wiggle test...that's how I determined that my short block was toast...just compared the pistons in my old engine to the ones in the replacement and the wiggle test showed that the original pistons had serious wiggle, whereas the newer block was more like a teenager that hasn't quite figured out what the wiggle does to a man...

 

[grummph]

Hey, just a note to mentioned that I mis-identified the item that was failing when I performed the wiggle test. It is the throttle position sensor. It continues to be troublesome and corrects itself when I move the wires going to the connector. After the contacts in the connector are cleaned, all is ok. But, then the problem returns after a while. Sometimes it is good for a couple of weeks. Then it was noticed that wiggling the wires that go into the sensor will cause it to be trouble free for a while. I am going to replace the sensor. Will report later.