Ford Mustang Forums banner

121 - 124 of 124 Posts

·
Indo-Canuck-Yankee
Joined
·
2,739 Posts
Voltage drop is a right pain in the ass to test if you don't have the right kind of meter, though. I have a GWInstek GDM-461 that has a datalogging feature via an RS-232 output - with that I'm able to capture a voltage drop when loading a circuit. Surely there are cheaper and faster ways to test voltage drop, right?
 

·
Registered
Joined
·
46 Posts
After fighting with it some more, trying different things, I finally found the problem to the engine not wanting to run after cold start. One of the things I found out a while back was that if I unplugged the MAF connector, the engine does run, but probably in the limp-home mode. So I should have pursued that, as the problem turned out to be a slight distortion of pin 50 on the EEC connector. It seemed that I broke off the little plastic finger that kept the pin in the connector, so that when I plugged the connector onto the EEC, the pin in the connector was pushed to out the back. Yet when I pulled off the EEC, wire tension pushed the pin back in position, so it always LOOKED OK, even when I was doing continuity test. Once I saw the pin in the connector being pushed out, I forced it back in, and magically, the engine cold starts and runs as well as the SD computer did.

Now it seems to have an idle surge when warmed up, where it bounces between 500-800 rpm about 2 times a second. More fun to be had.
 

·
Registered
Joined
·
24,574 Posts
that is great advice.

with these old connectors, pin integrity is def something to check

and is very difficult to diagnose

I had that exact issue with a head light connector, pin pushed out when connecting and was hard to notice.
 

·
Registered
Joined
·
46 Posts
I had to get a break-out box to monitor the voltages in KOER to find this out. The readings on pin 50 jumped from 0 to wildly fluctuating as the engine was running, so I started looking more closely at that signal. I also measured right at the sensor, and it was much more smooth and stable. So then I looked again a the wire; looked good. It was kind of by accident that I saw a bit of the tail of the pin sticking out the back of the connector.

I would like to thank you again for your assistance on this.
 
121 - 124 of 124 Posts
Top