OK, everybody is down at the pond looking at my alligator. I told them my leg hurt and I did not feel like walking down, so I could start on this.
My Ford has always started really well. ( After all, it is a Ford........)
Normally, unless its really cold, one quick bump of the starter and its running.
About a month and a half ago, I cranked it up at a friend's house. Started normally.
Drove to the store, came out, and it failed to fire. Good hot battery, good connections. Spun nice and fast, never even sputtered.
Stopped, let the starter spin down, tried again.
After a few seconds, it sputtered once.
Tried it a third time, and it cranked and ran. Sputtered for a few seconds, then ran normally. I thought that was odd, headed to the house.
Got there, tried it, and it took two tries to start.
When it does start, and its cold, the exhaust would gag you. Not rich, smells lean. If it were rich, I would expect to see some black smoke before the cat lights off.
Do not see any.
Fuel pressure reg on this engine is vacuum controlled, and easily replaced. Since it was fairly old, and I was doing some work in that area anyway, I stuck a new one on there.
Normally don't just throw parts at a problem, but I wanted to replace it anyway due to age.
Did not help a bit. I still was thinking that it was a lack of fuel problem. The rail is supposed to hold pressure, but even bumping the key off and on to cycle the pumps did not help.
Its real easy to check the pressure on this truck, it has a test port on the rail. But I do not have a gauge handy. Even so, I doubted it was bleeding down because of the new reg and the cycling of the pumps.
So, if it is starting lean like it seems, it may be that the injectors are not firing while starting at first. Since it has 8, one bad one should let it start normally but with a skip.
I put the truck in the shop Wed. to fix the AC. My mechanic is busy, and I had told him as long as it was cranking, we would let the starting problem slide until we both had extra time.
He had ordered me a new condenser and of course replaced the drier and orifice tube. It took a while to crank in the parking lot to pull it into his shop.
BUT, after pulling a vacuum on the system, and getting ready to fill it, he hit the key and it cranked like old times. He looked at me and started swearing that he had not done anything to the starting part.
I switched it off and it cranked back instantly like it should. When I went to leave though, it was back to its old tricks.
However, now I am getting suspicious of the ignition switch. Especially since it seems to crank well after a couple of tries.
There was a recall about 3 years after I got this truck due to a faulty switch that caused some fires. Mine was replaced, but it has switched thousands of times since.
Maybe the start contact was getting flaky.
So, just before my guests arrived, I went out and popped the hood. Cycled the ignition switch on a couple of times to make sure the rail was pressurized.
Then, I left the switch in the run position. Pulled the little quick connect off the starter solenoid and used a piece of wire to fire the solenoid.
Thus bypassing the start contact in the switch.
It actually seemed to start quicker than it had been, but still not right.
My company drove up to the gate, and I hit the remote control to let them in. As they drove in, I reached to close the hood but then remembered that the starter solenoid was still unhooked.
I reached out, plugged in the wire, and the engine idled up faster instantly. I thought, NO WAY. Since it was cold, the computer was changing the idle as it warmed up.
Had to be a coincidence.
I unplugged the wire, and it idled down some. I stood there, feeling like a fool plugging and unplugging a wire that should be dead, and even if it wasn't should not have an effect on the engine.
But, everytime I did, the engine changed slightly. Sometimes it idled up, sometimes down. Not necessarily the same each time, but it did have an effect every time.
I always have a meter in the truck, so I grabbed it. Measuring between the wire and the contact, i got varying voltage of between 5 and 6 volts.
I wanted to measure from it to ground, but did not have time.
Came in here and posted the question.
Since, I have pulled out my electrical and vacuum troubleshooting factory manual for that truck. And it turns out there is a way for voltage to get on that line.
The start contact not only supplies power to the starter solenoid, but using the same wire, it supplies power to the start terminal of the TFI module mounted on the distributor.
Its an external module that is similar to the module in a GM dizzy.
The computer controls the timing by sending a signal called a SPOUT signal to that module. When it gets it, it fires on the leading edge of that square wave.
But, if the module sees 12 volts coming in on the start terminal, it ignores the SPOUT signal and runs the engine at base timing until that line goes dead.
Thus telling the module that the engine is running, and to let the computer take over the timing.
From what I am reading, that wire should be dead except when cranking. Since is it not, then either the TFI module is breaking down and letting some voltage bleed back on that line, or the ignition switch is crudded up and leaking some voltage to it.
If that is the case, then I am changing the timing when I plug in the coil and bleed off the voltage.
Right now, that is where it stands. I am tied up this weekend, but maybe Sunday I will get a chance to do more investigation.
The gator watchers are back. Watch this space for future developments........
