TBI 350 Will not crank. Any thoughts?

[mikayak390]

Hello

I have an annoying little problem I could use some help with.

The truck and I are in another small argument. It does not want to start sometimes.

As in turn the key and you get nothing no starter moving, no engine cranking. Other times it starts instantly. I figured the starter relay was getting old. So replaced it. Did not help. So I replaced the starter and relay together. It helped for a few weeks, now we are back to the love hate relationship again.

I am thinking about changing the ignition switch, any better suggestions???

yes the wires to battery, relay and starter are in good shape and tight. low impedence across all. Ground is also good.

oh and its a new ignition module in the distributor as of 4 months ago.

The switch (seems to work fine) but its the best suggestion I have.

Any thoughts would be appreciated.

oh Battery is also new not an issue here.

Thanks.

 

[BROKEN-ONE]

check

how much play does the key & tumbler have , this was a problem for me on another truck .

 

[dyeager535]

The switch is probably not bad. As suggested, tumbler assembly perhaps, or the switch may need adjustment.

One trick I've seen work is to turn the key as far as it will go (for start) then extremely slow, let the key work it's way back towards run. Sometimes when misadjusted there will be one spot where it will start, but it's a very small window.

 

[clarkjw24]

I've seen people have to wiggle the steering wheel left to right sometimes to get the ignition to catch.

 

[southernspeed]

Next time it happens try bypassing the inhibiter switch. (park/neutral)

 

[mikayak390]

The lock is not great, but seems tight. Neutral saftey switch is one I forgot. Thanks. other than starting in neutral, how do you bypass the saftey switch. (I am looking for wire colors to short and is the switch at the trans or on the colum) I plan to look it up tonight after work.

I know how to test and bypass a switch once I find it.

Thanks for the idea and the help.

 

[southernspeed]

As far as i remember the switch is at the lower end of the column. I've only done it on my B&M shifter so I'm not sure of the wire colour there.
On tbi models there are 2 switches though. One for cranking signal as on older trucks and one for the ECM. Hopefully the ever resourceful Mr. yeager will step in here with wire colours!

 

[dyeager535]

Clutch, ignition lockout uses yellow and purple wires, not sure what auto trans uses.

Links posted today regarding wiring manuals will probably show.

 

[mouse]

The TBI portion of the switch uses the orange/black and the black/white wires.

I have seen ignition switches cause this problem in the past (a couple of times). The contacts inside become worn and usually burn from a deteriorating connection, until they intermittently work.