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Truck- Starter/Battery help

I'm having very intermittent lack of starter rotation on a Toyota T-100. Over the last 14 years I have replaced the contacts it the solenoid and more recently (1 to 2 years) replaced the starter. For trouble shooting I have a meter with one lead connected to the bolt on the solenoid and the other to the frame. The plan is; if I can get it to malfunction while trying to start it and the voltage on the solenoid is 13.7v vs 10.7 then I know the solenoid contacts didn't connect (if they clicked) or the starter is open (less likely). If the solenoid clicks and the voltage drops to a low value then I probably have a bad connection in the wiring.

So far I have engaged the starter 25 times without malfunction. Letting things cool, then I'll try again, if I hit 100 my work is done for this go round!

Question 1) The battery voltage sets at 12.7, when I energize the starter it drops to 10.7. Is that a normal voltage under starter load?

Question 2) In the old days, you could remove the coil wire to run a starter without starting the motor. How do you disable the spark on these newer vehicles without a distributor cap? (newer 1997) :-)

Mikek

Reply to
amdx
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Ok, after about ten more times switching the key to start, the starter did NOT engage. and the voltage stayed at 11.9v VS 10.7v when the starter engaged.

So by my logic I suspect the contacts in the solenoid.

Anyone have other thoughts and a way to differentiate. Oh, I like that going for a differential diagnoses!

Mikek

PS. I lament selling my Simpson 260, I had to grab a panel meter and adjust it from a 75 volt meter to a 15 volt meter. Digital meters are not real helpful for this type of testing.

Reply to
amdx

Is the replacement starter a new one or a rebuild?

Reply to
Tom Miller

For what it's worth, I had repeated problems with the starter on a Ford Aerostar I owned - I believe the engine and starter were of Mitsubishi origin.

The symptoms were that every three years or so, cranking would become intermittent - occasionally slow to start cranking. It would get worse and worse, and eventually the starter would fail to engage at all. Sometimes, if the starter wouldn't work after the vehicle had been stopped only for a short time, I could let the vehicle sit for a couple of hours and it would start again.

I had to have the starter replaced two or three times during the time I owned the Aerostar. It would always fix the problem... for about three years... and then it would recur.

What I was told, by one of the mechanics who worked on it, was that the starter was prone to developing a bad spot on the commutator... I'd guess it was due to arcing. If the bad spot was bad/burned enough, then when the starter happened to stop rotating with this spot under one of the brushes, there wouldn't be adequate contact and the starter would not crank.

It would probably have been possible to service the starter (open it up and re-turn the commutator ring) and I imagine that's probably what was done to the "remanufactured" starters I bought.

Reply to
David Platt

I didn't put it on, my had here nephew put it on, and he usually gets parts at Napa. However my wife gave me orders to get new contacts at Toyota, so I figured she must have talked to him (she wouldn't now such a thing to say) That makes me think maybe he got it at Toyota. The receipt is in 2012 0r 2013 file, but I don't care to dig it out.

But I don't want to throw parts at it, rather figure it out first. I have notice oil on the starter/solenoid, it is dripping from the valve cover, I tighten the screws, they were all very loose. So, a new theory, oil has contaminated the contacts making for intermittent starting. I'm holding off until the problem clears or becomes more consistent. Mikek

Reply to
amdx

Remember that another set of "contacts" involved are the contacts the brushes make to the commutator....

Jonesy

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Reply to
Allodoxaphobia

Yeah. The starter can be drawing up to a couple of hundred amps, so it's normal for it to go down some. I have heard various values for the line between "good" and "bad", usually somewhere between 9 and

10 V.

Probably the most common is to remove the fuel pump relay or fuse, or unplug the fuel pump. Note that if the vehicle has been run recently, there might still be enough pressure in the injection system to run the engine for several seconds the first time you crank it after removing the fuse/relay or unplugging.

If you have the style where multiple coils sit on an ignition module, unplugging the low-voltage connector to the ignition module will usually kill the spark.

Matt Roberds

Reply to
mroberds

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