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Discussion Starter · #1 ·
Hi All,

I've been running a 1990 4BD1T in my FJ40 Land Cruiser for about six years and I love it. My only problem is that I have been plagued with starter issues--the kind where you get the dreaded "click" in the solenoid but the starter motor doesn't engage.

The starter works nineteen times out of twenty, but always fails at the worst possible moment. 😩

Sometimes another couple tries and it will engage; at other times I just need to hit the starter solenoid housing with a hammer and it will start. This has been a very persistent problem. I have cleaned or replaced the starter internals three times, and I've fully replaced the starter, battery, and all cables once.

I'm using the big starter with the three-bolt flange, and a single 12v battery with 850 cca. Is the two-bolt flange starter an option? Should I move to a dual-battery 12v system?

Best, JD
Wheel Tire Sky Car Water
 

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Are you using a relay in addition to the switch on the starter? I had the same problem you describe and the cure was to re-install the factory ford starter solenoid which I had “engineered” out when I did the swap. Larger, shorter wires= less voltage drop. That switch on the starter is an electromagnet and if there is enough voltage drop, it will not pull hard enough to pull the switch in.
 

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Discussion Starter · #3 ·
Are you using a relay in addition to the switch on the starter? I had the same problem you describe and the cure was to re-install the factory ford starter solenoid which I had “engineered” out when I did the swap. Larger, shorter wires= less voltage drop. That switch on the starter is an electromagnet and if there is enough voltage drop, it will not pull hard enough to pull the switch in.
Thanks, Levis!

No additional relay here. I've been searching based on your suggestion and it sounds like a relay between the battery and starter is the common fix. I'll wire one up and hope this problem goes away forever. I may check back here with a wiring question. Cheers!
 

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How big are your starter cables and how good are the connections?

Holding a multimeter on the starter lead while someone else turns the key will show you what real voltage drop you're getting.
 

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Discussion Starter · #5 ·
How big are your starter cables and how good are the connections?

Holding a multimeter on the starter lead while someone else turns the key will show you what real voltage drop you're getting.
Thanks, Dougal:

The cables and connectors are all new 2 gauge, the battery is new, and all the connections are perfect. I'll try the test. JD
 

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Yeah, 2 ga is a might small for diesel starter and ground cable. As Dougal said, 2/0 cable is the normal size which is 4 gauges larger than 2 ga. Be sure your ground and hot are the same size wire. Also, those old Ford starter relays are near bullet proof if you want to use one. Those darn things have been around forever,
 

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Discussion Starter · #8 ·
I think you need to double your wire size. 00 guage (67mm^2) is about right. 2 gauge is about 34mm^2.
Thanks again. I will have to order the heavier gauge (I just got the heaviest gauge NAPA has in stock :sneaky:).

However, this is a problem in the switch/solenoid side of the circuit, is it not? The starter motor cranks it over fine if the solenoid switches it on.
 

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If the Isuzu starter is like most, and I think it is, there is a "pull in" coil and a "hold in" coil in the solenoid. The pull in coil provides the muscle to throw the bendix drive out and mash the high current carrying disc into the two big contacts that spin the motor itself. Then the pull in shuts off and the hold in takes over. Seems like maybe your pull in isn't working up to snuff?
 

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Thanks again. I will have to order the heavier gauge (I just got the heaviest gauge NAPA has in stock :sneaky:).

However, this is a problem in the switch/solenoid side of the circuit, is it not? The starter motor cranks it over fine if the solenoid switches it on.
A big voltage drop will impact the working of the switch/solenoid. I'd expect these to pull around 300A if healthy.
 

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Ya, what Levis (and the others) said. Did a 4BT in an '87 Land Cruiser for a Customer. Twin Optima Yellow tops in the rear, full double ought gauge welding cable to starter, same thing. Got one of the old school Ford remote mounted solenoids (think early '90's) and piggyback it as close to starter as possible. It's not the amps (power) that is going to the starter, it was the lead to the solenoid that couldn't flow the current from keyswitch down that couldn't pull the solenoid in enough.
 

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I had a similar issue , the connection from solenoid was slightly loose and carbon on it from arcing .cleaned installed a stainless steel nut retighted all has been fine . Always try to look for simple first .
 
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