freddie

My fj40 f4 engine quits after running for about 15 minutes and will not restart until it has sat idle for 30 minutes or been towed home! I have put fuel in the carb when it has stopped but that will not get it cranked only after sitting for awhile. help!!

apalmer1

check out your ignition system, specificaly the distributor and the coil. it could be that one of the two is almost completely dead and the heat of the engine warming up is increasing the resistance just enough to make a component stop working. Im not familiar with that particular engine but to check any ignitioin coil you should find the resistance across the primary winding and secondary winding. The secondary winding resistance is between the distributor lead terminal on the coil, and ground leg. The primary winding is between the power input to the coil and the power ground leg. Typical primary winding resistance is low (under 10ohms) usually the secondary winding has a resistance between 10-15 thousand ohms. Also if your ignition system uses a pickup coil in the distributor check the resistance across it, they are notorious for breaking down though i dont know if an engine that old would use one.

freddie

Changed the coil out and started it up and it ran for 20 minutes and then quit. I guess I can eliminate the coil as the problem. Next I will start changing out the distrib components?

Yoda

Mine has not had the 6 in it for a long time, but it sounds like the ignitor may be going out.

FlyingLow

Is there fuel in the sight glass on the front of the carb? Start it up, run it until it dies and then pull a plug and check for spark. Let us know after you do this.

freddie

Cranked engine again and ran it checking the + side of the coil and had 12 volts with a multimeter as it was running. After 13 minutes engine died and when I checked the + side of the coil without changing anything the reading was 3 volts. Help, what happened?

FlyingLow

Do you have electronic ignition? Does it have a ballast resistor near the coil? If so try again and check the voltage going into the ballast resistor after it dies. If there is 12 volts going in ot the ballast resistor then change the resistor. If there is low voltage going in to the ballast resistor or there is no ballast resistor, then I would start checking connections. If you have electronic ignition then I would check the power wire going to the module. If there is not 12 volts there then there is probably a poor connection somewhere that is heating up and increasing resistance until the voltage drops too low. It could be a bad contact in the ignition switch itself. If you have too big a wad of keys it will wear out the ignition switch. Clear as mud?

freddie

Bought a new universal ignition switch (hopeing that was at fault) and cranked the engine while holding the wire from the coil to a ground and saw sparks. Ran for the usual 15 minutes before dying. Took same wire and tried cranking again with wire end against groud with no sparks.

My 2f engine was built 10-1977 the transition from semi-electronic to eletronic ignition. Considered a 1978 and does not have a ballast but does have an ignitor.

Another question I have is can I convert to pertornics and avoid a $388.00 ignitor, if that is the problem?

Thanks in advance; this forum has brought me back to the appreciation of how these toyotas were built; so a simple non mechanic like me can be talked through problems by knowledgeable forum participants .

FlyingLow

I've been at work, I get home today so I will look at my wiring diagram.

freddie

E-mailed pertronixs who said they did not have a system that would work in place of the original ignitor. Ordered a coil and ignitor from toyota parts and will try that when it comes in to see if that was the problem. I will post results once I install it and crank the engine.

FlyingLow

I wouldn't buy that stuff. If you have 3 volts at the coil then you have a problem upstream of there so I don't think you need a coil. I think you will be wasting your money. The ignitor is a 'black box' mounted on or near the coil. It has some sort of heat sink on the case. I will look in my wiring diagram in the morning and check which wire should have power to it.

FlyingLow

black-yellow wire going to the ignitor should be ignition power from the switch. I would run it again until it shuts down and check the voltage on that wire.

freddie

I've had the flu, but anyway you were right the ignitor I bought from toyota parts didn't even work, nice company! I will get a new multi meter this weekend (old one died last week) and track down the source of the bad voltage; what I do know is that it is between the end of the coil wire where it attaches to the distributor and the wires that attach to the ignition switch. Will write again this weekend when I track it further. Thanks Bob

FlyingLow

I am away at work now until Tuesday so I don't have a wiring diagram here but I will try to help from memory. Let me know what you find.

freddie

Tested the black and yellow wire from the ignition switch to the ignitor after shutdown and found good power. Changed out coil to distributor wire and engine still shutdown after 20 minutes. Will test all the wires from coil and ignitor today before and after startup.

grex

Freddie, I am having same issues!

Did you ever figure out what was going on?

Thanks

Greg 1978 FJ40

Did you ever solve the problem with the engine quitting after running for a short period of time? I have the same issue.