I bought a 1992 toyota pickup 22re last march, and I am now on my third alternator, which is currently on it's way out. Looking at the past receipts from the truck, this is the fifth alternator that my truck has eaten in less than 2 years. When the engine is completely cold, It seems to work perfectly fine, but as soon as I drive it for a while and the engine warms up, It quits charging and I have to leave it for several hours before it will start to work again. I can tell when it is and isn't charging by the battery voltage meter on the dash. Also, as soon as it stops charging, it starts to do this surging idle thing where the engine revs up slightly, then the rpms drop rapidly. I have checked all the connections, and it seems to have a good ground and being supplied with the proper voltage. The first alternator that died just straight up quit working, but the second one did this exact same thing for about two weeks before I finally got around to changing it. Both times, as soon as I put in a new alternator, it worked normally, but a few months later this problem came up.

 

Hi ismith17,
Please see 22R-E charging system in my sig.

Double check all your connections. When materials warm up, their resistance usually increases. There could be a poor connection somewhere

Battery post to connector should have bare metal to bare metal contact. Gun-metal/grey metal is not bare metal in electrical sense. You should have silver color or copper/brass surfaces contacting each other.

Exactly What voltage do you read?

How did you make sure alternator was getting the proper voltage? Which terminal did you check?

Engine fuse supplies excitation current (IG) to alternator, the ECU and the back-up lights.

If engine fuse is bad or not making good contact, or wiring (usually red) from engine fuse is intermittent, has high resistance or intermittently shorts to ground (just lightly shorts so engine fuse does not blow), it will affect charging and could affect idle.

Check to make sure your Engine fuse. Is it good and that it consistently sends proper "IG" voltage to alternator?

Is your "S" wire making good connection with battery terminal and alternator? If alternator momentarily loses "S" voltage, it would think battery is low and try to increase output. When "S" voltage comes back, you'd have voltage surge, then voltage would come down again.

 

When it is working normally, it will output about 14V, but when it quits, I am just reading battery voltage.

I checked the three pin connector, and the other larger wire, and according to a wiring diagram that I have, they all have good connections.

I checked the engine fuse, and It is still good.

 

Cool. Typical.

However, problem is intermittent, correct? So you need to see if you're still getting 12V at IG when it's acting up.

Also, did you verify the old alternators were really bad? Could be just acting bad when intermittent problem with truck struck?

 

I have to wonder given it seems fine till engine temperatures increase if the problem in not old brittle thermal cycled wires.

Could be the B terminal wire or the 3 wire plug coming off the alternator either of them getting hot would cause the intermittent issue .



Because of just where that 3 wire plug sits it is a royal pain to see let alone clean.

In case it could even be a poor ground cable causing all the problems.

Do you have massive electrical loads not seen on a normal 22REC electrical system??

Then just what rebuilds are you using there has been some real junk as of late??

 

Yes, I did make sure they were bad before I replaced them.

I get normal readings on all 4 connections, regardless of whether the engine is hot or cold. Also, the problem disappeared both times as soon as I installed a new alternator.

 

Just what has failed on all these alternators??

If all these alternators have gone bad perhaps another vendor might be in order.

Think if you were paying labor to have these changed.

 

I don't know what exactly has failed on these alternators, but I know at 3 of them were new/rebuilt bosch alternators, and one was a stock one I salvaged from a parts truck. I don't know what kind the other one was.