SOLVED!!! FJ62 dies while idling but restarts (1 Viewer)

[Fieldtester96]

Consider this: You don't need an alternator at all to run. If your battery is healthy your truck should be able to drive at least 50 miles without all the accessories on. My FJ60 recently drove over 100 miles and still started fine after I discovered the alternator wasn't charging as it should....even ended up driving about 25 miles with the headlights on and didn't stall.

So Alternator issues do cause problems but you have a battery for a reason. The battery is your power reservoir and it will run a car....even a modern car for quite a long time if the alternator has died. The only thing I think is happening with your alternator is that you are putting a load on it and a loaded alternator gets harder to turn and requires more horsepower. It sounds a lot like your fuel system isn't compensating for your various loads on the engine and thats causing a stall. This could be due to an unfound vacuum leak or a bad sensor, a dirty ground, or one of your main EFI components going bad...due to age, cleanliness, etc.

Alternators usually fail due to the brushes i the voltage regulator wearing out and or the contact surfaces the brushes riding on wearing. At which point the alternator stops charging or intermittently charges. I am sure that windings do fail now and then but I can honestly say that it the 27 years I have worked on and been around cars I have never seen an alternator fail due to a winding issue. Also if you are seeing 12.8v at idle with all the accessories on and over 13v with none on then you your alternator is charging fine. if you had a bad winding you wouldn't be seeing that.

"From what I understand extra load from lights and windows shouldn't cause the efi to bump up rpms because there is no extra load from the alt. The alt just has a constant torque needed and doesn't go up or down like when the AC kicks on. I may be wrong but even on carbed engines there is no compensator for loads being put on the Alt. Its the voltage regulator that tells the alt to put out more volts, because alts are supposed to keep around 14.2 volts no mater what rpm. "

I can assure you that when you put more load on the alternator the amount of torque needed to turn it does increase. A carbed engine will react to the increased load and the carb will do its best to maintain its idle speed but often the idle speed will in fact drop due to alternator loading if there is no other idle up switch. Alternators are not designed to output 14.2 volts regardless of the rpm. They are are designed to output max voltage at a certain rpm and if that rpm is say 2000 rpm you are not going to see 14v at idle

That all makes alot of sense, but wouldn't a bad sensor not be intermittent? I get that cars can run just off the battery, but when I was doing research intermittent stalling wad a symptom of a bad alternator.

Regardless of if this is my alt or not I have had issues with it in the past where it wouldn't start charging until I hit the gas a few times. Plus this alt at least has 50k miles on it, probably more. I'm not saying your wrong or anything, its just that this is the only solution I found where people have had the same symptoms.

My thought process is that most likely my alt had been running off of 2 phase for a while. I have no extra accessories so the reduced charging can keep up with my cars needs. Recently its been sitting for a while without being driven. When I have been working on it I have run the battery down. Not low enough to prevent it to start but still low. So when I drove it the other day with the lights an AC on the alt wasn't able to keep up with the demand which caused it to stall when I had been idling for a while.

This would explain why I can start the car, let it idle for a bit and then turn the accessories on and be fine. With the reduced performance of the alt the battery can still charge, just slowly. That's why it can idle for 10 minutes before stalling, because 80% of the power is coming from the alt and 20% is coming from the battery. Again though I could easily be wrong, but so far this is the only thing I found that makes since. If you are right and it is a sensor then I would be happy to know where I should start looking

 

[Seth S]

good luck. let us know how it turns out.

 

[Fieldtester96]

good luck. let us know how it turns out.

Will do, sorry if seem hostel I really appreciate your input. I just tend come off as an a****** some times. I'm really just trying to explain my own mental steps that led me to this conclusion because I'm not 100% certain about it. Though from what I remember from my electrical engineering class, my problem has to be something related to power issues. So it could be the alt or an electrical gremlin that has popped up.

Regardless I'll let you all know because this has been a great resource for slowing problems. 9 out of every 10 problems i have i find a post about. Its that 1 in 10 problem that gets me a drives me nuts. So sorry again if I seemed like a hot headed a******, its really because I'm going crazy over here. I greatly appreciate your input Seth and I honestly your probably right but incase I have that unique case it's worth the shot.

 

[Fieldtester96]

So I put a new alternator in and things are fixed, sorta. I'm now getting a constant 14.3 volts whether its idling in park or drive with the accessories on, and it doesn't die when I have the ac and lights on. Though after idling for about 15 minutes I held the window down and killed it, but it started right back up. So I'm guessing I still have an electrical problem, but its not that bad with the new alternator.

For the time being ill just have to make sure im either driving or in park when I put the windows down, and try to not have the ac running on full blast when idling. I'm guessing this problem showed it self because i haven't driven it enough to keep the battery charge up. After I take it on a good drive ill check again to see if the symptoms still show up. For now at least I can trust it not to die at a light.

 

[Fieldtester96]

Alright so i figured out this problem, but things got crazy and i forgot to update on it.

Basically what was happening is my car would die when there was too much electrical load, as well as when it got too hot it would not want to restart. After dinging through the FSM and the wiring schematics i found that if i bridged the connectors in the engine bay to keep the fuel pump going it wouldn't die or have a problem restarting. This lead me to finding out that my fuel pump relay was bad, and when i say bad i mean BAD.

As you can see from the pictures, the relay was just trashed. For some unknown reason Toyota had this relay mounted upside down in the passenger side kick panel. Which i guess wouldn't matter to much if you dont have a slight leak in your drip rails. Well since the drip rails leaked the relay housing acted as a cup, so basically there was water constantly in here for God knows how long.

Luckily this part is like 40 bucks on rock auto, and once i put it in ive had no problems. Ive actually ended up getting better gas mileage, which i think has to do with how the fuel relay controls the fuel pump (or im just crazy). Ive also redone my drip rails and gutter so now i have no water coming in, just to be safe i mounted the relay right side up so it wont catch water.

Just some friendly advice, if you have had water pooling near the passenger side kick panel id check the relays before the rust to s*** and leave you stranded in the road outside of a Taco bell

 

[Randy88FJ62]

Good find. Thanks for the follow up.

 

[Fieldtester96]

Good find. Thanks for the follow up.

Hopefully this will help someone else, took me a solid week of troubleshooting to find this out. Couldn't find this issue anywhere on the forum so im just happy to be able to contribute a my small part to this wealth of knowledge.

 

[wrc3]

Well I am pretty sure you saved my bacon. I had mostly the same issue and was looking at replacing the alternator but then saw your post. Only difference is my relay was installed correctly so it wouldnt catch water and when I pulled it open it looked fine. I decided to get a new one anyways, because I have found water in the past on passenger side mat after a heavy rain. I just drove about an hour in stop and go traffic with no dying. Hopefully that’s it. Thanks for your work and updating your post!

 

[Fieldtester96]

Glad I could help! Honestly I hate when people don't find the problem and I'm happy me updating posts finally payed off for someone. Cause let me tell you that was like a solid week of troubleshooting to figure that out. I actually had to read the field service manual.

 

[HemiAlex]

What part did you use for replacement?

 

[Fieldtester96]

What part did you use for replacement?

I'm not sure what wrc3 used, but if I recall it's a common Toyota relay and I bought my replacement off Rock Auto for like 20 bucks

 

[wrc3]

Same ordered from Rock Auto. denso 5670036

 

[vipergrhd]

Glad I could help! Honestly I hate when people don't find the problem and I'm happy me updating posts finally payed off for someone. Cause let me tell you that was like a solid week of troubleshooting to figure that out. I actually had to read the field service manual.

Glad that you were able to find the real problem. It really helps to look at wiring diagrams and schematics to trace an electrical issues.

 

[Fieldtester96]

Glad that you were able to find the real problem. It really helps to look at wiring diagrams and schematics to trace an electrical issues.

It was a combination of that and finally learning how to use the diagnostic port with jump leads. Funnily enough I used this problem as a example of my troubleshooting skills in my job interview. I doubt that's why I got hired but it definitely didn't hurt.

 

[MiyamotoMusashi]

@Fieldtester96 - great post. Thanks for the updates. Super helpful