Cold Start and Idle Issues

[mgriff67]

Hi all,
I am having a bit of a problem on cold starts. 1994 FZJ80. Aside from the occasional dead battery, it will turn over fine, however, it immediately settles at ~650rpm without holding at a higher rpm to warm up. Coolant system seems to all be fine. Only recent work I did was remove throttle body, but the coolant lines running underneath are in fine shape. I have yet to check coolant temp sensor. Any/all advice would be appreciated.
Thanks!

 

[jonheld]

Hi all,
I am having a bit of a problem on cold starts. Aside from the occasional dead battery, it will turn over fine, however, it immediately settles at ~650rpm without holding at a higher rpm to warm up. Coolant system seems to all be fine. Only recent work I did was remove throttle body, but the coolant lines running underneath are in fine shape. I have yet to check coolant temp sensor. Any/all advice would be appreciated.
Thanks!

Please add vehicle information to either your signature or your question so we know what vehicle you're referring to.
And when you say, "occasional dead battery", how often does this happen?

 

[mgriff67]

Please add vehicle information to either your signature or your question so we know what vehicle you're referring to.
And when you say, "occasional dead battery", how often does this happen?

Sorry, thought I had it set in my profile. I’ve got a 94 fzj80. More often than it should. If I don’t drive it for 2-3 days it’ll need a jump. I plan on going through the fuses and seeing if there’s any parasitic draw.

 

[jonheld]

Sorry, thought I had it set in my profile. I’ve got a 94 fzj80. More often than it should. If I don’t drive it for 2-3 days it’ll need a jump. I plan on going through the fuses and seeing if there’s any parasitic draw.

That's not normal. Either you have a faulty battery/charging system or there is a substantial parasitic draw.
Normal quiescent current draw should be in the 20-30 mA range and it should be no issue to leave the truck for 10 days without starting.

When the battery dies, the ECU will reset. This typically results in a higher than normal idle for 2 or 3 drive cycles until the ECU relearns all the sensors.
However a partially discharged battery might yield different results. Once you identify the underlying issue and effect repairs, I would remove the 15 amp EFI fuse from the relay box on the left fender for a few minutes. That will essentially reboot the ECU and clear out any stored error codes.

 

[mgriff67]

That's not normal. Either you have a faulty battery/charging system or there is a substantial parasitic draw.
Normal quiescent current draw should be in the 20-30 mA range and it should be no issue to leave the truck for 10 days without starting.

When the battery dies, the ECU will reset. This typically results in a higher than normal idle for 2 or 3 drive cycles until the ECU relearns all the sensors.
However a partially discharged battery might yield different results. Once you identify the underlying issue and effect repairs, I would remove the 15 amp EFI fuse from the relay box on the left fender for a few minutes. That will essentially reboot the ECU and clear out any stored error codes.

That's not normal. Either you have a faulty battery/charging system or there is a substantial parasitic draw.
Normal quiescent current draw should be in the 20-30 mA range and it should be no issue to leave the truck for 10 days without starting.

When the battery dies, the ECU will reset. This typically results in a higher than normal idle for 2 or 3 drive cycles until the ECU relearns all the sensors.
However a partially discharged battery might yield different results. Once you identify the underlying issue and effect repairs, I would remove the 15 amp EFI fuse from the relay box on the left fender for a few minutes. That will essentially reboot the ECU and clear out any stored error codes.

Thank you! I very quickly went through the fuses and couldn’t find any draw from the system but this was last month. I’ll try again today and see if I can figure out where it’s coming from.

 

[jonheld]

Thank you! I very quickly went through the fuses and couldn’t find any draw from the system but this was last month. I’ll try again today and see if I can figure out where it’s coming from.

Easiest thing to do is put an ammeter between the positive battery terminal and the bonded fusible links. That will give you the total draw. From there you can subdivide by going between the positive battery terminal and each individual link.
Consult the Toyota EWD under the POWER SOURCE section.