Toyota 4Runner won't start

kegan

I just worked on a friends 4 runner, re did his battery connections because they were bad. (and it wouldn't start). But now it will not stay above five hundred rpms. Is it a fuel issue? It is driving me nuts. Thanks for looking!

kegan

it has 227,000 miles btw

93tracker5spd

Hello! This can be a frustrating problem, and it seems no one is forth-coming with information to solve it. I see that you have said the vehicle has 227,000 miles, but not the year or engine of the vehicle. I will assume from the mileage that this 4Runner is an early to mid 90's model SR5 with either a 2.4 or 3.0 Litre engine. If so, it has an ECU or Engine Control Unit, a computer module that adjusts things as the engine runs. Now since I am working by guess here; I will assume that the engine was running fine before the battery work occurred, if this is indeed the case, and the battery work was done correctly, then your problem is a simple one to solve. You see the ECU controls throttle body air flow into the intake to set idle speed depending on load placed on the engine; example; cold weather idle, or AC running at idle, or returning to idle after a hard pull, etc, etc. The ECU is set at factory for a specific amount of air flow, but over time as the engine runs and builds carbon on the butterfly valve and in the intake the ECU adjusts that setting to compensate for this ware. When the battery is completely disconnected for more than about 1 minute the ECU forgets everything it learned and is left only with the factory settings. When the engine left the factory there was no carbon build-up and the air flow required was a smaller amount. So, if everything I have assumed is true in this case, you simply need to do a good cleaning on the throttle body intake hole and butterfly valve, then run some engine cleaner through a tank of gas and all should be fine again!
Good luck to you.