Idle surge and stalling 99 df70

[vrodrig]

DF70 surge problem at idle then engine dies! Back fires some times. Checked battery and charging under 14 volts, seems ok. Good battery connectons, I did notice a small pipe just under the IAC but there is no hose connected to this brass looking pipe. There is also a screw next to it, turned it in and out and idle did not improve continues to stall out. Suggestions any one?

 

[clanton]

Re: Idle surge and stalling 99 df70

You have to readjust the idle, you just can`t turn the screw. I will try to pickup my manual tomorrow for more help.

 

[99yam40]

Re: Idle surge and stalling 99 df70

If it has run fine before then you have something going wrong.
These things do not just need to be readjusted from time to time, you need to find what is wrong with it and fix it

 

[vrodrig]

Re: Idle surge and stalling 99 df70

Thanks Clanton and 99Yam40 the only service i did on this was rebuild lower unit and reinstall it, I did disconnect the battery before removing the lower unit. I did absolultly nothing to the engine its just strange that it would start acting up like this i have looked all around the engine and nothing looks out of place. Ill wait for your return Clanton, Thanks guys!

 

[clanton]

Re: Idle surge and stalling 99 df70

Idle adjustment. Engine up to operating temp.
Raise rpms to 1000 or higher, by turning the bypass air screw, and hold for 10 seconds.
Buzzer will sound to indicate the IAC is in fixed mode.
Turn air screw to adjust idle. Spec is 650-750 rpms.
After idle is adjusted increase rpms with throttle control to return the IAC to computer control.

 

[clanton]

Re: Idle surge and stalling 99 df70

Iac valve will set a code if not working. May be dirty and sticking, can be cleaned.
Engine problems with no codes most likely fuel problems.

 

[vrodrig]

Re: Idle surge and stalling 99 df70

Thanks again Clanton, I will follow the procedure and get back with you on results. I appreciate your help.

 

[vrodrig]

Re: Idle surge and stalling 99 df70

Clanton the procedure worked, the engine idles well now. Big difference Thanks!