dt-140 IDLE PROBLEM

[corrjas]

Hi All,
I Have A 89' Dt-140 With An Idle Problem. It Will Not Idle (but Runs Great At Higher Rpm's) With The Throttle Control Sensor Connected. When It Is Disconnected It Will Idle Fine But Won't Run At High Rpm's. It Will Slowly Go Up To About 3500 Rpm But That's It. I Have Adjusted The Idle Sensor To Specs And Double Checked It With Three Different Multi Meters. Again, With The Throttle Control Sensor Connected It Runs Great At High Rpm But Will Not Idle. I Have Also Rebuilt The Carbs Twice And Set To Specs.
Can Anybody Please Help Me? I thought it had to be the carbs or a fuel problem that is what makes sense, but, it idles fine with the sensor disconnected and it runs great at high rpms when the sensor is connected. again the sensor seems to be working it is set to the proper voltage and if i change the voltage id definitly makes it worse. The compression is good and consistant with each cylinder.
Jas

 

[James R]

Re: dt-140 IDLE PROBLEM

Have you checked the compressions. If you have one cylinder down, or not firing, the slow running will be affected dramatically.
The fuel pump is also a candidate, with the rpms up the pump may be pumping enough but at slow running it may not be. Try squeezing the primer bulb when the slow running is failing. If the motor picks up then it is a good chance that the pump need work, or the carbs or a carb needs further attention.

 

[corrjas]

Re: dt-140 IDLE PROBLEM

thanks for the reply James R,
the compression is good on all 4 cyls. and I just did rebuild the fuel pump. I'll try squeezing the bulb and see if that wont help.
jas

 

[corrjas]

Re: dt-140 IDLE PROBLEM

everything tends to point at poor gas delivery or compression but it does idle fine with the sensor disconnected and runs good at high rpms with it connected. So I'm thinking it's something with the electronics, I hope i'm wrong. Any thoughts?

 

[James R]

Re: dt-140 IDLE PROBLEM

I am not certain about your system but on some of the carb/sensor setups there is a small amount of adjustment. Have to slacken the retaining screws of the sensor and rotate.
Take a look.

 

[corrjas]

Re: dt-140 IDLE PROBLEM

thanks for the reply james r, i'll check it out and let you know.
jas