Hi, all. I have an 89 Dakota 2.5 5 speed base model. It has 319,100 miles and counting. It has high tail pipe emissions. The scanner shows all the sensors are within parameters. I think. The injector pulse stays at 1.0 MS till you let off the throttle. Then it comes down to .5 MS. Is this normal for a throttle body? The truck runs great. Thanks in advance for any help.

 

What is high? ie: hydrocarbons? etc. Does the truck burn oil? Cat still on the truck? Oh, and how far out of specs was it when tested?

 

My real concern is the injector pulse width. MPFI changes the injector pulse width depending on load, temp, ect. I am not as familiar with TBI.

 

Works pretty much the same way, just fewer injectors.

 

Is there an EGR system on this truck? I failed emissions a long time ago with high NOx and it was the EGR valve that was defective. If so you can try cleaning it out or buying a new one - sometimes the passages get jammed up with carbon or the solenoid fails. I remember around $75 from the dealer but that was a long time ago.