Differential Pressure Regulator[was No start WAS

[SJ]

Either of the two regulators will work. Up to a point.
During closed loop operation, the signal sent to the DPR is based on the
oxygens sensor inputs. If previously you needed 0 ma for proper emissions,
the ECU now will send out 10 ma to correct the O2 sensor readings.

The problem is that with the incorrect DPR, you are operating out of the
normal range of the mechanical portion of the DPR valve mechanism. At some
point, the valve will run out of adjustment, and the ECU will not be able to
adjust the mixture for proper operation of the emissions system.

I'm not sure why the change was made from 10 ma to 0 ma as the DPR current
at idle. The only reason I can think of is for better driveability during
the limp home mode. The 10 ma DPR will give you a lean mixture.

If you disconnect the electrical connector from the 10ma DPR:
1. The valve inside will move when it loses its current . ..it will move to
its natural "resting" position.
2. this will open slightly the internal valve, more fuel flows into the
lower chamber
3. Increased fuel flow means increased pressure in the lower chamber
4. Increased pressure works on the diaphram that seperates the lower chamber
from the upper chamber
5. The increased lower pressure causes the diaphram to rise and close off
the valve going to the fuel injectors
7. Less fuel flow to the injectors means a leaner mixture

If you disconnect the electrical connector from the 0 ma DPR, the valve
inside will not move when it loses its current . . .the valve is in its
natural "resting" position . . . the mixture remains the same as before.



SJ
85 Dodge PU, D-250, 318, auto
85 Audi 4k - - sold but still on the road
88 Audi 5kq
90 Audi 100q



> From: "Brendan K. Walsh" <bkwalsh4201 at hotmail.com>


> Simple answer is that by looking at the input range on the dprs you can
see
> it won't, heres the problem. At idle the cis-e sends out 10mA correct? At
> WOT the e3 sees the same input right?, so you would end up with a rich
> mixture all the time. if you recalibrate the output on the pot  to 0mA the
> ecu will still send siganl outside of the operating range of the dpr
> 02