[16v] DPR/mixture/timing questions

[doubt at inwave.com (Nate Mellom)]

Al, thanks for the tips.
I did some more checking today, and came up with these results:

I checked the voltage coming from the O2 sensor, and as it warmed up, it 
ramped up to 1v, and stayed there, fluctuating only .1v in either 
direction (.9-1.1v)

I checked the O2 sensor control unit values based on Bentley, which 
stated that between terminal 2 and 8, I should have no continuity when 
the O2 sensor is connected to the sensor lead, but I should have 
continuity when the O2 sensor was grounded.  In both tests, I got no 
continuity.  I checked all 3 wires on the sensor lead (it was a splice 
job), and all my connections were tight and dry.

I reconnected my DPR harness, and again, I got no reading unless I 
throttled the engine, where it would spike and return to 0.  Even 
testing the O2 sensor limp-home mode per Bentley (engine off, ignition 
on, checking for specific mAs), I got no reading.

The O2 sensor I used was a new NGK (yeah, I know, I should have used 
Bosch, but I am on a strict budget and got it for $6 shipped) with a 
vehicle-specific connector.  I don't know what vehicle it was for, but 
it is a 3 wire, 2 white and one black, so the connections were the same.

So now, I'm thinking I have a defective O2 sensor, or at least one that 
isn't working correctly.

I'll do some more checking, I did check the DPR and it tested okay per 
the ohm test.

Nate


Allyn wrote:
> Nate,
> 
> 
>>throw in, but what would cause a sudden loss of signal from the DPR?
> 
> 
> I believe if you intermittently open the circuit, the computer goes into a
> failure mode where it maintains 0 mA.
> Another alternative is that I think one of the limp-home failure modes results
> in a constant 0mA DPR.
> Third (not fun) alternative is that the DPR has an intermittent open in the
> coil. It would kinda make sense, espeicially if it was heat sensitive.
> Then there was the crazy crap with Dave Winchells red 16v, where the DPR had
> been wired BACKWARDS by someone (positive feedback in a negative feedback system
> is a nono).
> 
> 
>>run, poorly, but run.  I don't have an adjustable advance 
>>timing light, but a friend does, but is it necessary to get 
>>timing set on a 16v?
> 
> 
> I believe there is a 0 mark, as well as a 6 mark on the flywheel (opening in
> tranny bellhousing) - meaning you can use a normal light on it.
> 
> 
>>I'm going to install the new DPR and check the mixture again, 
>>I've had a sneaking suspicion that it's been bad or failing 
>>since I got the car.
> 
> 
> When I first got the rieger it was doing some funky stuff like yours was. I
> ended up troubleshooting by swapping major components (entire fuel / air handler
> assembly, ecu, etc). Result was that the fuel distributor was crap (uneven
> distribution at idle speeds).
> 
> HTH
> Al
> 
> 
>