Rich9928p

Bill,

Did you ever meet up with John to try his rebuilt LH module? That my be a good next step.

John Speake

Hi Bill,
yes, a weak idle mixture will give an erratic idle. Your O2 loop is definitely not working correctly, this could be the sensor or the LH ECU.

The quickest fault find would be to swap the LH for a known good one, as Rich suggests. Then check the O2 volts again, just to be sure.

If it is the LH ECU, there are at least 2 people who will be pleased to repair it for you :-)

BTW your old MAF was aged -3% so this would show a flat spot when the throttle is opened quickly, and some loss of power at WOT.

Regards

bgrabner

Thanks Rich and John - actually I tried to PM John here in VAabout borrowing his ECU - but apparently he has been banned? I don't know what is going on with that, but I have his number and will hit him up after the holiday is over. I will keep you posted, and thanks for sticking with me - you guys are awesome!

BTW - John S - I am not sure I understand your comments about the old MAF - could you elaborate a little bit? Is the wear you are seeing due to a present condition with my engine, or did the new MAF correct that? I can tell you the difference in power and throttle response is night and day - best repair I ever did

Bill

John Speake

Hi Bill,
The ageing of your old MAF, was due purely to miilage and number of journeys it had on your car. Nothing to do with any faults that may also have been present on the car.

The -3% ageing of your old MAF is at the limit for barely satisfactory running, so your MAF was definitelty due for replacement. The figure was just for your interest......

So your findings of a quicker throttle response and power are to be expected when you fitted the rebuilt MAF I sent you. Due to the richer mixture under those conditions.

These improvements will remain once you have sorted out the O2 loop problem. This is because at idle and cruise, the O2 loop will try and keep the mixture at stoich - so your cats can do their job, and also be protected from unburnt fuel.

But when you need extra power, when snappining open the throttle, or at WOT, then the system goes off loop, to allow the mixture enrichment. The quailty of the fuelling is then soley due to the accuracy of the MAF calibration. This is why it is such a critical component for correct running.

I hope this explains better..........

Regards

Bill51sdr

Bill,

If I'm reading you correctly you are not checking the O2 voltage correctly. You do not disconnect the sensor in order to check the output voltage. You need to probe the connector while in the circuit in order to do this.

bgrabner

Success!

15 MPH
HC ppm: Limit=103, Reading=16 PASS
CO %: Limit=0.58, Reading=0.02 PASS
NO ppm: Limit=778, Reading=491 PASS

25 MPH
HC ppm: Limit=100, Reading=32 PASS
CO %: Limit=0.61, Reading=0.03 PASS
NO ppm: Limit=709, Reading=708 PASS

Just made it by the skin of my teeth though with the nitrogen reading at 25 MPH. I ended up putting a new O2 sensor in, but since I failed last time by such a small margin, I don't know if that was ultimately the issue, or if the engine was a bit colder for this last test. Regardless, I don't have to worry about it for 2 years now - with any luck I will have a S/C kit in by then, and will have a host of new issues to deal with

Thanks again for all the advice everyone!

Bill

RazorRacer

My wrench simply adjusted my air / mass flow sensor and it PASSED!

Bill51sdr

Damn! That was close!! What a relief, eh?

FlyingDog

Bill, just move further from DC in the next 2 years. Then you'll have no emissions test.