94 pings at closed loop

[kwajite]

Hi,

I have a 94 coup that pings at low RPM and closed loop. Open loop seams to be fine. This all happened after I replaced the plugs, wires and fuel filter. Since then I have replaced the o2 sensors and the EGR valve (olny opening half way) I still have the same issue. I decided to datalog a run with datamaster to see whats going on with the ECM. I'm not sure how to read the file but it looks like it's ok not sure. Could someone please look at this file and see whats wrong. Thanks in advance for your help.

 

[gmjunkie]

Check the knock sensor connections,you may have knocked one loose doing the other stuff!

 

[Hib Halverson]

Your TPS is 100% most of the time so you must have run that test at WOT or nearly so. The engine will not run in closed loop when operated at that high a throttle opening. You need to take data when driving the car in a manner that duplicates the conditions present when the knock occurs, not at WOT.

Do some more testing and post the results.

I'll add that part throttle detonation can sometimes be a sign of a faulty EGR valve.

I did note however, in you WOT test, you're getting a huge amount of knock retard about 6 deg. most of the time and as much as 14 deg. That's not good.

Is this engine modified and, if so, to what extent?

 

[kwajite]

Hi Hib,

Thanks for the reply. The EGR valve was recently replaced. The old valve was opening about 1/2 way. As far as I know the engine is stock no mods have been performed. The car ran perfectly when I bought it in 2003. In 2010 is when I noticed it was running rough so I did the minor tune up after that the roughness went away and now I have the ping. I am also going to include more of the datamaster file that I have. I couldn't upload the .xlsx file. I checked out the knock sensors a couple of weeks ago they seemed ok. What could cause the 6 degree retard? That last snapshot was the car at 1700 rpm and taking it to WOT. Notice the knock counts going up rapidly. The next snapshot is the car just going down the road. BTW the car has 100k on it. Just did the water pump and the opti looked ok.

 

[kwajite]

I guess what I am asking is for someone to look at the last post of the data from datamaster and determine if the sensors look right. Is the MAF working properly? I replaced the 02 sensors are they putting out the proper voltage? With the throttle open a little does the Lterm and Sterm look ok and the injector data? After I replaced the o2 sensors should I have reset the ECM? If my datamaster data looks ok then I have to look at other things like the opti or the new plugs I installed. :ugh BTW my second post has a different data set from my first post. Thanks again.