Drove my truck a long distance yesterday for a cruise and car show ~300 miles round trip. Nearing the stop for the car show the wideband kept showing LEN when I was pulling up to traffic lights for stops, no recovery. It idled poorly and wanted to die unless I 2 footed it or dropped it in neutral and idled it 2k rpm. Under throttle, boost and cruise it seems to be fine. Left for home and had issues once again when hitting traffic lights the AFR dips way low to 17-19 but recovers very slowly to 13-14ish, better but seems like something isnt right. The cruise was from Apache Junction to Prescott Valley a change in elevation of ~3600 ft. Possible that has something to do with it? Possible failing oxygen sensor or MAP? The truck is equipped with a Turbo Tweak and a PLX wideband.
AFR Issues
- Thread starter Static
- Start date
Couger1968
Dazed and Confused
Re: AFR Issues
Maybe a vacuum line cracked or fell off.
Maybe a vacuum line cracked or fell off.
Re: AFR Issues
This was my first thought as I read thru that thread recently. I figured if it really started running bad I would unplug the O2 and it would just run open loop till I got it home. Worse case was I call Hagerty for a tow. I will order one this week and report back.
This was my first thought as I read thru that thread recently. I figured if it really started running bad I would unplug the O2 and it would just run open loop till I got it home. Worse case was I call Hagerty for a tow. I will order one this week and report back.
Re: AFR Issues
I have had issues keeping the truck connected to datamaster. Not sure if its my cable or the laptop has issues. I just went out to test a usb stick in the CD deck and when I key on no start it reads 14.7 and takes a full 30 seconds to reach full lean. I waited 30 minutes and tested again it does the same thing. Not sure if this is normal PLX behavior. Also if anyone has a link to an inexpensive replacement I am on the search.
I have had issues keeping the truck connected to datamaster. Not sure if its my cable or the laptop has issues. I just went out to test a usb stick in the CD deck and when I key on no start it reads 14.7 and takes a full 30 seconds to reach full lean. I waited 30 minutes and tested again it does the same thing. Not sure if this is normal PLX behavior. Also if anyone has a link to an inexpensive replacement I am on the search.
Don W.
Stab it and steer it
Re: AFR Issues
Do you have a DM-5 or DM-6? I believe with key on before start a DM-5 will full lean (I think it actually says lean) However I think it does it almost instantly. A DM-6 reads "air".
IF you have a DM-5 there is a black wire that is not used. Make sure it is not grounded. Also on the PLX box there is a little jumper that "terminates" the system. This for when you have multiple sensors. Water, oil, etc. I imagine you don't so the terminator should be there.
If you want it to stay in open loop just disconnect the 4 term connector. This takes the PLX out of the system entirely, no WB and no NB.
Lastly make sure the gauge is plugged into the TX jack. Probably is but should be checked.
HTH a bit.
Do you have a DM-5 or DM-6? I believe with key on before start a DM-5 will full lean (I think it actually says lean) However I think it does it almost instantly. A DM-6 reads "air".
IF you have a DM-5 there is a black wire that is not used. Make sure it is not grounded. Also on the PLX box there is a little jumper that "terminates" the system. This for when you have multiple sensors. Water, oil, etc. I imagine you don't so the terminator should be there.
If you want it to stay in open loop just disconnect the 4 term connector. This takes the PLX out of the system entirely, no WB and no NB.
Lastly make sure the gauge is plugged into the TX jack. Probably is but should be checked.
HTH a bit.
Re: AFR Issues
I do have a DM-5. I will check into those as well as try to get a datalog. Looks like all the new gen4 PLX wideband boxes use the new Bosch 4.9 sensor and sensors aren't backward compatible. So if I can determine for certain the sensor is the issue its probably best to upgrade the whole thing to a gen4 with the DM-6. The 4.9 sensors seem to be faster reacting and have a longer life.
I do have a DM-5. I will check into those as well as try to get a datalog. Looks like all the new gen4 PLX wideband boxes use the new Bosch 4.9 sensor and sensors aren't backward compatible. So if I can determine for certain the sensor is the issue its probably best to upgrade the whole thing to a gen4 with the DM-6. The 4.9 sensors seem to be faster reacting and have a longer life.
Re: AFR Issues
Ok grabbed a log this am. Couldn't really reproduce the issue. Going to grab another when it gets a bit warmer this afternoon. Was lean and laggy when i first started it and backed it out of the garage but it should have been in open loop still? https://onedrive.live.com/redir?resid=7B2B331058212480!332&authkey=!AEkIsT2y232tR5U&ithint=file%2cuni
Ok grabbed a log this am. Couldn't really reproduce the issue. Going to grab another when it gets a bit warmer this afternoon. Was lean and laggy when i first started it and backed it out of the garage but it should have been in open loop still? https://onedrive.live.com/redir?resid=7B2B331058212480!332&authkey=!AEkIsT2y232tR5U&ithint=file%2cuni
Don W.
Stab it and steer it
Re: AFR Issues
Opening the throttle makes the IAC count go higher doesn't make any sense, to me anyway. (See below)
The idle screw (IE blades) works opposite the IAC. Turning the screw in reduces IAC pos, out increases IAC pos. IOW closing the throttle plates require the IAC to open (bigger number) to compensate.
I see it says Code59 turbo. I'm gonna stop because know zip about Code59
Opening the throttle makes the IAC count go higher doesn't make any sense, to me anyway. (See below)
The idle screw (IE blades) works opposite the IAC. Turning the screw in reduces IAC pos, out increases IAC pos. IOW closing the throttle plates require the IAC to open (bigger number) to compensate.
I see it says Code59 turbo. I'm gonna stop because know zip about Code59
Re: AFR Issues
Not running code59 anymore. Switched to turbo tweak a year ago. Im sure I forgot to change the setting in datamaster. Shouldnt really matter? I know the IAC counts don't make sense to me either I cranked it out initially and counts rose to 80. Stepping on the throttle also increases the IAC counts to about 100.
Heres the log I had running while adjusting the IAC. You can see it rise with RPM. https://onedrive.live.com/redir?resid=7B2B331058212480!333&authkey=!ALzK-k_UsXSabhM&ithint=file%2cuni
Not running code59 anymore. Switched to turbo tweak a year ago. Im sure I forgot to change the setting in datamaster. Shouldnt really matter? I know the IAC counts don't make sense to me either I cranked it out initially and counts rose to 80. Stepping on the throttle also increases the IAC counts to about 100.
Heres the log I had running while adjusting the IAC. You can see it rise with RPM. https://onedrive.live.com/redir?resid=7B2B331058212480!333&authkey=!ALzK-k_UsXSabhM&ithint=file%2cuni
Eric Sy GN
Donating Member
Re: AFR Issues
Check the IAC fully warmed up, in park. In your log, it's about 66-68. I would rather see that down in the 30-40 area. In your case, you need to open the throttle by turning the throttle stop screw clockwise to get the IAC down. However, sometimes, if you do it while it's running, the TPS % will come up too high and it will switch to throttle follower mode (which will bring the IAC up). In that case, adjust it with the engine off, say, a half turn at a time. Restart and let it settle down, and the IAC should be lower.
Since my chip takes IAC position into account for idle fueling, the IAC position is a little more critical. You might need to drive it around a bit to let the idle BLM relearn. Your current idle BLM, which is down around 118, will probably come up.
Check the IAC fully warmed up, in park. In your log, it's about 66-68. I would rather see that down in the 30-40 area. In your case, you need to open the throttle by turning the throttle stop screw clockwise to get the IAC down. However, sometimes, if you do it while it's running, the TPS % will come up too high and it will switch to throttle follower mode (which will bring the IAC up). In that case, adjust it with the engine off, say, a half turn at a time. Restart and let it settle down, and the IAC should be lower.
Since my chip takes IAC position into account for idle fueling, the IAC position is a little more critical. You might need to drive it around a bit to let the idle BLM relearn. Your current idle BLM, which is down around 118, will probably come up.
Davemc1963
93 Ty Owner
Re: AFR Issues
When I was trying to get my IAC counts where they should be, I ended up having to tweak the throttle stop bracket slightly.
However, one other thing that did catch me out and is/was possibly due to some throttle body wear around the spindle as well, but was the CC cable ever so slightly being adjusted to have zero slack. I couldn't get repeatable idle/0 throttle IAC numbers.
The 'zero slack' CC cable adjustment just sometimes, ever so slightly held the throttle off its stop. Moved it back a hole at the actuator and sorted it. If you still have your CC, its worth a check.
Dosent solve your PLX issues though. I would add and I think DonW touched on it, that the wiring configuration of the earlier versions of the Plx wide band units (as per the diagrams attached earlier) are different to the later Gens at the 4 pin Molex connector, so beware.
When I was trying to get my IAC counts where they should be, I ended up having to tweak the throttle stop bracket slightly.
However, one other thing that did catch me out and is/was possibly due to some throttle body wear around the spindle as well, but was the CC cable ever so slightly being adjusted to have zero slack. I couldn't get repeatable idle/0 throttle IAC numbers.
The 'zero slack' CC cable adjustment just sometimes, ever so slightly held the throttle off its stop. Moved it back a hole at the actuator and sorted it. If you still have your CC, its worth a check.
Dosent solve your PLX issues though. I would add and I think DonW touched on it, that the wiring configuration of the earlier versions of the Plx wide band units (as per the diagrams attached earlier) are different to the later Gens at the 4 pin Molex connector, so beware.
Re: AFR Issues
OK this is driving me crazy. I adjusted the screw 1/2 a turn at a time after turning it off as Eric suggested. Its doing the exact opposite of what it should. Backing the screw out seems to be the only way it lowers the IAC counts. Inevitably the screw stops touching the lever, even with removing the cruise control cable. I tried resetting the IAC position by turning on in diagnostic mode, waiting 30 seconds, unplugging the IAC, remove diagnostic, start(wouldn't run without throttle). I plugged the IAC back in. Still the same. WTF is going on here? Log taken during this attempt https://onedrive.live.com/redir?resid=7B2B331058212480!334&authkey=!AMF8tnwQBiy3XJo&ithint=file%2cuni
OK this is driving me crazy. I adjusted the screw 1/2 a turn at a time after turning it off as Eric suggested. Its doing the exact opposite of what it should. Backing the screw out seems to be the only way it lowers the IAC counts. Inevitably the screw stops touching the lever, even with removing the cruise control cable. I tried resetting the IAC position by turning on in diagnostic mode, waiting 30 seconds, unplugging the IAC, remove diagnostic, start(wouldn't run without throttle). I plugged the IAC back in. Still the same. WTF is going on here? Log taken during this attempt https://onedrive.live.com/redir?resid=7B2B331058212480!334&authkey=!AMF8tnwQBiy3XJo&ithint=file%2cuni