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Jared

Link G4+Fury -No AFR reading

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Hi, 

 

With my engine running, laptop connected and viewing the PC Link software, no AFR reading is being displayed. I have "Internal Lambda 1" set to ON.

The wideband O2 sensor is wired as per below:

Blue/white         RE               Pin14

White                  APE            Pin32

White/blue         IPE             Pin31

Blue/black          MES          Pin11

Blue/purple        HEATER    Pin10

Grey - positive switch

 

Does the above wiring look correct? If so, then I assume it must be a setting in the ECU? Any ideas?

Thanks

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Ok, thanks.  I just wanted to check there was no CAN lambda device set up by mistake in the tune before making a suggestion, that looks ok.  I just noticed you have another thread with same content so I will delete that one and leave this one to prevent confusion.

 

So the error you have "open circuit R Comp" , this means the ECU cant measure any resistance on the two wires that should have the calibration resistor connected between them inside the oxy probe connector.

To confirm, I suggest you unplug the ECU, then with a multimeter set to ohms, measure the resistance between the two wires in the ECU B plug highlighted below (APE & MES).  The resistance should be in the range of 30-300ohms.  If you dont have the correct resistance here, that would indicate there is a bad connection, incorrect wiring or bad sensor.  

Report back what you find.

 

jq5O3f4.png

 

 

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Hi Adam,

Thanks so much for your help. Yes please, delete my other post.

Have tested resistance across these two wires and am getting no reading (Did a few other random tests to ensure it wasn't my multi meter or user error). Curtaining getting nothing between MES and APE. So assuming this would indicate there's a flaw in my wiring somewhere?

I'll dig into the wiring over the next couple days and report back.

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Those two wires mentioned above should go to pin 1 & pin 5 at the lambda sensor plug.  So you could start by unplugging the sensor and measuring resistance across those two pins, that will at least confirm the sensor is correct.  If you get correct resistance there but not at the ECU end then it should be easy to figure out where the disconnection is.

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Hi Adam,

Was quite a few years since I wired my car up. Hoping you may be able to clarify for me what wires on the wide band should correctly go to which pin on the ECU? The sensor is a Bosch LSU4.2 5 wire. Interestingly it has 5 wires from the sensor to its supplied plug, then 6 wires out from this plug (see attached diagram). Of these; black, grey, white, yellow, red, green. Which are to be be connected to where on Loom B (or elsewhere)?

 

IMG_9238.JPG

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Probably the most artistic picture on this forum...

2 hours ago, Jared said:

The sensor is a Bosch LSU4.2 5 wire.

Are you sure?  It should be a LSU4.9, no Link product supports the 4.2.

The sensor only has 5 wires but you need to have all 6 wires on the other side of the plug.  The 6th pin that has no wire on the sensor side is for the calibration resistor that is inside the plug.

u6FZJSD.png

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Thanks for your help. It is indeed a Bosch LSU 4.9 that I'm running. I've traced my wires back and there was an error. It's corrected now and working perfectly. Much appreciated.

Another question; How effective is the autotune function on a large ported rotary? 20B Semi PP turbo. Challenge I'm having is the car runs smooth and pulls seamlessly up in the higher RPM. But idle and lower RPM it appears excessively rich, very fumey, coughs and splutters, stalls when RPM comes down approaching an intersection, and almost undrivable.

I'm well familiar with ported rotarys and know how aggressive they can be at low RPM. What I'm experiencing is certainly in the tune and not the engine itself.

As I'm relatively novice the using the various tuning tables, I thought the autotune maybe able to assist?

 

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Quick tune is really designed for steady state tuning on a dyno.  It would be pretty difficult to use on the road.  I would suggest just trimming the tune from logs, the mixture map works ok once you know your way around it but the "quick trim" function is usually what I use if things arent close.  I will attach a quick video of how you can use these tools.

The big thing I found with tuning PP's is you need the injectors relatively low down in the manifold/ports for decent lowspeed behavior, the last NA PP rally car I tuned had the injectors up in a IDA style throttle body and it was a dog until I had the owner move them down to the bend.  Injector timing will probably have quite an effect to.  

Video: https://1drv.ms/v/s!AiYbYlZQuRHPszz5hTxJ8ec0MitL?e=fuUKqZ

 

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Got an opportunity to drive the car over the weekend log about half an hour of driving which highlighted a few things to look into. Will correct these before trying the quick trim function.

Noticed the inlet air temperature remained consistent on 20 the entire time throughout the log. After testing the sensor and wiring to find it all ok, I found I had not set the air temp input in the PClink software. Corrected now.

Is this something likely to have an impact on the data currently set in the fuel table and how the car performs?

 

 

 

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49 minutes ago, Jared said:

Is this something likely to have an impact on the data currently set in the fuel table and how the car performs?

That will depend on how far off 20 deg the real temperature was, but probably wont have a large imp[act.

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