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Curtis

Link ECU lost tune?

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Hi so about a month ago my  cut out on me and wouldnt start again. So i took it to the mechanic and they did some tests and found it was one of the wires for the coilpacks was shorting so got that fixed and it runs.Also put in a new coilpack loom cause the connecters on the other one were broken and taped up the coilpacks to stop it from missfiring in high revs. Car was also tuned about a couple months ago and running smoothly with no problems before this problem happened.

Now when i drive im sure it feels a bit slower then what it use to be  but it still runs the same boost levels it was tuned at 0.8 bar low boost up to 1.1 bar high boost. And i think it also is running a bit more richer cause it uses alot more fuel and backfires a bit more when i change gears. The car also use to idle a little higher but it idles perfect now so im not fussed with that one lol.

I pluged the laptop into the ecu and had a quick look but im a novice with this tuning stuff so all i could find was the fault codes which some could be old ones most likely.

fault code :17 an volt 3 below

                  20 an volt 4 below

                 46

                 43

might try  some different sparkplugs with wider a gap now that coilpacks are working good for now.

And maybe new fuel filter and fuel pump

Also the mechnic had taken the ecu out of the car and had one of his computer guys try to have a look but he didnt do much to it so was wondering if having the ecu completley unplugged could have reset it somehow maybe.

Any help would be appreciated thanks

The car is a R34 GTT with a rb25det

 

 

     

 

 

 

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Hi Curtis,

From the info you have given I think it is quite unlikely there is an ECU issue.  It is more likely to be a failed sensor, a wiring issue, or possibly something like the CAS has moved (I think remember reading the CAS drive sometimes shears or comes loose on RB's?).  There is no volatile memory that would be lost, reset or changed by disconnecting the ECU. 

The fault codes may or may not be part of the issue, they are all related to AN/AT inputs and are often generated when a sensor has been disconnected.  So they could be just from when the mechanic was working and he unplugged a few wires or they could indicate a faulty sensor or bad connection to a sensor (they could also just be a lazy tuner that never set the fault conditions right in the first place).  So it would be a good idea to do a quick reality check on all the sensors.  A quick test of the basics would go like this: With the engine cold (after car has been sitting overnight), attach laptop and turn on ignition - eng not running.  Air temp and water temp should both read similar values and they should be close to room temperature (say about 20°C depending where you live).  MAP should read about 100KPa.  TPS should read 0% with throttle closed and 100% with foot on floor.  Those are the main ones that will influence how the car runs.  Start car and warm it up, make sure air and water temp still give realistic numbers, TPS should be the same as before and MAP should be <50KPa at idle.  If you have access to a timing light it would also be worth putting a timing light on it and make sure the timing marks show the same timing as the ECU is commanding.

Read the help file about how to do an ECU datalog and if you can do that it might give us some further clues too.

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Ah yes could probably be the CAS they did play around with it while testing stuff as well. And from memory I think all the temps were reading fine  and TPS was working when i had the laptop plugged in. I'll read up some more on that help file too. Thanks for your help

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Sorry just wanted to check im reading this right to check what timing should actually be.  On the ign tab in runtime values I have Ign Angle ( BTDC ) at around 5 degrees and Ign Table 1 is around 17/18 degrees at idle warmed up. So when i check the timing it should be matching with these numbers ?

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With engine running, and laptop connected, go to ecu settings>triggers>calibrate, then click on "set base timing".  This will bring up a new screen where you can set whatever figure you want to lock the timing to.  For you probably 10° is a convenient number.  The with timing light pointing at pulley, then adjust the "offset" number up or down until the 10° mark on your pulley/engine lines up.

After you click done on that screen you need to hit F4 to save changes to ECU.

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