Rich Idle (11.3) with no more trim left?

[Mdh]

Hi Eric,

I have purchased a Typhoon where the previous owner had a known issue that the truck was running super rich at Idle.
Since purchasing I have completed a number of jobs to try and get the truck up to speed however I'm stumped at this issue.
The TT chip is 15542 for 60lb injectors and 3bar 93 fuel with a AEM WB.
I have double checked the vac lines and have replaced as required., confirmed 60lb injectors are installed and fuel pressure at 42psi (lines removed), checked the coolant sensors are providing resistances as expected. There is a 3 bar fitted but appears to be a cheap item so not sure if this is causing a problem. The ignition timing has been set with the tan wire removed so believe that to be good (haven't checked balancer has spun though). I have replaced the fuel pump for a new unit along with the filter so confident that the fuel system is in good condition.
I have the same setup in my Syclone and was a simple plug and play and was able to trim the AFR to 14.7 ish with the pot on the board and has behaved perfectly since installation.
Here I have the trim all the way down but doesn't appear to be pulling enough fuel?
I have attached the below log from a cold start and let it run for nearly 10 minutes. Can you please kindly have a look through and let me know your thoughts?

Regards

Marcus
91 SY#2123
93 TY#1609

 

[EricM]

Hello,
What ADX file did you use to make that log? Also what exact AEM wb is installed (the model number)?

 

[Mdh]

Hi Eric,

Sorry its taken so long to follow up on this post as the Typhoon had taken a backseat for a while.
However I can update as follows but still have a problem where I think the Chip is unable to full enough fuel at idle and fast idle so is failing its MoT here in the UK

The Truck came with another TT chip for stock injectors so thought I would go back to as close as stock to try and diagnose what is the problem.

The setup is as follows:
Chip ID - 11767
Injectors - Stock - P/N 0280150756 red tops
Adjustable Fuel Pressure Regulator - Wound out to lowest fuel pressure setting at 40 with the vac line disconnected after initial 43 test
AEM 30-0300 with Bosch LSU4.9
3 Bar MAP installed
Idle fuel trim (rotary dial set to 0)
Dipswitches 1-3 off 4 - On

Attached is a cold start where I just left the engine to warm up to temperature. It enters closed loop and is trying to get to 14.7 but 13.3 is the best it can do for a short period before falling back to about 13.2 and then settling at about 12.3 I note that INT and BLM are both down to 118 so assume there is no more that the chip can do to pull fuel?
At about 11:04 mins in I clicked the Idle rotary trim on the chip 1 click anticlockwise which is why the AFR's drop further before I returned to 0 (I was just checking I was on the lowest setting).
I double checked the Fuel pressure from the rail and it was at 43 with vac line off, I backed out the adjustment to reduce the pressure to 40 (lowest it would go) and made no difference.

The IAC count is way above the 25-35 count at between 50 -55, I have backed the adjustment screw out and this is as low as the IAC count will go. I'm not sure if this is the issue as have not been able to locate any vac leaks.

Not sure if its a coincidence that with the 60lb injectors and TT 15542 chip it was a similar problem of running rich and that the idle trim rotary on the board would not pull out enough fuel for that setup either?

Any help would be greatly appreciated,

Thanks,

Marcus

 

[Mdh]

Forgot to mention the EGR valve is blanked off also

 

[EricM]

The IAC is critical to the fuel calculation with this chip. If you backed out the throttle stop adjustment screw, then you went the wrong way.
Start by putting the idle fuel dial back to default (8).
To lower the IAC, the throttle stop screw needs to be turned in (clockwise), to open the throttle blade.
I would start by turning the screw until it just touches, then another full turn (engine not running). Then reset the ECM by removing power or the ECM-B fuse, for at least one minute. Then start the truck and let it warm up and settle, see where the IAC ends up.
Shoot for around 25 for the IAC. Might need to remove ECM power again during the adjustment process.
Once you get it to around 25, then we can go back and adjust the idle fuel dial if necessary.

 

[Mdh]

Thank you for your quick response and guidance, its really appreciated.

So following your instructions this morning and after adjusting and resetting the IAC I have it at 26 counts, AFR is sat around 14.7 and idle fuel dial is still on 8 so all good. when I took a step back and looked at what I was doing and how the truck was learning it made perfect sense and clearly operator error from myself.

Thanks again for your aftercare support, excellent service.