Tuning turbo with PCV problems

lunatic

.040 Over
Joined
Jul 11, 2017
Messages
64
Location
Nebraska
Ride
2005 Rocket 3
How many of you have done pressure based tuning? I am having issues with the pcv ignition module. Is there any other software or ways of tuning via pressure base besides Dynojet? I am not impressed with the them. The auto-tune is slow, I can do better with data logging and manually putting in numbers. I was having issues of it surging and cutting out. I have since diagnosed it was the ignition module malfunctioning.

 
Last edited:
Yeah you can make up a splicer harness to plug in between the MAP and the main harness so you can run the 5v signal wire to the analog input on the PCV.
Then use a couple of TuneECU pressure and volt readings to calibrate the 5v signal to correspond with the pressure, and switch autotune over from %TP based mapping to pressure based mapping.
Trims can then be imported to the L tables in TuneECU so it runs much much better at idle and low throttle positions.
The F tables work differently to the L tables which is why trims from % throttle based tuning do not work when imported into L tables. And vice versa.
But autotune as good as it is can get stuck in a vicious cycle, when this happens you have to manually intervene, with data logging.
I found %TP mapping good then for larger throttle openings with the supercharger.

Have you double checked ignition module wiring and updated to latest firmware?
 
Last edited:
Yeah you can make up a splicer harness to plug in between the MAP and the main harness so you can run the 5v signal wire to the analog input on the PCV.
Then use a couple of TuneECU pressure and volt readings to calibrate the 5v signal to correspond with the pressure, and switch autotune over from %TP based mapping to pressure based mapping.
Trims can then be imported to the L tables in TuneECU so it runs much much better at idle and low throttle positions.
The F tables work differently to the L tables which is why trims from % throttle based tuning do not work when imported into L tables. And vice versa.
But autotune as good as it is can get stuck in a vicious cycle, when this happens you have to manually intervene, with data logging.
I found %TP mapping good then for larger throttle openings with the supercharger.

Have you double checked ignition module wiring and updated to latest firmware?


Here is how I have it setup for tuning, maybe this is why I am having issues with the autotune at idle and low throttle pos. The stock map sensor wires are plugged in but the vacuum lines are not connected to it. I left the wires connected as not to throw a check engine light. I have all the TuneECU F- L switch numbers on 0. I wasn't using the stock map sensor because I thought is was a 1 bar map. If I am reading your post correctly. You can use the stock map sensor to read boost pressure? If that works, i will go that route and use that.

I have a bosh 3 bar map sensor in the pcv analog input for tuning via pressure. The autotune does have issues at idle, it sometimes gets into the cycle like you mentioned.

Thanks for replying, I need all the help I can get on this.


Oh, yes it does have the latest updated software. Im not sure about the wiring. All I could do is make sure everything was pluged in and tight. It only does this after it has ran for about 20-30 minutes.
 
Last edited:
I only ran 9psi and didn't have problems with the stock MAP sensor, but I had it switch over to throttle based or F tables before boost. I ran on boost and tuned with throttle position.

If you adjust the tables manually around the idle cells to get a good idle, and then 0 the target AFR table for this area in the PCV map, it will not try to autotune around idle and get stuck in a cycle making it worse.
But it will still autotune for all other map areas, once it has a target AFR other than 0.

I haven't done it yet, but I wonder could you wire the 3 bar bosch to the stock MAP sensor plug, ECU should ignore its signal since you've F_L switch to 0, but the 5v signal can be used to set pressure range in the PCV
 
I only ran 9psi and didn't have problems with the stock MAP sensor, but I had it switch over to throttle based or F tables before boost. I ran on boost and tuned with throttle position.

If you adjust the tables manually around the idle cells to get a good idle, and then 0 the target AFR table for this area in the PCV map, it will not try to autotune around idle and get stuck in a cycle making it worse.
But it will still autotune for all other map areas, once it has a target AFR other than 0.

I haven't done it yet, but I wonder could you wire the 3 bar bosch to the stock MAP sensor plug, ECU should ignore its signal since you've F_L switch to 0, but the 5v signal can be used to set pressure range in the PCV

I wired the 3 bar bosch map sensor into same power source as the stock map sensor but only the power source. The 5 volt signal coming from the 3 bar is feed into the pcv only. The only advantage I see with the bosch is it capable of higher boost levels. If I had known the stock map sensor would read boost I wouldn't have purchased the 3bar, I am only running 8psi.

When you tuned for boost, you was adjusting the fuel in the throttle position. What throttle position map was you adjusting? The pcv or the TuneECU? I started to manually doing that in the pcv throttle position map because it was easier to see where the fuel needed adjusted vs the pressure based map. If I am understanding you, we are kinda doing the same thing. Im Just not sure which throttle map you was using, the TuneECU or pcv. If it even matters which one to use.


Wiring the 3 bar in into the factory wiring harness. I assume that would be a way to remove the stock map sensor and not get a check engine light? Wonder if that would work?
 
Last edited:
Your stock map sensor cannot see boost or you will have Allsorts of issues.

I was thinking the same thing before I asked. I am not sure what the stock map sensor is. I would guess its a 1 bar? That's why I didn't run a hose to it.

I just have it seeing atmospheric pressure and put all the switch points on the f-l table on 0. I'm not even sure if that's the correct way to do it but that's how it is now.
 
Here is another video of it acting up....Im not sure what going on with it. I will run fine for about 20 minutes then start doing this. It will die and not start unless I cycle the ignition switch. I have checked all the wires and didn't find anything.

 
Last edited:
I wired the 3 bar bosch map sensor into same power source as the stock map sensor but only the power source. The 5 volt signal coming from the 3 bar is feed into the pcv only. The only advantage I see with the bosch is it capable of higher boost levels. If I had known the stock map sensor would read boost I wouldn't have purchased the 3bar, I am only running 8psi.

When you tuned for boost, you was adjusting the fuel in the throttle position. What throttle position map was you adjusting? The pcv or the TuneECU? I started to manually doing that in the pcv throttle position map because it was easier to see where the fuel needed adjusted vs the pressure based map. If I am understanding you, we are kinda doing the same thing. Im Just not sure which throttle map you was using, the TuneECU or pcv. If it even matters which one to use.


Wiring the 3 bar in into the factory wiring harness. I assume that would be a way to remove the stock map sensor and not get a check engine light? Wonder if that would work?

Sorry I didn't mean the stock MAP reads boost, I meant mine only gets used for mapping when engine under vacuum. By the time any boost is fed it was onto % throttle map.

The new autotune kits apparently retain the stock o2 sensor, is this the case with yours, or did you stick the autotune o2 sensor into the pipe in place of the stock one?
Assuming if you did you have a stock wiring harness o2 sensor plug blanking plug, or unlocked the box in TuneECU?

Sounds like something up with your ignition module, if you remove that does everything work ok?
(Without going into area of map where timing has to be retarded of course)
Also not sure about the way the stock MAP is still there and the Bosch 3 bar MAP is also wired in, I haven't done the 2 or 3 bar MAP thing myself so cannot help.
 
Back
Top