So my 94 rx7 single turbo is having a consistant lean issue at/around ZERO vacuum/boost, but runs great all other times.

My shop has done cold and hot smoke tests and visual inpections to check for leaks and found nothing. They also tried playing with the tune at that section of map with no effect.
Not sure what to do.

Any ideas??

 

How lean, what ecu?

 

Apexi PFC, basically pegs AEM wideband gauge straight to red, so 16, 17+

If Im at a low enough speed, like around the neighborhood, the car will start bucking once this happens. But give it more gas and start building boost and back to running fine, in the green.

 

thats strange.. have you done the FP rewiring all though it shouldnt be the case.

in this situation what condition is the map sensor? maybe something is in the way and causing lag , dirt? in the filter if you still have it

 

Was the car running normally with the single turbo, tune and everything as it is now and it just developed this issue or is it a fresh setup/build? The fuel base and correction maps look to be normal in those cells? Do you have a datalogit? Providing your map and a log of the car producing those symptoms is probably the best thing you can do to get some help from the forum.

 

Injection transition, when the primaries kick on.

Injection map not smooth.

Need more info... data logs, rpm, duty cycle's. A data logit would help alot.

 

Need to see the map and the logs.

 

"when the primaries kick on. "

secondaries not primaries...

 

I dont have access to the datalogger info to be able to post any maps.
This is all on a brand new fresh rebuild and single conversion. The car was running fine during break in and for a while after final tune. Had to replace a bad turbo manifold gasket and one of the turbo seals then this problem started.

I assume the data in these cells in looking normal as my tuner has messed with the tune in various area, timing and fuel and such and that has made no difference. I am thinking it has to be something mechanical.

 

It could be something "mechanical"

I would suggest you need to mess with your injector overlap and your primary secondary transition/ secondary ms, which is only accessable with the data logit. The picture shows the page that needs to be looked at. What it sound like is when your secondary injectors are coming on line, your going lean. If you have upgraded your secondaries and not messed with these settings, you need to.

 

There is also "Accelerate inj "setting they are able to be gotten to with the PFC commander. You can add fuel/time fuel is released at throttle tip in.

With the data logit, its setting page 2.

 

My tuner says all is well with injector time, overlap, transition and such. I asked him about that again last week to be sure. Nothing he changes on the tune has an effect.

 

What injectors are you using?

Between all those settings I mentioned you should be able to work something out. If you can post screen shots of the settings from the data logit, it would be helpful, without that info, its like playing darts in the dark. If "all was well" you wouldn't be having problems and your tuner would be able to figure it out. If you could post the settings you could get a second opinion on the actual setting, instead of an "all is well" answer.

 

If i remember correct, 600P 1300S injectors.

Id post log info if i could, but neither I nor my tuner has the Apexi data logit.
Im wondering tho, if the car was running great on this same final tune, how can this be a tune issue and not something mechanical? And changing the tune settings should have an effect on the isse, but they are not.
Not saying ur wrong, just trying to understand how it could be a tune issue. All other shops we've talked to think its a tune issue.

 

It has to do with the staging of the injectors and Accerler Inj Milli seconds(similar to a accelerator pump on a carb, which you can adjust with the commander). Has nothing to do with the 20x20 injection table, you could change the 20x20settings all you want but the staging when the secondaris come online is still off.

Most likey its 550 and 1300. You NEED a dat logit to access some of those tables. The Data logit box opens up many more things than can't be accessed with the Commander.

Either buy the data logit and figure out how to do it your self. Or find a differet tuner. Ray at PFS, located in Fredricksbrug Maryland, is Top Notch. I would not let the person thats doing the "tunning" do anymore, go find some one with more know how. Trying to tune a PFC with out a data logit is kinda like trying to win a fight with your arm tied behind you back.

 

Now that you explain it like that it makes sense.
PFS would be my only option as I have not been able to find any other shops in my area willing to touch a rotary.

thanks

 

Thanks for the info from everyone. Bought the data log it stuff and got the lean issue worked out. Car is back and running great.

Does anyones know a tuner in Northern VA that knows this data log it software really well?

 

In the early days of PFC tuning, many people changed (increased) the injector overlap values to make the engine run smoother during overlap.

But my logging and using the chart function to look at what the injectors were doing showed they were treating the results not the cause.

The problem was the Pri/Sec transitions values. The primary inj was dropping off too much while the secondary was over flowing for a while during the crossover.

Log the injectors with the stock Pri/Sec transitions values and stock overlap values with the ADVANCE function and chart them.

Then try these transition values.

Trans % of 30
Trans ms of .1

It has worked on all engines that I have worked on.
Even makes the stock injectors with stock setup work better.


Contact arghx to join the PFC tuning group to learn the most about using the PFC.

 

thanks cewrx7r1, this is good info. I'll pass it on to my tuner since he is trying to get a much better handle on the advanced settings.

I didnt end up messing with any of my overlap settings. Just used the live trace feature to pin point where the lean issues where on the injector map and then richen them up to a good range.