Powerjection III Install and Review

Hi. I just ran across your post and have a PJ-III system also. Just thought I'd throw a few things out there to check if you haven't already. The system has a few niggles in it and I apologize if this is stuff you already know.

I didn't see where you had posted anything from your monitored AFR ratios during operation or adaptive learn tables so here goes...

The base map that is initially calculated (at least in my experience) is way too rich. They limit the amount of fuel that can be added or subtracted to the base map via adaptive learning to +/- 25%. You may already know this but they did that so that if someone ran their car out of gas (which would result in the system going way lean), the ECU didn't richen the fuel map so much that the car wouldn't start once the tank was refilled.

So, say you load a brand new base map and nothing has been learned by the ECU yet. Say your target at some load and RPM is 14.2:1 but the car is running at 11:1. Once the computer goes into adaptive learn and subtracts 25% it will not subtract any more even if that only pulls the AFR up to 12:1. If that is happening you can change the AFR target to 20:1 and it will still never lean up past 12:1.

To see if you have an issue with that, just open the adaptive learn fuel table under "Edit" -> "Adaptive Learn Fuel". If any of the cells have -25 (or 25) in them it means that the ECU has subtracted (or added) as much fuel as it can but still cannot reach your AFR target and never will.

If that is the case, you just have to note what RPM ranges have the issue and then adjust your base map under "Setup" -> "Fuel Wizard". Adjust the fuel percentage in the RPM ranges that have the issue up or down a few points and drive some more and check the adaptive learn table. The slider MUST be set to "Locked" when you make changes under the Fuel Wizard or any changes you make will be lost when you shut the car off. That whooped me pretty good for awhile. Note that 25% in adaptive learn is not the same as 25% on the fuel wizard.



One other thing you can check with the car running and the adaptive learn table up is the idle. On mine, the base conditions for the idle cell were set so that the car was jumping in and out of the idle cell. You'll see whatever cell the car is running in highlighted green. If the MAP boundaries are borderline for the idle cell you may see the green box jump between the idle cell and one of the normal running cells which makes the ECU jump between two different fueling modes and thus fluctuate since the AFR targets between the two cells are most likely different.

If yours is doing this, open up "Setup" - "Main Setup" and watch the green highlighted box on the MAP line at the top. If "Idle Cell Enabled" is checked, you want the box for "AND MAP IS LESS THAN" set to some value a few boxes higher than where the green highlight is going.

I have a manual transmission so I don't have load changes at idle like you do so I don't know if this will cause issues with adaptive learning constantly adjusting fuel when you put it in drive. The RPM follower function should be adjusting the IAC to keep your idle target.

 

Thanks. good to see another person with this sytem. Overall, the car runs really well. I've changed the AFR table quite drastically from the base map (as you said they had it WAY rich). So far the Adaptive Learn hasn't gone any lower than -18 or higher the 12 on any of the cells. My idle cell is actually running perfectly at 14.4AFR @ 800 rpms.
Right now, the thing I'm trying to figure out how to tune out is the surging I get during decel. When the rpms get down to whatever rpm I have the decel limit set at, there is slight surging as the fuel map and the decel scale go back and forth. I'm not sure this can be tuned out, since I can't seem to change the AFR table enough to make the transition smooth.
I wish they would come out the Advanced Tuners guide that they hint about in the instruction manual so I can try my hand at manual Tuning as I think after a certain point, would be more beneficial to getting the tune spot on.

 

Yeah, I asked Cody about the "advanced tuning manual" and he said "I am the advanced tuning manual". Now I heard he's left the company.

I just disabled the decel fuel shutoff as it seemed to make my car more prone to little backfires, especially when clutching in to shift at low RPM's. You just enter 9000 or something absurd in the "RPM greater than" window and it never comes on. I supposed I could've played with the pulse width but it works well like this.

They have new firmware and software that can be loaded which changes some things. The new manual is on their website and you can download it to see if it interests you. The new manual also says for the base map torque value to enter rear wheel torque which isn't mentioned in the old manual. This results in a leaner base map right off the bat if you put in flywheel torque which I assume most would. Off the top of my head the changes are:
-Base maps supposed to be better.
-New function added to cold start which allows user defined pulsewidth of extra fuel to be injected during after start enrichment for a user defined amount of time. This finally helped me to get mine to start right up when cold. It would catch right away and then die for the first few cranks.
-IAC control function added to let you predefine RPM for idle based on temperature. Now you can select RPM target or IAC step target. Also added in user defined IAC step limit for RPM follower function.

One other thing that I forgot....you may not have an issue with it but I do. When saving the ECU configuration, I have to switch the tuning mode in the main setup to "Manual" or else when it saves the fuel wizard will revert back to what would come up if I hit the "calculate" button. In other words, any changes to the base map that are actually in the ECU are not saved on my laptop. Everything else gets saved, but the fuel map gets blown out. Then I have to switch the mode back to "Automatic" if I want to change the base map or else if any slider on the fuel wizard is changed the car immediately dies. It'll start back up but as soon as it comes off the after start enrichment it just dies even if the slider changed was way up the RPM band. Weird. I just found that out a few weeks ago as I always saved my configurations before changing everything but I never reloaded one. I looked at some old ones offline and was like wtf, I know that's not right.

 

Good to know. I'll see if there's a way to get the new firmware...it sounds like they made a few advances that would help me out as well. Also, did you or do you have problems with hesitation and sometimes a small "pop" when trying to go WOT from a stop? I noticed that if i depress the pedal to about 3/4 I can roast the tires and take off very well, but as soon as i try to go WOT from a stop...blah. I figured i was too lean and added a lot to the accel pulsewidth to try and help with minimal results. Maybe it's time to re-curve the distributor and see how that works for me.

 

I'll be honest with you. When Cody sent me the new firmware (which is needed for the new software functions) he seemed convinced that it wouldn't need anything because one of the main things changed was the cold start. I still had to fool with it a lot to get the cold start down. You know how that is....you only get a couple of tries and then the car pretty much has to sit for a day or else the window is blown and it'll start every time. I think I was 95% there with the old software and had to start all over so I think I would've been better off to just have not loaded it at all.

Also the new software has its own little issues. Like the the IAC step limiter functions. If I changed the cranking IAC position to a value higher than the upper limit set in the running IAC table, the IAC would stay open to that value after a hot crank and just sit there at 1600 RPM or whatever until I put a load on the engine. Another thing is that now the IAC setpoint never goes below 10 no matter what the lower limit is. Even if I try dropping the RPM target way low it will not go below 10.

Yes, I have issues with acceleration similar to you. If I mash it hard it hesitates and then goes like hell. I've been fooling with the acceleration enrichment tables off and on but lately just haven't had time to drive the car at all. If you have the table up, the delta window it's working with when you mash it will highlight green so you can kinda get an idea where you need to adjust.

One thing you can do is datalog a full throttle run, then pull up your RPM, MAP, and AFR in the log. As you know, adaptive learn is broken up into MAP and RPM boundaries. I found a little blip on mine where the AFR leaned up a lot during full throttle in first gear. According to the log, at that point MAP dropped just below 90 for a split second which meant it shifted to a different cell in the fueling map. I pulled up adaptive learn and sure enough the 90+ cell at the RPM where the lean spot happened had maybe +6 in adaptive learn but the next lower cell had zero so when MAP dropped it changed to a different and leaner fueling cell.

With your issue, MAP can be pretty much related to throttle opening. 3/4 throttle will most likely result in lower MAP (higher manifold vacuum) than full throttle. If it is indeed a lean condition you should be able to just enter some additional fuel in the adaptive learn table in the 90+ cells and get more fuel that way. Cody said it can take some time for the high MAP cells to get populated since usually the engine spends so little time in those areas. He recommended putting the car in a higher gear and flooring it so that it would both load the engine up to high MAP and pull through the RPM band slower. That's easy for me since mine is a manual but I guess you'd have to pull off your kickdown cable or something.

 

Second tank of gas now, averaged 9.35mpg. One thing I dislike about these old cars is how inaccurate the stock gas guages are. My needle was past "E" and when I filled it up this morning I STILL had 6 gallons in the tank.

 

Gas mileage took a big hit after I retarded the timing...8.26mpg. And that's with quite a bit of highway driving at 55-60mph. I should buy stock in Exxon.

 

Ouch. I'll quit complaining about my 17mpg's.... Though I really want to crack 20mpg and would really really like to crack 25mpg. I have some more work to do with the ignition timing though (and need to drive <80mph....)

 

Set the initial timing back to 12* and re-installed the fuel vapor canister. Here's hoping for better mileage.

 

Hey guys, it Cody (the advanced tuning manual) haha. Yeah I quit back on 10/7/10 But I'll help you guys out if you need anything...

Steiner is good and so TheSilverBuick.

How is everything going as of now?

The popping on decel is your decel fuel cutoff. You can just turn it off if you like or turn the rpm threshold up. I like the decel feature as it save a bit of fuel and saves the brakes too. Some people dont like the racecar popping sounds but I love it. I have the rpm set to 1300 on my car with 0 PW. But I also have my idle control very sensitive, in that the butterflys need a VERY fine adjustment. Saying that you adjusted the screw an 1/8th of a turn for example is way too much!

Going from 0 to 3/4 throttle is significantly different than going from 0 to 100 as far as fuel is concerned. That throttle body flows 930cfm! at the bottom of the accel enrichment ares your going to need a ton of fuel to fight that lean pop that's happening through the intake. Like Steiner said, watch the delta TPS to see where its landing and make adjustment above and below that.

Keep in mind that's its always easier and less noticeable for the EMS to pull fuel out of the map than to add fuel to it.... You don't notice a rich condition like you do a bucking bronco lean condition.

The more timing you can throw at the motor, the more fuel you will save and the cooler it will run...

Lemme know how things are going. You can reach me on Facebook as well ... I cant post links yet so just search for RetroTek Speed.

 

Cody,
Good to hear from you. I decided to completely shut of the decel function, since nothing I did seemed to get rid of the surging at whatever rpm i had it set at.
One thing I'm not understanding is the whole cold start/after start enrichment. With a carb, you turn on the car and the fast ilde solenoid idles the car up until the engine is up to temp and then the idle goes down. With this system it does the complete opposite. It starts up and idles really low and the warmer it gets the faster the idle until it normalizes at whatever i have it set at.
Thanks for the help.
-Jason

 

Yeah that doesn't sound right. I have my car set up to idle high when cold, and it idles down as it warms up. Some times it's a dance between the Warm Up Enrichment and IAC settings so it's not being overly rich or lean at different parts of the warm up, but it definately starts at high idle and works it's way down.

How's idle controlled on your car? Is there an Idle Air Control (IAC) valve? If you don't have a way to introduce more air into the engine when cold, then you will get what you are seeing, running slow when cold (and overly rich) and warm up to normal idle speed.

Also, usually the choke on a carb controls both the upper butterfly and a detent to open the lower butterflys (the reason you have to hit the pedal at least once to set), the fast idle solenoid should only be for air conditioning as far as I know.

 

Yes there is an IAC but the hole is only 3/8" and Ive found that on big motors it sometimes isn't enough to bring the idle up when these things are cold.

Effin big blocks haha. I think we went over this already ... Buts thats why I had you open the butterflies as much as possible and close the IAC when the engine is hot (180 deg). That way when the engine is cold and the IAC is needed to raise the idle, its has as much room as needed (which may not be quite enough with your setup).

Dont get sad yet! First thing you need to do is make sure the air fuel ratio is correct when the engine is cold (it may need to be different than when warm). Open the butterflies a TINY with the primary adjustment screw to bring the idle up when cold so you can get the C-Temp Enrichment set. Make note that I have never needed to adjust this...



:idea2:The secondary screw is not needed to adjust the butterflies. the linkage rod that connects the primary and secondary butterflies should have NO slop/play in it. Plus it should be an adjustable rod, if its not, then call Bryce up and have him send you one. You should have that linkage adjusted in such a way that the butterflies are open the same amount and both move via the primary adjustment screw.

Once you get the Air/Fuel Ratio (AFR) correct then you can play with the IAC to get the correct amount of air into the engine that's needed. Timing will also play a key part in helping the engine idle nice.

IAC:

Depending on how old your throttle body is, make sure that the IAC hols is drilled 3/8" all the way down to the bottom. The hole should have a chamfer on the top.

Well I can explain this!

1. Sounds like his idle RPM control limit is set too low (lower than 1600)... That will make this happen, I have mine at 2000. If the engine revvs up past that rpm when it fires up then the EMS will never try to control the RPM for idle.

2. If you set the lower step limits down to 0, the IAC should close down to 6. 6 Is hard coded into the firmware and will not go any lower...


My IAC settings are below...



I had one customer who adapted a larger IAC from an LS motor into his throttle body, Just took some drilling of the passages so it could be done and he said it helped quit a bit... I'll see if I can get a hold of him

 

I don't know exactly how your system works, but on mine there are two types of starting enrichment - cold start and after start. Cold start is like the choke function on a carb (except instead of on/off, you can set it up to gradually lean inself out).

After-start is a different animal - that adds extra fuel for a short period after the engine starts, regardless of engine temperature. AFAIK there is no similar function in a carb.

With regards to IAC, I have my car set up so that when it is warm, in neutral, the IAC is closed. I adjust the butterflies to get my idle speed. Then as soon as I drop the car into gear, the IAC will open just slightly. When warm, mine idles at 800 RPM (IAC=0), then when I drop it into gear the engine will drop to 650-675 then gradually recover to 725 as the IAC opens slightly.

Surging can be cause by running lean or timing. On my car, I have to idle around 14.1 A/F in order to stop the surging, and I had to play with timing too. I don't know if the Holley system allows you to tune the P&D of the IAC action, but mine is very damped (i.e. very low P&D numbers).

-Bob C.

 

Yeah, my IAC bypass hole is 1/2 inch, and boy does it whistle when cold, lol. Slight hi-jack, does the powerjection set up open all four butterflys simultaneously or progressively? Sounds like from the description, simultaneously. Just a curiousity.

Bob, sounds like you have a cold idle valve instead of an idle air control valve. Cold idle valves are ON/OFF style (which work great too!).

 

The last time I called Bryce to get help tuning, I was told to cover the the hole behind the secondaries to help me with getting the idle charactoristics straight. (everytime that is left uncovered there is always a VERY loud sound of it sucking in air and the idle goes crazy) I'm assuming this is the IAC hole you're talking about. So, how am I supposed to tune this thing properly if that's covered up?
Also, the primary and secondary butterflies are only adjustable independantly. Having them both adjust with one screw would be most helpful, so I guess I'll have to give Bryce a call to see about getting that linkage you're talking about.
The AFR at idle is setup perfectly. I've never really had an issue with that.
Also, I guess the software i'm using is old because on my IAC Control menu, I do NOT have the RPM / Step Target portion like you have in your attachment. Is their an upgrade I can dowload?

 

I think what the Doctor was saying is programming your IAC to be closed when fully warmed up (which sounds right), and that should be the equivelant to plugging the hole for setting a good idle warm. Then when you have a good idle warm, look at the IAC settings to make sure it's fully open when cold.

As I said, mine is a 1/2 inch and it whistles pretty loudly when cold idling at 1100-1200rpm, then by the time it's warm it's idling at 800-850rpm and quieted down completely.

(I'll have to find some of my early youtube video's when I set the IAC to be the only source of air at idle, lol, I didn't know any better!)

 

Huh? Not sure how you would conclude that, but definitely not... (How would an on/off solenoid open slightly or have P&D values?)

If I didn't explain myself clearly, I'm happy to try again. But I think everyone has the jist - to adjust the butterflies so that the majority of the idle air still goes through the butterflies, and the IAC is used to "tweak" the idle speed (i.e. when dropped into gear, cold starts, etc.).

-BC

 

Yup, I mis-read your previous post. I don't consider carb chokes as on/off (there is usually three or four idle steps on the fast idle cam and the upper butterfly will gradually open as it's heated), so I thought you meant the EFI high idle was on/off.

 

Bob Has got it!

The PIII works the same way on the cold fueling. You have afterstart enrichment which is set to decay the cranking fuel away to a normal running pulse width over a certain amount of time (7 seconds by default). The C-Temp area is like the choke of a carb but instead of restricting airflow to get the engine to run rich, it just adds additional fuel in percent. 100=0% 110 would equal 10% additional fuel.

The PIII IAC works and should be set up the same as well. The PIII IAC values can be anywhere from 6 (closed) to 255 IIRC (wide Open) but with only a 3/8" passageway there will be no additional airflow after about the 110 position...