EFIDynoTuning Forum

After a pause, getting back to trying understand TPRT and A9L2.

My totally stock engine is still having the same issues running the A9L2 bin. To recap:

- have set idle stop screw to get 0.28 ISCDTY
- have set NUBASE to 700
- cold idle seems to behave after a little bit of stumbling right after cold start
- idle creeps up to 1100 rpm after the engine warms up and hunts
- transient response sometimes stumbles and backfires

Found this in A9L2 through TPRT:

SP** (WARNING) AHISL - Injector High Slope **SEE COMMENTS** 19.641 lbs/hr (= 1.0337 * 19 lb/hr)
SP** (WARNING) AHISL - Injector High Slope (lbs/sec) **SEE COMMENTS** .00545573 lbs/sec (consistent)
Are you referring to comments on this page:

http://efidynotuning.com/fuel.htm

SP** ALOSL - Injector Los Slope [lbs/hr] 26.099 lb/hr (= 1.3736 * 19 lb/hr)
SP** Injector Low Slope - ALOSL - [lbs/min] 0.0072496 lb/min. Label says "lb/min", but value says lb/sec. Which is correct?


With my new engine with bigger HCI, I plan to use the Ford Green Top 42 lb/hr injectors. The specs on this page:

http://efidynotuning.com/injdata.htm

Says:

K-Constant 30.00
High Slope 43.009 (= 42 * 1.0260)
Breakpoint 0.0000212
Low Slope 46.066 (= 42 * 1.0968)

Are these still accurate?

TIA

Thanks Michael.

I don't know what this means:

"thata debyma clipping it"

Is it normal for my ISCDTY to never drop below 0.28?

Should I back off the throttle stop so it's not always stuck at 0.28 when idling?

Thanks Michael, Paul, for your inputs. I had to deal with some other issues so I could not work on my car for a while.

I made more adjustments on the idle stop screw to try to get ISCDTY down to between 0.15 and 0.35. I don't think it goes below 0.28, even as I bottomed out the screw to where the spring bound up. I did this by stopping and starting the engine each time, and settled on an opening where the ISCDTY JUST floats above 0.28 at idle. It seems to be idling steadily at around 700 rpm now.

The DESMAF_PID_N does not want to settle between -0.1 and + 0.1. It starts out at 0.5x and slowly drops to -0.3x after a couple minutes of idling. How important is it to keep this between -0.1 and +0.1?

I realize this is step 0 of many steps to tuning my new engine, but I'm still learning. If I set a new value for ITHBMA, how do I "poke" it into the running parameters? In the PROM read/write utility, the "Program chip" button is greyed out when the engine is running.

According to the reference, the FUEL_APT_LAST is the "last value" stored..., and =-1 indicates closed throttle. That does happen quite a bit when I'm driving around town.

I guess I don't understand what that number is really indicating. Can you elaborate?

No reds on the dash, just the FUEL_APT_LAST going yellow to -1 occasionally. And the WB-1ER_AEMEUG is yellow all the time, showing 0.65.

I get that when I hover my cursor over a parameter in Tunerpro, it will flash up documentation about that parameter. Is there some place on the web site where all this documentation is stored? If so, I must be missing it somehow. I'd like to look through as much of them as I can.

thanks

resetting the base idle speed per:

http://efidynotuning.com/idleair.htm

where you baseline the tps.

So what might cause the EEC to crank up the idle speed as the engine warms up? A failing ECT?

Clearly, the stock A9L is doing something to bring the idle back down as the vehicle speed goes to 0.

Reset TPS and idle according to directions, ran some more test drives and find:

The stock A9L programming also seems to creep up the idle as I drive, topping out around 1000 rpm. But when I come to a stop, the idle slowly drops back down to about 700, the stock setting. The A9L2 does not seem to look at VSS, so when the programming brings the idle up to 1000, it just stays there, and may creep higher the longer I drive.

The issue with the stumbling has been narrowed down to cruising on the highway in 5th gear at around 1500 rpm. One characteristic I notice with the A9L2 code is that as soon as I let off the gas pedal (close the throttle), the air is cut off immediately, so if I was a little late in releasing the clutch, I create a shudder due to the engine speed dropping suddenly. When I do the same on the stock A9L, it cuts the air slowly, like an anti-stall dashpot. I think this is to reduce the enrichment that would be caused by fuel wetting the runner walls evaporating due to a sudden drop in MAP.

I think the abrupt cut-off of air by the A9L2 code may be the cause of the shuddering I'm experiencing, as it over-reacts to the condition. I can either stop driving at such low speeds in 5th gear, or try to dial in a little more dashpot delay.

I made a couple more attempts to reset the idle speed,but got the same results. After the engine warmed up, it would start idling around 800 rpm, and the only numbers showing up in yellow were FUEL_APT_LAST flickering to -1 occasionally and WB_1ER_AEMEUGK hanging around .64. As I drove around, the idle steadily crept up to about 1200 rpm. I didn't drive around long enough to see if it kept increasing. But each time after I shut the engine off and restart, it would start idling at 800 again, and again wold creep up as I drove more.

Tonight I set NEWBASE to 700 and uploaded the otherwise A9L2_240103.bin into the QH and ran the engine to let it warm up. It idled between 700-750, and seemed to behave itself, the idle never exceeding 800 as I did the same around-town driving test.

I'm going to update this bin to work with my newly built 331 stroker. It will have bigger injectors and MAF sensor, so I will at least have to update those tables. I'll also be installing a more aggressive cam. I'm sure there are other adjustments that have to be made.

Where is the best place to start?

Thanks Michael,

I'm concerned that my stock engine would have so much problems with your more sophisticated tuning that I was hoping to take advantage of.

It ran fine without the QH and with the QH using the stock A9L bin/ADX/XDF. All the issues started when I installed the latest A9L2/ADX/XDF.

Would the EEC self-test be able to find the source of the problems?