2.7 x-faktory PMO EFI Upgrade.

[Showdown]

Rutager, are you familiar with tuning via “left foot dyno?” It’s the most efficient and effective way of getting your VE table nailed down without an actual dyno…

I’ll post it even if you are familiar so it’s here for others… this is not my invention; taught to me by Jamie (JPNovak)…

-Find a stretch of road that will be free of traffic where you can turn around. 1/2 mile is fine, probably less

-open up your computer and TS and go to VE analyze live and in the advanced tab, change the “Cell Change Resistance” to “easy” and click “Start AutoTune”

-select the cells on your VE table around idle and right click and select “lock cells” so that TunerStudio doesn’t mess with your idle.

-you’re going to run through each of the rpm columns in TunerStudio at the bottom of your table starting at 2000 or so

-for rpm’s under 3k or so, you’ll want to be in 3rd or 4th gear, for rpm’s above 3k or so you’ll want to be in 2nd gear.

-With your left foot resting on the brake, use the accelerator pedal to bring the car to the desired rpm and then use the brake to hold it there as you continue to press the accelerator pedal all the way to 100% tps or your max kpa value. Once you hit 100% tps you can stop, turn around and do it again but for the next rpm column. After each column click “Send” and “Burn”

-it will take some getting used to- braking, accelerating, watching TunerStudio, and steering but you’ll figure it out. Open or secluded roads help.

-Run through the entire rpm range all the way past redline (you may have to set your redline in TunerStudio higher, or on your MSD if you’re running one)

-You’re basically simulating having the car on a dyno and loading the engine at a particular rpm so that every cell in your VE table gets hit and TunerStudio can make adjustments to the cells to match your AFR table.

-Once you’ve completed one or two runs through the columns with “Cell Change Resistance” on “easy” switch it to “Normal” and do it all over again, then to “Hard” and again.

-at this point you should have a table that is only changing by tiny amounts indicating that it’s really spot-on.

You should notice immediate and consistent improvements. Be aware that you may boil your brake fluid and all of a sudden find mushy brakes- just let it cool and you’ll be fine.

You can then go into the new VE table and start smoothing it out and refining it for acceleration enrichment, idle or any other characteristic you want like fire-spitting on sudden decel

[rwest]

Hi Julian,

Thanks.

Jamie send me those instructions as well and I did it once before I messed my tune up trying to use the IAC! Now I just need him to have business in St. Paul so he can tune it in person- it was fantastic that he was able to help you out.

I thought I went back to the tune before my IAC messing around and I may have, but since I changed the linkage, that may have negated the tune.

I’m trying to “save as” tune and label them so I can back track, but apparently not well enough.

Best,
Rutager

[Showdown]

Awesome!!

I had some ridiculous names for my tunes :”kindaGoodButNotAtWOT” “iDontKnowWTF”

[jpnovak]

Well. The secret is out. haha.

Rutager, You are at the point where you need to spend actual time tuning the car. The tip-in problems you describe are where your fuel mixture is likely too lean. So, you need to program more fuel in those locations on the VE table. This is likely about 1800 rpm and above 80kPa.

Don't get discouraged. Just spend the time to tune the ECU to your particular car.

[rwest]

Originally Posted by jpnovak

Well. The secret is out. haha.

Rutager, You are at the point where you need to spend actual time tuning the car. The tip-in problems you describe are where your fuel mixture is likely too lean. So, you need to program more fuel in those locations on the VE table. This is likely about 1800 rpm and above 80kPa.

Don't get discouraged. Just spend the time to tune the ECU to your particular car.

Hi Jamie,

Thanks for all your help on my car, it has really helped a lot.

The tip in was weird in that as I tried to take off from idle it bogged to below idle and yes, went lean. It did that twice, but wasn’t predictable.

You are right, I need to spend more time tuning. I also am going to reach out again to the one guy who has a dyno and who has done hundreds of MS, but never an aircooled car. I think he was too busy this summer, but maybe if I can get there before the snow flys...

[al lkosmal]

rutager.
I would recommend that you use the Left Foot dyno method...and get the 911 in good tune and then, if needed,... head to the local dyno shop you are mentioning.....

a dyno tune is a good thing, but does not necessarily replicate all of the driving conditions that you will experience in every day driving ...i've found that a blend of "real world" driving/tuning and dyno tuning seems to produce very good results.

I suspect that the combo of real world and left foot dyno will produce very good results too!

To date, I have primarily used real world driving (right foot dyno) to tune my installs....I have some great driving roads available to me...., nice twisties, stop & go, freeway and nice long stretches of frontage roads along the freeway...but after a ticket and...luckily being let off with a warning after getting clocked doing over 100 on a frontage road in a 911 with a 3.5 I built.......the left foot dyno method is sounding like a much safer/saner alternative to me.

Very cool idea, Jamie.

regards,
al

[911MANN]

Al- If I were a Policeman, I would let you off every time! Keep Going!! YOU DA MAN!!

[bigwizz]

Hi, i am interested in upgrading my cis and this looks good, could you tell me the cost all up.
And where to go to order, cheers.

[timmy2]

Originally Posted by bigwizz

Hi, i am interested in upgrading my cis and this looks good, could you tell me the cost all up.
And where to go to order, cheers.

X-Factory

[jpnovak]

Originally Posted by bigwizz

Hi, i am interested in upgrading my cis and this looks good, could you tell me the cost all up.
And where to go to order, cheers.

Spammers are out this morning

[timmy2]

Lol, 10 posts the day you join, in random threads…
Gotta be real….
Probably has a good friend with the parts we all need too.

[rwest]

Well, it’s been awhile since I updated the thread or even messed with the car.

A couple weeks ago With a quarter tank of gas and winter bearing down on us Minnesotans, I thought I should fill the tank, so off I went on a Saturday morning 1.7 miles to the gas station- got a few blocks away and the car stumbled on acceleration from idle. Luckily there are several large parking lots between my house and the station, so I turn into the ice arena lot and start looking at my computer and see that car is going super lean- 19+AFR, so I started adding fuel to the cells and driving around the lot, adding more and more fuel until the AFRs get decent.

I drive out of the lot and more stumbling and going lean; pull into the County nursing home lot (nursed the car into the nursing home lot!) still going lean, so more fuel it gets and I turn towards home still having lean stumbles, now I’m at a church lot doing some more fuel adds; finally I get home and I’ve had to almost triple most of the cells that before then where giving the right amount of fuel.

I looked at my fuel pressure regulator and it was at 37psi, it was at 40 originally, so I adjusted it back up- nut was tight, so likely hadn’t moved mechanically from vibration. I was able to return it to 40.

Fast forward to this morning and I decide I need to try and drive it again. I had reset the fuel tables to before the getting gas run and car started and after getting it slightly warmed up, it idled on its own and I drove up and down the driveway a few times without issue, so decided to go around the block- nope it started stumbling and I had to start tripling fuel to get it into the garage. Pressure was still at 40 psi and operating the throttle linkage, the pressure didn’t move. I’m suspecting a bad fuel pump- not enough volume? I had not changed anything else before the problem occurred.

Had a ten percent off coupon here on Pelican and a fuel pump has been ordered and with a quarter tank, less fuel to worry about.

The fuel pump has been replaced during my ownership, but have no clue when I did it and I have had this car for 32 years. I don’t feel bad about guessing on the pump being the problem.

[al lkosmal]

rutager,
Are you still data-logging? did you have it running without stumbling and now it stumbles, using the same VE table and now you had to triple the values in the VE table? Doesn't sound right, unless something else has changed.

You might want to swap in a new o2 sensor....your current one may be toast and lying to you. I have killed more than a few while tuning, because I tend to drive/log and then I often have the ignition still on, with the engine off..overheating the O2 sensor. That combined with running overly rich etc, while tuning can really shorten their lifespan. Also, if you are very.very rich....the o2 sensor can't read/measure the unburnt fuel and ......it reads lean.

So, i would go back to your last known good tune and install a new o2 sensor....if this gets you back on track, it is an inexpensive fix.....if not, the worst thing that will happed is you end up with a spare o2 sensor


regards,
al

[rwest]

Hi Al,

I don’t think my O2 is bad, because as I add fuel, the AFRs come back to normal and the engine runs better. If it was reading wrong and I added 3 times as much fuel value, I think that it would still read lean and the car would die, correct?

There is a definite problem as I did an hour drive and over 50 miles a couple months ago doing the “left foot dyno” and my fuel values were at the lower numbers and car ran well.

Something has changed and it seems like when I first start it, it’s running fairly well and as it warms up it starts going lean. When I say warmup, it is still in enrichment mode by quite a bit; engine is less than 100F. Leading me to think as the pump gets hot, it pumps less volume- I could be wrong, but it makes sense to me.

Rutager

[rwest]

Oh and yes, I did datalog, but since I made so many changes, not sure how valuable the information is?

[rwest]

Well, here we are, summertime and back to trying to get this thing running. I’m retired now, but still lazy, so got that going for me...

I sourced a new fuel pump, engine compartment filter and tank filter screen.

Working on emptying the tank, luckily my lean condition happened on the way to filling the tank before winter storage and I never made it there, so gauge said between 1/8 and 1/4 tank- if I was in the middle of nowhere, that would have been two gallons, but since I had to deal with draining it, it was much more. I didn’t spill too much and it only made it halfway down my arm- yea, no gas in the armpit.

[rwest]

I’m using an EZ Carlift to raise my Targa. I use the corner seams front and rear. When it is in the air, the doors bind, so I measured the difference in gap- roughly 2mm bigger gap in the air. So a bit of chassis flex; I always lower it after doing what I need to do.

[pampadori]

I wish there was somewhere behind the rear wheels to lift from. I hate leaving mine up on jackstands for days at a time. I always worry i'm going to come out to the garage and find the car in two pieces.

[rwest]

Originally Posted by pampadori

I wish there was somewhere behind the rear wheels to lift from. I hate leaving mine up on jackstands for days at a time. I always worry i'm going to come out to the garage and find the car in two pieces.

It wouldn’t be too difficult for me to make a cradle that lifted it by the torsion bar tube in the wheel well, but not sure if that would make any difference?

Another member says he just made wooden blocks for under the back wheels, so just lowers the car wheels unto the blocks at full height taking the weight from the back- I may be doing that.

[rwest]

Well, new pump and strainer screen fitted- old screen was completely clean as I figured it would be, but now I know for sure. Very little frustration or swearing on this job.

I’ll replace the engine compartment filter tomorrow and them put a few gallons in the tank, test for leaks and set pressure.

Hopefully this takes care of the issue... if not, might be an injector or ECU issue.