Self tuners advice wanted. Lean wot issue

MalcolmV8

Well-Known Member
Established Member
Joined
Mar 27, 2003
Messages
7,353
Location
Tampa, FL
Your car was going lean on the dyno right? It looks like you were data logging MAF and it suddenly flat lines. Either air flow quit increasing, belt slip, or the ECU hit an internal limit and clipped.

What about your fuel. Did you data log "pressure drop across injectors"? That compares manifold vacuum / boost to fuel pressure and gives you the 1:1 relationship you should be seeing. Much much more useful than data logging straight fuel pressure which is useless unless you data log boost as well and then it's a manual process of validating.
What about injector duty cycle or pulse width? data log any of that?

At a quick glance I see your injector tables are all stock with only the scalars of high/slow/breakpoint/min pulse adjusted. Did you not have any data for your injectors?

Ah just glanced at your MAF transfer. Even though it's in #mass/tic it still has limits. There is not a hard limit in PRP preventing you from putting in what ever number you want but I have found in reality the various strategies do indeed have internal hard limits in the ECU. You're around 110 ~ 115 lb/min equivalent at your lean spot more or less.

A quick easy test is grab another slot sensor, re-do another MAF transfer for it and see if the lean spot occurs at a different RPM but the exact same #mass/tic point. That would confirm an ECU / strategy hard limit you're hitting.
 

03Steve

Active Member
Established Member
Joined
Sep 18, 2002
Messages
1,867
Location
St. Louis
Stopped after about 5 minutes of looking. So far...

-Load with failed MAF is still stock
-Returnless fuel pump voltage table has all cells set to "15" with fuel pump type set to returnless
-No scaling present for 4.00 fuel flow clip
-No renormalization of Y axis in returnless fuel pump voltage table

-Greater than 51lb injectors specified in a 24MHz PCM
-Base fuel table Y axis not normalized for load in excess of 0.95
-BA5000 in large tube results in MAF transfer scaled to 361 lb/min peak airflow
-Open loop forced on (intentional?)
 

cj428mach

Well-Known Member
Established Member
Joined
Sep 21, 2012
Messages
7,609
Location
Kansas
-Greater than 51lb injectors specified in a 24MHz PCM

I've always heard 60lb injectors was the limit for the stock PCM, apparently you've found otherwise?

He's also running a return system so that might explain some of his tune settings.
 

MalcolmV8

Well-Known Member
Established Member
Joined
Mar 27, 2003
Messages
7,353
Location
Tampa, FL
I've always heard 60lb injectors was the limit for the stock PCM, apparently you've found otherwise?

He's also running a return system so that might explain some of his tune settings.

60 is correct on stock ECU, OP is running a 99 ECU I believe.
 

03Steve

Active Member
Established Member
Joined
Sep 18, 2002
Messages
1,867
Location
St. Louis
60 for 27MHz. Then there is the limit for the other clock speeds. 99 computer is 24MHz.
 

cj428mach

Well-Known Member
Established Member
Joined
Sep 21, 2012
Messages
7,609
Location
Kansas
Thanks for clearing that up Malcolm/Steve, I'm just use to Terminators.

The fuel pump type and other variables are set to returnless values.

I was also under the impression that fuel pump type can be left as returnless in a return style system. This allows for the PCM to adjust fueling based off fuel pressure fluctations using the fuel pressure injector slope modifier tables.

Once thats done all the other tables returnless values really are irrelevant except for the fuel pump voltage table being set to 15 which is necessary to keep the FPDM energizing his relays for the return system. I'm sure you guys are seeing a ton more as I sold my PRP package and can only look at BE tunes.
 

MalcolmV8

Well-Known Member
Established Member
Joined
Mar 27, 2003
Messages
7,353
Location
Tampa, FL
Thanks for clearing that up Malcolm/Steve, I'm just use to Terminators.

I was also under the impression that fuel pump type can be left as returnless in a return style system. This allows for the PCM to adjust fueling based off fuel pressure fluctations using the fuel pressure injector slope modifier tables.

When configured return style the ECU will still increase / decrease injector pulse width based on FRPS to compensate for fuel pressure fluctuations if configured so.
I've had return style cars, configured correctly, have fueling issues and the injectors went all the way to 100% trying to get enough fuel when the pressure tanked.
 

cj428mach

Well-Known Member
Established Member
Joined
Sep 21, 2012
Messages
7,609
Location
Kansas
When configured return style the ECU will still increase / decrease injector pulse width based on FRPS to compensate for fuel pressure fluctuations if configured so.
I've had return style cars, configured correctly, have fueling issues and the injectors went all the way to 100% trying to get enough fuel when the pressure tanked.

Interesting and good to know. Hey now that you're a tuner aren't you supposed to talk in vague generalizations and be really unclear. :p

We appreciate guys like you and Steve sharing knowledge. Since I don't have prp anymore can you confirm wether or not load can be changed to allow 2.0+. I've never heard of that being possible.
 

MalcolmV8

Well-Known Member
Established Member
Joined
Mar 27, 2003
Messages
7,353
Location
Tampa, FL
Interesting and good to know. Hey now that you're a tuner aren't you supposed to talk in vague generalizations and be really unclear. :p

We appreciate guys like you and Steve sharing knowledge. Since I don't have prp anymore can you confirm wether or not load can be changed to allow 2.0+. I've never heard of that being possible.

What's load? lol. In the newer ECUs load can go above 2.0, not in ours.
 

svo/svt

Member
Established Member
Joined
Jul 19, 2010
Messages
225
Location
Humboldt County
I purchased my prp software and the dvd from Lasota about 3 months ago. Ive been trying to learn as much as i can but theirs only so much thank can be learned from a video. I'm lacking the years of experience but hope to get there one day as the closest tuner to me is 6hrs away. Originally lasota sent me a base tune and i tried working with it but could not get the car to run very good so i built my own with what knowledge Ive picked up so far. I know its lacking which is the reason i am looking for advice which i greatly appreciate.

This is the lasota base tune. I noticed that its missing the return fuel file completely. Is that normal?
 

Attachments

  • lasota Base Tune original .zip
    195.3 KB · Views: 176

svo/svt

Member
Established Member
Joined
Jul 19, 2010
Messages
225
Location
Humboldt County
If it makes a difference i no longer have a fprs. It wasn't on there the whole time i ran my 2.3 whipple but im thinking i should put it back in now.
 

svo/svt

Member
Established Member
Joined
Jul 19, 2010
Messages
225
Location
Humboldt County
I went back in the tune and set it up for return style which I then realized that it removes the whole return fuel system options. I also looked thew my datalog and scaled the failed maf table.
Can the fuel table and spark table be normalized to except greater then .95 load. I tryed to adjust them. Should the tables show a higher load on the y axis after adjustment?
 

01yellercobra

AKA slo984now
Established Member
Joined
Oct 5, 2005
Messages
21,282
Location
Cali
I went back in the tune and set it up for return style which I then realized that it removes the whole return fuel system options. I also looked thew my datalog and scaled the failed maf table.
Can the fuel table and spark table be normalized to except greater then .95 load. I tryed to adjust them. Should the tables show a higher load on the y axis after adjustment?

Yes, they can be. I'd have to look in my tune to find it. But I was able to change the load on my 01 (MSE3) to 1.7 to match what I was seeing in my datalogs. I'm sure one of the pros knows exactly where to change it. I want to say it's in the same sub group for timing and is under Y Axis normalizer or something.
 

badcobra

It's Fast
Established Member
Joined
Aug 25, 2004
Messages
2,516
Location
Mpls/St Paul, MN
You would be best off having someone help you with the tune and then learning as you go. 03Steve would be someone I would highly recommend working with, or Malcolm. Get the tune configured right and it will be so much easier.

You also have the Lasota DVD, but I find the tuning book much more useful because you can have it with you in the garage when you are out working on trying to tune the car. And having that manual around when building a tune from scratch is much better. Good luck
 

03Steve

Active Member
Established Member
Joined
Sep 18, 2002
Messages
1,867
Location
St. Louis
If it makes a difference i no longer have a fprs. It wasn't on there the whole time i ran my 2.3 whipple but im thinking i should put it back in now.

I recommend having it on there. There are three applications for it:

-Fuel pump compensation, fuel injector compensation, logging pressure at rail
-Fuel injector compensation, logging pressure at rail
-Logging pressure at rail

I'm an advocate for the last two. I favor the last. The injector compensation is nice when the FRPS is operational. It is not nice when the FRPS fails. Especially on a ZMR2.
 
Last edited:

svo/svt

Member
Established Member
Joined
Jul 19, 2010
Messages
225
Location
Humboldt County
Thanks 03steve. I'll just put it back on and hooked up the boost reference line. So can I set the tune back to retuenless and rescale it?
 

03Steve

Active Member
Established Member
Joined
Sep 18, 2002
Messages
1,867
Location
St. Louis
It's a matter of personal preference. If it was my car, I would:

-Put the FRPS back on
-Set the fuel pump type to return
-Turn the injector compensation off
-Start with an 03 Cobra failed MAF table and increase cell values as needed
-Start with 03 Cobra base fuel table. normalize Y-axis accordingly, populate upper rows as desired
-Replace BA5000 MAF with stock Ford slot meter or VMP 3500
-Scale the MAF, injectors, engine displacement, manifold size, down by ~50% to work around the 53 lb/hr PCM injector limit
-Restore the Load for Open Loop function to stock
 

svo/svt

Member
Established Member
Joined
Jul 19, 2010
Messages
225
Location
Humboldt County
Perfect thank you very much. What's the thought on replacing the ba5000 with a 3500 and if I went with a stock maf would a factory 04 cobra one work. I would just like to understand.
 

Users who are viewing this thread



Top