VE table maxxing out when Base fuel pressure is set at 280 kpa.

[jindakwa]

Hi Fam 

Long post alert!

I'm learning how to tune. I got a link G+ and been trying very much to read and learn with the help of support both from  this forum and the vendor who sold me the ecu.  

Now here is my problem: 

1. When cold, the base map will start the car after say 2 to three clicks.  the values on the VE tables when cranking are abt 73-75: crank enrichment is abt 60s.  Base fuel pressure is abt 280 kpa.  However when hot, the engine cannot start whatsoever with those values on the VE table. So i have two maps to start the car depending with temperatures lol.  i have to increase those numbers  to about 127 start when hot.  

NB: I haven't done any tuning coz ofcos you cant do anything if the car is not starting. 

2. After the car has started, it idles at about 40 kpa.  Initial VE's were in 70s, however, its will run lean if i maintain this values. To make it idle at  lambda of 0.9-1, I  had to increase these VE numbers to almost 130s. And if I rev it up a bit, some sells goes lean even after maxxing out the VE numbers in those cells at 150.  

So I decided to move from modelled fuel set up to traditional with master fuel at 9 ms. This didn't help, same thing happens. keep maxxing out the VE table at idle or slight rev up. 

I did some research here and came across a post on an sr20 which had similar issue and Adamw had responded to it as follows  in qoutes  - "If you need to reduce your VE numbers then you need to make the ecu think there is less fuel flow or more air flow than there actually is.  So you can reduce injector flow rate setting, reduce base fuel press setting, or increase engine capacity.  No real advantage on which one you change. " 

I went to my base map changed the base fuel pressure from 280 kpa to 150 kpa and all of a sudden those numbers are too rich and I had to trim them down 55-65s to attain my target lambada of 1s at idle. Now even the VE values of starting when hot was changed from 126s to 73s after I changed the base pressure. 

This has  left me totally confused on my understanding of base fuel pressure. The help button says, and I quote, "The Base Fuel Pressure is the fuel pressure in the fuel rail when the fuel pump is on, but the engine is not running".  I di this when setting the base fuel pressure.  It looks like either it doesn't matter or my fpr is bad?  What is the experience with you all.  I want to be sure before I order another fpr from aeromotive which are quite expensive . 

Below is a log of the car starting and running after changing the base fuel pressure to 150 kpa. note it was able to start even with VEs of abt 76s while previous it would have required the VE number to be in 130s for it to start if the Base fuel pressure was 280 kpa.  In addition, idled way better and calm than before. 

Feel free to point out as many issues as you can as am learning and i promise to list them dwn and work on them. 

22.11.2022_starting_2.llg

[jindakwa]

I should add am ruuning walbro 450 pump which is brand new and am positive abt it. 

[Confused]

You've missed out lots of critical information - mainly what injectors do you have, and do you have good, correct data for them, especially deadtimes.

If you don't have good injector data, then forget Modelled Mode, and stick with Traditional.

The Master Fuel value here can be adjusted to allow you get a good range of values in the fuelling table. It's not VE in this instance, so it doesn't matter what the numbers are, so long as the maximum value you have is under 150.

There's a whole host of cold start enrichment that needs modifying once you've got your fuelling correct at operating temperature.

 

Post a copy of your actual tune (.pclr file) as this contains all the settings the ECU is trying to run with.

 

I got myself a fuel pressure sensor, and found it was reading vastly different to the mechanical gauge on the FPR. I added a 3rd source (the MAP sensor of the ECU itself) and used some regulated compressed air with the fuel sensor, fuel pressure gauge, and ECU's MAP sensor (away from the fuel system totally) and found that my MAP sensor and new fuel pressure sensor read the same values, but my fuel pressure gauge was different. Swapped this gauge out with a new one (which is MUCH cheaper than a whole new FPR) and low and behold, the gauge matches the sensor now.

 

What I'm getting at is that I had been running what I thought was 3 bar fuel pressure, but I was actually running about 4.5

[jindakwa]

5 minutes ago, Confused said:

You've missed out lots of critical information - mainly what injectors do you have, and do you have good, correct data for them, especially deadtimes.

If you don't have good injector data, then forget Modelled Mode, and stick with Traditional.

The Master Fuel value here can be adjusted to allow you get a good range of values in the fuelling table. It's not VE in this instance, so it doesn't matter what the numbers are, so long as the maximum value you have is under 150.

There's a whole host of cold start enrichment that needs modifying once you've got your fuelling correct at operating temperature.

 

Post a copy of your actual tune (.pclr file) as this contains all the settings the ECU is trying to run with.

 

I got myself a fuel pressure sensor, and found it was reading vastly different to the mechanical gauge on the FPR. I added a 3rd source (the MAP sensor of the ECU itself) and used some regulated compressed air with the fuel sensor, fuel pressure gauge, and ECU's MAP sensor (away from the fuel system totally) and found that my MAP sensor and new fuel pressure sensor read the same values, but my fuel pressure gauge was different. Swapped this gauge out with a new one (which is MUCH cheaper than a whole new FPR) and low and behold, the gauge matches the sensor now.

 

What I'm getting at is that I had been running what I thought was 3 bar fuel pressure, but I was actually running about 4.5

Am running stock injectors. my engine is a 3s gte st246 - 540cc. Am not sure if the setting are correct since they were set by the vendor who sold me ecu and i should say he mostly  specializes on 3sgte's so i trust his values somehow. 

See map attached below.  this is after adjusting the base fuel pressure to 150 kpa. NB: I didn't get to change all the values in the VE table after changing the BFP hence some values are as had been adjusted when at 280 kpa hence the table is all over the place( i only changed values around starting and idling when i changed the BFP). 

 

Toyota ST246 engine in ST185 celica startup_3.pclr

[Adamw]

Your fuel pressure, injector flow rate and dead times need to be measured, not guessed or assumed.  As confused says, if you dont have this info then you are best to use traditional fuel equation.

[jindakwa]

1 hour ago, Adamw said:

Your fuel pressure, injector flow rate and dead times need to be measured, not guessed or assumed.  As confused says, if you dont have this info then you are best to use traditional fuel equation.

Adam

what master fuel would u recommend. I tried 9 and still maxxed out.  So wondering if i should go higher or lower. The help function doesn't talk much on this. 

secondly , i know the other adjustment should be done after the main fuel is tuned but one also need a starting car to tune the main fuel. So i think both are important to get them to a tentatively good values that can start and hold the car idling so that one can do tuning. 

 

 

[Confused]

If you're struggling this much with a tune that's come from another vehicle with the same hardware, then I suggest that you've probably got a physical issue on your car. My first port of call would be to confirm your fuel pressure - don't just trust the gauge you have, it might be wrong. You need two separate additional known values to confirm against.

 

"A man who has one watch always knows what time it is. A man with two watches is never sure."

[jindakwa]

1 minute ago, Confused said:

If you're struggling this much with a tune that's come from another vehicle with the same hardware, then I suggest that you've probably got a physical issue on your car. My first port of call would be to confirm your fuel pressure - don't just trust the gauge you have, it might be wrong. You need two separate additional known values to confirm against.

 

"A man who has one watch always knows what time it is. A man with two watches is never sure."

hahaha.. 

i will go ahead and order an aeromotive fpr and see what it says. hope it reads different from the tomei that i have to be at ease. Am also eager to discover what the issue might be. will confirm in due time. 

[Confused]

A new gauge is about £15 - and that's all my issue was - my actual FPR was working perfectly, but my gauge was not.

 

[jindakwa]

Hey good people. 

 

i am still stuck with above. 

I'm now bordering frustration and disappointments. 

No matter what, this  car does not want to start consistently when cold.  it might start sometimes but 99% of the time it will not. 

I have done as many checks as I can think off. Moved from modelled to traditional,  checked all my ground and added more ground to the block, changed ignition coils, spark plugs,  fuel regulators, rechecked my wiring harness,  rechecked my base ignition timing but still no successes.  

On the lucky days that it starts when cold, most of the time it will be on modelled fuel. I have hardly had any success starting it on traditional while cold.  In addition, same tune that made it start yesterday may not make it start the following day (for instance one time i kept increasing the VE number to almost 127% for the car to start, the next time, i had to cut it to abt 52% to start hence the inconsistency am talking about lol). Now, After it starts on modelled, once warmed up, it runs lean and you may max out the VE cells at idle but still lean. Hence I prefer switching to traditional after it has warmed up (70 degrees and above ).   Once warm, it  will start on first crank on any map whether modelled or traditional fuel set up.  

I have even sort a professional as i thought perhaps i was the problem as i was learning to tune but still same thing.

What am I missing ?  What is there to be checked? 

Can it be software related ? if hardware, am trying to think what will make it start almost always while hot but not when cold. 

PS: today it refused to start completed on all the start maps i have had success with.  am almost going mad. 

[INSW20]

First thing I noticed upon opening your map is your fuel pressure is set to 21.8PSI:

I'd start by aligning that to your actual base pressure and see if anything else is working better after that.

 

EDIT: I read your post more closely, I would still reset your base pressure to match reality. Seems like there’s a different problem to me. Where is your wideband mounted?