and if you have any ideas please let me know what they are as I'm new to tuning Evo's. I haven't sent my ROM in yet, I'm working with the base map as of right now. First log is a partial log when I was messing around, knock much? Second log is a 3rd gear pull from 3500-redline with no issues. Where the heck did that come from?!

 

Wow really aggressive timing there padna. Do a log in WOT in 4th.

The knock there could be road conditions or a whole host of things.

 

The partial log where you're getting all the knock, I think it's because you're at part throttle... The stock maps don't seem to be very good for relatively high load/part throttle conditions.

On the WOT pull, everything looks pretty decent, only showing a tiny little bit of knock.

However, based on your fuel trim and O2 sensor readings, it looks like the car is running insanely rich. I'd be willing to bet that you have a walbro fuel pump installed.

You're not running much boost either from the looks of things, not hitting a very high load at all.

Phenix fyah, the timing map is the stock map. It's not that aggressive, he's just not hitting a very high load.

 

actually after I posted this last night I got to digging into the fuel tank. I bought a Walbro and went to install it only to find out he already put on in there. Thanks to the dealership in Houston for doing as I requested and talking to the previous owner, those guys rock. Anyway yeah, it has a fuel pump installed, will update my mods listing now. The timing is full stock, I haven't touched a thing but will be sending off to Jestr soon. The gauge I have shows I am hitting 18, spile to 21 or so but settles to 18. What formula do you use to compare load vs actual boost psi? It's a percentage right? 100 load is 14.7 lbs? So 120 load is roughly 17.6?

 

No. Unfortuneatly there is no direct conversion for load to boost. Its just one of those things that you have to log to find out what cell you need to change. Thats why 2 byte load helps, since its just that much more accurate for tuning.

 

wanna sell me your other walbro 255?

 

just sold it back to the guy I bought it from. He only charged me like $5 to send it back otherwise I would gladly have! Does the 2 byte load work on VIII's?

 

Ya know, I think you can just tune it yourself. Since you have the fuel pump in..... I think the easiest solution would be to get an adjustable fuel pressure regulator and turn down the fuel pressure back to the factory level.

What happens with the Walbro is that the stock fuel pressure regulator can't handle it. I think the stock fuel pressure is suppose to be 3 bar (referenced to atmospheric), so ~43.5psi. When you put in the walbro though, the pressure jumps up 5 psi or so because the stock fuel pressure regulator can't handle it. So if you get an adjustable FPR, and put the pressure back to where it's suppose to be, it should fix the excessively rich condition you have, improve power, and improve your gas mileage

Another method I thought of is adjusting the injector size in the ROM. Basically say that you have a bigger injector than stock. So I think the ecu will then inject less fuel and things will go back to normal. I also don't think you have to mess with any of the injector latency stuff because it's still the stock injector. You do have to know how much higher than stock the fuel pressure is though in order to input the 'correct' value for the 'bigger' injector.

I've never done any of this myself, and I don't know what any of the 'tuners' do, but it makes sense to me Heck, I might just get a walbro and try out changing the injector size in the ROM. Would be more than helpful to have a wideband hooked up!

Also, I would ditch the MBC and go back to the stock boost control system. Or maybe upgrade to the 3-port solenoid. You can control the boost infinitely better using the ECU than a MBC.

https://www.evolutionm.net/forums/sh...d.php?t=259494

 

Hi

Looking at the load calc and the timing your running, I would question the boost level you think you are running. How are you logging boost?

MB

 

Just with a gauge T'd into the FPR line like usual. It's spiking to 19-22 but settle at 18-18.5 give or take .5. Remember I have NO idea what this guy did to the car before I got it tho...how can I easily tell if they're stock injectors? Or can I? As for the stock boost control system I'd have to "reimplant" the pill and such. Does the ECU control for boost fix spiking and such?

 

Thats funny. Im in the same boat. The rabbit hole got a lot deeper than I thought it was. I too bought a Walbro, just to find out it already had one in it. But Im keeping the "older" one around. Also, after I sent my roms to Jestr, he told me they definitely werent stock. And it runs a ton better now. Im going the Jestr route, until I get a wideband, and learn to tweak it on my own. And think that is a pretty safe way to approach it.

 

Please, be careful with this sort of thinking. The Walbro does increase fuel pressure. Stock is actually 33psi. The increase in fuel pressure is one of the biggest reasons why we use a Walbro 255, along with it being able to outflow the stock pump. Having the fuel pressure increased allows us to "stretch" the stock injectors, which actually decreases the duty cycle.

The proper way to do this is to re-tune AFR's using the new found fuel pressure. Obviously, you will have to pull out fuel to get AFR's where you want them again. First off, you force open loop and re-tune idle and all part throttle areas. Once you get them to 14.68:1 (stioch) then, start tuning part throttle boost areas, then WOT full boost areas. Obviously, part throttle boost areas over 2psi and under 10psi need to be tuned for about 13.0-13.5:1 AFR, Over 12psi, you want to run 11.5:1 tapering to 11.1:1 over 6500rpm.

After re-tuning AFR's, put the ECU back into closed loop feedback and watch what your fuel trims do. They should be close to 0%.

Use a good wideband thats properly calibrated. The innovate LC-1 is a great unit that is easy to free air calibrate at will.

You DO NOT want to alter injector size to alter injector pulse width, you also don't need to get a FPR to fix this issue either. I don't recommend a FPR unless you are running really large injectors. The stock FPR does a fine job at keeping a rising rate static fuel pressure on it's own. The reason why you would want to use a aftermarket FPR with really big injectors is to help tune out idle misfires a long with a couple other reasons regarding AFR tuning.

If you have any questions, by all means, ask me.


CJ

 

yes, 2 byte load works great on the VIII, i use it. The real question is; what is your ROM ID? Patching your ROM for 2 byte load or any other patch, is different for each ROM ID. Some share the same procedures, other do not. Your ROM ID can be seen after you download the stock ROM into ECUflash and look under ROM info. It will look something like this : 96940011

Once you determine what ROM you have, search what patches are available for it on here and be sure you know what you are doing before you attempt to patch your ROM.

BTW, where did you get your pump from? I'm looking for a spare pump, thats why i'm asking.

CJ

 

what's the easiest way to force open loop? Min coolant temp map?

 

Well, my whole thought on using an adjustable FPR is so that you DO NOT have to retune the fuel maps, which is a good option if you do not have a wideband. But then again, the price of an adjustable FPR is about half a wideband, so might as well get the wideband right? And I guess a downpipe with a bung installed... but it's good for more power anyways

I just thought a little more about changing the injector size value and it would be a bad idea. The fuel pressure with the walbro should stay a constant value above what the stock setup would be. So say the offset is 5 psi. Then at idle, it'd be roughly 38psi vs. 33psi stock. At 20psi of boost, it's be 58psi vs. 53psi. Therefore, the % offset is different, which would mean that you can't use a single 'bigger' fuel injector value.