The MegaSquirt Project has experienced explosive growth other the years, with hundreds of new MS installations occurring every week - a phenomenal success! MegaSquirt has been successfully used in all aspects of Internal Combustion engine applications including R&D, Industry, Race, and Research. The MS project has transformed itself from a simple R&D project into a full-featured mature engine control system. To reflect this the support structure has also changed to meet the needs of MegaSquirt Users.
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However the forums will remain available for view, they still contain a wealth of information on how MegaSquirt works, how it is installed and used. Feel free to search the forums for information, facts, and overview.While the R&D forum traffic has slowed in recent years, this is not at all a reflection of Megasquirt users, which continue to grow year after year. What has changed is that the method of MegaSquirt support today has rapidly moved to Facebook, this is where the vast majority of interaction is happening now. For those not on Facebook the msextra forums is another place for product support. Finally, for product selection assistance, all of the MegaSquirt vendors are there to help you select a system, along with all of the required pieces to make it complete.
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Forum rules
Read the manual to see if your question is answered there before posting. If you have questions about MS1/Extra or MS2/Extra or other non-B&G code configuration or tuning, please post them at http://www.msextra.com The full forum rules are here: Forum Rules, be sure to read them all regularly.
Hey guys, I've been trying to tune up high so I can start making full throttle runs. I've been having kind of a difficult time in doing this. I have realized that I have to add A LOT of fuel up high to make the car run better. For the longest time it would lean out real bad up high. Well its still not perfect but its finally starting to get where it needs to be with this current map. At the moment im running MSnS-E version 029q with MT version 2.25 final on a v3 board.
Im just curious if this is normal or not. The engine is a stock 1.8 16v vw engine with a 2.5bar fpr and 24lb injectors. Other than this everything seems fine. I don't know if there is a problem that im tuning around or not but id like to address it if so. Please review and throw somthin at me guys. Thank you.
captain16vgti wrote:Hey guys, I've been trying to tune up high so I can start making full throttle runs. I've been having kind of a difficult time in doing this. I have realized that I have to add A LOT of fuel up high to make the car run better. For the longest time it would lean out real bad up high. Well its still not perfect but its finally starting to get where it needs to be with this current map. At the moment im running MSnS-E version 029q with MT version 2.25 final on a v3 board.
Im just curious if this is normal or not. The engine is a stock 1.8 16v vw engine with a 2.5bar fpr and 24lb injectors. Other than this everything seems fine. I don't know if there is a problem that im tuning around or not but id like to address it if so. Please review and throw somthin at me guys. Thank you.
-Chris
I'll take a guess that it either Pulls like hell at about 4700 RPM's or it coughs and bogs there. If it pulls really hard you're probably hitting a resonant peak of the intake manifold. (resonant supercharging effect), in that case the table seems OK, though the point after it at 5000 rpms shows a really steep dropoff, (might be too steep) as it could cause some bucking around that point..
You might consider taking the more "linear" parts of your table (where things have a fairly even slope across a group of RPM bins and compress that down to two bins. (the effect is a freeing up more RPM bins to use to allow you to fine tune around that peak in your table.) I.e. the 1500-2600 rpm stretch could be trimmed to just be 1500,2600 and knocking out the middle column, as the slope there looks fairly flat across all three columns This will free up a column to be used for that peak. (it's a bit of work shifting the table around like that, but it may be worthwhile to pursue if you find you need more resolution up top)
Another thing to check would be your rail fuel pressure under load. Going lean under heavy load when the numbers look OK is one symptom of inadequate fuel flow/pressure due to many reasons - pump going bad, clogged filter, kinked supply line, etc.
Thank you guys very much for the replies. As of now the fuel table does look a bit weird. On that map (current) I haven't reached 5500 so I haven't tuned that far yet. Im just trying to make it not lean out up high like it has been. Even with this map the a/f ratio still goes up to about 16 which is still to high. I believe I still need to add more fuel around there to safely reach 5500 or higher.
I also need to change some bins around to make tuning easier. At the moment its kinda difficult because of my kpa bins. I have also wondered if it is something mechanical but at the moment it doesn't seem to be. I haven't checked fuel pressure at wot but I have gave it quite a bit of throttle in the driveway. At idle its a little less than 2bar and goes up to a little less than 2.5bar when throttle is applied.
I just installed 24lb (245cc) injectors because I had 17lb injectors in there before. Also, my fuel pump does sound kinda bad sometimes but it always works and stays running. Ill make a few changes to things and keep you guys updated on the happenings. Thanks again guys.
captain16vgti wrote:Thank you guys very much for the replies. As of now the fuel table does look a bit weird. On that map (current) I haven't reached 5500 so I haven't tuned that far yet. Im just trying to make it not lean out up high like it has been. Even with this map the a/f ratio still goes up to about 16 which is still to high. I believe I still need to add more fuel around there to safely reach 5500 or higher.
I also need to change some bins around to make tuning easier. At the moment its kinda difficult because of my kpa bins. I have also wondered if it is something mechanical but at the moment it doesn't seem to be. I haven't checked fuel pressure at wot but I have gave it quite a bit of throttle in the driveway. At idle its a little less than 2bar and goes up to a little less than 2.5bar when throttle is applied.
I just installed 24lb (245cc) injectors because I had 17lb injectors in there before. Also, my fuel pump does sound kinda bad sometimes but it always works and stays running. Ill make a few changes to things and keep you guys updated on the happenings. Thanks again guys.
-Chris
One thing I forgot to suggest is to do a VOLUME test of your fuel pump. This means, depressurizing the system (carefully), disconnecting the feed line coming from the filter/pump, and putting it into a suitably large container (coolant jugs work nicely) and manually running the pump for 30 to 60 seconds and see how much fuel you get in the container. (should get at least 1 quart/litre in abbout 30 seconds. IF the flow comes out kinda sluggish, it means that either A. your filter is clogged, or B. the fuel lines are internally corroded and severely restricted. I've seen this on many vehicles where they'd idle and drive fine under light/moderate load and then buck, surge and act funky under hard accel and it was because fuel pressure dropped off and became unstable due to demands of the injectors/engine exceeding supply volume from restricted lines.
A word of warning, though. HAVE A FIRE EXTINGUISHER nearby, as you'll be working with exposed fuel and electricity (very dangerous mix). Take all precautions and wear safety goggles at the very least.
Valvers come on cam between 4k and 4.5k rpm, mine is earlier due to the Kents and VE is in the 180`s at that point (it`s supercharged but that shouldn`t make a lot of difference).
Are you using the k-jet fuel pump? these things can flow enough for 400BHP but it`s worth checking if you`re unsure, normally the small lift pump starts to fail first and starves the main pump.
Thanks for the replies and suggestions guys. I am pretty sure there is something up with my car. I have reviewed many ve tables for the same engine that have been tuned and even untuned for wot and they all look very very similar.
None of them look like mine up high in the ve table. What should be the main things I should look at in trying to diagnose this problem. It seems like im tuning around a lack of fuel problem. Please throw some ideas at me guys. Thanks.
If you can, check volume flow through the whole system... up to the injectors.
(or if you have MSII you could even try the experimental flow test feature, have not tried it myself)
I installed a new billet fuel filter setup during the whole ms install. That was only 6-8 months ago. Is it possible for a fuel pump to work on average but then not flow enough when is needed. At the moment im still using the stock CIS fuel pump which was good on a 80+ psi system.
Im using a 3 bar fpr off of a later vw that's seems to be working fine. Im just kinda stumped here. I have an extra fuel pump I might install tomorrow just to see if that fixes things. Ill keep you guys posted.
captain16vgti wrote:I installed a new billet fuel filter setup during the whole ms install. That was only 6-8 months ago. Is it possible for a fuel pump to work on average but then not flow enough when is needed. At the moment im still using the stock CIS fuel pump which was good on a 80+ psi system.
Im using a 3 bar fpr off of a later vw that's seems to be working fine. Im just kinda stumped here. I have an extra fuel pump I might install tomorrow just to see if that fixes things. Ill keep you guys posted.
-Chris
Before you waste hours and hours of time installing a new pump do the SUPER EASY and simple volume test... depressurize system, disconnect feed line from rail and feed into suitably large container (5 gallon bucket works nice to contains splashes). run pump directly for 30-60 seconds and then measure out how much comes out. Also note flow rate during the run, it should start strong and stay that way. If it comes slow and then speeds up there's a restriction in the line (kinked line, or internally corroded line) Notice if the pump sound DIFFERENT when running the volume test vs when under pressure connected as normal. The pump may sound different, but drastic differences (excessive whining, metal sounds) indicate potential imminent pump failure.
Do NOT use copper fuel lines (they can react with gasoline and corrode) as well as the fact that copper work hardens and can fracture. Use the proper metal lines
