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Forum nameEngine Management Systems & Controllers
Topic subjectMegasquirt help
Topic URLhttp://forums.2gnt.com/dcboard.php?az=show_topic&forum=54&topic_id=3619
3619, Megasquirt help
Posted by taclipse, Dec-31-69 06:00 PM
I am in the process of getting my ass kicked by my car and my MS install. Ive got the car to start and idle but i have been having an issue with the car idling at 3500 rpm...I checked for vacuum leaks and even changed out my modern performance throttle body, that i just put on. My buddy messed with my injector characteristics and my idle came down to about 1400 rpm and about a 10.4 afr. I was wondering If any one could help me out with a msq. My mod list is as follows-
motor:
pnp head
crower turbo grinds, springs and retainers
1mm oversized valves
stock intake manifold with a modern performance 60mm t-body
je pistons 8.8:1, crower rods, Stock MLS headgasket, arp head studs.

turbo setup:
gt3076r .63 exhaust
3" all the way back to thermal R&D
synapse synchronic wastegate
2.25 hotside intercooler piping, 3" cold side

Fuel:
850cc fuel injector clinic injectors
custom -6an fuel rail with all -6an lines (return line system)
aeromotive 1:1 FPR with static fuel pressure set at 45 psi
rewired walbro 255 lph

MS setup:
Rs-autosport pre super420a
MS1-extra v3.0, flyback board and internal vb921's
running 029y4.

I am BANME! when it comes to MS, so please excuse my lack of knowledge. I have been reading 24-7, My girlfriend hates me and my car lol. I have a friend doing most of my MS tuning for me that has been driving a megasquirted mazda for about a year. I will try to get him to chime in if needed.
3620, RE: Megasquirt help
Posted by taclipse, Dec-31-69 06:00 PM
well we THINK we figured out why the car is acting so erratic. The stock ecu isnt doing anything. Previously i wasnt getting power to the coil or injectors and the fuel pump was priming but not kicking on during cranking. My buddy lives about 45 min away from me and when he showed up to tune my car is when i found out everything wrong. I was in a rush to get the car started so i jumped power to the coil and the injector harness and fuel pump relay. The car started but ran like ass....after messing with the settings it smoothed out but i still had the idle issue (3500 rpm idle). I checked for vacuum leaks, changed out my throttlebody and finally came to the conclusion that i had none.....I was wrong. Once I sat down and thought it over I realized the stock ecu wasnt doing anything thus causing the IAC to remain open and cause a major vacuum leak. That is also why i didnt have power to the coil, injector harness, why my fans were not kicking on, why my stock tach wasnt working and why my fuel pump was not kicking on during cranking. I tee'd into the crank angle sensor wire for the MS install. I get a correct rpm reading in MS. Im thinking maybe the stock ecu isnt getting a signal from the crank angle sensor. I am going to test all my connections at the factory ecu and make sure im getting signal.Please chime in with any comments or suggestions. Thanks for the time guys!
3621, RE: Megasquirt help
Posted by Jungy, Dec-31-69 06:00 PM
You're probably going to want to ditch the ecu and go by wickedesi's MS install. Everyone I have heard of running a v3 board gets a noisy cps signal when t'ed off the stock ecu and has problems with tach spikes. Although I think corbin got it to work with the stock ecu some how, not positive though>
3627, RE: Megasquirt help
Posted by taclipse, Dec-31-69 06:00 PM
Originally posted by Jungy
You're probably going to want to ditch the ecu and go by wickedesi's MS install. Everyone I have heard of running a v3 board gets a noisy cps signal when t'ed off the stock ecu and has problems with tach spikes. Although I think corbin got it to work with the stock ecu some how, not positive though>


Im pretty sure thats the route i will have to go. I got the car to idle and drive but i am experiencing tach spikes. I am going to try to ground everything out better and hope for the best. I appreciate the reply Jungy!
3628, RE: Megasquirt help
Posted by Star Turbo Talon, Dec-31-69 06:00 PM
Why dont you take up the issue with RS-Autosport since he advertises it works fine without removing the stock ECU.
3629, RE: Megasquirt help
Posted by eclipse982nrRST, Dec-31-69 06:00 PM
I kind of have this issue too.

The car will sit and idle for awhile, but then randomly, if I give it gas, the idle will hang up around 2800 to 3500 and stay. Looked for vac leaks too and found nothing. I havent dug deep into this problem yet though because I am working the body over on it again, but my fans wouldnt turn on either, so I am thinking I might have a junk ECU as well. But everything else works fine, I have no troubles getting it started and have power to everything else I believe.

Interesting.
3630, RE: Megasquirt help
Posted by taclipse, Dec-31-69 06:00 PM
Originally posted by eclipse982nrRST
I kind of have this issue too. The car will sit and idle for awhile, but then randomly, if I give it gas, the idle will hang up around 2800 to 3500 and stay. Looked for vac leaks too and found nothing. I havent dug deep into this problem yet though because I am working the body over on it again, but my fans wouldnt turn on either, so I am thinking I might have a junk ECU as well. But everything else works fine, I have no troubles getting it started and have power to everything else I believe. Interesting.

the problem seems to be intermittent. Once i wired in a voltage regulator, blocked off the IAC, wired in relays and a switch for the fans and fuel pump ... the stock tach decided to start working, I assume that it was performing all its other duties as well. Well as the car sits right now the MS is basically a full standalone minus the factory ecu supplying a power source to the sensors. I ran a 0 guage wire from the back of the block to the rear of the car where the MS is grounded along with the battery, relays and wideband. SO FAR this seems to have taken care of the tach spike issue! I am very excited and am learning a lot about tuning cold starts lol! All the bullshit aside I am very happy with MS. Thanks for all the input guys!

3635, RE: Megasquirt help
Posted by WickedESi, Dec-31-69 06:00 PM
Glad to hear you got it running!
3636, RE: Megasquirt help
Posted by taclipse, Dec-31-69 06:00 PM
Originally posted by WickedESi
Glad to hear you got it running!


thanks bro. I stand corrected about the tach spike issue. Looks like I am going to have to do your board mods and make it a full standalone. I just dont feel comfortable messing with the board myself.
3637, RE: Megasquirt help
Posted by WickedESi, Dec-31-69 06:00 PM
How many grounds to the board do you have? and what size?

If you're running spark, you'll need 5x 18 gauge grounds. Try this first.
3638, RE: Megasquirt help
Posted by taclipse, Dec-31-69 06:00 PM
Originally posted by WickedESi
How many grounds to the board do you have? and what size? If you're running spark, you'll need 5x 18 gauge grounds. Try this first.


I bought the kit from rs-autosport. From what I recall there are 6 grounds that tie into one. I am going to try a shielded wire for the tach sig next. Thanks for the input Wickedesi
3639, RE: Megasquirt help
Posted by WickedESi, Dec-31-69 06:00 PM
What size the the ground it ties into? I'd make it 8 awg because of all the noise problems these have. I still got an occasional glitch, till I added 3 extra 18 awg for a total of five 18awg grounds going from the Megasquirt directly to my battery.
3650, RE: Megasquirt help
Posted by taclipse, Dec-31-69 06:00 PM
Originally posted by WickedESi
What size the the ground it ties into? I'd make it 8 awg because of all the noise problems these have. I still got an occasional glitch, till I added 3 extra 18 awg for a total of five 18awg grounds going from the Megasquirt directly to my battery.


thanks for all the help wicked! This project is put on hold due to my stupid AEM cam gear bolts snapping on me. I didnt notice this until the motor was out.... i felt pretty crunchy! I got on the car..... it was extremely fast then it shut off. I did a compression test and the results were devastating, the first thing that came to mind was the gay total seal rings i used. So without thinking i decided to pull the motor and get to fixing it. On the way out is when i noticed the intake cam adjustment bolt. I decided to remove it, fix my water pump, paint the engine bay, fix the TOB and order some fidanza cam gears. This thread will hopefully be back alive in about 2-3 weeks.
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