Go back to home

aw11 sc fuel or ignition cut out

Page: < 12 Showing page 2 of 2 - Powered by APG vNext Trial
Author
MCT_MR2
MR2 Deity
  • Total Posts : 626
  • Scores: 104
  • Reward points: 4232
  • Joined: 2011/04/07 19:51:15
  • Location: Melbourne Victoria Australia
  • Status: offline
Re:aw11 sc fuel or ignition cut out 2011/07/15 21:02:39 (permalink)
0
Yeah, it is a cusco adjustable bypass valve. What happens is instead of bypassing the vsv's that normally control the factory vsv, this allows you to adjust the point that the bypass valve opens. the nut at the bottom locks the bolt in place, and the bolt can be wound in to increase boost levels, or wound out to lower them (this is provided you have a pully setup to make the boost in the first place)
 
You will probably find if you unwind the bolt two turns, your boost level should drop. If it doesn't, there is a good chance is it over-preloaded, which may cause some running issues (tho unlikely the ones you are experiencing.) This bolt should be adjusted to work at the boost that you want. Maybe try taking down the preload, dropping the boost to say 8 or 9 psi, and see if you still have the cutting out problem.

'88 MR2 4AGTE W/ EFR6258

224.6KW @ 20PSI

more to come......
#16
Fab4mr2
MR2 Enthusiast
  • Total Posts : 83
  • Scores: 0
  • Reward points: 1528
  • Joined: 2011/04/07 19:51:15
  • Location: San Diego USA
  • Status: offline
Re:aw11 sc fuel or ignition cut out 2011/08/21 05:37:38 (permalink)
0
Yes, that is definitely a Cusco adjustable abv, so don't toss it out, lol. Those are worth money! They are designed to allow an adjustable boost level, as mentioned, but also allow the sc to spin up a bit more normally, as throttle is applied. Basically, the system will act more like a stock system than if just the abv mod is performed. It is not necessarily a huge difference, but is nice to know everything is working as designed. What I like about them is that you can essentially dial out over-heated boosting, by checking your max boost when the engine is cool, and then setting the abv for that boost level. Anything above it will mostly be wasted over heated boost that eventually does more damage than good.
 
As for you real issue though, it currently sounds like you have what is known over here as the low-end lean out, although your initial problem sounded more like the jdm top end issue that is also known.
 
The low end lean-out is usually caused on non-jdm 4agze engines/ecu's that have different ecu maps than the jdm versions, and are being over-boosted. The issue is more apparent under wide open throttle at low rpm, and causes a massive lean out issue and stumbling, before regaining its proper fueling at around 4k rpm. You can test that easly enough by lowering the boost level with the Cusco down to around 8-9 psi as mentioned previously. If that solves the issue than you most likely have a non-jdm ecu that is hampered by over boosting.  The solution would be to either get an aftermarket ecu/stand alone, or get, what is known in the US as a Grunt Box, a device made to use the CSI to provide extra fuel at the point of lean out.
 
The initial issue you mentioned, however, the 5,500 rpm one, sounds like the jdm upper rpm problem that is caused by knock issues, and I believe is found with slightly newer jdm ecu's than what came in the MKI MR2 originally. When over boosting, the knock signal overwhelms the ecu and cause a dramatic drop in timing temporarily, until the rpm's drop and the ecu can correct itself. There has never been an easy solution to that issue that I am aware of, other than going with a stand alone ecu.

So long, and thanks for all the fish!
#17
ozhummer
MR2 Aficionado
  • Total Posts : 296
  • Scores: 11
  • Reward points: 4739
  • Joined: 2011/04/07 19:51:15
  • Location: Brisbane QLD Australia
  • Status: offline
Re:aw11 sc fuel or ignition cut out 2011/08/22 11:53:07 (permalink)
0
Thanks for the info - I have decieded to "go for the doctor" and so a complete race spec rebuild - Including a Haltech Sport 1000 ECU! .... I think my issue will go away without me ever really knowing the true cause!. ... :)

Cheers
Keith
#18

pressure cooker
MR2 Enthusiast
  • Total Posts : 119
  • Scores: 1
  • Reward points: 4659
  • Joined: 2012/08/10 13:24:35
  • Status: offline
Re:aw11 sc fuel or ignition cut out 2012/08/10 13:39:31 (permalink)
0
just wondering where i can get a grunt box?
#19
Kookabanus
MR2 Enthusiast
  • Total Posts : 157
  • Scores: 0
  • Reward points: 4904
  • Joined: 2011/04/07 19:51:15
  • Location: Melbourne Victoria Australia
  • Status: offline
Re:aw11 sc fuel or ignition cut out 2012/08/10 16:31:00 (permalink)
0
http://www.gruntbox.com/
 
jury is out on whether it only makes a difference on usdm ecu's or jdm as well but that site should get you started.
#20
Knightrous
MR2 Deity
  • Total Posts : 2045
  • Scores: 272
  • Reward points: 5721
  • Joined: 2011/04/07 19:51:15
  • Location: .
  • Status: offline
Re:aw11 sc fuel or ignition cut out 2012/08/10 20:54:55 (permalink)
0
For $150 you could build a MegaSquirt I and enable yourself to do a proper fuel and spark tune.
http://www.diyautotune.co...-black-case-p-128.html
 
 
#21

Page: < 12 Showing page 2 of 2 - Powered by APG vNext Trial
Jump to:
© 2025 APG vNext Trial Version 5.5