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  #1  
Old 05-31-2012, 06:39 PM
tombstone tombstone is offline
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Join Date: May 2012
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Default Fuel cut @1800rpm?

Hello I installed the maft pro on my 7mgte supra a couple of years ago but now I have ran into some problems after doing upgrades to the engine.

It seems that i just cant get the engine running over ~1800rpm.

If I raise the rpm realy slowly from idle the engine runs realy well upp to aprox 1800rpm then the afr goes up to 22isch and the engine stalls untill the revs comes back down under ~1800 were it will go back to around 12afr.

Its like the ecu/maft cut the fuel over 1800rpm!?

The upgrades made since the engine ran well are:
Walbro intank fuel pump
900cc injectors
Custom intake
100mm throttle housing

Anyone have any ideas?
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  #2  
Old 06-01-2012, 11:57 AM
TerrenceLP TerrenceLP is offline
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What are your F-in and F-out readings?

The bigger throttle body my be giving you the issue as the ECU see a way too fast increase in air volume. I've learned that no matter what, the stock ecu doesn't like too much air over stock, 2x max in my testing - 12psi, fuel cut at 14psi. Hence why I'm going MegaSquirt v3. Standalone is where it's at once you reach the limits of the MAFT pro.

The Pro is great, but my learning curve is leading me to the Standalone ECU so stuff like max boost and fuel cut are a thing of the past.

If your not doing sequential a MS2 would do just fine.
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  #3  
Old 06-02-2012, 01:39 AM
TurboBob TurboBob is offline
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if you are revving in neutral, and running those big injectors, most likely the ECU thinks you are in Decel fuel cut mode because the throttle is not open very far and the airflow is very low.

how does it drive?

B
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  #4  
Old 06-02-2012, 01:31 PM
tombstone tombstone is offline
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It seems youre on to something there Bob, as shown in the log i had the TPS set to ~0 volts at idle earlier. When it was adjusted up to 0.25 volts I was able to rev the engine, it stills oscillates a bit around 2000rpm in neutral but its much better now. And when accellerating hard it doesnt happen at all
Going to the dyno this tuesday with pretty much stock engine at 1.5bar boost so wish me luck ;-)
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  #5  
Old 06-06-2012, 12:58 PM
tombstone tombstone is offline
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Dyno result:

Blown head gasket @ 5800rpm on 1bar boost, 365rwhp though.

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  #6  
Old 06-06-2012, 01:02 PM
TerrenceLP TerrenceLP is offline
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What was your HG set up? (ex. Fel-Pro with ARP studs)
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  #7  
Old 06-06-2012, 03:28 PM
tombstone tombstone is offline
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Standard, except from the tightening tourque on the bolts which was around 100nm.
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  #8  
Old 07-02-2012, 02:32 PM
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super60daytona super60daytona is offline
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We went to the HKS leak stopper with ARP BOLTS (not studs since studs require removing the engine to change head gasket. As any 7M owner will know, head gasket changes are like oil changes on a 7M) Still have the used and reused HKS gasket in the garage. Seems it doesn't fit a 2JZ... hmmmmm

Bright side was no head gasket leaks since the install of the HKS. Though we did go through 2 heads, 1 of them went on twice (before and after full P&P).

Not sure of the For Sale rules on this site, so PM me if you are interested in any 7M parts. Was a full built motor.
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There is no such thing as too much boost, until you find out there is.....
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  #9  
Old 07-02-2012, 04:02 PM
TurboBob TurboBob is offline
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all private sales are no problem here.

B
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