Please forgive the newb.

91 gmc · 06-24-2011, 03:06 AM

OK, I trying to help a friend who is somewhat forum phobic and have a few basic questions to help me get started.

First here are his mods:

1990 Toyota Supra, 7MGTE automatic.
3" exhuast
2.5" intake with Sparco intercooler
K&N Air filter
MSD ignition DIS-4
GM coil packs

We drag race with others at a track and his issue is fuel cut around 10.3 Fuel cut when racing takes the fun out of it. Anyway, 10.3 actually seems correct to me at this point. He’s waiting on a set of injs to do the Lexus mod but meantime…

I've been searching and reading and have some basic newb questions so thanks ahead of time.

As I see it the ECU controls fuel pressure. What is base FP and by what rate does FP follow boost? IOW does a pound of boost get you a pound of additional FP? If not then what? How is fuel pressure set? I see AFPR's mentioned where do they fit in?

What are the limits of (what I would call) the MAP or Manifold Absolute Pressure sensor? 2 bar, 3 bar, or? What happens (if it's even possible) if that boost level is exceeded? I know, besides a blown motor... :-)

I've searched but haven't been able to find the actual writeup on the Lexus/550 inj conversion. A link would be appreciated.

DAQ But what does the Knock Sensor rewire mod actually accomplish?

Direct links to the answers are fine. I appreciate your input. That will help me get started.

Regards,

Don

Sonyps307 · 06-24-2011, 05:21 PM

They do a rewire on the knock sensors because the wire gets old and starts to brake. If u have a check engine light code 52 then most of the time it's the wire not the sensor.

Nathaninwa · 06-25-2011, 12:08 AM

The ecu does not control fuel pressure directly. If its hooked up to a VSV valve is ecu controlled to run base pressure to prevent gas lock at startup and what not. And yes it is an rising rate fpr

When I ran my Lexus and 550 injectors, I was running 15psi with more than enough power for the street. I had a friend running 18psi on the same setup. Google search it more, its a really nice write up.

91 gmc · 06-25-2011, 03:15 AM

Thanks. And others, continue to post if you'd like, I'll keep searching & learning, and will probably throw out some more questions.

mkiiisupra · 06-25-2011, 10:44 AM

lexus and 550's
http://mkiiisupra.net/bbs/showthread...ide+controller

More guides from him
http://www.mkiiisupra.net/bbs/showthread.php?t=11469

06-24-2011, 03:06 AM	#1
91 gmc Stock Join Date: Jun 2011 Location: Calif. Posts: 2	Please forgive the newb. OK, I trying to help a friend who is somewhat forum phobic and have a few basic questions to help me get started. First here are his mods: 1990 Toyota Supra, 7MGTE automatic. 3" exhuast 2.5" intake with Sparco intercooler K&N Air filter MSD ignition DIS-4 GM coil packs We drag race with others at a track and his issue is fuel cut around 10.3 Fuel cut when racing takes the fun out of it. Anyway, 10.3 actually seems correct to me at this point. He’s waiting on a set of injs to do the Lexus mod but meantime… I've been searching and reading and have some basic newb questions so thanks ahead of time. As I see it the ECU controls fuel pressure. What is base FP and by what rate does FP follow boost? IOW does a pound of boost get you a pound of additional FP? If not then what? How is fuel pressure set? I see AFPR's mentioned where do they fit in? What are the limits of (what I would call) the MAP or Manifold Absolute Pressure sensor? 2 bar, 3 bar, or? What happens (if it's even possible) if that boost level is exceeded? I know, besides a blown motor... :-) I've searched but haven't been able to find the actual writeup on the Lexus/550 inj conversion. A link would be appreciated. DAQ But what does the Knock Sensor rewire mod actually accomplish? Direct links to the answers are fine. I appreciate your input. That will help me get started. Regards, Don

06-25-2011, 10:44 AM	#5
mkiiisupra Lexus & 550's Join Date: Sep 2007 Location: Las Vegas, NV Posts: 570 Blog Entries: 1	lexus and 550's http://mkiiisupra.net/bbs/showthread...ide+controller More guides from him http://www.mkiiisupra.net/bbs/showthread.php?t=11469 __________________ 1990 Toyota Supra Turbo A/T ------------------------------------------------ Questions about oil? take a look http://www.supramania.com/aehaas/

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06-24-2011, 05:21 PM	#2
Sonyps307 Lexus & 550's Join Date: May 2010 Location: Baltimore Posts: 526	They do a rewire on the knock sensors because the wire gets old and starts to brake. If u have a check engine light code 52 then most of the time it's the wire not the sensor.

06-25-2011, 12:08 AM	#3
Nathaninwa Intake Join Date: Jun 2011 Location: Aberdeen, WA Posts: 43	The ecu does not control fuel pressure directly. If its hooked up to a VSV valve is ecu controlled to run base pressure to prevent gas lock at startup and what not. And yes it is an rising rate fpr When I ran my Lexus and 550 injectors, I was running 15psi with more than enough power for the street. I had a friend running 18psi on the same setup. Google search it more, its a really nice write up.

06-25-2011, 03:15 AM	#4
91 gmc Stock Join Date: Jun 2011 Location: Calif. Posts: 2	Thanks. And others, continue to post if you'd like, I'll keep searching & learning, and will probably throw out some more questions.