8746 doesn't have a built on fan switch and I was thinking about making one. The easiest way I could think is to use the EGR on/off temps AND the EGR on/off speeds. I'd disable the EGR code from being displayed in as an SES and change all the values it effects to zero. Does anybody see any problems with this? I think it's a cool idea considering a lot of us are just disabling it and not doing anything with it. Please let me know your thoughts and other options I could explore. I think I'm really upset that the TPI guys got the ecm controlled fan switch built on and us TBI guys get the crappy in block sensor . I know I'm new at this stuff so if this is really stupid please let me know.

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, Jon (350 TBI!)
91 Red My website

 

Get a 87 GN Rad Fan switch (closes at 210dF) and have the best available..

 

I personally think you are making alot of unessesary work for yourself. It will take a bunch of work to figure out all the parameters that are affected by the EGR routines. Even then you might miss something that bites your *** later on.

Like Grumpy mentioned, a lower temp fan switch is fine, not mention cheap and easy. If you want more control you can buy one of the adjustable fan switches.

I've found that unessesary complexity leads to trouble, keep it simple.

[This message has been edited by Brent (edited April 28, 2001).]

 

The idea is to not have to buy anything and still have an adjustable fan switch. From what I've explained is there anything more that that. If so please tell me what would make this so difficult.

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, Jon (350 TBI!)
91 Red My website

 

I say hack away!

Why not give it a shot and see what happens. It may or may not work, or may give you intermittant problems down the road , but experimentation is what leads to discovery.

In the past it was said that manned flight could not be done, and space exploration was sneered at by many...Well....what would happen if everyone listened to the critics???

Give it a shot. Experiment. See if it will come to fruition or not. Nothing stupid at all with giving it a try.

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86 Trans Am WS6 Black with tinted windows, shaved door handles
ZZ4, Mini-ram, true duals, LT4 HotCam, AFR 195 heads.
***Too many other mods to mention***

"In the future, cities will become deserts,
roads will become battlefields, and the hope of mankind
will appear as a stranger" The Road Warrior

 

Okay, I'm going to do it. I just wanted to see if anybody see's a problem with this. I figured if I made it so nothing was changed when EGR was on then there wouldn't be any problem. It would be an extra speed or temp activated switch. Another idea I was playing with was to have an overheating light to warn me if the temp went to high BEFORE I'm at 240 and the thing is running like ****. I'd like to know exactly how the EGR on/off works. I don't know if I set the EGR off speed below 50 and on at 60, what really happens. Or what about if I set the EGR on/off temp but the speed requirements weren't met, would EGR still go on or what? If anybody has the answers to the order and relation of the ecm to EGR please PLEEAASE let me know. I don't want to spend half a day and half a tank of gas figuring this stuff out if somebody here knows the answers.

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, Jon (350 TBI!)
91 Red My website

 

Jon,

I was looking through the hack and noticed that a lot of things are very dependent on the EGR position. I believe it has an effect on the Fuel injection, spark advance, abd the vacuum has an effect on the egr valve. Now I'm not so sure about hacking all this. I think it can be done. WE need to be able to change the SA numbers and the other stuff before we can hook a fan relay to the EGR position sensor.

Also I noticed that there are about a dozen different places where the ECM calls for a EGR test. Does the flag disable kill the SES light all together even though the ECM is running the test?

Just my .02

-Lars

IM me maybe we can talk about it a little more

 

The flag kills the light, not the egr functionality though.


Brendan

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1987 IROC-Z L98,SuperRam,EB 6085's,LPE 219/219 Roller, Crane 1.6RR, EB TPI Base, 58mm TB, ADS 24#, AFPR, K&N, EB TES, Catco Cat, 3" Borla Cat-Back, Accel cap,rotor,distro/other crap, MSD 6AL, MSD Blaster 3, Aluminum DS, 94 Disk Rear, Adjustable Valve, Precision 3.73 Gears, Sub-Frame Connectors, Hotchkis Lower Control Arms, KYB Shocks/Struts, Suspension Techniques Lowering Springs, Polyurethan Bushings all over the place, Moog Upper/Lower Ball joints and Tie Rods ends/Idler Arm,

To see the ROC, Check out the webpage Here

 

Yeah, flag should kill the error code. Or you can just use a check valve inline for the EGR but the flad is a better idea. I'm looking at it all now and I'm editing my tdf file to display all the EGR effected tables and constants. Please list here the location of the stuff you've found that are effected. Like the 005D is the SA for EGR. I don't know exactly what that does but the value in degree's is usually 35.2 Is that the max SA when EGR is in use or what?
Please lest all the locations in the hack that you find so I can make sure I don't skip over anything. I still think this isn't going to be all that hard. Just take some time. I'd appreciate ALL the help and info people can dig up like links for EGR and 7747 ecms etc. Grumpy, can you think of anything I might miss?
Thanks guys.

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, Jon (350 TBI!)
91 Red My website

 

Jon, You and I discussed this before but I thought we'd run it through here too. How many people on this board alone, took off thier EGR valve and still run the stock chip? Probably a bunch. Why can't you just find the input wire for the EGR Sensor and plug that into the Fan relay(directly or indirectly)? Granted, the fan won't exactlty turn on at the right times with the stock chip, BUT it will turn on. With a few mods to the EGR based parameters and some actual testing, I think this can be a huge breakthrough.

-Lars