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Cts mod
Topic Started: Apr 16 2017, 07:25 PM (1,652 Views)
Boosted geo
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Hi new to the geo form but have had my 2000 Chevy metro for years love it . I have a turbo set up an currently running 7-8 psi but after she warms up I only get about 5-6 I have tried to find info on the CTS mod but all I find is its mod on older 2 wire models the 2000 model has a 3 wire on the thermostat I have looked to make sure there is nothing else . was wondering if some one could help or put me in the right direction how to mod the 2000 model cts. Any help would be great thanks
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freegeo
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What are you wanting to do to the coolant temp sensor?
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Woodie
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He wants to lie to the computer and tell it that the engine is cold in order to get into fuel enrichment to compensate for the extra air the turbo is pushing in.
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Boosted geo
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Trick the system to get more fuel if possible when car is cold I can get more boost so I want to trick the system to stay into open loop. I have looked up the cts mod but not much about the 3 wire system like I have or any pics how other have done them . been trying to find the SDS EIC system but can't find any one that sells it . I ordered a water meth kit that you can ajust and use boost reff going to convert to run fuel Hopfully that will help was going to pull the cts all together and run a stand alone with adjustable temp setting an see if that help just have to keep the old one from getting hot maybe even gap the o2 sensors . right now I have a full exshaust turbo cam underdrive pully . but not enough fuel but its deff better then before. Lol


Thank you freegeo and woodie for the help .
Edited by Boosted geo, Apr 17 2017, 09:10 AM.
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MarkZ28


Buy another sensor but hang it loose and plugged in. Will bever get hot so ecm thinks its always cold. That, or place a resistor in the right wire.
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freegeo
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I can help you with that. Do you have any type of scan tool to give live data?

Is this a 3 cylinder? If you want it to stay in open loop you have to keep the ect value below 68 degrees F. There is a time limit for the system to go in closed loop. It will set a po125 code for not going into closed loop, but sounds like you don't care about that.
Edited by freegeo, Apr 17 2017, 06:28 PM.
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Boosted geo
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Yes I have live scan tools . and yes its a 1.0 3 cylinder. And no don't care about the check light coming on. I will set it back to normal emission . when its to.e to test they don't care if its has the turbo as long as it passes the sniffer and dosent have a light on
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Boosted geo
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I'm thinking just pull the the cts but leave it plugged in and run a stand alone cts to run the fan . and maybe space the o2 sensors . I want to be able to Chang it back fast I'm in Colorado so never no when we might randomly get snow .
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Boosted geo
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My other delema is my tbi hat can't find the right one on line to handle boost . I have a full time job but work at ATS diesel part time . so I'm hoping I can fab one but don't want to wast my time to make it already have made so much for this thing lol any ideas who sells some thing like that ?
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freegeo
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I get home I can post the wiring diagram for the CTS.
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Boosted geo
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Thank you freegeo .
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Hanuman
"The Almighty Grounds Cleaner"

If it were me, I would unplug the front o2 sensor to prevent open loop, and run eather put a large resistor in series with the cts, or iat sensors. That will richer it up some. But you'll need to adjust timing a little to compensate....advance 1 or 2 degrees. Rich mixtures needs more burn time.
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Hanuman
"The Almighty Grounds Cleaner"

But just unplugging the cts will disable closed loop and set the cts at I believe it's 68 degrees.
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freegeo
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Here is the wiring diagram. Double check the wire colors. This is from the 1999 FSM, but should be the same for a 3 cylinder. I have used a potentiometer to drop my CTS value before.You would need to put it across the gry / wht and lt grn / blk wires. You will need a pretty big one too. Probably around a 15K size.

You need to keep the CTS value under 68 F to keep it in open loop. The 1st O2 sensor will still report values the the PCM. You could probably use those values to get an idea of how rich or lean the system is.


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t3ragtop
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Turbo3 and Twincam Tweaker

first, the cts mod was ginned up for the mk2/3 obdI controls and only ever provided brute force fueling. by no means is it a great way to provide proper afr control for a turbo mod.

the operational range of the map sensor will stand some boost but fueling becomes non-linear after only a few pounds of boost.

the factory ecu was never able to be re-mapped for turbo operation like the gt's twincam. back in the day we pulled the eeprom from the gt's ecu, read the mapping, and burned new replacement eeproms with mapping adjusted for turbo operation. nobody ever cared enough about the 3 bangers to ever do the research and development for modifying the mapping.

this was the reason i built my own controls from the megasquirt. it gave me the advantage of writing my own fuel and ignition maps.

trying to boost a g10 using the factory ecu is difficult because the factory mapping isn't designed to pull advance vs boost fast enough nor is it designed to provide proper fuel trim. the fuel pump, pressure regulator built into the throttle body, and oem injector can't provide enough fuel to cover the needs of the engine under boost, either. the g10s intake manifold was never designed to handle the air flow under boosted conditions.

an air hat on the throttle body changes the manifold absolute pressure which is applied directly to the throttle body's built in fuel regulator, which also was never designed for anything over atmospheric pressure. you need to neuter the built in fuel pressure regulator and run a rising rate fuel pressure regulator externally to provide fuel pressure that increases as manifold absolute pressure increases.

the turbo3 versions use a rising rate fpr that maintains a fuel pressure in the rail at 38 psi over the manifold absolute pressure so that the injectors can efficiently squirt into a pressurized system.

having been through all of this from the day i started my metro turbo work 16 years ago, i ceased trying to turbo a g10 this way. believe me when i tell you that i have blown up more g10 engines than just about anyone else in 16 years of trying to boost geo 3 bangers. ;)

i have my own highly researched methods that have resulted in boosted g10 engines that don't hand grenade in a week. it's not cheap and it's not easy, but i build boosted 3 bangers that work.

i learned something from every failure. i'm not inclined to tell you that what you are doing won't work but i am inclined to tell you some of the pitfalls you will encounter. ;)
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