Timing retard via Coolant Temp sensor?
Timing retard via Coolant Temp sensor? I know many people have been using the IAT timing tricker (resistor) mod with their nitrous setups for years. I too used it and have great reliable results with a MAF. I understand its not a good idea with a SD tune since accurate IAT's to the PCM are more important for precise fueling. Ie...if you tell the pcm the IAT is -10F its going to add fuel and vise-versa. You'd be forever chasing a proper fuel curve when conditions vary.
What about doing this same thing to the coolant temp sensor? What will the effects be? How much change in fueling would there be from say my current normal operating range of 170-190 to say 220 (with a resistor mod) to tell the pcm that what the coolant temp is?
I don't see any table in hptuners that would really affect fueling, just timing (ECT base spark) which is what you want!
What about doing this same thing to the coolant temp sensor? What will the effects be? How much change in fueling would there be from say my current normal operating range of 170-190 to say 220 (with a resistor mod) to tell the pcm that what the coolant temp is?
I don't see any table in hptuners that would really affect fueling, just timing (ECT base spark) which is what you want!
Last edited by redgto4u; Apr 4, 2014 at 10:42 PM.
I can second you in saying that IAT tricker with SD is bad news. There is a table that will allow a PE adder to account for the leaning out affect that high IAT's will give you.
I'm on SD using the CTS method from a homemade switch tapped from the computer w/HPtuners to pull timing a lot similar to the picture below, except I'm on a toggle switch now. It's also wired so the nitrous will NOT activate unless the timing switch is on. The only effects I see is the temp gauge showing the engine hotter than it actually is and the a/f ratio will be a tad richer:
Staging Lane
Joined: Mar 2014
Posts: 81
Likes: 0
From: Southern IL
I'm on SD using the CTS method from a homemade switch tapped from the computer w/HPtuners to pull timing a lot similar to the picture below, except I'm on a toggle switch now. It's also wired so the nitrous will NOT activate unless the timing switch is on. The only effects I see is the temp gauge showing the engine hotter than it actually is and the a/f ratio will be a tad richer:
Staging Lane
Joined: Mar 2014
Posts: 81
Likes: 0
From: Southern IL
Seems so simple, but we have something wrong, with a voltage drop from 5 to 2.47. Could you help me out with the diagram you used? And what year sensor did you use?
It is a plate system with heater, opener, stand alone, progressive, and resister to pull timing with HP Tuner. Just confused at this point, I think I need a week off.
LOL
It is a plate system with heater, opener, stand alone, progressive, and resister to pull timing with HP Tuner. Just confused at this point, I think I need a week off.
LOL
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I don't have a diagram.
My previous tuner tapped into a wire from the computer to go to some sort of Radio Shack square connector that makes the nitrous activates only when timing is pulled. That's also tapped into the wot switch and a toggle switch. Unfortunately, I don't know which wire.
My previous tuner tapped into a wire from the computer to go to some sort of Radio Shack square connector that makes the nitrous activates only when timing is pulled. That's also tapped into the wot switch and a toggle switch. Unfortunately, I don't know which wire.
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I am in the process of doing exactly this, timing retard as well as fuel enrichment via faking out the coolant temp sensor. A 90 ohm resistor sets the coolant temp to ~255*F as I verified over the weekend. I am wiring 2 resistors into 1 relay. One will fake out the PCM and the other will sweep the in car gauge to 255*F also so I can verify that the relay actually energized. In my instance, the car will go into "Engine Protection Mode" and gives me different tables to command the timing as well as commanded AFR.
