Car idle dips really hard when fan kicks on!
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Car idle dips really hard when fan kicks on!
Hello everyone! well like the topic says, my idle dips really low when my fan kicks on and sometimes it will stall if I'm sitting at a light. I'm sure my alternator might not be cranking the juice its supposed to anymore but is there a setting in tuner studio to prevent this dip when it sees an electrical load like the fan kicking on?
Thanks in advance
Thanks in advance
Re: Car idle dips really hard when fan kicks on!
If your using MS3 to control your fan, you can also check a setting that will idle the engine up right before the fan kicks on.
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93 Foxbody...under construction Barra 4.0T
94 Jeep ZJ Bone Stock
97 Jeep ZJ Bone Stock
08 Buell XB12R, custom exhaust, soon to be turbo'd and MS3'd
Re: Car idle dips really hard when fan kicks on!
i'm not using the ms3. using ford taurus fan with volvo relay.midnite88 wrote:If your using MS3 to control your fan, you can also check a setting that will idle the engine up right before the fan kicks on.
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Re: Car idle dips really hard when fan kicks on!
increase idle richness may increase idle stability
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http://web.aanet.com.au/arran
Re: Car idle dips really hard when fan kicks on!
Doesnt matter what fan and relay your running. If the ECU is telling the relay when to kick on you can make the ECU idle your engine up before the fan kicks on. Also, if you have a RPM row below you set Idle RPM, add a few degrees of timing. That will help more than adding fuel. Fuel will generally make you bog, timings increases engine torque to compensate for the extra load the alternator puts on the engine.
88' F150 5.0 TFS Heads Comp XE258 Cam....Block now in two pieces
93 Foxbody...under construction Barra 4.0T
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97 Jeep ZJ Bone Stock
08 Buell XB12R, custom exhaust, soon to be turbo'd and MS3'd
93 Foxbody...under construction Barra 4.0T
94 Jeep ZJ Bone Stock
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08 Buell XB12R, custom exhaust, soon to be turbo'd and MS3'd
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Re: Car idle dips really hard when fan kicks on!
I'm not sure but check the dwell time, battery correction and battery voltage (while the car is on) to see if your alternator is running ok...it looks like the fan is getting a good amount of power.
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Re: Car idle dips really hard when fan kicks on!
This is a 40amp fan and the draw is just that.
Use the timing trick to get close, but if you can wire in a Air Idle Valve then you can control idle when they kick on.
Also Check the alternator, get a true reading of how it is working.
I do recommend a 105 amp or better alternator, because the fan draws 40 amps [continuous] on high running at 14V ... not counting any other accessories like A/C, or audio systems.
Use the timing trick to get close, but if you can wire in a Air Idle Valve then you can control idle when they kick on.
Also Check the alternator, get a true reading of how it is working.
I do recommend a 105 amp or better alternator, because the fan draws 40 amps [continuous] on high running at 14V ... not counting any other accessories like A/C, or audio systems.
Re: Car idle dips really hard when fan kicks on!
If its a 40 amp fan, the influx current is probably close to 50 or 60 amps. That will certainly make any vehicle dip.
88' F150 5.0 TFS Heads Comp XE258 Cam....Block now in two pieces
93 Foxbody...under construction Barra 4.0T
94 Jeep ZJ Bone Stock
97 Jeep ZJ Bone Stock
08 Buell XB12R, custom exhaust, soon to be turbo'd and MS3'd
93 Foxbody...under construction Barra 4.0T
94 Jeep ZJ Bone Stock
97 Jeep ZJ Bone Stock
08 Buell XB12R, custom exhaust, soon to be turbo'd and MS3'd
Re: Car idle dips really hard when fan kicks on!
Use adaptive idle spark. This can work even with no actual idle airflow control.
Set the table such that when the engine is idling "on target," actual idle spark is 5-10 degrees lower than the "ideal" value. I define ideal value as the classic "peak vaccum" condition. for Most engines/families, this winds up in the 20-25 degree range.
When the engine is below target idle speed, rapidly feed in timing. As an example, assuming 25 degrees is that "ideal" number, I would idle "on target" at 16 degrees. At 100 rpm below target, I would enter a value of 21. At 150 rpm below target, I would enter a value of 25. If the engine is above target, I would pull even more timing.
I can't remember if the current firmware is setup with absolute timing values, or if the adaptive curve is a "delta" curve.
What will happen, is since you are running reduced idle spark, when "on target" it will take the engine more airflow to idle. Even if idle airflow remains constant, the instant the engine begins to slow down, the extra timing will have a substantial "impact" in catching the engine.
before the adaptive software feature was added, I did this via table switching at low throttle positions, and dedicated a timing table to idle.
People want to fix slow idle with air, but engines (particualrly ones with large cam shafts at low speeds) respond slowly to changes in airflow. We have to tell the valve to move. We have to wiait on the valve to move. We have to wait for manifold pressure to drop. We have to wait for the engine to induce the aiflow. All this can actually add up to a very real amount of time, particularly at idle when we don't get many cycles, and if your engine makes little vaccuum at idle (big cams), we have a very limited ability to induce much more air at idle anyway.
Set the table such that when the engine is idling "on target," actual idle spark is 5-10 degrees lower than the "ideal" value. I define ideal value as the classic "peak vaccum" condition. for Most engines/families, this winds up in the 20-25 degree range.
When the engine is below target idle speed, rapidly feed in timing. As an example, assuming 25 degrees is that "ideal" number, I would idle "on target" at 16 degrees. At 100 rpm below target, I would enter a value of 21. At 150 rpm below target, I would enter a value of 25. If the engine is above target, I would pull even more timing.
I can't remember if the current firmware is setup with absolute timing values, or if the adaptive curve is a "delta" curve.
What will happen, is since you are running reduced idle spark, when "on target" it will take the engine more airflow to idle. Even if idle airflow remains constant, the instant the engine begins to slow down, the extra timing will have a substantial "impact" in catching the engine.
before the adaptive software feature was added, I did this via table switching at low throttle positions, and dedicated a timing table to idle.
People want to fix slow idle with air, but engines (particualrly ones with large cam shafts at low speeds) respond slowly to changes in airflow. We have to tell the valve to move. We have to wiait on the valve to move. We have to wait for manifold pressure to drop. We have to wait for the engine to induce the aiflow. All this can actually add up to a very real amount of time, particularly at idle when we don't get many cycles, and if your engine makes little vaccuum at idle (big cams), we have a very limited ability to induce much more air at idle anyway.
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Re: Car idle dips really hard when fan kicks on!
How do you have the fan wired? Do you have a nice large gauge wire running off the battery versus the alternator? If wired off the alternator- that could be your problem. The battery not only starts your car but also stabilizes surges- like when the fan kicks on.
Richard
Richard
Re: Car idle dips really hard when fan kicks on!
ok for starters my ECU isn't controlling the fan. my setup is a ford Taurus 2 speed fan, Volvo 2 speed fan relay and bmw coolant switch. i have this setup conneced to the battery since i could find a good 12v switch in my engine bay. i was thinking my alternator is just too weak and can't keep up. i just purchased a 130amp alter. and will install it first to see if it makes a difference and go from there. thanks for you input guys and i will keep yall posted
Re: Car idle dips really hard when fan kicks on!
so i added a 130amp alternator and ditched the factory crap and it seems a little better but still has a dip! i just adjust the iac idle to 900 rpm at the temp where the fan kicks on. seems to be fine for now but you can tell when the fan kicks on when the car is just sitting.
thanks for all your input guys! Msextra to the world! lol
thanks for all your input guys! Msextra to the world! lol
Re: Car idle dips really hard when fan kicks on!
These fans will draw 100 amps at start up then ramp down to 30-40
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Re: Car idle dips really hard when fan kicks on!
In that case, I suggest you change the fan control from a thermoswitch to ECU controlled so the ECU can know when the fan is engaging and increase idle air flow to compensate.
Matt Cramer -1966 Dodge Dart slant six running on MS3X
Re: Car idle dips really hard when fan kicks on!
yes i know that when was researching these fans, but they work very well even with the 7mgte that i known to be a hard motor to keep cool with e-fans. need high cfm's on the mk3 supras.hessdawg wrote:These fans will draw 100 amps at start up then ramp down to 30-40
Matt Cramer wrote:In that case, I suggest you change the fan control from a thermoswitch to ECU controlled so the ECU can know when the fan is engaging and increase idle air flow to compensate.
yes this is my next step!
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Re: Car idle dips really hard when fan kicks on!
Can't closed loop idle control be used to deal with this?
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Re: Car idle dips really hard when fan kicks on!
i never set up closed loop idle before. if you have some settings i can go off of, i wouldn't mind trying it.mickeymarrows wrote:Can't closed loop idle control be used to deal with this?
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Re: Car idle dips really hard when fan kicks on!
Closed loop idle will help. You will still have a dip but tuned right it should recover. Using fan control's feedforward mechanism is still the only way to avoid the dip altogether.
Megasquirt is not for use on pollution controlled vehicles. Any advice I give is for off road use only.
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Re: Car idle dips really hard when fan kicks on!
I'm still running open loop 'PWM warmup' but I intend to adopt closed loop in the very near future as my car has a compressor for the air suspension and when that kicks in, like yourself, it will stall the engine if I'm at idle. I'm relying on closed loop idle to prevent the stall, I know it will dip and I can live with that if closed loop will bring the idle back up...3tc power wrote:i never set up closed loop idle before. if you have some settings i can go off of, i wouldn't mind trying it.mickeymarrows wrote:Can't closed loop idle control be used to deal with this?
However, whenever I look at the closed loop settings page in the manual it goes completely over my head!
'82 Golf GTI ABF 16v MS2 Extra sequential COP
'77 Scirocco G60 MS2 Extra sequential
'77 Scirocco G60 MS2 Extra sequential
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Re: Car idle dips really hard when fan kicks on!
What do you not understand?
Megasquirt is not for use on pollution controlled vehicles. Any advice I give is for off road use only.