V3 idle control with 2 wire bosch not working

bertelli_1 · Post by **bertelli_1** » Thu Jul 06, 2006 5:49 am

I'm running msns-e on a v3 board and have just modified it to use the idle control valve. I am getting 12v at the valve but when i measure the voltage across the pins I only read 0.5v. Does this mean I have done something wrong on the ecu? I have tried to alter the settings but the voltage does not change, nor does the valve show any signs of life (it was working fine on the standard ecu). According to the help I should run the algorithm as B&G on/off not fielding PWM, is this correct? Does anyone have the settings required for a Vw Golf 8v lump, either in warmup or closed loop? I'm running 2.25b514

Keithg · Post by **Keithg** » Thu Jul 06, 2006 8:51 am

You need to run it as fielding PWM. IF there is no voltage measured across teh pins, the transistor is not being turned on or is 'open'. Try PWM and open loop (warmup) first to see if you can get it to control idle speed first before trying to run it in closed loop mode.

KeithG

bertelli_1 · Post by **bertelli_1** » Thu Jul 06, 2006 9:33 am

I have tried that already - no luck. Is it safe to assume there is a problem with the earthing side of it? Are there any tests I can do on the MS to help diagnose the fault?

Keithg · Post by **Keithg** » Thu Jul 06, 2006 9:38 am

Hook it to the stim and see what it does. Try setting one of the gages in MT to IdleDC. That helps as well.

KeithG

Posted by email.

bertelli_1 · Post by **bertelli_1** » Thu Jul 06, 2006 9:54 am

Thanks Keith - if only I had a stim....

bertelli_1 · Post by **bertelli_1** » Thu Jul 06, 2006 3:07 pm

Anyone else got any ideas?

screamer69 · Post by **screamer69** » Thu Jul 06, 2006 3:16 pm

bertelli_1 wrote:Anyone else got any ideas?

i had that problem with mine m8 i gave up in the end and run no idle controll and the car runns sweet as a nut ( just been setup on the rollers part boost though) i tryed for weeks to get mine to run but couldnt work it out

Keithg · Post by **Keithg** » Fri Jul 07, 2006 4:12 am

Well, all I can suggest is to turn on an idleDC gage. Then try setting warmup mode and try different values of idleDC until you get it to regulate idle. If you get no voltage across the IAC, then you probably have a dead transistor (open) or a broken wire somewhere. Once you find out what value will allow it to regulate idle near your target speed in Warmup mode, then you can start to tune closed loop mode. If you can borrow/buy a stim, diagnosis will be easier, it definitely helps me. Which transistor did you swap out the 2n2222 for? Did you change the base transistor as well?

KeithG

Post by **jsmcortina** » Fri Jul 07, 2006 4:35 am

If you want someone to test your Megasquirt there are people in the UK that will provide the service. Phil R, Bill S or myself.

I use warmup only PWM idle on my car and it does exactly what it is supposed to do.

James

bertelli_1 · Post by **bertelli_1** » Fri Jul 07, 2006 9:12 am

Thanks guys, i will try using the idleDC gauge. I used this guide http://www.megasquirt.info/ms2/IAC.htm#fidle when converting. If it still won't work I'll trace the MS circuitry and see if I can discover the fault.

Post by **jsmcortina** » Fri Jul 07, 2006 9:28 am

You are best to use the MS1 instructions when working on MS1 because MS2 does some things differently.

James

bertelli_1 · Post by **bertelli_1** » Sat Jul 08, 2006 9:54 am

I have found the fault - I took a peek inside ms and found the TIP transistor had quite literally exploded. It seems although i used a mica insulator I didn't insulate the mounting bolt (no mention of this in the manual?) and it had earthed through the bolt and overheated. This has now been rectified and its working now. Well sort of anyway.....

Jon k · Post by **Jon k** » Sat Jul 08, 2006 10:01 am

bertelli_1 wrote:I have found the fault - I took a peek inside ms and found the TIP transistor had quite literally exploded. It seems although i used a mica insulator I didn't insulate the mounting bolt (no mention of this in the manual?) and it had earthed through the bolt and overheated. This has now been rectified and its working now. Well sort of anyway.....

Anyone have a good source for nylon bolts/nuts?

PSIG · Post by **PSIG** » Sat Jul 08, 2006 10:50 am

Jon k wrote:Anyone have a good source for nylon bolts/nuts?

Most local hardware stores have nylon screws, nuts, washers, bolts and standoffs for cheap.

Megasquirt Support Forum (MSEXTRA)