Idle seems to be in reverse!!
 

Hi Guys, I wonder if someone could help me please. I built and fitted my MS1 over a year ago, it is all running fine apart from the Idle which seems to work in reverse, when I start from cold the revs are low (850-900rpm) and when the engine gets to normal operating temperature the idle sits at 1200-1250rpm).

The car is a 1993 1.6 with FM hardware and an FMIC. This is what I have tried so far to try to cure the problem:

1. Checked the MS build and it seems fine.

2. Changed the polarity of the Diode on the 2 wires on the Idle valve to see if I had fitted it wrong.

3. Applied voltage to the idle valve and I can hear the solenoid working (I also changed the idle valve).

All of the above made no difference. I have asked a few MS Guru's here in the UK and we still cant seem to find the problem. I am about to order the MS2 daughter board so I can use the EBC but I would really love to get rid of this final problem before I do that, very grateful for any help.
Cheers
Barry

Please post a copy of your MSQ so we can check your idle speed settings. It's quite possible to tell the idle solenoid to operate in reverse (or not operate at all).

When my idle control is turned off it will idle a few 100 rpms lower when cold.

Here you go Matt:

Attachment 19658

Nothing blatantly wrong with the settings; can you post a data log of this behavior?

Will do Matt, will a 10 min log from first cranking suffice?
Cheers
Barry

My guess is that your idle speed screw is open too far and all your idle control circuit is doing is sitting at minimum trying to fruitlessly bring the idle speed down. Try this:

1. Set "When to use PWM idle" to "Warmup Only."
2. Your "Idle duty at lower temp (dc)" and "Idle duty at upper temp (dc)" will now be un-grayed. Leave your existing setting for lower temp but change your setting for upper temp to 19 (to match your "Minimum (dc)").
3. Change your "*Fast Idle (lower) Temp (F)" from 54 to 130. Remember, it's °F, not °C.
4. Change your "*Slow Idle (upper) Temp (F)" from 71 to 160. Same comment about units.
5. What the squirt will now do is slowly change the idle control valve duty cycle from 27 when at or below 130°F coolant temperature to 19 when at or above 160°F coolant temperature. The dc change will be slow and steady without oscillations (you are now running open loop). Setup your gauges so you can monitor coolant temperature and dc to confirm proper operation. If everything is correct, the higher dc will give more RPM.
6. Once you're stabilized and warmed-up, with all accessories, lights and fans off (minimum alternator load), you can turn the idle screw in to achieve the desired idle RPM.
7. Now you can return to "Closed loop only" and start fiddling with those adjustments. However, if you're not running AC, you might consider just staying in "Warmup only." Many users find this mode to be perfectly satisfactory.

Hornetball, thanks for that, my idle screw is almost fully screwed in but I will try what you suggest. I have just tried to upload a 10 min datalog to show this happening but the upload keeps failing, I dont know why!!
Barry

BTW, when operating in "Warmup only" mode, you can manually control the signal to your idle control valve (once you're warmed up) by changing the "Idle duty at upper temp (dc)" value. This will let you troubleshoot if needed.

Hornetball, thanks. When you say:

3. Change your "*Fast Idle (lower) Temp (F)" from 54 to 130. Remember, it's °F, not °C.
4. Change your "*Slow Idle (upper) Temp (F)" from 71 to 160. Same comment about units.

How do I change it from C to F?, the settings are in C, do I just change the54 to 130 and the 71 to 160?

Sorry for the bone questions!!
Barry

Oh. Well, you're software must be different then. When I opened your *.msq in Megatune 2.25, those values were shown in F. I doubt that the squirt reads the *.msq differently, so I wonder if there is a bug in your tuning software so that when you think you're setting up in C, you're actually burning values in F?

Anyway, it's easy enough to test. Just do a warmup cycle in "Warmup only" mode and observe/chart the dc behavior. That will tell you what it is really doing.

What you're really trying to achieve here is a way to steady state the Idle dc under your control so you can troubleshoot what's going on and get your idle speed screw set. From that standpoint, fine tuning the Fast Idle and Slow Idle coolant temperatures can be done later.

C and F are local settings.

And to keep going . . . .

It's not good that your idle speed screw is almost completely in. That makes it succeptible to changing the size of the orifice as the respective needle and seat temperatures change. Make sure your idle spark advance is set so that the idle speed screw is at least one turn open to get a decent, unloaded idle speed at 19dc. You'll probably have to retard a bit.

I've seen Brain post before that he runs in "Warmup only" mode with an idle spark advance around 12°BTDC. He also likes to keep all the advance bins in the idle area the same to minimize variability. Brain is someone we should listen to.

I acutally use table-switching on my spark table. I keep all idle cells at 12° (use no spark advance anymore). The less the timing fluctuates, the more stable the idle is. Then I trigger table-switching when the A/C is activated and then hold 18°. My idle is as smooth as Hustler's mouth. But I use PID closed loop idle.

So just leave the fast and slow idle as they are and just change to warm up only?

Brain - I have removed my A/C so that is not an issue.....

Barry

Yes, I would just leave as is and then data log idle dc vs. coolant temperature so you know what you have.

Bottom line, "Warmup only" gives you control of dc. You can raise and lower it at will. This will let you troubleshoot what's happening. If you are getting the expected response (i.e., increase in dc = increase in RPM), then you can move on to setting the idle screw and fine tuning the other idle settings. If you do not get the expected response, then there is something else wrong that is reversing the response of the idle air control valve to the squirt commands.

Let us know!

Cheers Bud, appreciate the advice and I will try what you have suggested. I have a datalog of this happening but I cant seem to upload it (keeps failing?) if you are interested I can email it to you or matt if you pm me your email addresses. Thanks for your time....
Barry

OK, just tried it on warm up only and messed with the dc and it dident change anything, I brought up a idle dc gauge and I can see the needle (%) moving down as the temp increases but it dident seem to change the rpm. I have emailed my datalog to Matt so hopefully he will be able to spot something. This is driving me nuts!!
Barry

Sounds like the idle air control valve is completely unresponsive to the squirt. If you unplug the idle air control valve, does it change anything?

No, I have just tried that and there is no change in RPM at all?