Well after much ado, My car is running!
It is a streetported 87 TII megasquirt 1 V2.2 error daughter card running dual VR, innovate LC-1 wideband O2. 550cc primary, 1000cc secondary.

So after much screwing around i found that putting the .01 capacitor between G- and G+ smoothed my tach signal out to the point were it would actually start, however i now have the difficulty of a no idle condition. I warmed it up and tried to tinker a little with the VE table but with not much success. On startup i think it is a little rich as i have to keep the throttle open a decent amount to get it to fire. While running it sounds good but lumpy at the bottom (perhaps the streetport). My questions are 1) do i have to do anything special to get the streetport to idle properly? 2) there seems to still be noise bouncing around in my TPS signal? which i dont get. If someone could look over my data log and give me any hints i would be grateful. I am trying to get the thing to run without the turbo connected currently is that a bad idea? I figured it wouldn't matter as per the idle. also i dont think my wideband i s doing anything, it seems to just sit at .5V.

So i have a lot of questions. thanks in advance for wading through any of this.

 

low imp. inj's, high imp. inj's, or low imp inj's with resistors?
what WB are you using?
"active above coolant temp": set to 155 instead of 66
start your map at 800 rpms instead of 200
"Wheel docoder routine": mine is set to 024s9 instead of 025
"cranking rpm": 300 instead of 500

 

I'm gonna try and attach 1 of my files.

 

Hey,
they are all low imp with a flyback board, the WB is a bosch LSU.
Thats actually 66 centigrade, sorry i like the metric measurements.
I originally experimented with the two different wheel decoder styles and did not see much of a difference, i will try it again.

Thanks for any and all help!

 

The wheel decoder settings won't do **** for fixing this.

You need

#1 Stable Fuel pressure
#2 Stable MAP pressure reading to ecu
#3 Stable RPM's

If any of these fluctute you will find it very hard to tune idle (just like me).


Solution for #1 and #2 is to put a restrictor in series with your map line before it goes to the FPR and the MAP sensor in the ecu

Solution for #3 is to use the twin wheel CAS (rather than missing tooth) and have good shielded cas wires.

 

I have the twin CAS, I am using the stock shielded wire with a .01 Capacitor connected to G+ and G- (as suggested by mauythaibxr). That smoothed the signal out significantly, however i do not know by looking if it is smooth enough, it definately starts easier now. I will try the restrictor.

 

Make sure your timing is correct too.

Ken

 

You can post up a graph from megalogviewer. I might put one up of my 'old setup' with completely feral noise on the rpm.

I compared it to rx7ben's logs.

Between subsequent samples of idle rpm he would have an rpm delta of about 1rpm and I would have anywhere from 20-80rpm. I'm assuming this was causing my problem. But I am going to try and follow mauitaibxrs advice and setup the dual wheel vr sensor. I'm meant to be collecting one next monday or tuesday.


Not knowing your level of experience, I suggest Ken is saying your idle timing should be roughly between 5ATDC and 5BTDC. I found 0 split at idle made it slightly stronger also. You may try but my setup may have other funny things going on.


I totally understand your frustration too, I got the car cruising ok, and got it ok under load. I was still getting random stalls returning to idle when changing gears and stopping at traffic lights. And its damn hard to drive the car anywhere when it won't idle or return to idle without stalling.

 

If you are able to hold an idle, then you should really richen up the decel areas of you VE table. For example: My lowest kpa table is 20 and lowest rpm is 800. So, I richen up the 20 kpa area from 800 to about 2000. My idle # is around 45 or so, but my decel area #'s are between 70 - 80. It stopped my car from stalling out everytime I came to a light or after I revved it and let off. My overrun fuel cut starts above 1500

 

why is your timing table at 0 under the 500rpm bucket? seems a bit low to me and then it jumps very agressively as rpms increase.

I have almost the same setup you got, streetported etc, and my car idles perfectly, but timing is way different. like Muythaibxr pointed out timing is crucial.

 

When you say richen do you mean like 10-25% or even more

What rpm increments are you using? Does that make a difference?
800 1000 1500?

 

BTW, I set my timing at 5 degrees advanced around idle region in my spark table and it's wayy more consistent now and no longer dies like it used to when I had it at -5. (All my timing values are absolute --> 5 is 5 and 0 is 0)

 

I really appreciate everyones suggestions. I will try them out, and get back to you all.

 

i figured i would post a portion of the datalog which i think epitomizes the problems with my tuning. I think the map going all over the place is definately my vacuum hook up (no pellet) the signal from my CAS could need some further smoothing out, but the TPS going all over the place like that still baffles me, noise from the alternator? it is right next to the sensor, but i had thought that it was not susceptible to this sort of interference. the one thing i thought was interesting is the fact that the signal from all of the sensors fluctuates at the same pace, WTF is that?

 

and this is without stepping on the gas at all? wow

 

I am actually stepping on the gas, but not like that, it is more on then off over the entire time, not oscillating up and down like that. mperformance, would you mind giving me your MSQ so i can compare?


Thanks

 

Usually when several sensors bounce up and down at once, it's a ground issue. However, your TPS and MAP bounce up and down at the same time without your other sensors doing that. Both of those sensors run off the +5v from the MS's internal voltage regulator (same supply as the processor actually), so maybe you've got a short or another problem with the +5v supply to the TPS...

I mean it looks like you were just tapping the throttle up and down... it pretty much looks normal.

Ken

 

I guess I could have been, i just dont recall tapping it on and off like that. When you say "normal" do you think i need the pellet? Is the tach signal exceptable? I wish i had a frame of reference.

Thanks ken

 

try to post a datalog without stepping on the gas...maybe that way its easier to see the issue at hand. I know there are a few guys here that will pinpoint that idle issue right away. Im just too new at megasquirt so my comments are my personal experience although I have built more than 30 engines already from 12a to 13b.

question if it has not been asked before, with your setup what is your personal reference as to say that the idle is lumpy, did the engine run before with a stock ECU or its a new streetport going live with the MS.

Mine idles a bit high but perfect at 1200 and under 1000 it becomes unstable due to the large street port it has. Also I used to run it without staging with the 1600cc firing at idle with a special map I made which actually worked but idle was extremely weird and rough, yet it sounded exactly as when you run a big carb on a really large streetport. Point is that once I switched to staging with only the 550cc firing at idle, the engine sound changed close to factory ECU sound. I can actually switch from stock ECU to MS and compare both idles...


Also another thing I noticed from your MSQ is your ignition settings, I still agree with the previous comments that your ignition is the issue. With a streetport ignition settings make a big different at idle. I learned by swapping ignition maps and its like taking the engine from stock idle to a very aggressive sounding engine that idles just like a very small bridge port if set aggressive enough.



I will try to get you the MSQ tomorrow when I get to my shop. Also I wouldn't like you to damage your engine with it as mine is totally untuned although I have taken it to redline without any problems while just sitting at the shop idling. It hasn't been tested on the road at high boost yet as Im getting a new wideband and a FMIC setup.

good luck man