I have run into a few problems with my Megasquirt.

I have a 96 Turbo 2.4 I was controlling ignition but decided to take it back to stock to let the stock ecu control everything. Well first I needed a tach signal so I decided to use the "Tach" in the fuse box that wasnt being used.

Problem being is that the Megatune sees the rpms being about 14-1600 rpms and the stock cluster is seeing about 700-800 rpms, essentially its seeing half on the cluster...It idles crazy and I have tried setting it to a 2 cylinder as recommended by a friend, well when I input it to have 2 cylinders it immediately dies.

Can anyone shed light on this? I have heard from a few people that I need to use pin 10 on the black connector I believe it is...but I am not sure if its that same being I have the first year of obd2, which blows....

I am completely stumped on this.

change the cyl to two on your constants. it will give you your rpms perfectly. I had the same problem with my setup so I just lowered it to 1 and no worries. you are going to have to raise your ve tables to basiclly dobule. you might want to also looki into your constants a bit. you want to make sure you have it all set right


hope this helps



"boobs now with Riboflabin"

Quote:

you are going to have to raise your ve tables to basiclly dobule

Or you could raise the req fuel.

I have already tried switching it to the 2 cylinders, as stated in my first post, when I change it to 2 cylinders it immediately dies.

it dies because it's now not putting enough fuel in. You need to double your VE tables or you may be able to just double the req fuel like robbie c said

I dont think you would have to double the fuel if you change it to 2 cylinders and 2 injectors would you?

I think the biggest problem is the fact that I really dont know what its idleing at, the megasquirt is saying 1500 and the tach is saying alot less, I dont know which one to believe because the car is so loud anyways...

stock tach is off. I know when i was having idle problems, i hooked up a scanner and it was actually idling at 1000-1100 when my tach said 1300-1400. Could be off the opposite way for you.

What did you do to fix it?

Are you controlling idle?

get rid of it..... swap to a 97+ and let me hook the HPT to it

good luck Jay....... I have no other input for ya




SPD RCR Z - '02 Z24 420whp
SLO GOAT - '04 GTO 305whp
W41 BOI - '78 Buick Opel Isuzu W41 Swap

on the ECm there should be an open pin, pin 10 on the black harness i think, that will give you a 4cyl tach signal that you can use.

Tried that as well, got nothing out of it...

I think my Megasquirt days are numbered, prolly just going to finnally move to the 99 ecu with the HP Tuners software, cause SpeedracerZ is a good buddy of mine....

Move on to the HPT Jay.... Swap yur ECU and and end your headaches.....



P&P Tuning
420.5whp / 359.8wtq

first off be a real man and stick with MS. HPT is for girls that like spending money


Again I have had the same problem. I wouldnt stear you wrong. up your ve tables. The only reason I wouldnt use REQ fuel is because there is alot that use that for a reference. that and the fact that I know just uping your ve will work.
BTW dont you find it funny your MS is idleing at exactly twice your cluster


feel free to PM me, Im sure I can help you. trust me

one other thing thats really getting to me, is you said you were running spark right. then what the hell were you using for your tach? now I could be wrong but I belive that the ms still needs the input via whatever pin it is regardless if you use fuel only or spark.






"boobs now with Riboflabin"

I was controlling spark, but my idle was too crazy, I couldnt get the idle control in the MS to work either, so I moved it back to the stock ignition to rectify it, and it didnt. I was running the older obd1 module on the idi and then i was running the stock 96 ignition module down by the ecu.

I have tried everything bro trust me, I am not a Newb to the Megasquirt...I have doubled req. fuel, I have up'd the VE Table and even tried changing it to every cylinder/injector combination possible.

The fact of the matter is that it idles at 1500 on the MS, sometimes it idles at 800, and all the while the stock cluster is saying it sees 700, or even as low as 300, now why would the stock cluster see 300 rpms?

I have had nothing but hell trying to use any tuning methods with the 96 ecu and I need to go to something that I know for a fact will work.

^listen to JCAVI he gets real excited when he gets his stuff working.

I do, I admit



Well I didnt know about the other spectrum of the idle. the only thing I can say is to get a tach adapter. something you know will send the right signal. if you want I could send you my code. mabye one of your settings is off in the configuartator? have you tried from a clean slate?



"boobs now with Riboflabin"

I have tried uninstalling Megatune and reinstalling it.

I have tried starting all over about 4 times. I have tried controlling idle through Megasquirt, I have check all my wiring several times and tested to make sure power and ground was correct in the ignition module. I have checked for any kind of small vacuum leaks. I have uploaded a vex file to my megasquirt from a friend of mine who is running his perfectly.

I have a working tach signal coming from the fuse black, the cluster works and so does the megasquirt, so I dont think a tach adapter would do me much good.

Volumeking333(Ryan) wrote:on the ECm there should be an open pin, pin 10 on the black harness i think, that will give you a 4cyl tach signal that you can use.

Jay has a '96.... his ECM has 3 plugs...... the 00+ have the open pin (the 97/98, and I think 99 have a wire in that pin.... which goes to the fuse panel)




SPD RCR Z - '02 Z24 420whp
SLO GOAT - '04 GTO 305whp
W41 BOI - '78 Buick Opel Isuzu W41 Swap

ahh thanks.. i did not know that information.

Hey if you decide to sell your megasquirt hardware and its in good condtion, drop me a line. I'm in need of a megasquirt setup, and I could possibly help hook you up with an odb1 ecu as well. I'm working the odb1 ecu project, and we have a few things figured out like VE tables, Spark tables etc....

You should be able to pm me, post in the thread if you cant.

You may need a tach adapter. The mega squirt needs a voltage signal, where as certain wires will actually be a current signal. What most tach adapters do is convert a current signal to a voltage signal. Although when i was having that issue I got no tach signal at all.

The other thing that pops into my head is that fact that our cars run a wasted spark system. Meaning they spark twice as much. This would actually explain why you are reading double rpm. You could try getting a signal striaght off one of the coil packs. Where do you tap for an after market tach in your car? That would be where you want to tap into.

Also if you are cranking and the car wont start, datalog with megatune to make sure you are getting a tach signal.

The mega squirt is a great system once you figure it out. I had many days where I was ready to give up but after working through all of my issues I'll never go back, it's a simple system with more upgrades then anything else I can think of in the sub $1000 range. The tach signal is the most important signal (I've run without temps and tps before) and as soon as thats sorted out you just have to tune it.

The cars don't really spark twice as much. Each coil fires once per crankshaft revolution. That's 2 spark events per rev. That's the same as a distributor car with one coil firing 2x per rev. The fact that there's a spark plug on both the + and - terminals of the secondary is what allows the DIS system to work as a waste spark system.

If you have access to a service manual you might look at the various circuits to see what signals they produce. You might find out the one you're trying to use produces 4 pulses per crankshaft rev, which means the signal would read double the rpm as what's actually occurring. 8 cyl engines typically produce 4 pulses per crank rpm, so you might need to adjust things the opposite way as what you're expecting.

-->Slow