06-11-2007, 01:03 AM
Join Date: May 2007
Total Cats: 24
I broke ohms law
and ohm won.
So I went ahead and borrowed a friends car (and took a week off) while I started to make major progress on squirtsville. Shipped the supercharger off to get rebuilt, got my 440cc injectors back from the cleaner, finished the PWM mod, WI circuit, got knocksenseMS wired up, used Al Hounos's map as a base, and got the car running great (alot better than attempt number 1)
Attempt number 1 was roughly 2 months ago..
followed directions blindly (didn't think about it) and put the TPS vref on the same wire as the signal. This caused the stock ECU to think it was tipping in and made the idle (still controlled by stock) terrible. Killed the TPS too... had switch back to the stock ECU for fuel and raise the idle to 2000 to keep from stalling at decel. ( I reset it back to 850 before starting the megasquirt install this weekend). AND I had the injectors batched at 1&3, 2&4 but on INJ1 and INJ2, not INJ2 INJ1 as it is now (and seems to be much happier that way)..
Supercharger didn't get back till Saturday so I didn't get a chance to start tuning till this weekend. I'm much happier now that it appears to be working so I can start playing whackamole on individual issues rather than pulling my hair out going ITS ALL BROKEN WAAAAH.
So - current issues (literally).
I'm trying to keep the stock ECU in the car so I can pass smog, using a switchbox similar to cjernigan's for switching idle/spark/fuel back and forth. Now that I've installed the 440cc's I'm past the point of no return. Much of the wiring harness is shared sensor-wise. Trying to tune idle, we turn the car off and hear the radiator overflow burbling. I thought I might've screwed up easytherm, or blown a fuse (I had a few fuses pop installing the aquamist pump.. long story) or relay somewhere. After doing end to end ohm checks, everythings fine. Finally realize that HEY YOU CAN'T SHARE THE CLT CABLES FROM MEGASQUIRT AND THE STOCK ECU. (now where's that head banging into wall emote).
So - before I go about adding the GM coolant sensor into the heater core hose (which will be a pita since the JSRC takes up alot of that space) anyone know what I can cut to get the vref power off the megasquirt? both the stock ECU and megasquirt appear to use 5v..
second question - PWM circuit seems to be almost completely unresponsive at any frequency setting. Diode is soldered across the iac. I disabled all warmup enrichments, etc - but idle seems to want to jump up to around 2k and stay there when I turn idle control to the megasquirt. I'm going to go back and doublecheck the circuit, but does anyone have a hint?
third question - I am running low impedance injectors, I believe I've got them tuned correctly according to the megamanual. In case I want to add ballast resistors (after I get idle working on MS and try to retune them..) where would be the best point? Can I add them on the wiring harness on the MS side, or do they need to go on the fuel injector wiring harness?
last question - is there a major difference between a 1n4002 and a 1n4003 diode for use in a pull up circuit (in my case, for the water injection output).