Anyone notice the Tach reads higher than EvoScan or was that just me?

 

I know they are having problems with the tach readings. Mine bounces at idle from 0-1000 rpm and one of the guys on dsmtuners said above 4,000 rpm at WOT it drops to 0 and bounces until he lets off the gas. So far I haven't had that problem with the WOT but I haven't driven it much either.

 

snip the white wire goin to the ignition amplifier stops tacho fluctuation at idle

 

mine bounces aroundat idle as well not sure why yet. thats next on the list to figure out.

 

Disconnect it at the ECU, but yeah, this fixes it.

 

^ Do you know which Evo ecu pin# that might be?

DSM wiring harneses differ alot from year to year and that may or may not be the wire color on some of those cars.
-?

jjgrizz73, a few others and I have discussed some of the Evo ecu into a DSM swap details over on dsmtuners.com (my username is delta448 over there). I haven't begun my install yet but would absolutely love to know the answer to this tach issue so we could pass the info along, as well as know what to do with our own cars.

 

both the EVO8 ecu and eclipse ecu are pin 58. i just pulled mine, so far so good but the ecu still needs to go trough its re-learn process so we will see. i cant remember if it did it before with a high/clod idle or not...

anyway i might have made some progress on the crank/cam sensor problem... i found an EVO8 FSM and did some looking. apparently it seems that pin 40 on the EVO8 ecu is a ground for the crank/cam and inlet air sensors... on the eclipse wiring there is nothing there....so from what i can see on the EVO8 wiring, the cam/crank sensors do not ground to the chassis like on the eclipse. also something that might be playing a factor is according to the eclipse there is a chassis ground going to pin 91, on the EVO8 this pin goes to the inter-cooler sprayer (ICS) manual switch. basically the way i see it is when you push the ICS manual it completes a ground path to that pin. so with the chassis ground from the eclipse run to that pin you are basically telling the EVO8 ecu that you are permanently holding the ISC manual switch in. i don't know yet it that does anything to the way the EVO8 tunes but i am going to ask the question.

so basically what i think i am going to do this weakened is this. i already pulled pin 58 and 91. next i am going to pull pins 13 and 26 then disconnect the that chassis ground. then i am going to ( with an adapter ) plug one of those pins to the EVO8 pin 40 and tape the rest of the pins/ ground terminals of. finally i am going to run a separate ground to pins 13 and 26 otherwise i don't think i will get the car running again without the ecu grounded.

wish me luck...

 

slo crx. wasn't sure if you had gotten that wave form image yet. i pulled this from the FSM i have. the top image is the cam sensor the bottom is the crank. not sure if that is exactly how they line up they originally were two separate images.

 

I don't think 13 and 26 should be pulled as they are grounds for the 8 ECU also. The pinout list I work with for the 8 doesn't have 40 as being a ground but I looked at the AEM pinout list and it does have it as a MAF ground. When I look at the US FSM I confirmed that it does ground there and on the JDM Evo VII it grounds at 92. So as long as I have nothing connected there on my car. I I have pin 91 grounded. It doesn't seem to cause a problem but I should really disconnect it.

 

well that didn't work as well as i would have hoped. moving pins around wasn't as easy as i thought it would be. so this is what i did i put all the grounds back where they were and ran a separate ground from pin 40 from the ecu to the cam and crank sensors. unfortunately it didn't clear the problem at all. i also tried changing some of the periphery bits. so i think i am going to switch over to my EDM map for now. I also pulled the wire from pin 91. i don't think there is a reason to pull it but if it is grounded it makes the ecu thing you are holding the ICS manual button down. haven't gotten confirmation that it changes anything in the tune but you never know.

 

The only thing I could think the pin for the ICS could be for is feedback or control, on my car the ICS has two modes, an automatic mode where the ecu controls when to spray or a manual mode where the user controls when to activate the ICS by holding down the button. More than likely the wire from the ecu is the one to activate the sprayer.

 

I just did a 2003 evo 8 ecu swap into a 1990 DSM. I too messed around with the CAS grounding circuit and it had no effect. I ran a 90 CAS and a 94 black top CAS, same codes. If I set the timing with the stock ecu and plug in the evo 8 ecu everything likes up the same with the timing light on the crank pulley. So I believe the ECU is getting a good enough signal to operate properly. However it may not like the voltage signal it gets from the style of sensors in the 1g cars. Either the pulse duration or the peak voltage achieved. Hope this helps someone.

 

2005 ECU with 9653xxxx cured the P0335 and P0340 for CAS equipped DSMs. On the 97 we did it had the standard Evo style exhaust cam sensor but we did speed density on it and used this same ROM. I am not sure how it would have ran on a normal 9694 2005 ROM.

 

I just flashed the 90550001 rom to my 2g and put 200 miles on the car no cels.

 

The 3G's share more similarities to the Evo 8's than the 1/2G's do so I would have guessed that you would have a better time with some of the CEL issues.