4g61t.org

Ok so I've been reading every tach thread on this site and I'm still struggling to get my tach working in my Summit and need some opinions on what to try next.

What I have in the car electronics wise:
-'89 Eagle Summit 4dr Original 4g61 N/T
-6-Bolt 4g63t swap
-'91 ECU with DSMLink V3
-9k/145mph CSM Tach
-90 coil with Tach Adapter
-I didn't put the harness in the car, but I believe it's a '90 because of the throttle body wiring/coil pack 4-pin plug among other things

I bought another '90 coil and tach adapter from 89Mirageman and plugged everything in with no luck. At idle the tach doesn't move but if I blip the throttle the needle will try to move a little bit but barely.

I also think I tried Lilevo's trick (http://www.lilevo.com/turbo/tach/body_tach.html) to jump the ecu and go straight to the tach, but not entirely sure I did that correctly as the tach still did the same thing and barely moved when I blipped the throttle. Here's what I tried with that with no luck. Please let me know if I didn't do this correctly...

My first question with Lilevo's write-up is whether to use the white or yellow wire off the tach adapter. There is a red and white wire coming from the coils themselves that say "IN" and one yellow wire going to the harness that says "OUT". In his write-up he says to use the white wire, but I tried that and it instantly made the car start missing. Then I tried using the yellow output wire which didn't make the car miss or idle any different but definitely didn't make the tach work. Here's some pics to show what I tried.

Here's the tach adapter with the yellow wire cut and a jumper wire going to straight to the white tach wire off the ecu connector inside the car.

Same wire and connector as in Lilevo's link


My other issue that I've been trying to read up on is the Noise filter. For some reason I currently don't have one and can't even find the connector where it would go on the harness. Some people say you don't need it and others say you do, but it seems people have made it work both ways. My question though is if I find one, can I just run it inline somewhere on the jumper wire that is going from the tach adapter to the tach cluster wire itself? I really hope that's not too confusing.

Here's the standard noise filter you usually see on early DSM's in the first picture and the 2nd picture is a piece that I also received from 89Mirageman. Can anyone identify if that is a noise filter as well? Unlinke the typical DSM noise filter which has 2 wires, the unknown one only has 1.



Unless my wiring is incorrect, I guess my next plan is to try and find a dsm noise filter and go from there. Any help or input would be great as this tach issue is driving me nuts. Thanks in advance, Chris

_________________
'89 Summit Sedan AWD - 9.1 at 157
'92 Evo 1
'10 CTS-V

I had same problem once and it ended up being the actual tach cluster...

_________________
91' Mitsubishi Colt 4G67T FWD "The Minion" - 12.26@118
94' Mitsubishi Galant GS 4g63 Swap "White Unicorn"
95' Eagle Talon Tsi FWD "Ernie's car" - 13.92@104 *Rest In Parts*

That could be a possibility as well as I've never actually seen this one work since I've had it, but as the most expensive piece I want to make sure all the other stuff is correct before buying another one.

_________________
'89 Summit Sedan AWD - 9.1 at 157
'92 Evo 1
'10 CTS-V

Yellow wire goes direct from the tacho interface, to the connector at the end of the coil pack assembly.



Here is the noise filter/capacitor setup, resting where it has always been, and should be located on most 4g6X motors. You need this piece, it is there for a reason.



This is the fanout sheet for the 4g61t, 90 DSM coil wiring.

Compare this to the wires you see in the first pic. It shows a tap-in to the white wire on the fanout sheet, that says tach.

Now Mitsu sometimes got things a little wonky, when they translated and had it drawn up. Does this mean tach filter or tachometer ?

That wire is spliced into (also a ground braid to keep unwanted RFI from being inducted into the wiring), which is also another white wire and that leads up to pin 109, fuel pump control. I "assume" this is the spark induced signal, and either the ECU or the MPI relay keeps the fuel pump running until the ignition feed is interrupted.

Big picture, I know. Use a "Control" + "-" key combo, and it may shrink the picture in your browser.

http://www.lilevo.com/mirage/ECU%20edit ... mplete.jpg

Section 8 Page 26 of this 90 Talon Technical Manual shows the 90 wiring yet again:

90 TALON Technical Manual

Section 8 Page 27 shows more wiring at the ECU, proving pin 109 is the tachometer signal spliced into the ECU and out to the tachometer.

Your coil pack setup must have the capacitor wired in, and be functional. This capacitor is above and beyond the one sitting on the top of the intake manifold.

For reference, the JDM Cyclone dual runner manifold wiring had a capacitor in the same location at the top corner of the manifold where it takes a turn down to the injector wiring.

BINGO!!!!

This next picture shows the transistor inline with the white wire as it heads up to the tachometer assembly:

Click me for HotRodCoffeeShop's DSM wiring for Dummies, 90 DSM wiring fanout

Pic of my capacitor installed on the 90 coil assembly bracket.



Pics of the inline filter.






^^^ Looks like the two wire inline filter is required. The one wire option strikes me as a simple noise filter off a coil pack, or a 4g15. Can't quite place it ....

Just figured I would post this up.

1990 DSM/89 USDM CSM style wiring uses this:

Capacitor on the coil pack bracket, is for the coil packs only.

Noise filter with two wire connection, is the inline "filter" that takes the tacho interface yellow wire output signal, and conditions it so the tachometer can use it properly.

1991 DSM style wiring has the tacho interface wire, inside the transistor pack, as there is no separate tach interface module. They simplified things in that regard, but

not sure if that changed the signal, and or the tach that receives it.

You're the man. That's some great info, thanks again. So I guess my next step is to find a two-wire noise filter? Anyone got one hah?

_________________
'89 Summit Sedan AWD - 9.1 at 157
'92 Evo 1
'10 CTS-V

I actually saw one of those on a 3g hatch at the yard the other day, not sure if they're the same though. It did have two wires.

_________________
93 Mitsubishi Expo LRV 1.8/manual
95 Eagle Summit DL Coupe 1.5/manual
01 Mitsubishi Mirage ES Sedan 1.8/manual

I have a dozen of these or so.

But I remember never using a tach filter. I went from the 3 wire tach adapter right to the tach wire for the cluster and it worked. I only ever used the tach adapter. Stock, with an MSD DIS 2, and now with a Dynatec ARC2. I'm using the tach adapter and that's it, works fine.

Have you tried using a different tach adapter? Those go bad. I've had a few that were bad.

Yea you were one of the people who had success without it. But some people swear that as soon as they wired in the noise filter that the tach started working without changing anything else.

This is the second tach adapter I have tried with no luck. Would you be willing to ship me one of the noise filters? And also just for clarification did you use the white or yellow wire off the tach adapter to go to the cluster? Thanks again, Chris

_________________
'89 Summit Sedan AWD - 9.1 at 157
'92 Evo 1
'10 CTS-V