3.1L/3400 hybrid swap.

[fasteddi]

May be a few dumb question here but just want to make sure as my engine is in the shop getting bored out and such and will be back this weekend so i can start assembling it.

What is the normal for head gaskets on this setup? The 3.1L head gaskets or the 3100 head gaskets? Or are they even different....

Also I have to get some fresh tty head bolts. Do I just get 3.1L ones again or 3100/3400 ones. I notice that the lengths are different for the different heads but if i can get some insite on these things i would be very grateful. Thanks

[Canyonero]

When I went from Distributor to DIS in my Trooper, I used an MSD tach adapter module.

[IDCavalier]

I had a similar issue with my tach in my 1993 Cavalier. It is a 3.1 with DIS. I had a TON of issues with it, as seen in a thread on this site.

While I was repairing the problem (I hope!) I didn't get a tach signal. turns out that they put two white wires juxtaposed on the same harness! One is to the '7730 for EST functions and the other is TACH. I got them turned around due to my own lack of diligence- failing to label the wires before cutting. I was going to cut one at a time, but the next day, I walked out and said:"Well, I should shrink wrap the whole harness together, so I'll just cut them all...AAAWW! Why didn't I label them???

[fasteddi]

Ok thanks a ton fellas for the informative responce. On another note I have the block striped bare and ready for the shop. I'm quite excited that this is moving forward thus far. The one hickup is that I have to assemble the engine at another garage as mine is too dusty due to the stone floor.

Merry christmas everyone, have a safe one!

I have had several aftermarket tachs attached to DIS modules, Auto Meter/Auto Gage have never been an issue. Other no name cheapies I used for testing some ideas also had no issues. The only one I have had an issue with a Stewart Warner that I have no set-up information for and believe it's just a dip switch setting that needs to be tweaked.

[Maverick H1L]

Well, first try the tach attached to the wire like usual. If it fails to read, then you may need to add a transistor circuit as a signal booster.

[fasteddi]

Any idea how well they work with a autoguage tach? The stock one isnt accurate at all but the AG tach is what I use.

[Maverick H1L]

I forgot there's 2 white wires...

The wire at the DIS module's large connector, terminal C, is for the TACH. The other one is the EST wire. There is no wire, generally, in D, IIRC. Also, keep in mind that some have had issues with the tach when swapping to DIS.

[fasteddi]

Ok. Thanks guy for the info. That helps me alot!

I did get the engine pulled today and started dissembling the block for the shop. I just need to remove the cam and crank. Everything else is out, cleaned, and labled. Once thats done I can start cleaning up the engine bay area and doing some wiring connections this weekend after christmas.

White does sound correct for the other colour. The one in my Datsun (660 IDS was used) is a black/white for the tach output, IIRC the pigtail came from a late '80s or early '90s L-body.

[caffeine]

All the pigtails I've seen use a white wire for the tach output.

Maverick basically has it, with one exception, some modules have a tach output that can be black/white, you don't want to ground that. There is another colour that was used for the tach output. but I don't recall the colour off hand.

[caffeine]

Low reference always means ground afaik... Sometimes grounds are supposed to go through the ECM however. When I wire in the DIS I always end up with an engine ground on the two wire sensor (other wire is IGN+ power).

[Maverick H1L]

Simply:

Pink to pink
Black/White to Black/White or just to the frame/engine
Black/Red to Red/Black (IDK why they swapped the wire colors but they did and the function is the same)
Purple/White to Purple/White
White to White
Tan/Black to Tan/Black (you can leave the EST bypass connector if you want)

Crank Sensor:
Yellow to Yellow
Purple to Purple
There MAY be a ground but it will NOT be at the sensor and it's a shielding wire)

[fasteddi]

DIS questions.

The 2 crank sensor wires will connect into the DIS module. Then there is a reference output, a ground output, a system ground, a bypass output, and est outputs.

On my old wiring I would connect the est wire with the new one, i would connect the reference with the new one, i would connect the bypass with the new one, but then there is a REF Low on the old dizzy system? What would I do with that? Do I even need that input to the ecm anymore because I don't see what I would use it for.

I assume that the system ground and the ground from the Dis module is suppose to be separate? System ground is to the ecm ground and the other ground is to the frame?

Im running code 59 so hopefully i can set up the bin correctly but first i need to start some wiring as the engine is coming out tomorrow. Id like to start to straighten up my harness and any wiring that needs redone.. Currently I have piles of wiring diagrams in front of me so Im trying my best just to figure it out but if anyone can help i really appreciate it!