2G Manual ISC/BISS adjustment possible?

[Heryst78]

hi Guys

I come to you after my GST swap in my GS 2G.
Everything looks right after the swap but, my car still run between 1000 et 2000rpm

As a noob, I touch the screw BISS and now my engine doesn’t runs good.

What is the procedure for make a manual adjustment in our 2G ?
I live in France and I don’t have ECMLink.

I saw that for the adjustment I have to start the engine, unplug the ISC, turn Has I want the BISS screw to get the idle down and put the ISC back on.
Is that right ?

Thanks a lot

 

[pauleyman]

hi Guys

I come to you after my GST swap in my GS 2G.
Everything looks right after the swap but, my car still run between 1000 et 2000rpm

As a noob, I touch the screw BISS and now my engine doesn’t runs good.

What is the procedure for make a manual adjustment in our 2G ?
I live in France and I don’t have ECMLink.

I saw that for the adjustment I have to start the engine, unplug the ISC, turn Has I want the BISS screw to get the idle down and put the ISC back on.
Is that right ?

Thanks a lot

No. That is not right. You take away ecu control by grounding the check connector on the firewall. Isc then centers and you can set the biss. It's very well documented.

 

[Heryst78]

Thanks a lot !
So if I understood your words, I ground the brown wire with a wire connected to the firewall, and after that I can turn the biss screw as I want ?

 

[Tanro]

You can't adjust the BISS manually. You need a scan tool, ECM Link, or Evo Scan and a tactrix cable with the black case ecu.

Pauly, the check connector on the firewall in a 2nd gen is for the fuel pump...

http://vfaq.com/mods/BISS-2G.html

 

[Heryst78]

Yes i just shown that I don’t have a brown wire.

I don’t have a scan tool...
so I can’t adjust it this electronic help
So do you know how I can adjust it manually ?

Sorry I didn’t see you first sentence, ok so I can’t adjust it manually...
I saw an old post and the guy was telling that he just unplug the ISC and he adjusted the biss manually and he runs like that.
Is it a solution?

 

[JRich66]

Setting Biss in with ECM link. Do the following:

1) BLT
2) Put keys in ignition and turn to the on position
3) Open up ECMLink and then turn both grounds on
4) Turn out the BISS 1/2 turn OUT. (This should raise it high enough to start and idle somewhat)
5) Star car. It should now stay somewhat running. (If not, turn the BISS out a little more and see again)
6) Now that it is running, adjust the BISS until you get to your target idle RPM. This should also now get the ISC to 30 and your LearnedIdleAdjus to 140 (takes some time for it to adjust so just let it idle a bit once you get the ISC to 30 at idle)

Now see if it sticks once you turn off both grounds. If it changes, re-ground and adjust accordingly.

 

[Heryst78]

Sorry but I repeat, I don't have an ECM Link....
How can I do ?

 

[shinzon]

Wasn't it possible to ground a pin on the OBD connector to do the BISS adjustment without a scantool? I might be misremembering here...

Edit: I'm probably wrong about the connector, but from my '96 service manual mentions adjusting without scan tool:

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Basically, it want's you to get RPM signal directly from the blue wire on the firewall in place of the scantool.

 

[Heryst78]

And what will give me the fact to ground a pin on the OBD connector if I don’t have a Scan tool ?

 

[shinzon]

And what will give me the fact to ground a pin on the OBD connector if I don’t have a Scan tool ?

Generally you run a paperclip to the ground pin if you need to ground something on the datalink connector. I was wrong in any case, see my edit.

 

[Heryst78]

Thanks a lot
But... I don’t have a brown wire for ignition on my eclipse :/

 

[shinzon]

I just noticed you're in Paris. Euro spec Eclipse I assume? If I remember correctly they had naturally aspirated 4G63s? One would assume they used a similar engine harness as either a turbo 4G63 DSM or a 4G64 Spyder.

On a Turbo DSM, if they've never been disturbed, the connectors are usually about the center of the firewall, taped behind the main harness. One will be a blue connector, other will be black. Sometimes they're hard to spot.

Could you provide a picture of your firewall area?

 

[Heryst78]

Thanks a lot shinzon !
Yes I’m from’ Paris

Yes sorry i have two connector, one black and an other blue
But I have readen in your maintenance book that I have to ground the brown wire, and I think the brown wire is only in 1G’s eclipse, right ?

 

[shinzon]

Thinking about it, you're much better off getting some kind of scantool. They sell little bluetooth modules that connect to your phone for cheap; just make sure it can display live data. The only thing you need the scantool for is to get a direct reading of engine RPM because the dash tachometer is not accurate enough. As long as your scantool grounds pin 1 when connected (which it should), then you'd just need to follow the procedure from the manual I provided.

 

[Heryst78]

Yes i have a WiFi ELM327 and i can connect it to my IPhone
But... I don’t know why but it doesn’t work in the eclipse...
The ELM dont want to connect to the ECU...
that’s why i’m in a bad situation ^^

 

[shinzon]

You could proceed without a scantool and just use the dash tach, but you're never going to get it 100% right, but you should be able to get it close. To do that, you'll need to ground pin 1 of the OBD connector. Either jump a paperclip to the ground pin, or a jumper wire to a bolt under the dash or something. With that done, you can proceed from step 4 above.

The wirecolor is irrelevant really, maybe they used a different color on the euro Eclipses. As long as you have those two connectors on the firewall, you should be good to go from step 4.

Edit: Blue connector is the one you want. Black is for jumping the fuel pump (fuel pump test connector).

 

[Heryst78]

Amazing thanks !
So if I connect a wire from the blue 1pin OBD to a bolt, my scan should work ?

 

[shinzon]

Well, you wont be able to use a scantool with pin 1 connected with a jumper wire. You'll just have to use your dash tachometer to get engine RPM while your adjusting the BISS screw. Should be able to get it close that way, but not 100% correct. After jumping pin 1, just follow from step 4 (grounding the blue connector on the firewall) in the manual.

 

[Heryst78]

Ok so if I understood I start the engine, and after will it is running a put a wire in the blue connecteur for grounding ?
Sorry but my English isn’t perfect...

 

[motomattx]

Listen... Just find the corresponding pin on the ecu connector and ground it there, your going to damage something by grounding the wrong thing if you dont.

 

[shinzon]

1. With key off, connect a jumper wire to pin 1 of the datalink connector and ground
2. With key off, connect a jumper wire between blue connector on firewall and ground
3. Start engine
4. Adjust BISS screw
5. Turn key off
6. Remove jumpers

Listen... Just find the corresponding pin on the ecu connector and ground it there, your going to damage something by grounding the wrong thing if you dont.

More dangerous to backprobe the ECU harness, imo. Besides, Mitsu instructs you to do the same with a special tool (basically a jumper wire) if you don't have a scantool.

 

[motomattx]

He might not have that same blue connector, he has a European N/T car, and Im not suggesting that he "backprobe" anything, he needs to get the proper pin on the ecu grounded, its that simple.

 

[chrysler kid]

The jumper is used only to simulate position 30, which is what the ECU triggers at warm idle when the engine and intake temperatures are at a certain value.

So you are grounding the jumper to trigger the idle air control motor to get to a position where idle should always be 750+/- 100 rpm.

You're technically not resetting the idle air control valve, you would be adjusting the biss and throttle stop screw to idle at 750

 

[shinzon]

He might not have that same blue connector, he has a European N/T car, and Im not suggesting that he "backprobe" anything, he needs to get the proper pin on the ecu grounded, its that simple.

Yup, I confirmed he has the blue connector in the posts above. How would he run the engine to adjust BISS if the ECU connector wasn't connected? How would you put the ECU into diagnostic mode?

The jumper is used only to simulate position 30, which is what the ECU triggers at warm idle when the engine and intake temperatures are at a certain value.

So you are grounding the jumper to trigger the idle air control motor to get to a position where idle should always be 750+/- 100 rpm.

You're technically not resetting the idle air control valve, you would be adjusting the biss and throttle stop screw to idle at 750

Yup, absolutely right. You're commanding the IAC into a known position (where it should be with the idle at 750+/-), and then making mechanical adjustments to airflow with the BISS screw to achieve that idle.

 

[motomattx]

Yup, I confirmed he has the blue connector in the posts above. How would he run the engine to adjust BISS if the ECU connector wasn't connected? How would you put the ECU into diagnostic mode?



Yup, absolutely right. You're commanding the IAC into a known position (where it should be with the idle at 750+/-), and then making mechanical adjustments to airflow with the BISS screw to achieve that idle.

You would put the ecu in diagnostic mode by grounding the proper pin on the ecu, and Im certainly suggesting that he ground that pin right at the ecu rather than depending on a wire under the hood that may or may not be the proper wire.