14 replies to this topic

[mike_92gsr]

Alrighty, so i have ongoing idle issues with my gsr. I have been reading through a few threads on here but cant seem to find the info im after.
To start off im having an issue with idle at operating temp. Im running an e7 ecu, 1000 cc injectors and its on e85. It fluctuates from 1200 to sometimes 400 rpm. i have checked my isc and tps and both came up good. The car drives and boosts fine its only at idle theres a problem. The question i need answered is how to reset the biss as i have noticed it is conpletely bottomed out in the tb. And will it be a different process as it has the e7 ecu? I have had a quick play with it earthing out the timing wire but with no success. Any help will be much appreciated 👍

[jack be nimble]

Remove isc. Key on and off. Does the pintle move in and out?
If its hunting, and your biss is bottomed out, I'd say your isc is not moving properly. Or maybe the tps isn't set so the ecu doesn't know to idle the motor.

There would be a dealer way to do the biss. Either way, you need to be able to log the isc position. Probably evoscan....

[jack be nimble]

Or maybe the fiav is pooped. Get the car warm and block off the side of the fiav in the neck of the tb. See if it makes a difference to idle. It might be blocked open a bit.
I just covered port with a bit of masking tape. If you dont rev it, it can't get sucked in anywhere. Only cover the side that feeds the fiav, not the isc side.

[mike_92gsr]

Yep already removed it and it is moving in and out.
Yea thats what i have kind of put it down to that the isc is fully adjusted so it cant control it. I reset the tps so i knew it was right to eliminate that problem.
Ill have a play around with the fiav tomorrow after work and let you know how i go. I have a feeling i have seen isc step on evoscan so ill look at that too

[jack be nimble]

I had a fiav stuffed in my tb. It was OK when cold as it was bypassing air correctly. When it warmed up, it would misbehave as the ecu was trying to slow the engine but it couldn't as extra air was coming past the fiav. Having the biss screwed in all the way suggests air getting past the throttle somehow.

Maybe do a BLT also. Pay attention to leaks after the tb. Throttle shaft seals, injector seals....just a idea.

[bazeng]

Usual way, ground timing wire, set Base timing first, then set Base idle with bits. Ensure tps is in the correct voltage range. Get it to around 700 stable. Adjustment in the throttle stop and cable can also be made. One the above is correct and stable, re-enable idle control by removing ground timing wire. Ensure engine is warm, headlights on, air con off.

Unsure of e7 is the same. Have you verified the idle stepper motor sequence? It may be wired incorrectly to the ecu. Use leds to verify.

[jack be nimble]

I recall something about that too baz. That some ecu have reversed isc wiring. Can't remember details though

[mike_92gsr]

Yea that sounds the same as what is happening with mine. Ill do a thorough look over everything tonight to check for any air leaks.

Ill pinch a timing light from work and set it up from start tonight or tomorrow and see how i go.

With the wiring i have just matched up the ecu pinouts from the e3 to the e7 ecu for the harness. Seems to have been working fine for a few months then all of a sudden it has started playing up. Sorry for the noob quiestions but unsure on how to verify the sequence?

Cheers for the info guys

[bazeng]

The sequence should be smooth. So on power up, the voltage should be in sequence, 1234. This can be indicated on the leds. If out of order, you have a wiring issue. Example 1324 . Where are you located.? I could lend you my tester if in Melbourne.

[mike_92gsr]

Yea no worries. Ill see if i can work something out to test it. I suppose the only problem i will run into there is what pins complete each circuit for the step sequence from 1 to 4. Did you make yours up or purchase it from somewhere? Nah im in adelaide sorry, thanks for the offer tho. Ill have a play around with all the info you guys have given me and ill keep you updated on how i go

[leadfoot]

unplug the ISC then set the BISS and trottle plate stop and TPS with it as close to 1 ohm as possible but not on of over (if it's a 4 wire) under 1 ohm = throttle close wire live tells ecu it's at idle over 1 ohm tells ecu throttle is in use.

if you don't unplug the isc when you adjust the BISS you can go to far so unplug ISC and then use BIS with timing locked to get a base idle of 850+- 50 rpm this should also be done at operating temp

[vr401]

If you have evoscan follow this


The following conditions should be met before setting the BISS:

Engine coolant temp 176-203 degrees F (engine fully warmed up with the temp needle in the center of the range)
Lights, cooling fan, and accessories OFF
Tranny in neutral (AT trannies in Park)
Steering wheel in neutral position (centered, no load on the power steering)


Here we go
1. Once your car meets the following criteria hook up your Openport 2.0 cable and open Evoscan
2. In evoscan in the bottom right corner where it says actuators click that button.
3. A little menu pops up of different things to activate, you can not activate something while you are logging. Click the bottom one Speed Adj. Screw Mode
4. Your cars idle will probably fall and she might even die, this is normal, (if she dies you need to loosen the biss screw a bit and try this step again) Now you go to your throttle body and begin turning the BISS screw tighten to lower RPM and Loosen to increase rpm (your prlly here to loosen it) When she sounds like shes idling right (about 850 +/- 50) You need to go into the car and DEACTIVATE the Speed Adj. Screw Mode
5. Your RPM will go up to about 1500 or so, This is normal, You need to then turn evoscan on and begin logging watching the RPM drop. After about 8 minutes the actual RPM should match the TARGET RPM, if it does not you need to adjust the biss some more. Go back to step 2. If it does then you are done, congratz give yourself a pat on the back and enjoy your car not dieing when you come to a stoplight.

[mike_92gsr]

So i followed the evoscan guide but it seems like it makes no difference when activated. Noting really changes. Idles slightly smoother with less fluctuation in idle but when i turn it back off it goes back to how it was. I plugged another isc into it and activated it just to see if the pintle moves when activated and it does but not far. I will start by checking if the isc wired in correctly tomorrow and try work out if the fiav if stuffed or not.

[evo-gsr]

I might have a few of each spares if need be...let me know if you need one.

[mike_92gsr]

cheers man, hopefully i have it sorted now. Had a bit more of a look into it today and found that the seal that goes on the isc to seal it into the tb had perished and cracked so i replaced it. Re checked the resistance in the isc and tps. The isc was fine, since checking and setting up the tps a few weeks ago the 5k ohm resistance mesured slightly less at 4.76k ohm indicating there is possibly a problem there. Worked out that the catch can setup was breathing enough back into the intake to register as a leak. Removed the line from the can to the intake pipe and blocked it off. That seemed to cure the irradic idle along with replacing the isc seal. I think the biss still requires adjustment as the idle up on cold start is not working anymore. Tomorrow ill test the isc sequence and re test the evoscan setup for the isc. Im guessing the wiring for the isc is incorrect as the rpm doesnt really change from 800 rpm from cold start to operating temp. Or the tps is faulty and isnt registering as closed at idle. Might get a known good tps and test it with that too.