Resolved [RESOLVED] 1G BISS Grounding

[mindset]

My idle has been really high lately. Yesterday, I did the VFAQ way of grounding out the ECU/Ignition Timing Adjustment plug, and then you're able to adjust the BISS. Ok, when I ground out the ITA Plug, the idle will drop down perfectly to 750, with the adjustments I did to the BISS. Then when I unground it, as vfaq explains, the idle will go back up to 1000. Do you guys think this is idle surge? Or am I doing something wrong? I don't think I can drive around with it grounded because the cap that you take of the ITA Plug is for waterproofing reasons.

 

[cjridert1]

So its surging or just idling a bit high? If you have idle set to 750 and it's getting bumped to 1k after unhooking it you should maybe check the ISC. 2 minute job you can do with it right on the car.

 

[mindset]

I'm pretty sure it's surging. It likes to chill around 1000, but goes between 900 - 1300. I'm happy with the BISS results, but it'd be nice to get rid of the surge.
Another thing I forgot to mention:
When I rev it up with the 2 connectors grounded, it will drop down super low and it seems like the car was about to stall out. Is this an ISC symptom?

 

[steve]

Make sure to test that the IPS is functioning as well as checking the ISC coils.
Using your DMM on volts measure the voltage at the male spade connector, with the green wire attached and the ignition on. With the throttle closed you should read something close to 0v and with the throttle slightly open 5v or more. (varies between 90 and later ECUs and I don't remember the specifics ATM)

Many cars are missing the grounding strap for the throttle body and the ECU doesn't see the IPS close because of the missing ground. That means the ECU won't try to maintain the idle.

Surging is caused by too much bypass air.

It doesn't take much which is why the factory cautions people about touching the IPS adjustment. Just over-cleaning the throttle plate and removing the factory sealant from around the butterfly shaft is enough to cause extra bypass and surging.
After your sure the ISC and IPS are working and the ECU correctly raises and drops the engine speed when you turn the AC on/off you should pressure (boost leak) test the intake, clean the TB, and replace the PCV.

 

[mindset]

Thanks for the good information. The guy before me took out the A/C so I can't check if the idle changes if it's on or off. I did a boost leak test 2 days ago with no leaks. I'm going to try and check the ISC today. Thanks.

Man, this thing is being a headache. Soon as I fix on thing, another thing breaks/leaks.
Come out of my garage this morning to go to school and there's and puddle of coolant about 3 feet long.
Today I pulled out of my garaged and messed up the trim piece on the door. So now theres visible white fiberglass.
That's my fault, I was frustrated.
That's it, I'm not working on it today. I need a break.

Anyway, I don't know when I'm going to get this leak fixed now. I'm more concerned about that leak because of how big it was. The idle will do for now.

 

[tqmx1]

There are about a 12 coolant hoses under the under the hood from rad to heater and a bunch of smaller ones(turbo/oil cooler& trottle body). If one goes the rest will not be far behind.

 

[misphit]

Many cars are missing the grounding strap for the throttle body and the ECU doesn't see the IPS close because of the missing ground. That means the ECU won't try to maintain the idle.

That's a very good point. I wish this was applicable to the 90 TB. I have a 90 tb on my Colt and think that a ground strap would help some.

 

[mindset]

Update folks.
Ok, I didn't mess with the idle today.
I traced down the coolant leak and it was coming from the turbo. There's a line that comes off of it and it's leaking from it.
Do you guys think this is a blown turbo? Or should I replace the line/connection?

Anyways, I'm taking it to a shop Monday so they can do all the maintenance work. I'm also going to have them look over the entire motor/tranny so they can tell me what needs to be replaced. Maintenance before mods, right?
Everything besides brakes at least, which I can do no problem, who can't?

 

[misphit]

Is the coolant leak on the line itself or is it where it connects to the turbo? Might simply be a crappy/missing copper washer. I would suggest checking for a proper seal before replacing anything.

 

[steve]

That's a very good point. I wish this was applicable to the 90 TB. I have a 90 tb on my Colt and think that a ground strap would help some.

Why doesn't it apply.

If you do a search here your find examples of how the 90 ground strap attaches as well as the later versions. If you don't have the ground strap a wire run from the screw the strap would attached to run to the ground strap on the intake manifold will insure that the IPS has a good ground.

 

[mindset]

Alright I've tried adjusting the BISS screw several times now. As soon as I unground the ECU it will shoot back up to 1500 after I get it down to a 1000 RPM. When I start the car up the next morning it will start idling at 2300+RPMs. Then I go through the whole BISS adjustment process again. Am I doing this process wrong? Should I let the car run till its warm, and then ground out the ECU, adjust the BISS, let it idle for 20 minutes and then unground?

I've done research and I'm thinking it's the FIAV, TPS, CTP, or the ISC. What do you guys think? I really can't have the motor idling so high like this.

If I have to replace 3 of those things (FIAV, TPS, ISC), which belong on the TB, then why not buy a whole new throttle body from DSMGraveyard? If I buy one will it come will all 3 of those things?

Mods: I decided to keep forums clean by just continuing this thread. Could you please rename it to "Still Bad Idling Problems".
Thanks.

 

[steve]

Alright I've tried adjusting the BISS screw several times now. As soon as I unground the ECU it will shoot back up to 1500 after I get it down to a 1000 RPM. When I start the car up the next morning it will start idling at 2300+RPMs. Then I go through the whole BISS adjustment process again. Am I doing this process wrong? Should I let the car run till its warm, and then ground out the ECU, adjust the BISS, let it idle for 20 minutes and then unground?

What do you guys think?

They say that insanity is doing the same thing over and over and expecting a different result.

Define what your doing to "ground out the ECU".

What were the results from the other test's I asked you to make two weeks ago?

When you did your boost leak test how much pressure did you use and how long did it how without adding additional air?

What's your base timing?

 

[mindset]

They say that insanity is doing the same thing over and over and expecting a different result.

Define what your doing to "ground out the ECU".

What were the results from the other test's I asked you to make two weeks ago?

When you did your boost leak test how much pressure did you use and how long did it how without adding additional air?

What's your base timing?

Yes. Insanity.
I'm following what vfaq says to do. Ground out Ignition Timing Adj and grounding out the port underneath by the fuse box.
I'll be doing another BLT tomorrow because my previous one failed in sealing, it's actually drying right now. But the first time, I used about 7-10 psi.
I did not test the ISC because I don't have a DMM, what does that stand for? It obviously measure voltage correct?
How do I figure my base timing?

 

[nkosi]

Make sure to test that the IPS is functioning as well as checking the ISC coils.
Using your DMM on volts measure the voltage at the male spade connector, with the green wire attached and the ignition on. With the throttle closed you should read something close to 0v and with the throttle slightly open 5v or more. (varies between 90 and later ECUs and I don't remember the specifics ATM)

Many cars are missing the grounding strap for the throttle body and the ECU doesn't see the IPS close because of the missing ground. That means the ECU won't try to maintain the idle.

Surging is caused by too much bypass air.

It doesn't take much which is why the factory cautions people about touching the IPS adjustment. Just over-cleaning the throttle plate and removing the factory sealant from around the butterfly shaft is enough to cause extra bypass and surging.
After your sure the ISC and IPS are working and the ECU correctly raises and drops the engine speed when you turn the AC on/off you should pressure (boost leak) test the intake, clean the TB, and replace the PCV.

hey steve can u explain further the meaning of the abbreviation IPS and where is the ground strap on the throttle body u are taking about ...thanks man

 

[misphit]

I'm not Steve but the IPS is the Idle Postion Switch. It's mounted on the throttle body right above the spring that the throttle cable is attached to. There is one green wire attached to it which is usually covered by a black rubber shroud.

The ground strap he is talking about is located on top of the throttle body near the vacuum hoses; one end of the ground strap is mounted there, the other end mounts via one of the bolts which holds the throttle body/elbow in place.

 

[steve]

I'm following what vfaq says to do. Ground out Ignition Timing Adj and grounding out the port underneath by the fuse box.

Just making sure that you are getting the right pins in the right connectors. If you aren't you won't wind up with the right results. I know the first time I tried connecting to the timing check connector I clipped on to the purple/pink pin lock and not the real pin and miss pin 10 on the DLC by the footwell. If you were in adjust timing mode rather than set BISS mode that might explain what was going on.

I'll be doing another BLT tomorrow because my previous one failed in sealing, it's actually drying right now. But the first time, I used about 7-10 psi.

You need to pressurize it to at least the amount your running for boost and it should hold that. The longer the better.

I did not test the ISC because I don't have a DMM, what does that stand for? It obviously measure voltage correct?

DMM = Digital MultiMeter Measures volts, and ohms, and amps at minimum.
DVM = Digital Volt Meter Measures volts and maybe others.

In this case when you test the ISC you will be measuring resistance (ohms)

How do I figure my base timing?

With the engine at operating temp you ground the timing check connector and adjust the CAS while using a timing light on the timing marks on the front cover and crank pulley (harmonic dampener)

hey steve can u explain further the meaning of the abbreviation IPS and where is the ground strap on the throttle body u are taking about

Both are easily found by searching. The IPS is the Idle Position Switch located on the firewall side of the throttle body above the pulley on a 1G or inside of the Throttle Position Sensor (TPS) on a 2G. The ground strap runs across the top of the throttle body from one of the bolts into the intake manifold that hold the TB and elbow to a screw on the top of the TB.


I see misphit nailed the answers.

 

[mindset]

Make sure to test that the IPS is functioning as well as checking the ISC coils.
Using your DMM on volts measure the voltage at the male spade connector, with the green wire attached and the ignition on. With the throttle closed you should read something close to 0v and with the throttle slightly open 5v or more. (varies between 90 and later ECUs and I don't remember the specifics ATM)

Yes, I'm grounding out the right pin for BISS adjustment, or at least the one that's pictured in vfaq.
Redid the BLT and no leaks at all. I'm running stock boost (14b) so I did 10psi. Also did a quick check of engine bay for missing vacuum lines/connections.
The rest of my day I had to look for a job. Sorry I couldn't test the IPS. Could you explain the test above a little better? Do I let the car run when I do the test?

 

[steve]

Sorry I couldn't test the IPS. Could you explain the test above a little better? Do I let the car run when I do the test?

No the car doesn't need to be running but the ignition needs to be on.

Your going to measure the voltage between the chassis ground and the male spade connector on the top of the IPS while the green wire is attached to it. You may have to pull the boot back to get access if your boot hasn't turned to dust yet.

With the throttle closed you should read close to 0v at the connector. Turn the throttle slightly and you should read something more than 0v. Make a note of how much.
Close the throttle again and the voltage should drop to 0v again.

You can also measure the resistance between the throttle body and the negative terminal on the battery with or without the ignition on. That resistance should be close to 0 ohms.

 

[mindset]

No the car doesn't need to be running but the ignition needs to be on.

Your going to measure the voltage between the chassis ground and the male spade connector on the top of the IPS while the green wire is attached to it. You may have to pull the boot back to get access if your boot hasn't turned to dust yet.

With the throttle closed you should read close to 0v at the connector. Turn the throttle slightly and you should read something more than 0v. Make a note of how much.
Close the throttle again and the voltage should drop to 0v again.

You can also measure the resistance between the throttle body and the negative terminal on the battery with or without the ignition on. That resistance should be close to 0 ohms.

While my cars sitting apart I tested the ISC.
The test I did was the ISC testing on VFAQ.
Everything turned out good between all of the pins.

Now I want to test the IPS. The boot is still there and its not budging upward. I was able to slide the connector (green wire) off the male part. So what I do is leave the green wire connected, with the boot pulled up and measure the volts between the green wire connection and a ground on the car. Correct?

 

[mindset]

Ok Steve.
I did Ohm Readings on the TPS and the ISC.
The ISC Ohm Reading (I tested the actual part, not the wire connector)
1-2 28.9 Ohms set at the 200 Ohm switch on my DMM
2-3 28.9 Ohms set at the 200 Ohm switch on my DMM
4-5 29.0 Ohms set at the 200 Ohm switch on my DMM
5-6 28.9 Ohms set at the 200 Ohm switch on my DMM

According to VFAQ, the above is between 28-33.

The TPS Ohm Reading. I did this test by using my Haynes manual. So I tested Male and Female (wire connector) parts.

Female (wire connector): .342 Ohms set at the 2K switch on the DMM
Dont think I needed the connector ohms but its helps.

Male end (actual TPS): 5.34 Ohms set at the 20k switch on the DMM

So according the Haynes, they said it should be between 3.5 and 6.5.

What do you think?


*Edit: Testing the IPS, will give results in a little once I figure out how to do it.

 

[steve]

So what I do is leave the green wire connected, with the boot pulled up and measure the volts between the green wire connection and a ground on the car. Correct?

Yes.
The ignition needs to be on so that the ECU is powered up. The green wire needs to be connected to the IPS or you won't be testing it.

It's possible to just measure the continuity of the IPS but that doesn't verify the wiring which can get old, brittle, and corroded.

You ISC sounds good.

The Haynes manual is correct that the specification for the total resistance of the TPS is 3.5k to 6.5k ohms. It's also required that the resistance change smoothly between pin 1 and 2 or 2 and 4 as you more the TPS through it's range. The TPS adjustment requires setting it's output voltage on a 1G to about 0.5v at the closed idle position. You check this with a SAFC from the sensor check screen, a datalogger looking at the TPS (0.5v = 10%), or a voltmeter at the ECU pins between sensor ground and the TPS input.

 

[ilco187]

i had idle surge for a long time and doing the BISS would never work for me until i found this link http://www.dsmtuners.com/forums/bolt-tech/320799-my-solution-fiav.html post #19 i have never had high idle or idle surge.

 

[mindset]

Yes.
The ignition needs to be on so that the ECU is powered up. The green wire needs to be connected to the IPS or you won't be testing it.

It's possible to just measure the continuity of the IPS but that doesn't verify the wiring which can get old, brittle, and corroded.

You ISC sounds good.

The Haynes manual is correct that the specification for the total resistance of the TPS is 3.5k to 6.5k ohms. It's also required that the resistance change smoothly between pin 1 and 2 or 2 and 4 as you more the TPS through it's range. The TPS adjustment requires setting it's output voltage on a 1G to about 0.5v at the closed idle position. You check this with a SAFC from the sensor check screen, a datalogger looking at the TPS (0.5v = 10%), or a voltmeter at the ECU pins between sensor ground and the TPS input.

I dont need that boot do I? I'm about to just rip it off. Or is it there for waterproofing means?

i had idle surge for a long time and doing the BISS would never work for me until i found this link http://www.dsmtuners.com/forums/bolt-tech/320799-my-solution-fiav.html post #19 i have never had high idle or idle surge.

Thanks.

 

[mindset]

I got a voltage of 11.5. That was taken with just the ignition on and NO ONE hitting the throttle. As stated above, the voltage increases as the throttle opens up more and more. Correct? So therefore my throttle cable might need to be adjusted? What do you think?
The wire looks pretty beat up. Its about to almost break. Can I just splice in a new wire? And get rid of the boot?

 

[ilco187]

if you are talking about the ips single green wire i just used a shielded female connector like this.

http://www.jamestowndistributors.com/userportal/woeimages/Electrical/54665.jpg