Rough Start

[Popeye775 16]

 

Yes factory thermostat is in there as far as I know. The CO is at around 80 ohm right now because that’s where it was happiest so far. I will set it to 500 ohm and retest. The car was completely warmed up, as I had to drive it home from the welding shop haha.


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[Popeye775 16]

 

It is also a brand new CTS. I just put it in two days ago


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[Bennitoapplebum 2]

Did the idle raise when you plugged in the cts? Or drop? You might have to play more with the bypass screw to find a sweet spot, where the idle doesn’t change much from plugging back in the cts.

With the cts plugged in and the engine fully warmed up, record the idle rpm(ECU target rpm).  When you unplug the cts, the idle will raise, or drop.  Play with the bypass screw in the direction needed to match the recorded target rpm.  You need to find a good air/fuel ratio to reach this target.

Plugging in the cts will turn on the idle stabilizer back on. And the afr will change a bit, but the idle stabilizer won’t be working too hard to reach the target rpm.

If your CO pot is that far off I’m thinking the problem is elsewhere.

[Popeye775 16]

Did the idle raise when you plugged in the cts? Or drop? You might have to play more with the bypass screw to find a sweet spot, where the idle doesn’t change much from plugging back in the cts.
With the cts plugged in and the engine fully warmed up, record the idle rpm(ECU target rpm).  When you unplug the cts, the idle will raise, or drop.  Play with the bypass screw in the direction needed to match the recorded target rpm.  You need to find a good air/fuel ratio to reach this target.
Plugging in the cts will turn on the idle stabilizer back on. And the afr will change a bit, but the idle stabilizer won’t be working too hard to reach the target rpm.
If your CO pot is that far off I’m thinking the problem is elsewhere.

So set the CO to 500 and then set everything else from there? Meanwhile recording the idle speed with the CTS plugged in?


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[Popeye775 16]

Did the idle raise when you plugged in the cts? Or drop? You might have to play more with the bypass screw to find a sweet spot, where the idle doesn’t change much from plugging back in the cts.
With the cts plugged in and the engine fully warmed up, record the idle rpm(ECU target rpm).  When you unplug the cts, the idle will raise, or drop.  Play with the bypass screw in the direction needed to match the recorded target rpm.  You need to find a good air/fuel ratio to reach this target.
Plugging in the cts will turn on the idle stabilizer back on. And the afr will change a bit, but the idle stabilizer won’t be working too hard to reach the target rpm.
If your CO pot is that far off I’m thinking the problem is elsewhere.

With it fully warmed up it usually idles around 850-900 with the CTS plugged in and has been idling around the same with it unplugged or once I unplug it. Maybe just a tad bit lower. I will record it right now.


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[Popeye775 16]

So I learned I am reading the gauge backwards. By a quick google search I found that the higher the number, the leaner. The lower, the richer. I feel quite dumb but anyways. That means I am lean upon idle. Because my idle was around 15-19 on the gauge. So add more fuel I guess?


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[Bennitoapplebum 2]

It can be confusing at first.  The sensor reads oxygen 02 content so a higher number means more oxygen (lean).

I’m thinking your CO pot adjustment of ~80 ohms might be where you need it.  It was giving you a decent idle and driving air/fuel ratio.

[Popeye775 16]

It can be confusing at first.  The sensor reads oxygen 02 content so a higher number means more oxygen (lean).
I’m thinking your CO pot adjustment of ~80 ohms might be where you need it.  It was giving you a decent idle and driving air/fuel ratio.

80ohm gave me an idle of 15-18 AFR but good driving AFR


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[Popeye775 16]

Idle switch reads perfectly fine, and the connection to the blue temp sensor is perfect too. Could this eBay ISV be leaning out my idle? The only reason that’s my assumption now is because it idles so well with the CTS unplugged


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[Popeye775 16]

I apologize for all the constant replies to this thread but I found something interesting when I checked the resistance at the CO pot, the air temp sensor, and the harness at pins 9&5:

CO pot - ~80ohm
Air temp sensor - 2.27kohm
Pins 9&5 - 2.25kohm (at 22 Celsius)

Thoughts?


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[Popeye775 16]

bump


I checked the ISV harness connector for giggles and found that the ISV - when grounded to somewhere other than the ISV ground itself - gives me 12v. When I use the ground going to the ISV I get 11v. This sound like a bad ground to you guys?

If so where does the ISV ground route to, so I can pull that wire and run a new ground if possible.


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[Bennitoapplebum 2]

No apologies needed, this is all great info for others to read.  The resistance  readings for the CO pot and air temp sensor sounds reasonable.  Pins 9 and 5 would be a combined resistance of the CO pot and air temp sensor together.

For the ISV, the 12v is constant(ignition).  The ground is a pulse modulated signal from the ECU.  The voltage will always vary ~3-12volts, depending on how far off idle target is, engine on or off, etc.

You say you had an idle mixture of 15-18.  Was it idling decent at all?  That doesn’t sound too bad of a mixture at idle.

[Popeye775 16]

No apologies needed, this is all great info for others to read.  The resistance  readings for the CO pot and air temp sensor sounds reasonable.  Pins 9 and 5 would be a combined resistance of the CO pot and air temp sensor together.
For the ISV, the 12v is constant(ignition).  The ground is a pulse modulated signal from the ECU.  The voltage will always vary ~3-12volts, depending on how far off idle target is, engine on or off, etc.
You say you had an idle mixture of 15-18.  Was it idling decent at all?  That doesn’t sound too bad of a mixture at idle.

I’m not sure if you remember the video I had posted of the sound at idle when it sounded burbly, but it still sounds like that on idle.


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[Bennitoapplebum 2]

1 hour ago, Popeye775 said:

I’m not sure if you remember the video I had posted of the sound at idle when it sounded burbly, but it still sounds like that on idle.


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Yes I remember.  That is definitely a lean misfire.  The next steps would be to:

1.  Fully warm engine up.

2.  Leave CTS plugged in.  Adjust CO pot to obtain a decent idle AFR.

3.  Go for a drive and record the driving AFR.  

4.  Report back with the results of changes. Ex. drive smoother, misfire, kicked ass, blew away a MK5, etc.

[Popeye775 16]

Yes I remember.  That is definitely a lean misfire.  The next steps would be to:
1.  Fully warm engine up.
2.  Leave CTS plugged in.  Adjust CO pot to obtain a decent idle AFR.
3.  Go for a drive and record the driving AFR.  
4.  Report back with the results of changes. Ex. drive smoother, misfire, kicked ass, blew away a MK5, etc.

How much lower can the CO pot really be adjusted if it’s at 80ohm already??


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[Bennitoapplebum 2]

You can adjust that all the way down to full continuity (0 ohms).  By then, if you can't get the AFR's within a good range, it's safe to say the problem lies elsewhere.

[Popeye775 16]

You can adjust that all the way down to full continuity (0 ohms).  By then, if you can't get the AFR's within a good range, it's safe to say the problem lies elsewhere.

Sounds good. I am also redoing the grounds this weekend, just for the sake of having we grounds and peace of mind


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[Popeye775 16]

You can adjust that all the way down to full continuity (0 ohms).  By then, if you can't get the AFR's within a good range, it's safe to say the problem lies elsewhere.

Turning the CO pot down while the CTS was plugged in did nothing at all. No richening up what so ever. This picture is from when it first started up for about the first 30-60 seconds, then it leaned out back to 16-18 and started that burble noise again. With the CTS unplugged and warmed up, it’ll be around 13 and stay there consistently. Any ideas to try next?


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[Bennitoapplebum 2]

Not to complicate things further, but your spark plugs 1&2 are very lean.  The +12v power for the INJECTORS are wired from the center.  A heavy gauge wire splits into 4, feeding each injector. Meaning 2&4 gets dibs on power.  When you plug in your CTS, the ISV reactivates and draws more current.
 

Just something to think about.