Bennitoapplebum

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.

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.

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.

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.

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.

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.

35 minutes ago, Popeye775 said:

So how would I be able to adjust it down at idle with the CTS plugged in? because that is where my issue is. With it unplugged it 

1 hour ago, Popeye775 said:

SO here is where we are. The wideband is installed and started reading. When it is idling, the AFR is bouncing between 14-18.5. When on throttle/starting to drive, the AFR is around 14.5. With the CTS unplugged, the AFR will sit around 13.5-14.5 and the idle will sound smooth. So basically what it seems is that it is becoming very rich upon idle? 

Does anybody know what the PROPER AFR is suppose to be? From research it seemed to need to be around 14.75, but I could be wrong.

Was all this with the CO pot at ~500ohms?  Your CTS sensor might be out of range, or your engine may have been still warming up, while unplugging the CTS. By any chance you have the factory thermostat in there? 

25 minutes ago, Popeye775 said:

SO here is where we are. The wideband is installed and started reading. When it is idling, the AFR is bouncing between 14-18.5. When on throttle/starting to drive, the AFR is around 14.5. With the CTS unplugged, the AFR will sit around 13.5-14.5 and the idle will sound smooth. So basically what it seems is that it is becoming very rich upon idle? 

Does anybody know what the PROPER AFR is suppose to be? From research it seemed to need to be around 14.75, but I could be wrong.

This type of fuel injection system fires all injectors at once per engine cycle.  It requires a slightly richer idle. 13.5-14.5 is probably the leanest it will idle smoothly.  Anything leaner will surge and hunt for stability.  14.7 is ideal, but not realistic with this injection system.

Actually your #5 pic (ground bus) is not the correct one.  It’s above the fuse box.  I can see it in your other picture, after the aftermarket switch picture.  It’s bolted right above, has around 10 “fast-on” type connections, with about 4 brown wires occupied.  I also see a thin black wire connected to it (looks shaky) kinda burnt.  Might wanna check out what that is.

11 hours ago, Popeye775 said:

Car was fully warmed up. As far as I know, the CTS must be unplugged in order to adjust the CO accurately. But I could be wrong


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I remember why the CTS needs to be unplugged while adjusting the CO. The ISV idle stabilizer is inactive while the CTS is unplugged.  You get the idle speed close to ~800 using the bypass screw. And  adjust the CO using a wideband.  After the adjustments, you plug the CTS back in and the ISV will hold the idle speed closest to 800rpm with the varying load, power steering, fans, acc, etc.

So in your video, your idle was too high.  When you plugged your CTS back in, the ISV pulled the engine back to its target idle speed.  

3 hours ago, Popeye775 said:

Update for you sir,

I wanted to test something out. I put stock gapped plugs in the car (.024) and turned down the CO Pot until it idled smooth ( as in the video) with the CTS unplugged. BUT as soon as the CTS was plugged back in, you will hear the idle dip and hear a change in idle. Bad CTS maybe? The other thing that I am a little concerned about is the fact that the CO Pot is at 80 ohms of resistance in the video. From what I have read, 500 ohm is where fuel is neither added or taken out. 80 just seemed a little low, even if it is idling smoother. Ideas?

https://www.youtube.com/watch?v=3RCDoGGEUzU

Also another thing to point out:  The injector flow.  I recall you had purchased a new set of injectors.  If the flow rate deviates from factory, you may be having to compensate with the CO pot.  I’d say wait for the wideband installation to help simplify some things.

2 hours ago, Popeye775 said:

Update for you sir,

I wanted to test something out. I put stock gapped plugs in the car (.024) and turned down the CO Pot until it idled smooth ( as in the video) with the CTS unplugged. BUT as soon as the CTS was plugged back in, you will hear the idle dip and hear a change in idle. Bad CTS maybe? The other thing that I am a little concerned about is the fact that the CO Pot is at 80 ohms of resistance in the video. From what I have read, 500 ohm is where fuel is neither added or taken out. 80 just seemed a little low, even if it is idling smoother. Ideas?

https://www.youtube.com/watch?v=3RCDoGGEUzU

Was the car fully warmed up while the CTS was unplugged?  You could’ve bee adjusting the CO while the engine was warming up, or cooling down.  I don’t know what function unplugging the CTS serves while adjusting CO.  I do know that both CO pot and coolant sensors are important for fueling equations within the ECU.  
 

I kind of remember unplugging the CTS at one point, for adjusting CO.  But eventually ended up leaving everything plugged in while making any adjustments.  

Does anyone here know why the procedure calls to unplug the coolant sensor?

On 8/21/2020 at 2:26 PM, Popeye775 said:

Update: 

Took the car out for a little drive again - i have not pulled the plugs yet - and it still feels misfire-like under 2k rpm but it is off and on. It does it on take off and what seems to be under that RPM of 2k. Something new, when I turned the car back on after driving it for a while then letting it sit a couple minutes, it idled perfect and revved perfect for about 30 seconds then went back to it's misfire-like ways under 2k.

Shutting down the engine after a drive causes an engine to go into “heat soak” mode.  The entire engine heats up due to the cylinder’s heat not being transferred to the radiator, fuel cooling, etc.  When you restart the car during this stage the ECU delivers an increased ASE(after start enrichment) for a period of time~30 sec.

Judging from the symptoms you explain and from the color of your plugs, your issue seems to be fuel related.  Any ignition system will have a hard time lighting a mixture as lean as yours, especially during increased load.

A quick test would be to crank that CO pot up by a large amount and see if she drives better or worse.  I’m betting it will run way smoother and consistent.

15 hours ago, Popeye775 said:

Update: 

Took the car out for a little drive again - i have not pulled the plugs yet - and it still feels misfire-like under 2k rpm but it is off and on. It does it on take off and what seems to be under that RPM of 2k. Something new, when I turned the car back on after driving it for a while then letting it sit a couple minutes, it idled perfect and revved perfect for about 30 seconds then went back to it's misfire-like ways under 2k.

Would you say that your engine has reached a higher temperature while sitting?  If so, then heat related intermittent problems are, guess what... ground related.  When metal expands under heat it sometimes increases the current capacity in poor grounds.

This may not be your case.  Just something to think about.

10 hours ago, Popeye775 said:

Advice real quick here:

So I am considering trying this. I was adjusting the CO Pot today along with the idle air screw, but I am thinking that what I should do is set the CO Pot back to 500, then set the idle air screw from there and then set the CO Pot accordingly for that. Would this be a good way to go about trying to tune this thing or not? I am going to order a wideband as well because I think that will help a lot when it comes to trying to get this thing dialed in 100%

Yes you can tune the idle that way, the mixture and idle speed go hand in hand so constant back and forth adjustment might be required. Yes getting a wideband will definitely help with tuning and diagnostics.  

On 8/16/2020 at 1:48 PM, Popeye775 said:

Plugs after most recent run. One plug looks a little whiter than the others that’s for sure but they are looking better.


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That’s better lighting to read the plugs.  That’s too lean of a mixture for boost.  It might be okay for short runs, but will be inconsistent due to knock and timing pull. For economy you’d want all your plugs looking like #2.  Though that still looks too lean for my taste of tuning. For all out full throttle top speed fast and the furious runs, you want the plugs looking dark grey and sooty.

On 8/16/2020 at 11:51 AM, Popeye775 said:

So I did some research and from what it seems the CO pot should be set to 500ohm. That way it isn’t pulling or adding fuel. So what I did was set mine to 500ohm and I will see how it feels from that adjustment


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I think 500 ohm was the factory’s starting setting, but still needed adjustment before capping the pot off.  Each G60 got its differences and the CO pot was a way to tune for the right air fuel mixture.

On 8/16/2020 at 11:21 AM, Popeye775 said:

When it comes to adjusting the CO pot, do you do it while the car is on or off? Also I’m assuming in 1/4 turn increments clockwise?


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1/2 turn increments should be easier to tell if it’s getting better.

3 hours ago, KarlosG60 said:

I was thinking about my issue this weekend.

What relation can exists between the electrical noise from fuel pump relay, with the dead of my cluster gauge? A noise only heard in the first tries after the fuel pump has been replaced and also, last day when I connected all the wires from it when I was discarding the origin of the cluster dead.

How this fuel pump works in the very first turn on try? Maybe I make a mistake with the fuel pump? I bought it new from VWClassicParts.

The only thing I can think of that relates them are the shared voltage.  If the grounds are not good, you’ll get low voltages. Many components need full voltage to work properly.

Have you fixed the main grounds?

3 hours ago, Popeye775 said:

The 268 cam is not yet in there. I am waiting on a valve cover gasket to get here before I can put it in. So when I say burbly or missy I mean it sounds like it is stuttering and it lacks acceleration. Basically like it is hesitating. Here is an old video that has the sound captured pretty well. You can hear as soon as I go to rev the car, there is a burble like sound.

 

https://www.youtube.com/watch?v=4AOgdg1Hsps

Ah, I’ve assumed you had the cams in there already. Yeah that’s definitely a misfire.  With that understood I’m thinking it’s still a fuel issue.  Next step would be to try the CO pot adjustment.  You want those plugs looking a little more sooty.

5 hours ago, Popeye775 said:

Update: 

I just took it out after the gap being at .025 and increasing the timing by about one degree. It felt really good. It misfired a little full throttle at first but then stopped doing it after a couple pulls. It also didn't feel like it was missing while cruising. At least if it was, then I didn't feel it. Under 2k it was a little missy or burbly taking off unless I blurped the throttle. I am assuming there is a boost leak or vacuum leak somewhere causing it to do that because it wasn't consistent. But that is the best it has felt in a long time. Do you think I should decrease the gap back down to .024 and try it that way or take a look at the plugs first and figure out where to go from there?

 

 PS: I will post a photo of the plugs here in a little once the car cools off a little bit.

Sounds like she’s almost there!  There could be a vacuum leak somewhere, but it’s sounding more like a tuning issue.  

When you say ‘missy’ or ‘burbly’ do you feel a hesitation? Or just slightly jerky with a steady throttle?  From what I remember with the 268 cams there was always a light load/cruising misfire under 2000rpm that immediately went away upon throttle addition.  If there’s hesitation upon any acceleration, then I’d worry.  I’m not sure if that’s what you mean though.
 

You can leave that spark plug gap for now. It should be good, but if you wanna add more boost then you should close the gap.

Im assuming you just need a tad more fuel, but we’ll see after looking at those plugs.

5 hours ago, Popeye775 said:

The timing is set for 6 degrees BTDC currently. I only increased the plug gap by .001 (.024 - .025) so I didn't compromise the fuel igniting under boost. Advancing the timing maybe like one degree? Maybe two?

Yes, about two degrees should be good.  Be careful, with the power addition from the increased timing, you’ll want to keep advancing timing till the engine blows up😂it gets addicting. 
 

 Try 2 degrees.  See how she drives.

2 hours ago, Popeye775 said:

Here’s a drive on 4bar fuel pressure and .024 gap. Felt good shifting in boost but felt a little misfire-ish cruising. So I might increase gap to .025. Am I going about that the right way?


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Looking a little better now, still a little on the lean side for these motors.  But the 4th plug looks a little whiter than the rest. I’d look into that.  Increasing the gap will be harder to ignite under boost, but may help with the cruising loads.

The current plug conditions you show are safe for about 8-10 lbs of boost. If you’re running any higher boost you need more fuel.  

Are you comfortable with adjusting your timing?  If you’re running low boost ~8 lbs I feel that advancing the timing slightly will help with the cruising misfire.

52 minutes ago, Popeye775 said:

So I am running a 3-5 bar fuel pressure regulator so I could turn up the fuel pressure. My CO pot is set to a resistance of 550 ohms, what would you say this should be turned up to? Or should I turn the fuel pressure to 4bar and leave the CO pot where it’s at?


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I’d say leave the CO pot where its at, and just turn up the fuel pressure for now.  Then go for a drive and pull the plugs again to have another look.

It sounds bothersome, but it’s tuning😂

19 minutes ago, Popeye775 said:

New development as well. Took her back out again after regapping plugs. Car started right up, and this time if I eased into boost going into third, there wasn’t any misfire action. But if I shifted into third and immediately went foot down, then it misfired.


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Make sure those plugs are resistor type.  You seem to be running lean, most definitely causing the misfires.  The porcelain is white, lighter than tan.  The color for these motors should be more sooty, darker grey.  You’re almost there, after you sort out the fueling issue I’ll bet she’ll pull like a freight train.  It would help to have a wideband 02 meter to squeeze the most out of your motor, but pulling the plugs for a reading isn’t bad on the 8 valve motors.  

You can address the fueling with one of three ways:

1. CO potentiometer adjustment

2. Higher fuel pressure regulator (4 bar)

3. Stand alone fuel management.