Kroon Harness for 944 Turbo

[NCGermerican]

Where do things stand now from a symptoms perspective?

15-16 in HG at warm idle
NB+WB o2 sensors showing lean until closed loop, especially on warm start, but then hits 14.7
Can feel misfires at idle and hear small "pops" from exhaust and it smells VERY rich, like unburnt fuel
Goes lean when holding at 2,500 RPM, but doesn't seem to misfire

[Tom]

Where do things stand now from a symptoms perspective?

15-16 in HG at warm idle
NB+WB o2 sensors showing lean until closed loop, especially on warm start, but then hits 14.7
Can feel misfires at idle and hear small "pops" from exhaust and it smells VERY rich, like unburnt fuel
Goes lean when holding at 2,500 RPM, but doesn't seem to misfire

Smelling rich but running lean is curious? Although, sometimes lean misses can leave unburned gas to pop in the exhaust and smell 'rich.'

The wideband goes lean (over 15?) if you rev it to 2500 in the driveway when the car is fully warmed up?

You unplugged the altitude sensor, right?

Have you tried spraying starter fluid around the injectors while the motor is running -- to see air might be getting in there? Leaks right at the injector/intake can suck air but not appear on standard smoke/pressure tests. Just a random thought... For that matter, I'd spray it all over and see if you get any hits...

[NCGermerican]

Smelling rich but running lean is curious? Although, sometimes lean misses can leave unburned gas to pop in the exhaust and smell 'rich.'

Yes - I've posted the hypothesis from ChatGPT below. I posted my latest video this morning. At the end, I pull the plugs and you can see something very strange with the plugs. Plus, I borescoped the cylinders. ALL 4 have liquid pooling at the bottom and there was a gas smell.

The wideband goes lean (over 15?) if you rev it to 2500 in the driveway when the car is fully warmed up?

You unplugged the altitude sensor, right?

Yes - with the Storch MAF you need to unplug the Altitude Sensor.

Have you tried spraying starter fluid around the injectors while the motor is running -- to see air might be getting in there? Leaks right at the injector/intake can suck air but not appear on standard smoke/pressure tests. Just a random thought... For that matter, I'd spray it all over and see if you get any hits...

I have not tried that - mainly because I'm absolutely terrified to do it. The injectors are brand new from FiveO. Once I start the car, the headers and turbo get scalding extremely quickly.

Here is the ChatGPT hypothesis:

"A system-wide combustion problem (likely ignition or engine management related) is causing incomplete combustion. The resulting reduction in effective cylinder pressure lowers idle torque, which reduces manifold vacuum. The same problem leaves unburned fuel in all four cylinders, creates fuel wash and plug deposits, increases exhaust heat, and produces AFR readings that can be misleading because the wideband responds to excess oxygen from misfires rather than directly measuring fuel."

Problem is....I don't know where to begin to test any of this. I can test the coil (fairly new Bosch) and the plug wires (3 year old Beru), but who knows - it could be a degraded wire somewhere from the DME ignition drivers to the coil. It could also be a bad ground, but it's a brand new Kroon harness.

Here's something else that's strange. The red "i" light on the dash. When the engine is idling, it gets slightly dimmer/not dimmer as the car is misfiring. No other electrical component seems to do this. It's never done it previously.

Just to rule it out, I would love to pop in another DME and/or KLR and see if it makes any difference, but I don't want to drop the $$$ on another one just for testing.

[Tom]

Smelling rich but running lean is curious? Although, sometimes lean misses can leave unburned gas to pop in the exhaust and smell 'rich.'

Yes - I've posted the hypothesis from ChatGPT below. I posted my latest video this morning. At the end, I pull the plugs and you can see something very strange with the plugs. Plus, I borescoped the cylinders. ALL 4 have liquid pooling at the bottom and there was a gas smell.

The wideband goes lean (over 15?) if you rev it to 2500 in the driveway when the car is fully warmed up?

You unplugged the altitude sensor, right?

Yes - with the Storch MAF you need to unplug the Altitude Sensor.

Have you tried spraying starter fluid around the injectors while the motor is running -- to see air might be getting in there? Leaks right at the injector/intake can suck air but not appear on standard smoke/pressure tests. Just a random thought... For that matter, I'd spray it all over and see if you get any hits...

I have not tried that - mainly because I'm absolutely terrified to do it. The injectors are brand new from FiveO. Once I start the car, the headers and turbo get scalding extremely quickly.

Here is the ChatGPT hypothesis:

"A system-wide combustion problem (likely ignition or engine management related) is causing incomplete combustion. The resulting reduction in effective cylinder pressure lowers idle torque, which reduces manifold vacuum. The same problem leaves unburned fuel in all four cylinders, creates fuel wash and plug deposits, increases exhaust heat, and produces AFR readings that can be misleading because the wideband responds to excess oxygen from misfires rather than directly measuring fuel."

Problem is....I don't know where to begin to test any of this. I can test the coil (fairly new Bosch) and the plug wires (3 year old Beru), but who knows - it could be a degraded wire somewhere from the DME ignition drivers to the coil. It could also be a bad ground, but it's a brand new Kroon harness.

Here's something else that's strange. The red "i" light on the dash. When the engine is idling, it gets slightly dimmer/not dimmer as the car is misfiring. No other electrical component seems to do this. It's never done it previously.

Just to rule it out, I would love to pop in another DME and/or KLR and see if it makes any difference, but I don't want to drop the $$$ on another one just for testing.

Link to latest video?

[Dkraven]

Haven't read all the way back, so apologies if you've already done this, but I'm wondering about getting the injectors flow tested. New doesn't always mean good. It is odd that all four cylinders have pooling in them, that all four injectors would have problems. Do you have an original set to test in their place?

Is there someone with a turbo in your area who could lend you their dme for a day?

Yeesh, don't want fuel washing the oil off those nice new cylinder sleeves!

[NCGermerican]

Link to latest video?

[NCGermerican]

Haven't read all the way back, so apologies if you've already done this, but I'm wondering about getting the injectors flow tested. New doesn't always mean good. It is odd that all four cylinders have pooling in them, that all four injectors would have problems. Do you have an original set to test in their place?

Is there someone with a turbo in your area who could lend you their dme for a day?

Yeesh, don't want fuel washing the oil off those nice new cylinder sleeves!

No worries - this thread has turned out to be....lengthy! I do have a set of original injectors. The problem is, these issues were occurring when those were installed and I had them cleaned and flow tested.

I know of one friend that has an 89 Turbo in the area. Not sure if anything was different from the 87 to 89 DME's. I believe they had some tuning changes due to the K26/8 turbo and wastegate issues. I wonder if Elliott at 944 barn could "rent" me one.

[Tom]

What injectors from Five-O do you have? And what Fuel Pressure Regulator? Are your chips mapped for your injectors and fuel pressure?

[NCGermerican]

What injectors from Five-O do you have? And what Fuel Pressure Regulator? Are your chips mapped for your injectors and fuel pressure?

D1150BA 50lb/525cc - Peak&Hold - 2.5 OHMS. The FPR is a 3.0 Delphi (Bosch no longer makes 3.0 FPR's). I also tried a more "generic" 3.0 FPR to see if that would help, but no dice. I've also tried the factory and an aftermarket damper with no change. The chip is from John Behe. He actually created (3) chips for me to try, each one progressively adding more fuel and he recommended the injectors I bought. John is endorsed by Charlie at Evergreen Turbo and is also known by Joe at F9. Apparently John has been tuning these for years.

[Tom]

What injectors from Five-O do you have? And what Fuel Pressure Regulator? Are your chips mapped for your injectors and fuel pressure?

D1150BA 50lb/525cc - Peak&Hold - 2.5 OHMS. The FPR is a 3.0 Delphi (Bosch no longer makes 3.0 FPR's). The chip is from John Behe. He actually created (3) chips for me to try, each one progressively adding more fuel and he recommended the injectors I bought. John is endorsed by Charlie at Evergreen Turbo and is also known by Joe at F9. Apparently John has been tuning these for years.

Did he know you were running those injectors when he supplied the chips? If you feel like humoring me, I'd suggested installing the stock injectors, chips, and FPR while you diagnose. The fewer variables the better -- otherwise it can become like playing billiards on a row boat... I'm wondering if you are so rich you are missing, which passes unburied gas to the exhaust along with unused oxygen the o2 sensors interpret as lean. Those plugs are not happy campers...