360 P1125 & P1123 Fault codes?

I am getting these two codes on my new-to-me 360. I have a question related to post 11: is there a way to 'smoke test' the intake manifold gaskets? What can be disconnected to allow for a smoke test to be conducted? I don't have a way to test adaptive values, and thought a smoke test could serve the same purpose. Please correct me if I'm wrong.

I've searched and haven't found a DIY or instructions.

I'm also going to replace the primary O2 sensors, MAFs, and ignition coils as a form of preventative maintenance and faulty part elimination.

Thanks!

@rustybits

 

I seem to recall watching a vehicle maintenance video where some volatile substance was sprayed around the inlet manifold and there was an audible change to the engine when this was done (and there was a leak). Might this also be applicable to the 360?

I couldn't find any reference to "smoke" in the Workshop Manual.

 

By ‘smoke test’ I mean connecting an automotive smoke machine and using pressurized air and smoke to fill the intake manifold, the smoked air will find its way out of any gaps allowing you to visibly identify leaks. I hope that makes sense, I can try and find a video if that would help.

 

Ah, yes, we are all familiar with the concept. It's just that I can't find anything specific in the Ferrari manual. I don't know if there is anything you have to do beforehand. The engine has a complex inlet manifold system and lots of anti-pollution gear, so you might get smoke going somewhere you don't expect (and some smoke not going where you want it to go).

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Thanks for diagram and looking in the manual. I'll do some additional research before proceeding. Spraying a volatile substance is a little outside my comfort zone.

 

I measured by oil when the car was hot the other day, and I'm estimating it's about a quart overfilled based on the hole spacing on the dipstick. I recently bought my car, and it had a major in the fall about 100 miles before I took ownership. I'm guessing the prior owner didn't drive it long enough to get a CEL before he sold it. Looks like I'll be taking the intake manifold off for cleaning now. I will update this after I get around to it.

 

I recently purchased a 360 Modena. It is setting P1123 and P1125 suggesting long term fuel trim (LTFT) issues.

It does not appear that the engine is behaving poorly (no surging, rough idle, poor acceleration, etc.)

After I clear the codes, it takes quite a bit of time before the CEL illuminates again. I drove the car on four runs, each time driving about 10-15 minutes.

Checking the LTFTs on each bank, after each run, reveals that the LTFT is continually increasing. After run 4, LTFT1= +8 and LTFT2= +18. I am 99% sure that I'll be seeing the CEL again if I continue driving the car.

At first, the STFTs bounced around from positive to negative. They were negative only for a short time at first, then they remain positive.

I checked the O2 sensor, and found that "Low For Switch" is out-of-range. It measures 0.105
My cheap OBD2 tester suggests that the range is MIN=0.015, MAX=0.065.
"Hight For Switch" is within the suggested spec.

I've read the thread above; lots of good ideas. Wondering if, in my case, the out-of-range "Low For Switch" value, in addition to the P1123 and P1125, sheds any more light on the issue.

I plan to clean the MAF sensors, based on a conversation YelCab.

 

I pulled the sensors; they appear to be very clean; was expecting to see deposits or discoloration of some sort.

BTW: Wondering if I am actually running lean, or if the O2 sensors are messed up. Thinking that the "Low For Switch" being out-or-range might be an indicator of bad O2.

 

Intake leak.

 

Appreciate the quick response. Do you recommend any particular method to verify the leak?

 

A smoke test would be the next thing to do.

 

Shop performed smoke testing on the intake and the evap; no leaks detected. Cleaned the MAF sensors also.


Judging from how slowly the LTFT increases, I suspect the leak (if there is one) is small. The car needs to be driven more that 40 miles before setting a code (either P1123 or P1125).

BTW: The intake gaskets were replaced in 2021 when the heat exchanger was replaced.

Would appreciate any additional thoughts on this.

Thanks.

 

"Clean" doesn't mean they are within spec. Check history if MAFs have ever been changed.

 

Small intake leaks are hard to spot. Another member finally saw the smoke from the test machine only after using a strong flashlight in the dark.

 

Thanks. Do you know the location of the leak he found ?

 

I think in his case it was intake gasket for cylinder #7

 

Update for those interested:
1. I checked LTFTs, Banks 1 & 2; the numbers were 9.4 and 18.8, respectively.

2. After driving the car for a while, the Check Engine light appeared; error code P1123

3. Cleared the error code, and immediately checked LTFTs, Banks 1 & 2; the numbers were -0.8 and 8.0

> Every time I've cleared codes, LTFT (Bank 1) always goes to roughly zero, but Bank 2 never goes below 8.0

Anybody know where reset numbers for Banks 1 and 2 come from?

Also: STFT, Bank 2, displays erratic numbers. After reset, sometimes STFT will continuously display negative numbers for a minute or two, then switch over to all negative numbers, and finally goes (and stays) back to all positive numbers, no negatives. Has anyone seen anything like this?

I'm planning to replace both MAF sensors, and one upstream O2 sensor.

 

Quote: "...and finally goes (and stays) back to all positive... "End of Quote

That is saying the O2 sensor signal is detecting a lean condition, so the ECU continues to add more fuel (+ STFT) to try to compensate and it runs out of compensation when compensation is >25%. I think there is an intake gasket leak for bank2. It is a bit of work to fix it, but it looks like it's necessary to rule that out.

 

Thanks for your input.

Yes, I agree: The O2 sensors are detecting a lean condition and the ECU is compensating with additive fuel.

It could be an intake gasket leak, as you suggested. But as I mentioned, the intake gaskets were replaced in 2021, and smoke testing reveals no indication of leakage from the gaskets. Actually, smoke testing does not reveal any leaks anywhere.


However, my question was: Why does (LTFT Bank 1) never reset to zero.

I'm pretty sure that resetting the ECU will force the LTFT to zero; I think I'll try that, just for better understanding.

However, even if LTFT (Bank 1) does go to zero after ECU reset, there still a problem since the LTFT values continually increase.

 

Does anyone know if the "Pneumatic Capsule" (see circled below) is vacuum actuated? Wondering if this is associated with my P1123/P1125 problem.

I found that the hose connected to the "capsule" was rubbing against the drive belt pulley, and tore a big chunk out of it (see below, below).

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It is.

You would have a vacuum leak at certain rpms.... See OPEN values.

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It certainly wouldn't help performance.

 

Thanks for the helpful info.

Mostly concerned with finding cause of DTCs P-1123 & P-1125 right now.

 

Bosch 0280218012 on Amazon for $144
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That hose would cause a pretty big leak Steve. You should fix it and see where that leads.