360 CEL AIR FLOW LOW (CONSULTANTS PLEASE)

I'm hoping another consultant can help out here.

We were delivering a 360 after a routine 15k service. Upon start up for test drive we encountered a CEL and found a stored Low Air Flow code with SD-2 on RH Bank.

Since we changed the air filters during the service it seemed plausible a piece of dirt contaminated the MAFs. We cleaned both with CRC MAF cleaner. Switched MAF's side to side in case error came back. In SD2 parameters air flow was around 20 kg3/m both sides with lowest at 19.3. Ferrari specs between 18-25 and within 5 side to side at idle. Everything looks fine but is reading the same as before cleaning too (no change). Decided to check coil connections (also did spark plugs for 15k). All looked good but cleaned with contact cleaner and Stabalant 22 and reinstalled. Cleared code with SD-2. Started up and ran half dozen times with no CEL and no error on SD-2. Went for 30 minute road test, came back, no CEL and no errors with SD-2. We figured we have it licked.....WTFWIT.

Customer arrived to pickup his car (after we told him we had encountered a MAF CEL). Customer starts car to go home, CEL comes on.

Further diagnosis while customer waiting. SD2 shows "stored" Lo Air Flow error (but not present). Check all connections at intake manifold, all vacuum lines, etc. tighten up the intake hoses at the manifolds to the throttle valves and MAF, measure the same air flow even though they felt loose at start. Clear code, install another different MAF and ran car to compare actual air flow values and no change in values still around proper specifications. No errors either. Start several more times and CEL reappears. SD-2 showed "stored" not a present code. Problem stayed on RH Bank. Perform reset of all adaptive values and reset of learned throttle drive by wire. Perform cycle test. Restart car, runs great, rev a few times and then idle, CEL back. Sent customer home without car (Friday about 6pm).

Back in shop over the weekend. Check signals at each MAF connector for anomolies (5 wires, Air Temp sensor, Battery V, Earth Ground from ECU, +5V from ECU, MAF Signal out to ECU). All within spec, MAF signal to ECU hovering around +1.5V at idle.

Back in shop Monday. Begin "Ground Sweep" on chassis. All grounds are very oxidized with a good bit of corrosion. Clean all grounds at rear of chassis for ECU, clean grounds at kill switch area underneath front cowl, check battery connections again, clean ECU connections too. (We did a voltage/charging system check during the 15k and all was well). Takes most of the day to uncover and get to all grounds to clean and prep properly. Start up all is well. Reset adaptive values and throttle drives. Go out and drive car for half an hour spirited with SD-2 interfaced and recording data aquisition same as above. Car runs and shifts sweet. Bring back to shop, turn off and then back on, CEL.

Disconnect Alternator and run car to ensure no weird diode ripple or voltage spike occurring no change and of course we had already inspected the alternator connection known to be a standard issue on the 360 as part of the 15k and it is better than most.

Performed Data Aquisition of Air Flow, RPM, Battery Voltage, and Air Flow Lo Error with SD2. Ran for 5 minutes, no error present or stored graphed, but when switch back to partial errors, display Lo Air Flow, but no CEL on dash. Two more starting cycles and each stored signal converts to CEL on dash.

Back in shop Tuesday.

Check continuity and electrical connections again and pin out back to ECU, get tricked with a bad test lead for a few hours thinking weak ground signal only to find bad continuity in test wire. Go back through and find all to spec continuity measuring 0.6 ohms through both MAF's to ECUs (cross over) and check all values of common ground and voltage components, all good.

With Oscilloscope go back and measure all values in and out of MAF and all is good. Measure in both voltage and voltage in waveform looking at both banks sensors side by side on channel 1 and 2, pretty damn close. With scale at 4v and time at 4min (lowest) start engine through several cycles in order to find weak signal, nothing encountered but CEL reoccurs.

Swapped ECU's side to side....problem child is exactly same.

Going back to check wave pattern of ignition coils on scope to see if maybe we have a coil going bad causing some A/C over the top. However, checked that too at the sensor and did not see any signal in the background on the labscope.

Probably left out a number of tests here, but looking for some help here as I'm running out of things to check on a perfectly good running car.

Any consultants run into this? I've got a zillion hours now into this diagnostic on my own nickel. At first I thought it was something we may have accidentally bumped or disconnected as it sure seems unlikely to be coincidental but I have yet to find anything wrong at all.

 

You might want to reread my post
all of that was adressed STD procedure and sd2 is not a generic reader
camtiming is the same as before and unchanged as was not part of 15k

 

Yes, I know that is why we moved the two MAF's side to side to see if the code moved to the other ECU....it did not. We moved the ECU's side to side, code did not follow.

This morning I tried (4) generic code readers to pickup the CEL. None of them even picked up the CEL and SD-2 does not register it in data aq, or all codes, just partial codes.

Its very strange.

Hopefully a consultant with SD-2 may have run into this "electrical" glitch.

 

P1323 (it is not on my list of Ferrari proprietary codes) and only showed up on the last generic code reader of 4 I tried and does not register on Ferrari SD-2 either as standalone does not register the error only only in PC link mode and only in partial error list not all error list.

Other manufacturers have different meanings:

1. Ignition Control (IC) Module 24x Reference Circuit low frequency
2. Loss of High Resolution RPM Information

I've scoped every possibility for both, and nothing but perfection.

I'm about to call a priest for an exorcism.

 

I have done all that and more. I even had a friend in that was a senior engineer at AMD and fellow Fchatter to help me double check and go back through scoping everything and overlaying one bank wave form to the other bank at sensors individually at sensor and at ecu back probing on every wire for (MAF (all 5 pins each), TP signals (all pins), Coil signal, ground, power at each and overlayed to each other, ECU inputs, ECU power supply(s). With his eyes he even suggested we were chasing something that happens so fast without a logic tester we may never see it.

(yes) we switched Air filters, even old air filters, ecu's, spark plugs, coils, motor driven throttles, 2 completely different MAFs. Problem never moved to other side they are actually usually only 1 kg3/m difference side to side, we swapped them after we cleaned both very carefully as well, no change. Reconfirmed cam timing this morning just in case and is spot on as are variators now exactly same side to side (we adjusted as they were a few degrees different from side to side).

Actually you can look at with SD2 but it is slow. We datalogged it in SD2 but also used a generic tool to observe no abnormalities.

Four different Generic Scan tools do not even acknowledge a DTC and the 5th only did it briefly and how I was able to ge the pcode. Standalone SD2 does not acknowledge either, only in PC Link Mode can you see it as it occurs and as it is present with every single parameter spot on.....

We've cleaned virtually every connector in the engine bay and now all behind the seat including all the main power cables and battery "again".

I'm going out for a long test drive after resetting all learned adaptive values and throttle motors again and see if we can't get it through this "glitch" after the latest sweep of checks and cleanings.

Smoke for the second time again confirmed a tight intake system and vacuum lines as well as secondary air, etc.

I keep thinking its going to be something stupid but a week solid nearly has proven that to be wrong so far

 

Thanks Terry,

I have the 360 codes from FNA and that one is not on the sheet. The first 1300 code starts 1324 and is timing between ref and tdc signal.

Even though we did not touch the cam timing, thats why I went back and looked at it and made the exh variators identical in in mid spec.

I'll let you know after my test drive.......just taking a late lunch now and will finish button up of car to drive.

 

Yes I'm sure regardless that system was checked as well as smoke test the entire intake/vacuum system

 

Well it looks like we finally have it fixed.

All I can say is I believe the 360's are going to all start heading down this path with anode/cathode reactions with the aluminum frame with copper and steel connections.

This is a nice car and well kept but only after cleaning damn near every main connector, ground to chassis and power supply(s) in the car (and as any Ferrari mechanic knows there are a ton of them on this car), did the problem finally go away.

We have seen ground issues of corrossion a number of times on these models but never to the extent of "phantom" codes as this one presented.

We may go back into producing a supplimental rear chassis harness we have fabricated in the past but it doesn't take care of the cockpit and front chassis issues that also contribute to a lot of gray hairs.

 

Thanks Jerry.

We actually have a number of Houston customers so you are more than welcome to join the club.

 

Dave and I are very good friends and we share a lot of our issues with each other. He and I talked about this brain teaser together at least a dozen times. I'm fortunate to have Dave as my friend/mentor to double check with as well as lend some encouraging words just when you are about to throw in the towel. This car certainly put up a valiant fight.

Both of us have "Ferrari Memory" books on unique problems we have seen over the "21 years me" and "35 years him" working on Ferrari road and race cars. I am about to seperate the 360 from it as it is quickly overtaking my big book.

A couple of my customers have Dave's latest 355 gold pin connector kit and say their cars run better than when they bought them new.