2fcknfst

Although I am still learning about the systems, it would seem logical that the wide bands are an integral part of the start up procedure, ie, they get warmed up and kill the choke.

Mind you, I may also be off target.

I thought no, this weekend, I may hook up the durametric and log the start up procedure.

napoleon1981

I have some durametric logs for mine too so it would be good to compare. I have ones with and without MAF. I will post them once the wife leaves her laptop.................................

I think with the O2 wide bands it is important to note that the misfires occur before they are warmed up, so i excluded them as a culprit for the cold start misfires.

2fcknfst

Dedicated laptops are the way to go....

Carlo_Carrera

Have you two tried pulling the Cobb tune and seeing how it goes without it?

napoleon1981

I dont have a tune, car is 100% stock

Carlo_Carrera

Interesting, so you two having similar problems/codes under different conditions. Makes me think both of you are having simple ignition problems. Easy to say, difficult to track down.

2fcknfst

This morning I gave it a start by holding the throttle down a little so the engine speed would be a little higher upon ignition. When it fired, a big puff of smoke came out of its backside and I held it at 2k rpm for a couple of minutes and moved off - no codes.

As I am in the city and I cannot wring it out (really) I saw 1.0 bar at 5k rpm a couple of times in second; I suspect that it would have gone up to 1.2 if I really put my foot into it.

I then brought it over to my shop and went through the hoses - everything seems tight, no obvious rips or tears in the silicone.

It would seem logical to be able to rule out the tune as Napoleon is having the exact same issue on virtually my sister car (X50/Mileage), and because under load, my car absolutely howls and is not missing at all. Further contemplation about the familiarity of Napoleon's problem and mine is drawing me back to thinking that it may in fact be a bunged up throttle body; as both of these components are consistent between both of us, we have the same mileage, vintage and programming, this may in fact be the culprit.

My thinking is that the throttle butterfly is slow to react to the rest of the integrated systems (fuel primarily) and I am getting a momentary 'rich' cycle that does not have enough air to burn the fuel in the cylinder.

Thoughts?

Cheers,

Kevin

I would datalog a 3rd gear pull to 6K RPM shift into 4th gear and hold it for a few seconds. Upload your results or email it to me.. I will let you know what I see. RPM. Load, Lambda, Knock retard, CFM, and boost

s65e90

O2 go into open loop mode during cold start to warm up. So the ECU is not getting feedback from them until cold start sequence is over. Check coolant temp sensor too.

Carlo_Carrera

I do not think a throttle body issue would give you misfires on just two cylinders. Normally misfires like that are ignition.

Have you two tried doing a throttle position reset? Turn key to run position but do not start the car. Do not touch anything just let car sit like that for five minutes.

Also so have you two checked the two cam solenoid brackets?

napoleon1981

Brackets are fine. Cylinder 3 and 6 are both on different banks (closest to the fire wall). A failed bracket leads to failures on 1 bank so that also doesn't fit, but they were inspected.

Ignition coils are new, so are the plugs. I even swapped the packs from cylinder 1 and 4 to cylinder 3 and 6. If it is ignition related, it certainly is not plug and coil related.

Throttle calibration was also performed.

napoleon1981

that was also checked. It works like expected.

Carlo_Carrera

You have done your due diligence with all that. Good work.

The codes only pop up on cold start, correct?

You also mentioned you can see other pending codes on other cylinders but they do not pop up, correct?

Have you removed/cleaned/inspected the throttle body and check that the position readings are accurate?

Also have you check the readings from the injectors?

s65e90

Check cam angle sensor.

napoleon1981

Seems ok. Due the the symptoms, sudden onset on 2 cylinders on opposing banks, i have placed bank specific errors very low on the root cause list.

I appreciate the suggestions, keep them coming!

Leon