Engine failure after replacing cf2 manifolds

[Don Pietro]

Still having problems since I have let replacing the original manifolds for cf2 with wizard front pipes and clutch with flywheel.

I try to explain it.

It occurs not always, occasionally I get a engine failure. It appears when I have to slow down for an example a roundabout or traffic light, the engine has to go from x rpm to idle. But it goes under the idle rpm's and one ore more cylinders are going for few seconds / minutes off, sometimes even the engine warning light goes on. I can drive on, the engine sounds like a Subaru impreza, then the warning gets off and the cylinders a back.

Flywheel is now on the right marking point, and there is a minor improvement. Lambda sensors seems ok.

What could it be ?? Please some advice where to look for.

Do I have to remap ?

Why is the engine sound, revs changing when I use the clutch pedal ? This seems to be normal on the V6's.


156 V6 CF2 manifolds, Wizard front pipes, standard cat's, Novitec sound pipe and quad back box. Sprint Filter foam filter, inox air intake, Autolusso silicone induction pipe.

[olly6969]

Sorry Don, can't help with your problem but my engine revs drop slightly when I press the clutch sometimes. I assume it's cos the ECU "knows" you have pressed it - there is a switch on the pedal which deactivates cruise control.

olly.
.

[Pud237]

Did you mechanic weld a lambda boss into the exhaust manifold for the rear bank? Do you have a photo showing where the lambda sensor is installed into the manifold?

Motor Control System Failure = a fault is logged. Do you have the fault codes? They should be able to help work out what is the problem.

[Dr GTA]

Lambda's in the right banks?

[Don Pietro]

Thanks for the quick response.

Lambda's are (placed / connected) on there own banks.

The lambda from the rear bank is placed just above the flange, was first what higher in the closed (we reopened) connection boss. Mechanic has drilled a hole and welded a nut on it. Maybe lambda is not deep enough in the pipe ? I doubt that. Photo I can take when the car is on the (how you say) bridge. I will try asap.

Fault code I don't know exactly, mechanic told me that it said: rear bank ignition failure. And that can be everything. I can ask for more info.

Indeed Olly, that's what the mechanic also told me. But at the same time the ignition timing will be delayed, for what reasons ? Maybe we can take lose the switch as test ?!

All the help is welcome.

[Pud237]

Its hard to weld a lambda boss into the rear bank manifold just above the flange as the pipe is curved. You have to re-fabricate it a bit so the lambda sensor can be welded in straight rather than at an angle. It needs to be perpendicular to the flow of exhaust gas. This could be your problem but I'm not 100% sure. I'd be suprised if it was just a co-incidence that its the rear bank that is having ignition failures. Do you have the Pxxxx codes?

[AYAT]

I haven't put my lambda boss in yet, but I reckon I'm gonna put it on the downpipe instead, hopefully easier.

[Dr GTA]

I had problems with readings not being accurate when my lambda was not in at 90 degress to gas flow

[hughqv]

When i did mine i spaced them out as the standard rear gtv one looks with a piece of pipe cut on an angle (mine were 2.5 ones), just so the nozzle is getting a sniff, you dont want to block off half the pipe with the sensor after all that effort for flow, i doubt that is your problem.

[Don Pietro]

Tomorrow (when i get in time) i will go to the workshop and ask the mechanic about the placing of the lambda boss and the fault code.

Is it important where to put the lambda, i mean high or low in the manifold ? Because the first time it was fitted at the place which was closed pipe, mechanic opened it and placed there the lambda the first time. That place resulted in a fault code, then he placed it lower on a self made lambda boss.

You will hear more from me, asap.

[Don Pietro]

Back from the workshop.

Mechanic said that the lambda is placed good.

Error code, when i remind it correctly, something as P30-01/02/03.

Not exactly when, but they want to do some tests. First to disconnect switch from the clutch pedal. Recheck lambda's etc. Timing from the timing belt. Make a call with the man from Squadra Tuning when he is back (from holiday or so).

[silvervalver]

I have had these codes with same basic set up. Only happened after I had a remap and just before my front pipes snapped. Once they were fixed it was fine. However when I went up to see dan about the quarter wave tube a few months ago it did it again once. After that haven't had it since but haven't done anything to the car. Only happens after a very long drive to be honest.

[Don Pietro]

Strange error.

The mechanic has disconnected the lambda from the rear bank, and cleaned the throttle valve, now will see how the engine mange it.

The clutch pedal switch isn't a issue said the mechanic. So it's stays connected.

[Don Pietro]

Lambda reconnected, failure is still there.

Changed the flywheel sensor and the camshaft sensor for a used set.

Still not good.

Maybe there is a remap needed.

What .... could be the problem !!!

[silvervalver]

My theory is the loom gets knocked. It is all down near the rear bank. Maybe even just a loose connection in that area?

Mine hasn't done it since it was last looked at so my guess is the mechanic plugged it in properly

[thamaesta]

don pietro,

did you checked the ignition?
maybe you can reset the throttle, disconnect battery ed.

[Don Pietro]

So far i know, the mechanic has checked almost everything.
The throttle reset c.q. battery disconnecting has been done.

I will (let) check asap the wires and connections.

Next they will make a call to the Squadra man, perhaps he knows something more, remap if necessary.

[Don Pietro]

For a week ago, i have disconnected the clutch pedal switch tot test how the engine reacts on it.

The engine failure appears less often. Only sometimes when i for example shift back (directly) from 5th to 2snd, with not to much speed braking from 80 to 30 km/h. Or when i have driven the car in high revs, 5000 and up, and the have to slow down or stop.

When driving and lifting the throttle pedal, you sometimes can hear it burble in the exhaust, like the old times

It seems something like ignition timing failure or idle to low, throttle body ??

[Don Pietro]

Car went today to the workshop. Mechanic has controlled the timing-belt timing, and what did he found ?? Both inlet-cams were off sink, little bit but enough perhaps. Now see how the engine acts with this work. Hopefully no engine failures any more.

[Don Pietro]

These two days the engine is working better, smoother. Let it be good

[bluematt1]

Originally Posted by Don Pietro

These two days the engine is working better, smoother. Let it be good

I cant remember but when clutch pedal is pressed it advances or retards ignition timing cant remember which thats why exhaust note changes

[Don Pietro]

When i have it correct, it retards the ignition. The cam's where a little after instead before the .. point. And when the engine was in idle, pressing the clutch pedal it runs to lean, it occurs the engine failure.

[Don Pietro]

Since the car went to the workshop, there were occurred 2 times an failure, luckily less then previous. The failure is the same as previous, braking for a round about, traffic light or else.

At this time the workshop is closed for holiday, when they are back i will asked to investigate it.

Maybe it needs to be remapped, to set the idle revs a little bit higher. Reset of the throttle body needed ? Can i do it by myself and how ?

Everything is checked, but what could it be ???

[fewleh]

Sorry to hear that -

This might help -- http://www.alfaowner.com/Forum/alfa-...acle-cure.html (ECU Reset - It's A Miracle Cure !!!!)

ecu & throttle reset procedures.. there is some better description a few pages in I think.. must be worth a try

[Don Pietro]

I will give it a try, thanks.