Jump to content
Saabretooth

3.2 V6 Misfire Cyl 1, 2 And 3... And Now 4

Recommended Posts

Hi Smaky,

 

Need to borrow your experience again on this one.

 

I'm getting Misfires from Cylinder 1, 2 and 3. and also a P0130 Error, indicating Lambda.

MAF is was recently replaced to a standard 063(last 3 numbers) Bosch MAF

 

I've swapped the coil packs from rear to front, (12 months old)

Swapped the injectors and changed out the spark plugs

 

Its improved the drive somewhat, but I'm still getting the Misfire and Lambda Errors when I'm on the move.

When I check it again, its would give me a Error Pending, meaning its been clocked in, but no longer occuring.

 

Any idea what could be wrong? its not a constant error, but only when I drive the car and put it under load.

Share this post


Link to post
Share on other sites

It could be the Lambda is faulty and unable to control in a rich condition. Or it could be the Lambda. If I recall this has been remaped and modified, if the airfilter has been swapped then this may have also killed your new MAF.

Share this post


Link to post
Share on other sites

Great Memory!

 

But its a stock airfilter and intake pipe though.

 

Ok will check on the Lambda. but oddly, its the rear banks mostly. and not all 6 cylinders.

 

 

Any chance it could be the rear wiring harness?

Edited by Saabretooth

Share this post


Link to post
Share on other sites

Rear Harness Swapped with another car, MAF also swapped. Car feels better BUT

Error is still there.

P0300, P0301 P0302 P0303

and for

P0130, is it the front or rear Lambda?

Share this post


Link to post
Share on other sites

The code it's reporting is the rear bank upper sensor, check the plug is connected firmly (it's inside the black box on the intake manifold), but I think this could be a cooked Lambda caused by a map that is running too lean, Also check the ECU socket for bent pins, if there are any then VERY carefully try to straighten them.

Share this post


Link to post
Share on other sites

Troubleshooting...

 

1. Lambda swapped out, original one is not too lean, but its blackened as the engine is running a bit rich.

2. ECU opened, checked and placed back.

3. Wiring inside the black box checked, and pressed to make sure all the connections are tight.

 

Still the same errors popping out.

 

 

Will resetting the ECU via unplugging the battery for 45 mins help? I don't think it will ...but I've done just about everything.

 

Cylinder 4 is not misfiring at all, it was just a 1 off episode.

 

 

I notice it comes on sometimes when I accelerate and slightly throttle off to modulate my speed. Other times, midway through holding the throttle position. and only after moving, and I stop at the traffic, it might just pop up.

 

 

It is not a permanent error, but its logged as Pending.

Share this post


Link to post
Share on other sites

Check the continuity of the earth side of the injectors on 1,2 and 3, then check the fuel rail for kinks or splis in the fuel line between the front and rear banks.

 

Share this post


Link to post
Share on other sites

I actually swapped out the rear bank wiring harness, and the issue still persists.

 

are you suggesting that I look further than that?

 

I was heading towards a compression test next actually,

 

 

 

 

Sent from my iPad using Tapatalk

Share this post


Link to post
Share on other sites

1. No Problem with the Fuel Rail/pipes, no leaks.

 

2. Can't see anything with earth wiring for the injectors.

 

Could it be a failing fuel pump? although I would think it might affect all 6 cylinders, unless the pressure isn't holding up.

Share this post


Link to post
Share on other sites

I'm thinking it's possibly the MAF sensor and it's trimming the fuel too much, or that the remap is to blame, but you need to have the codes read or we are just guessing and if there are no codes then MAF is the usual suspect (even if it's new) or an air leak, the fuel pump is an option and the pressure can be tested but usually if the pump is failing then power is lost top end as the fuel isn't available.

Share this post


Link to post
Share on other sites

Thanks, will relook at it again,

 

The 3rd MAF sensor was borrowed from a working GTA which has no issues. I could swap again to another MAF just to test although I would think its unlikely MAF since the one that's swapped in now is a working one, and the one that I had is swapped to the GTA, is also working fine.

 

 

The remap has been fairly good for the past year or so, which is odd that it pops up now. I would think it unlikely that the map could change characteristics over the course of 18months or so....

 

 

 

Also, where do you suspect the Air leak to be from? between the MAF to the intake manifold pipes?

 

The errors come up at 2 points, its always logged in as Pending Error, as its not a continuous fault.

 

Between 2100 - 2700 rpm, and sometimes just under 3000 rpm, when I'm gently throttling to accelerate up through the gears..

 

 

Or when I'm at idle waiting at the traffic lights..... the min I hear the idle change note, the Error comes up within seconds of detecting it.

 

 

-Alfastumped!

Share this post


Link to post
Share on other sites

I'd expect an air leak to be at the corrugated section of pipe just before the throttle body if it was affecting this many cylinders.

 

Now you mention this is happening at the lights I'm beginning to think this could be tied in to another electrical system, So if possible can you check the codes on the ABS ECU, I think you may find the clutch or brake pedal sensor playing up.

Share this post


Link to post
Share on other sites

Ok did a check. No air leak at the pipe.

 

Will try to get this on a proper alfa diagnosis asap.

 

I did notice that if I drove the car a little harder. Throttle pedal a bid more than normal, the errors were less frequent.

 

 

Share this post


Link to post
Share on other sites

While waiting for a time slot and available lambda sensor to arrive,

I disconnected the bank 1 pre cat lambda.

Immediately misfires were greatly reduced and my drive was so much better without hesitation in the 2000 to 3000 rpm range.

 

Although the error code would be failed lambda ... car runs much better.

Although there are still some episodes of misfire.

 

 

Share this post


Link to post
Share on other sites

Hi Smaky,

 

I swapped out the rear bank top lambda, and the misfires from 2000-3000 rpm are gone.

Car runs fine.

Solved 1 problem.

 

But at the traffic lights, I still get the P0300, P0301, P 0302, P0303 Rear bank misfire error. Although a lot less frequently.

 

Am going to check on the Coil grounding again tomorrow to see if there's anything loose.

 

And maybe the brake switch as well, although I can't understand why it would only affect the rear bank.

Share this post


Link to post
Share on other sites

5f463b9a99273c848ecd35c1e820fb17.jpg

 

The rear bank lambda was replaced but seemed that the reading is slower than the front bank.

Car runs well though.

 

 

Share this post


Link to post
Share on other sites

Yeap, Codes Cleared.

 

Ran well, then misfire error came up again AT IDLe. on the move ZERO issues.

 

Swapped to another lambda, and P0141, heater element not working came up, but the voltages were stable at 0.035-55 front and rear bank, although rear bank (1,2,3) fluctuates more.

Share this post


Link to post
Share on other sites

They've messed that remap right up, though the Lambda you've swapped may be faulty the readings are wrong, all lambdas at idle should be closed loop.

Share this post


Link to post
Share on other sites

I'd also advise you have a compression test done to ensure the rings, valves and liners aren't damaged/worn by the extra heat caused by these misfires.

Share this post


Link to post
Share on other sites

Good news and bad news.

 

1. after changing out the lambda (AGAIN) both the signals are relatively equal, when its on throttle (not idling)

- but when on idle, it is slightly slower in bank 1,

2. Did a compression test, and cylinder 2 is showing slightly lower compression.

and there is no white smoke, car is running fine, power is good. ruling out the piston and piston rings. which then narrows it down to possibly a valve or two.

 

Going to take the simplest route first before opening up the engine

It could be a very dirty valve (not sure if its inlet or exhaust) and will be doing a valve cleaning thing first.

 

- if that doesn't work, then I'll have to open it up to find out if any of the valves are damaged.

And then replace the valves, if any.

Edited by Saabretooth

Share this post


Link to post
Share on other sites

For some strange reason..... We re-did the compression test before having to open up the engine and we got about 250kpa across all 6 cylinders.

 

Share this post


Link to post
Share on other sites

May I suggest you check the Brake Vacuum hose, is right at the back coming off the intake plenum. They fracture very easily right where it connects to the plenum. Had the exact same symptoms from a clients Brera 3.2 V6 and re-attaching the broken brake pipe solved the issue.

 

Baz

Share this post


Link to post
Share on other sites

I think he's jumped the gun and split the engine already, the trouble is that diagnosis from across the globe is only as good as the feedback to the questions, to this end just because it can be one thing doesn't always mean it is and other things should always be investigated before diving into the big fix, because when you've rebuilt everything you may inadvertently repair the issue which could be as minor as a loose clip or split hose and not even realise.

 

An as Baz suggest an what I was pointing to at the start, it may be unmetered air entering, this will lean out the engine and cause the lambda readings you've had all the way through.

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...

×
×
  • Create New...