Sluggish and misfire

[helmsy]

Ok had a CAI fitted about a week ago to the 175 Alloytech and it was going better than ever.

Had an exhaust system fitted today:
Pacemakers and full Stainless system with twin tips.

Now it seems sluggish on takeoff (hesitating) and then cuts out at 5000rpm (misfire?) under hard acceleration.

Will the ECU automatically adjust the timing, etc. (how long before the ECU adjusts itself) or will this last until a custom tune is available??

As always any help is greatly appreciated.

[Not_An_Abba_Fan]

You can reset the ECU back to default by taking the engine fuse out for 30 seconds. Then drive it around for about 1/2 an hour. It should get better.

[helmsy]

Thanks for the tip.

I took out the engine fuse (big yellow 60 amp fuse?) for about five minutes then took it for a drive for about an hour.

It still goes like **** (excuse the french) on takeoff, not too bad above about 3000rpm then cuts out at 5000rpm. I also noticed on cruse at 60kph and 80kph (on highway) it is slightly erratic trying to hold the speed.

It is like it is way too rich or timing is out? Did i pull the wrong fuse?

[Willz]

Bit of a head scratcher

plugs maybe?

cant be a loose lead cause they coil on plug so.....

only thing i could think of is that by fitting headers they may have played with the oxy sensors maybe....

you getting any warning lights on the dash and have u checked to see if you have any error codes coming up?

[helmsy]

Thanks Willz.

No warning lights so far, how do I check for error codes tho? Isn't it a Holden job?

I can bet Holden won't replace the o2 sensor under warranty.

It's using about 5L/100kms extra fuel too!!

Only thing i can think of is to take it back to the exhaust shop and get them to look at it or into a dealer and they can have a look ($$$$$).

[naf33n]

warm up your car. to normal operating temp. disconnect the battery for 15 mins. then when you connect it back up take it for a "spirited drive" straight away. and problem should be gone. it worked when my old sv6 had a flat spot at 5000rpm.

[helmsy]

Thanks again guys.

Started it up this morning to do what naf33n suggested and guess what "Check Powertrain" comes up.

Can't get it in to Holden till Wednesday so i'll keep u posted.

P.S. Is it possible that when u have new headers installed that the o2 sensors just need resetting (in the ecu) rather than replacing?

[Not_An_Abba_Fan]

That light has come up because the change in you exhaust has changed the torque, thus altering you transmission shift points. Holden will tell you stiff s*** because of the non gen exhaust and that this is the problem. Sometimes you need to get a tune to make everything run in harmony.

[helmsy]

OK thanks NAAF this makes perfect sense.

OK so I rang my mate and he said that Holden can remap/tune for the auto?

Does anyone know a VCM tuner in Adelaide yet? I am told at least two weeks by my guy and that is too long to be running the way it is. BTW i reached 20.3L/100km is that a record?

Will take it into Holden Wednesday and see what they say. Any idea how much it would cost?

[dan-0]

I have an MCAI, pacemakers, 2.5 exhaust etc etc, My cars shift points and fuel consumption were all over the shop for a while, but not as bad as yours.
I have put about 1000kms on it since and its going good now. About 9.5l/100km (not flogged) about 10-12l/100km (flogged).

Dont forget that putting extracies/zorst on takes low end power but increases mid range power.

[helmsy]

Ok turned out to be a disconnected knock sensor. Damn exhaust guys must have left it disconnected.

Reconnected and restarted ECU and its going better than ever. Still a little rough at idle for about 1-2 secs but hardly noticeable.

Takes off a lot quicker and sounds a lot better. They should come from the factory this way. Tisk tisk