Miss under load problem

kcej · 10-06-2010, 01:31 PM

My AU3wagon developed a miss under load.

The exhaust was drooping and a bit loud due to broken rubber "hanger" and I jacked the tailpipe up so that I could fit a new rubber hanger at the cat. At the same time I degreased the engine and since then it misses under load.

It idles fine, revs out smoothly in Park or Neutral if accelerator is pushed in slowly, but push it in fast and it coughs. While driving, it does the same, always coughing and missing under load.

I still haven't resealed the leaky exhaust yet, but the noise is tolerable. Don't really want to spend a million dollars replacing all the electrics if its possible that its related to the exhaust leak.

Any help much appreciated

Mr Hardware · 10-06-2010, 02:02 PM

Exhaust leaks don't make your car miss
the problem you have will be a fuel or spark issue - i'm putting my money on spark. How old are your leads and plugs? Is a lead full of degreaser? Did you degrease your coilpack by mistake?

Jimmyd · 10-06-2010, 02:30 PM

Quote:

Originally Posted by Mr Hardware

Exhaust leaks don't make your car miss
the problem you have will be a fuel or spark issue - i'm putting my money on spark. How old are your leads and plugs? Is a lead full of degreaser? Did you degrease your coilpack by mistake?

x2 - most likely leads with a miss under load

also possible to get water in injector plug/s if over exuberant with hose pressure...

kcej · 10-06-2010, 07:59 PM

Quote:

Originally Posted by Mr Hardware

Did you degrease your coilpack by mistake?

Is that not a good idea???

mik · 10-06-2010, 08:35 PM

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what does this mean?

mik · 10-06-2010, 08:37 PM

if it was`nt doing this before you washed the motor ,my first stop would be pulling the spark plug leads off one at a time and either spraying them with moisture displacer or wiping them clean and dry with rag and see how it goes, if its still doing it i would do the coil pack, knowing what a **** of a place the coil pack is in i`d probably try drowning it with crc/wd40 and give it another try rather than trying to pull the leads off.

mik · 10-06-2010, 08:39 PM

post 5 i tried to preview my post and that error came up mr moderator.

AUIIPURSUIT · 10-06-2010, 10:28 PM

mine was missing under load.

replaced the spark plugs (they were shagged) and fuel filter.

it will either be :

crappy fuel
fuel filter
spark plugs
leads
coilpack.

or possibly o2 sensor.

most likely, hit up leads/plugs first.

kcej · 11-06-2010, 12:14 PM

THANKS GUYS ............Problem solved

All replies appreciated

I replaced the coilpack with the one out of my Ute, and in doing so found there was still oily residue on the bottom of the leads and over the coilpack. I think the "old" coilpack is still good, and it was just the dirty residue, but will confirm or deny this when I clean it up and test it in the ute.

Thanks again, Keith

.

Mr Hardware · 11-06-2010, 12:20 PM

cool man

Spazzz · 26-10-2010, 08:35 PM

Hi ,

I seem to have the same issue. I have just changed plugs, leads and coil pack. Havent done a fue filter for about 50000ks. Its a AU series 2 Fairmont 2000 model with 195K on the clock. Its good at idle, on cruise but when you snap the throttle from a stand still or even when idling , it has a splutter and hesitation, then revs cleanly and pulls normally.

Could it be the O2 Sensor??

All help appreciated.

Thanks

Spazzz

robbyj · 26-10-2010, 08:58 PM

Quote:

Originally Posted by Spazzz

Hi ,

I seem to have the same issue. I have just changed plugs, leads and coil pack. Havent done a fue filter for about 50000ks. Its a AU series 2 Fairmont 2000 model with 195K on the clock. Its good at idle, on cruise but when you snap the throttle from a stand still or even when idling , it has a splutter and hesitation, then revs cleanly and pulls normally.

Could it be the O2 Sensor??

All help appreciated.

Thanks

Spazzz

I had the same thing, turns out it was my leads, but id try the other suggestions made above.

Spazzz · 26-10-2010, 09:10 PM

Yeah only other thing is to try the o2 sensor or the fuel filter.

Done leads, plugs and coil pack this evening, no joy.

Mr_Monty · 26-10-2010, 09:53 PM

Im guessing its and AU 6, they have sequesntial injection timing.... i know that squential plays up just like this when the syncroniser is disconnected, im quite sure the au's had a sensor of sorts to tell where its at.

try pulling the codes (you can get a scanner hand tool cheap as **** from ebay or even some good electronic shops)

im sure if you dont have a book for you car you can post it up here and someone can tell you what fault it relates too.

just thinking outside the box if all the above suggestions dont help.

Spazzz · 27-10-2010, 08:35 AM

Yep, its a AU series 2 6 cyl.

Was hoping for a solution without buying more diagnostic equipment. Its a pain in my A2se.

Thanks for the help.

Spazzz

Swedishmoose · 30-10-2010, 02:59 PM

Hey...

it sounds pretty much like plug and/or leads...

I had the same issue and after changing plugs and leads it runs smooth as new.

The Moose

Swedishmoose · 30-10-2010, 03:03 PM

Quote:

Originally Posted by Mr_Monty

Im guessing its and AU 6, they have sequesntial injection timing.... i know that squential plays up just like this when the syncroniser is disconnected, im quite sure the au's had a sensor of sorts to tell where its at.

try pulling the codes (you can get a scanner hand tool cheap as **** from ebay or even some good electronic shops)

im sure if you dont have a book for you car you can post it up here and someone can tell you what fault it relates too.

just thinking outside the box if all the above suggestions dont help.

Hi there....

can you tell me what code reader is suitable for the AU as it has no OBD-II coding ?

I spent hours online and all I could find were some suspicious dealer.
I found out that some code reader can only do the engine but not the auto tranny and so on...

Could ya please tell me what code reader is best for the AU and can in fact read everything ?

Didn't wanna change subject here.....but feedback is appreciated...

Thanks

cheers

The Moose

SIKSIX · 30-10-2010, 08:02 PM

i had simular problems, done coil packs, leads, plugs, filters, fuel reg. nothing same same. then i cleaned my map/maf and all is well. the easiest way to clean it i found was to remove my throttle body and spray CRC contact cleaner on it from the opening.

Swedishmoose · 02-11-2010, 05:57 PM

Hi SIKSIX...

I might try that as well because I"ve noticed that my Falcon doesn't idle that smoothly...it chakes a bit and the rpm is going up and down...not much but you can slightly notice it. If i turn aircon on the engine runs smoother than without.

By the way...where can I find that EGR valve ? I wanna clean that as well...

Cheers

The Moose