Hesitating and jerking..

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Delivan
Impreza 22B Driver
Posts: 1817
Joined: Tue Apr 29, 2008 12:18 am
Location: Sitting in the kitchen in Brisbane

Hesitating and jerking..

Postby Delivan » Mon Jul 17, 2017 5:57 pm

I have been chasing the jerking/hesitation problem in my wife's bugeye rex for a LOOONG time. I thought I would take out the AFM and see if it was clean or not. When i took it out I noticed that it wasn't sitting in position properly. When it came out I could see that the "0" ring had been squashed out to one side and the "0" ring was broken as a result..

I inspected it and it looked clean so I replaced the "0" ring with a new one and put it back together. This time it was sitting in straight etc.... I took it for a good test drive in different conditions and it seem to have fixed the problem.

This could be just wishful thinking and my imagination as it has been faulty for so long and all our cars are soo much different to drive that I don't dare to think that it may actually finally , be fixed....

Do you think a split "0" ring and a AFM not sitting perfectly in position due to the "0" ring being jammed to one side could cause this problem.. It would have been me who didn't install it properly and other things have also been at fault ..eg the front AFM sensor was also faulty and throwing up codes..An air flow meter possibly leaking air and not sitting straight in position could cause this issue couldn't it ??? I can't believe that it may actually be fixed.

Looking forward to your thoughts on whether this could be the culprit..Have anyone seen this before?????
'09 Impreza Charcoal Hatch Auto
'03 WRX Pearl Red Bug Sedan
'02 WRX Silver Bug Wagon
'98 WRX Blue Club Spec Evo 2 with 2.5 lt
'99 WRX White Sti Version 6 with 2.5 lt
'98 Mitsubishi EVO 5 (kept in the basement)

crembz
Impreza RS Driver
Posts: 179
Joined: Wed Mar 28, 2012 5:58 pm

Re: Hesitating and jerking..

Postby crembz » Mon Jul 17, 2017 6:49 pm

I've seen AFM problems manifest in many different ways. ANYTHING that can affect the air readings can cause jerking and hesitation amongst other things. If the afm isn't installed correctly, sitting on an angle, getting unmetered air, etc, it could certainly skew the air flow readings enough and cause what you've been experiencing.

I chased a stumble on wot in my Forester for 2 years ... Turned out those too good to be true injectors I installed weren't flowing evenly.

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mv75
WRX STi Driver
Posts: 857
Joined: Sat Dec 27, 2014 9:26 pm
Location: Brisbane Northside.

Re: Hesitating and jerking..

Postby mv75 » Mon Jul 17, 2017 6:56 pm

Holy sheet man, there there, it's ok. Settle down.

Of course it can cause the issue, if there is a leak there the airflow would be disrupted and it would be reading temperature wrong too. Plus it needs a straight cross section to read the volume of air passing by, if it wasn't straight, it would be like the maf scaler was off.

My hesitating and jerking was fixed by some new iridium ix plugs. :)

User avatar
Delivan
Impreza 22B Driver
Posts: 1817
Joined: Tue Apr 29, 2008 12:18 am
Location: Sitting in the kitchen in Brisbane

Re: Hesitating and jerking..

Postby Delivan » Tue Jul 18, 2017 4:51 pm

My wife did about 70 ks today and said it is running better than it ever has...I have replaced a few things trying to solve this issue with hesitating and looks like the "O" ring seal on the MAF was the problem all along so now with all its other new goodies all working well together finally it is actually fixed.. Zoom zoom ..Happy wife = happy life...
'09 Impreza Charcoal Hatch Auto
'03 WRX Pearl Red Bug Sedan
'02 WRX Silver Bug Wagon
'98 WRX Blue Club Spec Evo 2 with 2.5 lt
'99 WRX White Sti Version 6 with 2.5 lt
'98 Mitsubishi EVO 5 (kept in the basement)

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