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Registered:
February 2003
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4AGTE jolting/surging problem
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Tue, 10 May 2005 23:52
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Here goes it:
series 2 AFM 4AGZE with T28 ball bearing on stock computer
stock injectors
VL pump
Did the conversion about 6 weeks ago, drove it around for a few weeks - ran sweet, came on boost hard and didn't have any real problems
Until of late, there have been a few instances where it becomes a dog to drive:
- On the way to the gf's, after 20mins, it began to jolt and surge as if my clutch was not gripping (my initial reaction was clutch, because it kept on jolting back and forth everytime i planted it) so i managed to roll it to her house and park there. After 4-5 hours, i took it home, went fine?! 
- Few days after, i took it to the beach (about 1 hour drive) and on the way back it began to do it again, severely jolting, i could only rev the christ out of it and drop the clutch to have it running smoothly, managed to clutch it home and roll.
- Same thing the following weekend - to the city, went fine but on the way back on the freeway, major problems
So the other day, i called my mechanic over to check it out. We set timing back to 10 degrees, adjusted AFM screw, idle screw and adjusted the TPS and re-wired the wires that go to the AFM (previous connections were dodgy). Took it for a drive many times - ALL SWEET!! 
....UNTIL the next mornig i tried to take it out - but it happened AGAIN - this time on COLD START, went around the block and could hardly get it home.  
So judging from the latest scenario, i'm gathering it to be an electrical issue, and maybe a fuel problem, but not sure of which to conclude - maybe injector?
symptoms:
1. When it happens, worst is taking off, and if im cruising in 4th on the freeway it begins to jolt - if i drop back to 3rd, it sorta 'opens up' and runs fine- UNTIL i lift off - on boost is fine
2. There is VERY little throttle reaction, when i step on it at idle, it is full delayed and wants to stall.
3. Seems to only happen after a long drive - but the lastest instance was on cold start so it is getting worse.
WTF is it ?!?!?
*frustrated*
ps. i know, i need a new computer, but i've heard many setups with the stock comp that run fine
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Location:
Central Coast, NSW
Registered:
May 2002
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Re: 4AGTE jolting/surging problem
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Wed, 11 May 2005 00:09
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My car had exactly the same symptoms as yours two weeks ago... one of the pipes going from the turbo to the intercooler had a crack in it. Car was jolting around at low revvs when the accelerator was pressed and it had a funny idle. It sounds like a simple issue but it was incredibly hard to see and diagnose the problem
Hope this helps!
Dan
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Registered:
February 2003
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Re: 4AGTE jolting/surging problem
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Wed, 11 May 2005 00:48
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thanks dude
The cooler piping seems to be all fine - no cracks or leaks, all tightly clamped.
I've had a little hole in the intercooler before but it didn't have this sorta problem, just didn't come on boost properly when it was supercharged.
so yeah, anyone ?!
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Location:
Central Coast, NSW
Registered:
May 2002
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Re: 4AGTE jolting/surging problem
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Wed, 11 May 2005 01:03
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Does your check engine light come on?? Mine did and thats how the problem was isolated
Dan
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Registered:
February 2003
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Re: 4AGTE jolting/surging problem
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Wed, 11 May 2005 01:14
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yes, the check engine light has been coming on more than usual of late - particularly when the idle is hunting and i'm revving it up to get it smooth
hmmm so the light would be sensing vacuum leaks?
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Location:
Central Coast, NSW
Registered:
May 2002
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Re: 4AGTE jolting/surging problem
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Wed, 11 May 2005 01:51
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Sure would be. If the check engine light is coming on it means that its stored a code. Find out how to run the diagnostic on your engine and find the code. Reference the code to the manual and it should be easier to find your answer.
Mine was hunting at idle, and was very jolty under acceleration too... all because of a cracked hose. I stronly suggest re-checking all of your vacuum and turbo lines
Dan
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I supported Toymods
Location:
Australia
Registered:
November 2003
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Re: 4AGTE jolting/surging problem
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Wed, 11 May 2005 02:46
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Doesn't sound fuel related to me.
Air is a very high chance.
Just last night we found out that an injector wasnt in fully, and was leaking air past it.
Idle was hunting from stall to 2000rpm and down to 400, and back up to 2000.
If you can get the problem to occur at idle, get a hose, put one end in your ear, and the other end go around everywhere, listening for leaks.
You'll need to make sure the fan isn't running in order to do this properly.
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Registered:
February 2003
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Re: 4AGTE jolting/surging problem
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Wed, 11 May 2005 02:50
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good idea mate
will give it a shot
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I supported Toymods
Location:
melbourne
Registered:
June 2002
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Re: 4AGTE jolting/surging problem
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Wed, 11 May 2005 02:54
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i had a problem kinda like this,
long story short, check your TPS connector.
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Registered:
February 2003
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Re: 4AGTE jolting/surging problem
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Wed, 11 May 2005 03:03
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yeah could be this actually
i chopped mine up to fit a different part number (i think it could be same as ur prob)
i'll get the duct tape out!
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Location:
On your mum!
Registered:
May 2002
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Re: 4AGTE jolting/surging problem
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Wed, 11 May 2005 03:06
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Is this engine map sensed? it sounds like it may be a problem there, OR could be CAS related (weak signal maybe)
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Registered:
February 2003
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Re: 4AGTE jolting/surging problem
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Wed, 11 May 2005 03:11
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AFM
not Map
weak signal CAS? caused by?
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Location:
On your mum!
Registered:
May 2002
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Re: 4AGTE jolting/surging problem
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Wed, 11 May 2005 03:21
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I have had (with my car) too large an air gap between the trigger disc and CAS - resulting in many error codes and bullshit like 10500RPM showing up on the data recall. I doubt that is your prob though (being 4A with factory CAS).
One other time that I had a similar prob was the reluctor in the distributor had been wet and was RS - changing the distributor fixed it (electronic Toyota dist).
I think that your problem is with the spark delivery because if it were a vacuum leak (other than a MAP) then it would sense no such problem with your foot flat (IE zero vacuum condition followed shortly by boost). Does the tach jump or do anything crazy?
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Registered:
February 2003
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Re: 4AGTE jolting/surging problem
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Wed, 11 May 2005 04:05
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PROBLEM FOUND
| YelloRolla wrote on Wed, 11 May 2005 13:21 |
I think that your problem is with the spark delivery because if it were a vacuum leak (other than a MAP) then it would sense no such problem with your foot flat (IE zero vacuum condition followed shortly by boost). Does the tach jump or do anything crazy?
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spot on my friend
it was spark/ignition delivery - loose earth connection of the ignitor onto the firewall!
was checkin the lines for leaks etc, all wires and TPS connections -everything was fine until i touched the BOV vaccuum line, the engine began to idle smoothly, so i attached the bastard thinking that it was something to do with this, but on further inspection, the vaccuum line was touching the ignitor pack which bolts onto the firewall. The engine must have been vibrating the bolt loose - this explains why on a long drive it began to happen cuz it must have shaken loose in a particular gear (4th) and on idle.
out came Mr 10mm and tighten the mofo, went for drive and i'm all smiles 
boooooooost baby
thanks fellas, always a great help
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Location:
Central Coast, NSW
Registered:
May 2002
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Re: 4AGTE jolting/surging problem
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Wed, 11 May 2005 04:08
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Great to hear! Well done
Dan
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