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I supported Toymods
Location:
Frankston, Victoria
Registered:
April 2004
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Why the hell is my 4ag doing this?!!?
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Wed, 16 November 2005 11:14
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Ok, after a month and a half of this shit, I'm at a complete loss.
I finished my 4AGE conversion a month and a half ago. When I first started it, the timing was out and the thing didn't wanna rev. After a whole lot of fkn around, changed leads, plugs, new coil, playing with dizzy, playing with TPS, and everything else, I'm totally at the point of giving up...
In 3 days this thing has to drive 147km to Melbourne (I'm moving house) and then that night travel around 450-500km's on a night cruise I'm organizing...
The problem:
Basically, It idles perfect, Like I'm talking the thing purrs and sounds just like a 4AGE should. The second you so much as touch the throttle, the thing drops in revs, backfires like a bitch and basically just doesn't want to live anymore. But if you hold the throttle for a second and then let go, it revs! What I'm saying is that while the throttle is held, it gets sick, backfires, goes wacky, but as soon as you let go of the throttle, it revs for a second, then goes back to idle RPM...
What's wrong?! Please Toymodders! I really need this thing fixed...
Kev.
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Location:
Kita-Ku, Sapporo, Japan
Registered:
January 2003
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Re: Why the hell is my 4ag doing this?!!?
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Wed, 16 November 2005 11:22
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is it rich or lean cut?
all i can suggest is to quadruple check the cam timing... not by timing marks, i mean by physically checking what angles the valves are opening/closing..
then.. physically check the timing with timing light. if you set it as per manual, make sure you briudge the whatsit to short timing to 10deg (or whatever it is)
then physically check fuel pressure. swap your fuel pressure reg with someone else...
that it revs when you let go, seems to indicate that there is not enough fuel, so when you decrease the amount of air, the AFR is better, and it wants to rev....
basically, check everything step by step according to your 4AGE engine manual...
and if you don't have one, download it.
be methodical and rule things out one by one.. but don't be too quick to rule anything out.
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Location:
Kita-Ku, Sapporo, Japan
Registered:
January 2003
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Re: Why the hell is my 4ag doing this?!!?
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Wed, 16 November 2005 11:24
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got air leaks to AFM/MAP wrong sensors/ECU included with package?? check everything again with known working vehicles...
and then check your wiring.. like is the CAS/TPS wired up the correct way (so you are not going into decel fuel cut when you touch throttle?)
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Location:
Adelaide
Registered:
May 2003
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Re: Why the hell is my 4ag doing this?!!?
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Wed, 16 November 2005 11:35
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ok. i think MAYBE i know what might be going on. we get this sometimes on commodores at work.
fuel pressure problems.....could have something to do with the fuel pressure regulator on the fuel rail. if it is staying open then there will be no pressure and that can cause the symptoms you are describing.
also if the fuel pump is rooted and not supplying pressure that could cause it.
when you did the conversion, did you make a return line from the fuel rail to the tank?
if so, clamp this off, so that the engine gets full pressure all the time and rev the engine...... if the performance improves then the pressure regulator is at fault. if not, then the reg is fine. and its something else.....
are you able to get another ECU to swap to see if its an ECU fault?
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I supported Toymods
Location:
Frankston, Victoria
Registered:
April 2004
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Re: Why the hell is my 4ag doing this?!!?
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Wed, 16 November 2005 11:50
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Hmm I'll give the "clamping return line" a shot, I have a spare pressure regulator too, so if that is the problem I can do a straight swap.
The ECU was tested before I bought it, and bought from a good friend, so he wouldn't jib me.
The ECU is an ADM 86kW Bigport ecu. My engine is a JDM 96kW Bigport. TPS is 96kW. MAP is 86kW. Dizzy is 86kW (I have both and have tried both).
Eh.
Kev.
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Location:
Kita-Ku, Sapporo, Japan
Registered:
January 2003
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Re: Why the hell is my 4ag doing this?!!?
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Wed, 16 November 2005 11:52
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| Phrostbyte wrote on Wed, 16 November 2005 22:50 |
Hmm I'll give the "clamping return line" a shot, I have a spare pressure regulator too, so if that is the problem I can do a straight swap.
The ECU was tested before I bought it, and bought from a good friend, so he wouldn't jib me.
The ECU is an ADM 86kW Bigport ecu. My engine is a JDM 96kW Bigport. TPS is 96kW. MAP is 86kW. Dizzy is 86kW (I have both and have tried both).
Eh.
Kev.
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are both 86 and 96kw TPS the same?? ie both switch, or both variable??
mates or not, sometimes shit happens that is beyond our control..
check the VOLTAGES of the inputs to the ECU.
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Location:
ippy
Registered:
October 2005
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Re: Why the hell is my 4ag doing this?!!?
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Wed, 16 November 2005 12:19
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if u have a timing light, hook it up and see if the timing mark advances as you rev the engine....depends on how the advance is achieved, the wieghts in my old dizzy used to stick and cause similar syptoms..
cheers les
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I supported Toymods
Location:
melbourne
Registered:
June 2002
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Re: Why the hell is my 4ag doing this?!!?
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Wed, 16 November 2005 12:26
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unplug the TPS, see it it stil ldoes it,
clamp the vacuum line, see if it still does it.
is the ignition timing right?
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I supported Toymods
Location:
Frankston, Victoria
Registered:
April 2004
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Re: Why the hell is my 4ag doing this?!!?
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Wed, 16 November 2005 12:28
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It actually seems to retard when it you hold down the throttle, I take it that's due to the revs dropping... It then advances when you let go of the throttle and it revs though...
Oldcorolla's you said before to check the cam timing yet again, I took the cam covers off yesterday, they all close the appropriate valves at TDC, so it is perfect, and keep in mind that my engine purrs perfectly at idle...
Voltages... I will be hooking up a new relay tomorrow morning. Currently I have 1 single wire powering my: ECU, injectors, coil, and acting as a trigger for another relay... Could definately be a source of the problem.
I'm actually quite confident that it is the fuel pressure regulator on the fuel rail now that it's been brought up... I'll be trying that out first thing tomorrow morning. Also I have another TPS coming in on friday night... Saturday afternoon I leave.. So hopefully it will all work out...
Please anyone else that has ideas, post them, I want to rule out every possibility. As a guiding note also, This engine was completely rebuilt 10,000kms ago, everything acid dipped and cleaned, all seals replaced, all gaskets replaced. Compression test was done yesterday and came up with amazing figures (Almost that of a brand new 4AGE), so compression is fine.
Thanks,
Kev.
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I supported Toymods
Location:
Frankston, Victoria
Registered:
April 2004
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Re: Why the hell is my 4ag doing this?!!?
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Wed, 16 November 2005 12:34
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Ignition timing is right.
If I unplug the TPS it seems to raise in revs a tiny bit, but does the same thing when i push the throttle.
I've tried taking off the vacuum line to the MAP sensor and the engine just about stalls, so I'm thinking that that's working perfectly.
Kev.
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Location:
Toronto, Downtown
Registered:
September 2004
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Re: Why the hell is my 4ag doing this?!!?
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Wed, 16 November 2005 12:37
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incorrect spark plugs/gaps.... ignition leads???
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Location:
Kita-Ku, Sapporo, Japan
Registered:
January 2003
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Re: Why the hell is my 4ag doing this?!!?
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Wed, 16 November 2005 12:39
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for voltages, i mean, check that you have the right voltage coming from various sensors etc...
is the TPS variable or switch type? which is it meant to be?
ahh yeah, you might wanna put injectors/coil on seperate power.. in fact, you should have a single dedicated power for just the ECU itself and nothing else.. coil and injectors can be electrically noisy (esp coil ring  )
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I supported Toymods
Location:
Frankston, Victoria
Registered:
April 2004
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Re: Why the hell is my 4ag doing this?!!?
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Wed, 16 November 2005 12:48
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Can anyone enlighten me on which type of TPS is on a JDM 96kW Bigport and which TPS should be on a 86kW Bigport?
And yeah I probably will run 2 relays then.
Kev.
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Location:
Menai area of Sydney
Registered:
June 2003
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Re: Why the hell is my 4ag doing this?!!?
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Wed, 16 November 2005 12:58
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Had a similar problem some time ago on a bigport. Pulled nicely along the flat in 1st gear at idle but as soon as you touched the throttle it died. Rev'd out no trouble in neutral but wouldn't take any load at all. Check the earths around the ECU - couple of mine were loose - fixed my problem. Try jiggling the ECU or the leads that go to the ECU and see if you can get it to work properly.
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Location:
ippy
Registered:
October 2005
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Re: Why the hell is my 4ag doing this?!!?
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Wed, 16 November 2005 12:58
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remember once ..when to a mates place his car would idle and not rev up...the prob was he got the firing order right when he replaced the leads...how ever the dizzy turned in the opposite direction than what he thought...cheers les
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I supported Toymods
Location:
sydney.au
Registered:
August 2002
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Re: Why the hell is my 4ag doing this?!!?
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Wed, 16 November 2005 13:15
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| oldcorollas wrote on Wed, 16 November 2005 22:52 |
are both 86 and 96kw TPS the same?? ie both switch, or both variable??
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The part number is identical.
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Location:
The realist ghetto area P...
Registered:
April 2005
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Re: Why the hell is my 4ag doing this?!!?
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Wed, 16 November 2005 13:19
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hay phrostbyte im 120% sure the ecu is working, but if you need anything else let me know
cheers
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Location:
Kita-Ku, Sapporo, Japan
Registered:
January 2003
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Re: Why the hell is my 4ag doing this?!!?
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Wed, 16 November 2005 13:40
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| Scorpion wrote on Wed, 16 November 2005 23:58 |
Had a similar problem some time ago on a bigport. Pulled nicely along the flat in 1st gear at idle but as soon as you touched the throttle it died. Rev'd out no trouble in neutral but wouldn't take any load at all. Check the earths around the ECU - couple of mine were loose - fixed my problem. Try jiggling the ECU or the leads that go to the ECU and see if you can get it to work properly.
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ya know, that sounds like the exact symptoms of a blocked main jet in a carby car
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I supported Toymods
Location:
Frankston, Victoria
Registered:
April 2004
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Re: Why the hell is my 4ag doing this?!!?
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Wed, 16 November 2005 21:16
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| Scorpion wrote on Wed, 16 November 2005 23:58 |
Had a similar problem some time ago on a bigport. Pulled nicely along the flat in 1st gear at idle but as soon as you touched the throttle it died. Rev'd out no trouble in neutral but wouldn't take any load at all. Check the earths around the ECU - couple of mine were loose - fixed my problem. Try jiggling the ECU or the leads that go to the ECU and see if you can get it to work properly.
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I haven't tried the engine under load yet... can't get it to rev in neutral, no chance of getting it to rev in gear...
| leso wrote on Wed, 16 November 2005 23:58 |
remember once ..when to a mates place his car would idle and not rev up...the prob was he got the firing order right when he replaced the leads...how ever the dizzy turned in the opposite direction than what he thought...cheers les
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Leads are in correct firing order, numbers are written on the cap. If they werent the thing wouldn't "purr" in idle...
Keep the options coming
Cheers,
Kev.
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Location:
Melbourne - NthSubs
Registered:
January 2004
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Re: Why the hell is my 4ag doing this?!!?
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Wed, 16 November 2005 23:41
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make sure ur fuel filter is on the right way 
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Location:
Canberra
Registered:
September 2005
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Re: Why the hell is my 4ag doing this?!!?
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Thu, 17 November 2005 00:16
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Find out from expirienced person if Aus spec ecu it interchangeable
with the jdm bigport!
if your engine is retarding itself when you go to accelerate?,
i have a feeling your ecu is trying to protect something?
Look in to it perhaps 
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Location:
Canberra
Registered:
September 2005
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Re: Why the hell is my 4ag doing this?!!?
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Thu, 17 November 2005 00:23
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| oldcorollas wrote on Wed, 16 November 2005 22:22 |
make sure you briudge the whatsit to short timing to 10deg (or whatever it is)
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What's this shit? 
Please dont post like this in tech section in future! 
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Location:
Perth
Registered:
January 2005
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Re: Why the hell is my 4ag doing this?!!?
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Thu, 17 November 2005 00:45
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Hi,
After building and tuning my own ECU I have experienced this kind of thing several times.
It was usually due to lean mix on opening the throttle, like the carby guy said. Whether due to a bad ground, (or initial guess tuning in my case)or whatever.
Check your TPS. Usually they have a switch to tell the ECU the throttle is closed (i.e. 'idle mode' or not) and a potentiometer used to detected rate of throttle movement for enrichment/enleanement.
If these aren't working the ECU's fuelling stratgies wont function the way you expect. (i.e. properly)
Cheers, Nick.
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Location:
Melbourne - NthSubs
Registered:
January 2004
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Re: Why the hell is my 4ag doing this?!!?
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Thu, 17 November 2005 06:36
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| beige_bandit wrote on Thu, 17 November 2005 11:23 |
| oldcorollas wrote on Wed, 16 November 2005 22:22 |
make sure you briudge the whatsit to short timing to 10deg (or whatever it is)
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What's this shit?
Please dont post like this in tech section in future!
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i got something like this from toyospares
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I supported Toymods
Location:
melbourne
Registered:
June 2002
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Re: Why the hell is my 4ag doing this?!!?
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Thu, 17 November 2005 07:43
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is it running the cold start injector?
unplug it and see if it will run, worth a try.
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I supported Toymods
Location:
Frankston, Victoria
Registered:
April 2004
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Re: Why the hell is my 4ag doing this?!!?
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Thu, 17 November 2005 08:27
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Bit of progress today. I changed over the fuel pressure regulator... and it revs better now!
BUT, it will only accept a certain amount of throttle before it suddenly starts backfiring like crazy... I'm definately thinking it's the TPS now, and one is on it's way down to me tomorrow night.
I actually finally got to drive the thing! (Only up to 2500RPM or so, because i couldn't push the accelerator any further or I'd get backfires and it would just die in the ass). All those myths about the 4AGE being a bit of a dissapointment are completely untrue, even only 2500RPM in each gear was amazing. Even at that low a throttle amount, it was still accelerating faster than a 4K-C!
Kev.
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Location:
Perth
Registered:
January 2005
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Re: Why the hell is my 4ag doing this?!!?
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Thu, 17 November 2005 10:33
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Hi,
Not revving very well past a certain RPM, and backfiring as you say like mad can also be that your ignition timing is too retarded (like say by 10 or 20 or more degrees). But you say you've checked it?
With retarded timing the car is general quite noisey too at idle - big pulsey/puffy exhaust note, sounds mean though.
Cheers, Nick.
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I supported Toymods
Location:
Frankston, Victoria
Registered:
April 2004
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Re: Why the hell is my 4ag doing this?!!?
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Fri, 18 November 2005 00:52
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8 hours and 10 minutes till I have to drive this thing about 50km to Buxton...
I really need to figure this out... I'm just about to go down to the shops and buy another set of spark plugs, I've messed around with the gaps on these ones too much... TPS will be here at 6PM tonight... I've gone over all of my wiring this morning, matched up sensor wires with ECU pins, so to answer that question, yes an 86kW ECU is compatible with all 96kW sensors. I'm praying that this TPS works, because if it doesn't, I'll probably have to shell out alot of money to tow my car to melbourne, and probably won't be able to come to a cruise that I'VE organized...
Kev.
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Location:
Melbourne - NthSubs
Registered:
January 2004
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Re: Why the hell is my 4ag doing this?!!?
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Fri, 18 November 2005 02:01
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just drive on 2500rpms? 5th gear will get u about 70-90?
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I supported Toymods
Location:
Frankston, Victoria
Registered:
April 2004
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Re: Why the hell is my 4ag doing this?!!?
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Fri, 18 November 2005 03:50
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Lol...
As you go into further gears, 2500RPM takes more and more load, meaning the accelerator has to be further down, meaning BANG BANG FKN BACKFIRE BANG ahahh.
I've been told by an auto-elec it might be the MAP sensor... I'll get Jim to bring the one he got of you Leo.
Kev.
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Location:
Kita-Ku, Sapporo, Japan
Registered:
January 2003
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Re: Why the hell is my 4ag doing this?!!?
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Fri, 18 November 2005 07:19
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| beige_bandit wrote on Thu, 17 November 2005 11:23 |
| oldcorollas wrote on Wed, 16 November 2005 22:22 |
make sure you briudge the whatsit to short timing to 10deg (or whatever it is)
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What's this shit?
Please dont post like this in tech section in future!
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heh heh, correct thread this time, but still just as relevant 
| oldcorollas wrote on Fri, 18 November 2005 00:48 |
the moron who posted that i should not be posting in the tech section because i said timing should be 10deg can ....
GO FUCK THEMSELVES SIDEWAYS
http://toymods.org.au/Repository/TechDocs/4age_boo k/servicespecifications/a_06.jpg
RTFM FUCKWIT...
i'm sick of these fuckwits that jump on here, flame ppl for POSTING ACCURATE INFORMATION....
i hope to god they don't sign up to new forum, for their sake, as i will cut them down like the idiots they are...
have a nice day 
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so beigeboy... did you read the 4AGE tech book.. my copy is back home in Aus, but it says the same as the online version in the toymods tech doc linked above..
and i quote..
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IGNITION TIMING......10deg BTDC (w/terminals T and E1 SHORT-CIRCUITED)
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you do know this THIS is how you set timing on a 4AGE???
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Location:
Canberra
Registered:
September 2005
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Re: Why the hell is my 4ag doing this?!!?
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Fri, 18 November 2005 08:36
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| rthy wrote on Thu, 17 November 2005 17:36 |
| beige_bandit wrote on Thu, 17 November 2005 11:23 |
| oldcorollas wrote on Wed, 16 November 2005 22:22 |
make sure you briudge the whatsit to short timing to 10deg (or whatever it is)
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What's this shit?
Please dont post like this in tech section in future!
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i got something like this from toyospares
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I Never implied i wasnt sure how to set base timing on
a 4AGE
I was only taking a stab and you,ve thought into it too much
Dont get all worked up, you'll give yourself a stroke or something
Have a top weekend
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Location:
NSW
Registered:
September 2003
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Re: Why the hell is my 4ag doing this?!!?
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Fri, 18 November 2005 12:23
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Sounds exactly like the symptoms mine had when the AFM crapped out.
I would back the auto-elec's advice on the MAP sensor being stuffed or wrong for the ecu.
Check that it is sending the correct signals to/for the ecu you are using.
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Location:
Adelaide
Registered:
May 2002
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Re: Why the hell is my 4ag doing this?!!?
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Sun, 20 November 2005 11:44
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Hi there...
are you using an afm or a map sensor? The 97kw uses a map sensor. I have absolutely no Idea whether you can use an afm on the JDM ecu.
^^oops just read through the thread and you said that you used a map from an 86kw...
Also did you change over the injectors? The 86kw uses high impedence injectors and the 97kw uses low impedence injectors, they are coloured purple and bage respectively.
With all these people saying "fuel! fuel! Its a fuel problem!!" it might be worth a look.
Good luck,
Rob
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Location:
Kita-Ku, Sapporo, Japan
Registered:
January 2003
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Re: Why the hell is my 4ag doing this?!!?
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Sun, 20 November 2005 12:34
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| RobertoX wrote on Sun, 20 November 2005 22:44 |
Hi there...
Also did you change over the injectors? The 86kw uses high impedence injectors and the 97kw uses low impedence injectors, they are coloured purple and bage respectively.
With all these people saying "fuel! fuel! Its a fuel problem!!" it might be worth a look.
Good luck,
Rob
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thats a bloody gooid point..
lowZ ECU will snap open highZ injectors (enough for idle pulse width) but will not be able to hold them open longer than idle pulse width..
you might be onto a winner there!!!!!!
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Location:
Adelaide
Registered:
May 2002
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Re: Why the hell is my 4ag doing this?!!?
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Mon, 21 November 2005 11:01
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So it would be quite likely that the voltage output of the 97kw ecu would be less than the voltage output for the 86kw ecu?
Doesnt this mean that the ecu would have no problem opening the injectors? Maybe he has actually fried one of the injector coils due to excessive current?
Unless I am actually mistaken and the JDM uses high impedence and the ADM uses low impedence... (I have to admit I am going on hearsay, although from someone who I think knows their stuff quite well)
I suppose he could just try the right ones to see if that is infact the problem
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