Bigport 4age dizzy problem?

[RiceburnaGTV]

Hey I noticed on my cousins 4a that we can turn the dizzy while the car is running and it wont cut out we can do this both ways left or right,it seems to have a spot after TDC that changes the idle a little but then you can completly turn it left or right and the car wont stall.

Could this be just the dizzy?or is ther somehing more sinister at work here? The symptoms of the car was bad idle/cutting out/ no power and running very rough untill you started revving its tits off and then it would sort of come alive above 4500rpm..Everything else such as comp,fuel pressure etc have been checked..

Any advice would be greatly appreciated,
thanks in advance
Nath

[Cuzzo]

Are you doing it with the diagnostic terminal bridged?

[Hiro]

Hey I noticed on my cousins 4a that we can turn the dizzy while the car is running and it wont cut out we can do this both ways left or right,it seems to have a spot after TDC that changes the idle a little but then you can completly turn it left or right and the car wont stall.

Could this be just the dizzy?or is ther somehing more sinister at work here? The symptoms of the car was bad idle/cutting out/ no power and running very rough untill you started revving its tits off and then it would sort of come alive above 4500rpm..Everything else such as comp,fuel pressure etc have been checked..

Any advice would be greatly appreciated,
thanks in advance
Nath

A lot of 4AGEs have crappy idles, mine'll often cut out when you stop for traffic lights unless you downshift quickly and stay off the clutch as much as possible (doesn't seem to like dropping revs/load too quickly). The no power and roughness below 4500rm could be the TVIS is removed or stuck open, I think 4400rpm WOT is the opening point for the butterflies.

[RiceburnaGTV]

A lot of 4AGEs have crappy idles, mine'll often cut out when you stop for traffic lights unless you downshift quickly and stay off the clutch as much as possible (doesn't seem to like dropping revs/load too quickly). The no power and roughness below 4500rm could be the TVIS is removed or stuck open, I think 4400rpm WOT is the opening point for the butterflies.

The TVIS is removed apparently,naa this is a miss firing engine its abxolutely terible to drive.

Cuzzo,do you mean that diagnostic port thingo that is used to plug into toyota comp and give fault codes?If so it doesnt have one but I have picked one up and will re wire it in to get to the bottom of the prob if need be.

cheers
Nath

[RiceburnaGTV]

Just bumping this back up there...

anyone?

[blacktop]

Have you just checked the timing? (with a timing gun)

that just sounds like the timing/dwell is horribly out

I'm going off my experience with an old 4k motor but what describing was the same result when I was playing with the Tach/Dwell meter.

car would cough, backfire & have no power at all until I got it up to about 3,000RPM then it seemed to drive ok

[RiceburnaGTV]

Have you just checked the timing? (with a timing gun)

that just sounds like the timing/dwell is horribly out

I'm going off my experience with an old 4k motor but what describing was the same result when I was playing with the Tach/Dwell meter.

car would cough, backfire & have no power at all until I got it up to about 3,000RPM then it seemed to drive ok

Yeah thats the thing,we can turn the dizzy to get the better idle and have it run well,lock it all in and then 2 drives later it is back to running like shit again and it hasnt moved Might have to just source a new dizzy and see if that helps.

[blacktop]

Maybe check the wires leading to the Dizzy, if there loose they might be arching causing the problem you describe.

It seems plausible to if you have been playing around with the dizzy, you may have by accident pulled the wires to hard or something.

[KARNAGE]

are you setting the timing when the engine is at operation temp cos if your doing it when its cold it will be slightly out after the car is warm

[Chrisso]

just a thought, but is the timing of the cams correct? Belt might have slipped?

[MRMOPARMAN]

the computer will be varying the spark timing at all times.. so you adjust it one way, the computer will probably adjust it back.. hence why you adjust the timing with the terminal bridged.

my ae82 is displaying similar problems at the moment, farts around and missfires until you get hight up in the revs, then starts to run cleanly (most of the time).. checked it out last night, and i can hear the coil lead arcing out on something, cant see it tho. however the stuffed dissy cap and rooted plugs probably aided its cause.

moral to this story is make sure your ignition is in good nick.

when you say TVIS is removed. is it actally removed from the vehicle or just disconnected? its a characteristic of bigport 4ages to be pretty tame till 4500, then take off like a cut cat, like hiro said coz thats when the butterflies open

[Hiro]

its a characteristic of bigport 4ages to be pretty tame till 4500, then take off like a cut cat, like hiro said coz thats when the butterflies open

Only if the TVIS is non-functioning/removed. The whole point of TVIS is to produce low-down torque and remove any lag-ish characteristics. From proper dyno sheets it's been shown that the power doesn't change when the butterflies open, and it should be a smooth transition (you'll hear a change, but not feel it). That was how the opening point was designed originally (it's not like VTEC or VVTL-i).

Then again, most bigports these days are so rooted and rough that you can't tell.