20v blacktop ignition timing issue

stiness101
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20v blacktop ignition timing issue

Postby stiness101 » Mon May 27, 2013 6:09 pm

Hey club4ag,

Was doing a once over on the car and just noticed that the timing was previously set too advanced it seemed. Put the car in diagnostics mode and proceeded to set the timing to 10 degrees at idle but car refused to rev after that. It would idle but wouldn't rev and it would backfire if tried to rev.

Car is running stock ecu with stock ignition parts. It was previously set to around 17 degrees which it is now set back to. Did a leakdown/compression on the engine and it's healthy. Also checked the cam timing and everything seemed lined up at tdc. I do have to force it to idle low because the car wants to idle around 1400 rpm since the iscv is open but I am able to get it to idle at 8-900 rpm.

Anyone have any ideas what could be causing the issue with trying to set the ignition timing properly?

yoshimitsuspeed
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Re: 20v blacktop ignition timing issue

Postby yoshimitsuspeed » Tue May 28, 2013 7:00 am

I can't think of many things off the top of my head.
Is there any chance you have the wrong pulley? The MR2 pulley and maybe others have the timing mark in a different location than the 20v. If you had that pulley with and timed it off the 20v marks it would be way off.
Other than that I would test all your important electronics by the book. TPS, AFM/MAP etc.

allencr
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Re: 20v blacktop ignition timing issue

Postby allencr » Tue May 28, 2013 12:18 pm

stiness101 wrote: It was previously set to around 17 degrees which it is now set back to.


17? There's way in the world you can be that accurate, I'd be surprised if you were actually within + or - 5degrees of that.
Just set it so it runs well, idles fast & revs & doesn't ping too much on the octane of your choice, and forget the number. You've got no idea about the accuracy of the factory timing marks.

yoshimitsuspeed
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Re: 20v blacktop ignition timing issue

Postby yoshimitsuspeed » Tue May 28, 2013 12:42 pm

allencr wrote:
stiness101 wrote: It was previously set to around 17 degrees which it is now set back to.


17? There's way in the world you can be that accurate, I'd be surprised if you were actually within + or - 5degrees of that.
Just set it so it runs well, idles fast & revs & doesn't ping too much on the octane of your choice, and forget the number. You've got no idea about the accuracy of the factory timing marks.


What?
With a good timing light 5 deg looks like a football field.
It should be easy to get within .5 deg and I bet the timing marks are accurate within fractions of a degree.

I also dissagree with the idea of setting timing without a light. Even if you don't set it to stock it's important to know what it is set at. I also wouldn't go more than about 2 deg more advanced than the book recommends.

stiness101
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Re: 20v blacktop ignition timing issue

Postby stiness101 » Tue May 28, 2013 2:39 pm

Yoshimitsuspeed,

Is there any visual difference between the mr2 pulley that I can see? I can check it later and see, but I don't believe that would have been changed on the car. I am also going to go through the sensors asap to make sure they are functioning and calibrated properly. Looks like previous owner replaced the TPS sensor so I will double check that it's calibrated properly. The 02 looks new as well. Is there a way that I can check the VVT solenoid to see if that could be faulty?

allencr,

What would make the timing look so off? The timing marks seem pretty accurate on the car since if I check it all at TDC everything lines up. The timing gun is also digital so I can see at what degree exactly it is lining up which is why when i first hooked it up and set it at 10degrees the crank pulley mark was nowhere to be found.

onnaj
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Re: 20v blacktop ignition timing issue

Postby onnaj » Wed May 29, 2013 5:07 am

I'm having a bit of the same issue. Have a freshly rebuild Blacktop which run extremely rich with backfires. When i set the timing to about 15 degrees BTDC it run smooth without backfire...at least last time it did. I don't like to advance the timing too much while i'm on 98RON instead of 100RON on which the base setting is based.

I think i have a leak injector or a leak in the exhaust, couldn't that be your problem also?

Also check the resistance on your coil, plug cables, etc. Do it from the book. Take step by step. Also you can check the O2 sensor from the book.

When i solved my problem i'll let you know. Hope you'll do the same otherwise :D
Check my 4AGE 20V BT teardown, rebuild and transplantation over here --> http://club4ag.com/forums/viewtopic.php?f=7&t=3382

onnaj
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Re: 20v blacktop ignition timing issue

Postby onnaj » Sat Jun 15, 2013 6:01 am

Any new on your problem?

I had a leaky injector, that cause the difficult warm starts. But i still have the power loss i have to admit.

I think i'm going to ultrasonic clean my injectors with a pro.
Check my 4AGE 20V BT teardown, rebuild and transplantation over here --> http://club4ag.com/forums/viewtopic.php?f=7&t=3382

stiness101
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Re: 20v blacktop ignition timing issue

Postby stiness101 » Tue Jun 25, 2013 3:44 pm

Update!

I ended up re-doing a bunch of the vacuum lines/PCV lines and re-routing them properly on the engine. I was able to get the timing back to factory spec and the idle back down to normal so the car is driving a lot better now.

I also had the injectors cleaned and tested. Two of them were noted as dripping and down 20cc's from cleaned so i'm sure this helped with it.

One thing I did notice is that the injectors were flow tested to 310cc so i'm guessing that they aren't stock injectors? If I remember correctly 4age blacktop injectors are 295cc

onnaj
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Re: 20v blacktop ignition timing issue

Postby onnaj » Sun Jun 30, 2013 8:48 am

From my memory they are 295cc indeed.

I'm going to get my injectors flow tested and cleaned this week. Still have the same problem you had. To be sure i let my brother drive behind me to check for black smoke and yes there is black smoke. Especially from about 3750-7000 rpm, higher i didn't dear cause of the break-in oil ;) So i'm really suspecting the injectors.

To be 100% sure i'm going to someone who can get my throttle bodies balanced with a carb synchronizer

I'm glad for you that your problem is solved.
Check my 4AGE 20V BT teardown, rebuild and transplantation over here --> http://club4ag.com/forums/viewtopic.php?f=7&t=3382