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Hey Guys,

Well in the brave new world of OBDII emissions, there is a new game. No longer do you have to simply pass a "sniffer" test, all of your codes have to be clear. In Arizona, cars are no longer sniffed-- they're scanned. Here are the problems I faced getting my 97/OBD II single turbo though emissions...

I had been having a "sync" error for several months. A sync error basically means the crank position sensor (reference pulse) and your cam position sensor (sync pulse) don't agree. Though HOURS AND HOURS of painstaking trial and error (thanks to HiTekRedneck :) , we determined the intake cam gear was responsible for the error. Basically, if your intake cam gear is not zeroed out, the car throws a cam postion error code (PO340) AND ADJUSTS TIMING ACCORDINGLY.

I wanted to alert all 96+ Supra owners that changing your intake cam position will trigger this code. (assuming you're on the stock ECU of course) I also wanted to hear from any 96+ Supra owners with an adjusted intake cam gear to see if perhaps their car reacted differently.

Also, if you're single turbo, you will have codes for all of the VSV solenoids you removed. I did some math and determined 1k 1/4W resistors will trick the computer into removing those codes-- worked like a charm. If you do not have a cat, an O2 simulator on your second O2 sensor will do the trick. Be sure to weld a cat heat shield to your downpipe to pass.
 
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wow. Thanks for the heads up and the info. Would resetting the ECU prior to the smog test resolve the code(s) issue?
 

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Dennis,

I have an adjustable cam gear. I've never gotten that code -- the only codes I ever get are:

- catalytic converter efficiency below threshold (only get this code about once a month so I've been to lazy to install the new design oscillating 1/3 Hz o2 sim).
- P1511 Boost pressure low (it's expecting to see sequential's 1st turbo boost and it's not). I get this code even more rarely than the other as I've learned not to go WOT below 3K RPM. 90% and 100% throttle aren't that different when you're off boost.

My intake cam gear is set to -1 mark = -1 cam degree = -2 crank degrees.

Question-- are you saying that the computer's ignition timing is based on the intake cam gear and not the crankshaft, thus making the intake cam gear function almost like an ITC without the RPM control? Or is it only if the computer gets this out of sync code that there will be a problem?

I did an experiment with changing the intake cam gear settings between -1 marks, 0, and +1 marks. At WOT on the same octane, the obd2 scanner would report the same timing (16-19 degrees on pump gas, 18-22 degrees on race fuel). But these #s are of course based on a certain sensor -- hopefully it's from the crank sensor and not the intake cam position. Do you know which?

Andi


AZWildcat said:
Hey Guys,

Well in the brave new world of OBDII emissions, there is a new game. No longer do you have to simply pass a "sniffer" test, all of your codes have to be clear. In Arizona, cars are no longer sniffed-- they're scanned. Here are the problems I faced getting my 97/OBD II single turbo though emissions...

I had been having a "sync" error for several months. A sync error basically means the crank position sensor (reference pulse) and your cam position sensor (sync pulse) don't agree. Though HOURS AND HOURS of painstaking trial and error (thanks to HiTekRedneck :) , we determined the intake cam gear was responsible for the error. Basically, if your intake cam gear is not zeroed out, the car throws a cam postion error code (PO340) AND ADJUSTS TIMING ACCORDINGLY.

I wanted to alert all 96+ Supra owners that changing your intake cam position will trigger this code. (assuming you're on the stock ECU of course) I also wanted to hear from any 96+ Supra owners with an adjusted intake cam gear to see if perhaps their car reacted differently.

Also, if you're single turbo, you will have codes for all of the VSV solenoids you removed. I did some math and determined 1k 1/4W resistors will trick the computer into removing those codes-- worked like a charm. If you do not have a cat, an O2 simulator on your second O2 sensor will do the trick. Be sure to weld a cat heat shield to your downpipe to pass.
 

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Discussion Starter #4
Monkeyman said:
wow. Thanks for the heads up and the info. Would resetting the ECU prior to the smog test resolve the code(s) issue?
No it wouldn't... OBDII has something called "readiness codes" which require time before they are set. A readiness code insures that the emissions controls are working properly-- it normally takes two days of driving to trigger all readiness codes. The Supra ones are: misfire, componets, EGR, O2, heated O2, catalyst, and two others I can't remember. :)
 

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Re: Re: OBDII Emissions and Cam Gear Owners-- look here

Andi,

This was the response I was hoping to get...
Andi said:
Question-- are you saying that the computer's ignition timing is based on the intake cam gear and not the crankshaft, thus making the intake cam gear function almost like an ITC without the RPM control? Or is it only if the computer gets this out of sync code that there will be a problem?


No, I'm not saying timing is based on the intake cam gear. Its reference is the crankshaft. I'm saying that if it gives an out of sync code, it pulls a lot of timing.

I did an experiment with changing the intake cam gear settings between -1 marks, 0, and +1 marks. At WOT on the same octane, the obd2 scanner would report the same timing (16-19 degrees on pump gas, 18-22 degrees on race fuel). But these #s are of course based on a certain sensor -- hopefully it's from the crank sensor and not the intake cam position. Do you know which?


It's defiently from the crank sensor. Now this part makes me wonder...

There is little doubt that my sync error was caused from a compound error. Two days ago when my timing belt was redone, the gear teeth on the timing pulley had come unpressed. I thought I had found my sync problem! At that time, the cam gear was moved from +1 to 0. I drove the car around for 10 mintues, no sync error. Then the car was hooked up to a gas analyzer, and the intake cam was moved to -5 degrees for emissions reasons. (I thought I'd have to pass a sniff test too) At this point the sync code came back, but I had other codes related to the VSVs which I knew about, so I didn't think it was the sync code coming back.

So the bottom line is... I had the code at +1, but that could be related to another problem. The sync code was on at -5 and simply by zeroing the gear out and making NO other changes, the code went away. Now I'm wondering if there's a "safe zone" where the ECU can't detect the degree shift. I'll play with it when I get a chance. If you want to experiment with it too, if the code comes it's within the first 15 seconds at start up.

Thanks for the info.
 

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Supra OG
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Re: Re: Re: OBDII Emissions and Cam Gear Owners-- look here

AZWildcat said:
Andi,

This was the response I was hoping to get...


No, I'm not saying timing is based on the intake cam gear. Its reference is the crankshaft. I'm saying that if it gives an out of sync code, it pulls a lot of timing.

[/b]

It's defiently from the crank sensor. Now this part makes me wonder...

There is little doubt that my sync error was caused from a compound error. Two days ago when my timing belt was redone, the gear teeth on the timing pulley had come unpressed. I thought I had found my sync problem! At that time, the cam gear was moved from +1 to 0. I drove the car around for 10 mintues, no sync error. Then the car was hooked up to a gas analyzer, and the intake cam was moved to -5 degrees for emissions reasons. (I thought I'd have to pass a sniff test too) At this point the sync code came back, but I had other codes related to the VSVs which I knew about, so I didn't think it was the sync code coming back.

So the bottom line is... I had the code at +1, but that could be related to another problem. The sync code was on at -5 and simply by zeroing the gear out and making NO other changes, the code went away. Now I'm wondering if there's a "safe zone" where the ECU can't detect the degree shift. I'll play with it when I get a chance. If you want to experiment with it too, if the code comes it's within the first 15 seconds at start up.

Thanks for the info. [/B]
I'll do the experiment too when I get a chance... I will ask Dave to give me my obd2 box back.

BTW, Are you saying that the same 1K Ohm 1/4W resistors work i in place of all the stock twin VSVs to clear the codes when one goes single with an OBD2 ECU? i.e. EBV VSV, IACV VSV, EGCV VSV, and WGA VSV..?

Andi
 

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Discussion Starter #7
Re: Re: Re: Re: OBDII Emissions and Cam Gear Owners-- look here

Andi said:


I'll do the experiment too when I get a chance... I will ask Dave to give me my obd2 box back.

BTW, Are you saying that the same 1K Ohm 1/4W resistors work i in place of all the stock twin VSVs to clear the codes when one goes single with an OBD2 ECU? i.e. EBV VSV, IACV VSV, EGCV VSV, and WGA VSV..?

Andi
Andi,

I know it works for the EBV, IACV, and EGCV... Now the Wastegate it does work for, but my numbers show that it shouldn't on a manual car. The book says under 3V for a manual, so it's a little confusing. My car threw one pending (not DTC) wastegate code, but it hasn't since. I would say it's a good solution, though may not be perfect.
 

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Dennis-
So was that the problem you were having with your car? Remember i was talking with you about it a month or so ago, cause our cars had the same issues. I still havent figured mine out, so i was wondering if you had sorted your problems out and narrowed it down to a sync problem??

-Aaron Senft
93 T66 6-spd



AZWildcat said:
Hey Guys,


I had been having a "sync" error for several months. A sync error basically means the crank position sensor (reference pulse) and your cam position sensor (sync pulse) don't agree. Though HOURS AND HOURS of painstaking trial and error (thanks to HiTekRedneck :) , we determined the intake cam gear was responsible for the error. Basically, if your intake cam gear is not zeroed out, the car throws a cam postion error code (PO340) AND ADJUSTS TIMING ACCORDINGLY.

 
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