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RB CAS drive gear replacement info.


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#21 Vandergriff84

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Posted 09 June 2013 - 09:41 PM

So I tried to reset the ECU to see if that would help and that struck out. I noticed something interesting though, when I held the throttle plate closed by hand the BTDC numbers on the consult stopped jumping around and held at a constant 15 degrees which is where it should have been since I had the CAS about half way. Does anyone know if the consult is supposed to read exactly what the CAS is seeing or is it sowing some the ECU is computing? I am still hoping that some one has seen this before and will help a guy out with a magic fix. lol.


Skylady Z - 74 260z RB25det


#22 rayaapp2

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Posted 10 June 2013 - 02:19 PM

First verify timing. Use a spark plug wire and an actual advancing timing gun on the balancer.

Then check your TPS(sensor not switch) setting. Take it through full motion and verify with the FSM settings. The TPS as I found out recently has a massive affect on fuel and timing on the rb25.

 

Be sure to un-plug the TPS during CAS adjustment as well or it resets unless your using a real consult that will put the ECU in BASE mode.


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#23 Vandergriff84

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Posted 10 June 2013 - 07:05 PM

Ok so sorry for leaving the other half of the problem out. Before I had the consult I was trying to set the timing but I couldn't get it to idle below 800. I now have it idling low enough but when I check the timing with the light off of the wire as rayaap2 had mentioned it shows that it is extremely retarded to around -10 to -15 degrees. I have checked the cams belt and crank so I know that the motor is all lined up with the timing marks so that tells me that ECU is retarding the timing. I read another thread recently that said limp mode from knock only retards the timing by 4 or 5 degrees and I have no fault codes.

 

As far as the TPS I have it set to .47V like it should be it even shows up on the consult. If there is something else that I am supposed to do or check please let me know. I have unplugged the TPS several times when checking the timing with the light and it changes nothing.

 

So the question is what is the ECU seeing that I am not?


Skylady Z - 74 260z RB25det


#24 Vandergriff84

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Posted 13 June 2013 - 04:58 PM

Ok so this video shows you what the consult/ECU is reading. This is after I had started the motor with the tps disconnected and the CAS fully advanced. When I checked the timing with the light it was showing 0BTDC Just minutes before I shot the video I had the CAS half way and it read 15BTDC while the light was showing -5BTDC. I am at a loss with this thing so if anyone has any idea what is going on with this please let me know.

Attached Files


Edited by Vandergriff84, 13 June 2013 - 05:20 PM.

Skylady Z - 74 260z RB25det


#25 Manny

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Posted 17 July 2013 - 03:29 PM

Thanks Stony for posting this.  I just finished building up my RB with an AEM EMS V2, and after trying to start, it would crank for 4-5 times and catch and start for like 1 second and then die.  Then it would be difficult to fire back up, only to catch for a sec and die again.  I have a feeling after reading this that it's 180 degrees out.  Does this sound like the same symptoms you had?  I'm going to try your switched settings and see if I can get it to fire up.



#26 stony

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Posted 17 July 2013 - 04:08 PM

Mine would only backfire out the intake and exhaust. If you changed the cas drive gear like I described above then it may be your problem. Just rephase the coils as described above. If u havent changed the gear then its probably the start up cal just needs tuning. I found I needed to add 40% across the map just to get it started. Obtw I found that the injector wizard did not work for me.

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#27 Vandergriff84

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Posted 20 October 2013 - 07:55 PM

Ok, so I have been working on this problem now for about a year and I seem to be getting no where with it. I took the car down to a local performance shop that I knew would be familiar with the motor and they are telling me that the problem is the greddy style intake and the non circulating blow off valve. They said I would have to go with a stand alone ecu to fix the timing or put the stock parts back on. Can anyone confirm this? I was hoping to avoid the great expense of a stand alone and the added hassle.

Skylady Z - 74 260z RB25det


#28 Vandergriff84

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Posted 22 October 2013 - 06:59 AM

Ok, so Mack from McKinney says the intake and the BOV are not the problem and that there must be a mechanical knock or some sort of wiring problem. I checked the Knock sensors again today and they ohm out to what everyone says they should so I don't think they are the defective. I have checked continuity from the sensors to the ECU and the wiring is fine. So now my question is what else could cause this except for an actual knock? The check engine light is not on and there are no codes so how do I know if there is knock if the computer is not telling me so?


Skylady Z - 74 260z RB25det


#29 winstonusmc

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Posted 22 October 2013 - 07:17 AM

Have you checked the coolant temp sensor? Those play hell with the timing when they go bad.

'72 240z w/ RB25DE ITB MS3/MS3X

http://forums.hybrid...40z-rb25de-itb/


#30 Vandergriff84

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Posted 22 October 2013 - 07:16 PM

Have you checked the coolant temp sensor? Those play hell with the timing when they go bad.

As far as the temp sensor goes I am assuming it is OK sense the consult is showing the temp at 82 C which if I am not mistaken is the proper temp for the motor.


Skylady Z - 74 260z RB25det


#31 Vandergriff84

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Posted 22 October 2013 - 07:24 PM

OK so what about the Maf? Does it read air temp? Lets say it is to close to the motor because it probably is and it is getting to hot and there for giving bad info to the computer. I noticed the other day when I started the car up and put the timing light on the crank that at first it was spot on 15 degrees and as the motor warmed up it started to decrease until it was at zero or below.


Skylady Z - 74 260z RB25det


#32 winstonusmc

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Posted 22 October 2013 - 08:40 PM

The MAF does not have any type of temp sensor in it. Well not by conventional means as it measures air flow via the cooling effect on a hot resistor, kind of like a temp sensor but not. But its strange that the computer is doing this. Does consult have a timing indicator?

'72 240z w/ RB25DE ITB MS3/MS3X

http://forums.hybrid...40z-rb25de-itb/


#33 winstonusmc

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Posted 22 October 2013 - 08:48 PM

Also knock may not be your problem either. The ECU isnt listening to knock at idle. As I recall with the S1 to S2 compatibility, it is the MAF to ECU. It really only affected the AFR about 1 point between the two on my car.

'72 240z w/ RB25DE ITB MS3/MS3X

http://forums.hybrid...40z-rb25de-itb/


#34 Vandergriff84

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Posted 23 October 2013 - 10:43 AM

The MAF does not have any type of temp sensor in it. Well not by conventional means as it measures air flow via the cooling effect on a hot resistor, kind of like a temp sensor but not. But its strange that the computer is doing this. Does consult have a timing indicator?

 

Yes the consult shows the timing. If you look at the video that I posted earlier in this thread you will see how it is jumping around.


Skylady Z - 74 260z RB25det


#35 Vandergriff84

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Posted 23 October 2013 - 10:45 AM

I am going to go ahead and replace the temp sensor sense on other threads that I have read said that the computer did not give any code or error when it went bad and they were having similar problems as mine.


Skylady Z - 74 260z RB25det


#36 HowlerMonkey

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Posted 23 October 2013 - 03:20 PM

I've replaced the sensor with a resistor near 1 megaohm......might have been 770k to eliminate a false sensing of knock from pulling timing when I was chasing something similar but you have to be careful when running without that protection.

 

I was using a late ecu on a L28 and some sensors are sensitive enough that the valvetrain noise of the older engines trigger false knock senses.


Edited by HowlerMonkey, 24 October 2013 - 09:21 AM.


#37 SloperZ

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Posted 10 November 2013 - 10:21 AM

OK so what about the Maf? Does it read air temp? Lets say it is to close to the motor because it probably is and it is getting to hot and there for giving bad info to the computer. I noticed the other day when I started the car up and put the timing light on the crank that at first it was spot on 15 degrees and as the motor warmed up it started to decrease until it was at zero or below.

I had my MAF placed too close to the turbo and recirc from the blow off valve and I was having a lot of trouble once the engine warmed up. I moved the MAF about 12 in. farther away and put another bend in the intake piping and the problem was fixed. This may be worth looking in to.



#38 Vandergriff84

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Posted 11 November 2013 - 07:56 AM

I moved the MAF in front of the intercooler over the weekend and it seem to make it rev a little better but the timing is still retarding as the temp rises. I am going to plug the cold start valve today and see if that makes any difference.


Skylady Z - 74 260z RB25det


#39 Vandergriff84

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Posted 11 November 2013 - 02:03 PM

Ok, So I plugged the Cold start valve this afternoon to see if that would make a difference and again no change. Can anyone verify that a freddy intake manifold or a greddy will work with the stock ECU. I am preferably asking this in hopes that some one who actually has one running on a stock ECU will chime in and confirm or deny. I have ask a few people and I get conflicting answers. Mack from McKinney motorsports says that it should work fine and the performance shop in town says that you have to have a stand alone ECU to run an aftermarket intake manifold.


Skylady Z - 74 260z RB25det


#40 flatrate

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Posted 11 November 2013 - 05:31 PM

I had a Freddy intake manifold with my stock RB25 ECU, it ran like stock, stock turbo, stock 98 240sx exhaust, stock injectors etc..made 268whp and 273wtq on 12psi 






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