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Thread: SR20VE Help Need-Ignition Timing Fighting Me - High RPM Misfire-Sounds Like Anti Lag

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Posts: 51-60 of 68
2015-06-26 23:12:51
Factory Service Manual exact spec for TPS setting.
It calls for 4 volt for WOT.

Last edited by KillerKrossover on 2015-06-26 at 23-14-14.
2015-06-26 23:19:31
Originally Posted by KillerKrossover
Factory Service Manual exact spec for TPS setting.
It calls for 4 volt for WOT.

You are correct... Though the manual you are showing is for the OBD2 ECU and it is slightly different... He stated he is using Blue Plug OBD1 ECU .. OBD1 is .45-4.5V ..The FSM spec I posted was from OBD1 ECUs
2015-06-27 02:46:23
Boy you are stubborn. The spec is for both Obd1 and Obd2. If you want I can post the FSM for Obd1 and put this to rest.
2015-06-27 02:49:02
Originally Posted by VE-Baller
I understand. You have to work from the baseline that the ECU Talk is always thinking timing is at 15 base timing. So if I have added 7 degree to base timing I have to add 7 deg to all the timing readings it gives. Correct me if I am wrong.

Side question - Does the ECU use the MAF signal at WOT normally?

Originally Posted by KillerKrossover
Boy you are stubborn. The spec is for both Obd1 and Obd2. If you want I can post the FSM for Obd1 and put this to rest.

Not at all.. What I did post was from the 91 SE-R FSM
2015-06-27 08:03:22
MAF Voltage is 4 Volts and WOT 6000 RPM - It is the numbers on the far right of the log I pasted in previously

I checked the throttle body. It is completely closed when pedal is depressed.

Fully depressed pedal rotates the throttle body all the way round to the metal stop at the back of the wheel.

I will also visually inspect the throttle butterfly internally, I don't think I have ever done this.

99% the alternator is weak. Has been for years.


I will check voltage at the TPS
I will double check voltage at the alternator

I will try and rotate the TPS to get the signal where it should be.

& go from there.

Is it in fail safe mode? Or is it because of the the TPS signal is weak?

Does 16 deg timing with 80% throttle @ 5.5K RPM match the base map for a DE ECU?

ECU Talk shows no faults. Can it be in fail safe with no fault codes?

I have disconnected the narrowband sensor a long time ago and replaced it with a wideband with the signal going into an Innovate gauge and the AEM FIC.

Is a disconnected narrowband going to effect WOT?

Generally my AFRs are exactly where I want them.
2015-06-29 20:14:24
To adjust the TPS, loosen the two Philip screw on the TPS. Turn on ECU TALK, it will report the TPS voltage while you rotate the TPS. Once the TPS voltage is to spec, lock down the screws.

In your case, your current TPS range is .18 V closed and 3.76 V WOT. Factory spec calls for .45 V closed and 4 V WOT.

4.00 V – 3.76 V = .24 difference
0.45 V - 0.18 V = .27

This means your throttle body range of movement is within spec. All you have to to do is to up the closed throttle voltage by .27 V and the WOT voltage will fall in line.

Now, onto why the battery voltage is important. You want a healthy alternator to provide 14 volts or higher because:

1. bigger spark, more powerful spark. More voltage on the primary side of the coil will result in more output voltage(spark) on the secondary side. This is one reason they sell voltage booster.

2. fuel injector will open and close faster. Will be more stable, less variation, even though there is battery voltage compensation map.

3. brighter head lights

4. faster power windows

5. stronger coolant fans.

6. stronger fuel pump
2015-06-29 20:45:50
If you need an ALT .. I strongly suggest the DC Power units... A few of us SR20 guys are running them.. The Sales manager there Anthony is a Nissan S Chassis guy and runs the SoCal S-Chassis page on FaceBook.. Super cool dude... Any case.. 9 of the top 10 Class 1 / Trophy Truck guys that run the Baja 1000 use there ALTs.. They take some major abuse.. You can get 150-270A or even higher outputs for our cars.. The best thing about them is that the Voltage is SUPER stable.. Beating the crap out of SR20s when tuning I don't see more the 0.1V variance at all... There all high end Denso cores 100% new and NOT rebuilt with Anodized CNC housing... https://www.dcpowerinc.com/

Back to the TPS… Try setting it to 4.5V at the high side… OBD1 Blue Plug FSM says 0.5 to 4.5 and OBD2 White Plug ECU shows a max of 4V …
2015-06-30 04:54:21
You are stubborn as a Mule.

Here's the Obd1 FSM spec.

2015-06-30 05:20:51
I too have the factory FSM for the OBD1 and it says 90deg TB should be 4.5V .. I have a 91 SE-R book.. I also have a 93 240SX book.. I will check that tomarrow but I wounder if there is some differance between ECUs then... Because my book clearly says 4.5V ... Hummm .. All I can think is I feel bad for you son.. I got 99 problems but a stock ECU aint one !!
2015-06-30 08:37:10
About the TPS. Mine wants to see 4v at 0.5v. I have set the TPS to 4.5v high side but have not had a chance to drive the car

I have not tested the alternator yet

I am in Greece, Ill get an alternator here if I need one.....;-)

Ill let you know about the new tps position and alternator output.
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