EGR Help

[AHall]

Hello,

I have a completely stock 1993 S13. I continue to have problems with my EGR system. I live in Dallas so the system is required for emissions. I have completely cleaned the EGR valve, tube, manifold was removed and EGR passages completely cleaned like new, everything put back like it was before. Car runs fine. The problem is when the engine is rev'ed to 2,000 rpm the EGR valve is not opening to allow the exhaust gas to enter the intake and thus lower NOx. I have checked the EGR and canister solenoid and it functions as the factory service manual (fsm) states. I have a vacuum at the solenoid inlet C when the engine is rev'ed but it never gets to the EGR valve to open it. The solenoid is supposed to turn on when the engine speed rises to 2,000 rpm aand allow the vacuum to travel through solenoid inlet A and on to the BPT and EGR valve. For some reason this never happens. I followed the diagnostic procedure in the fsm on page EF & EC-111, but end up at the check ECM pin terminals at the very end of the procedure and the connection and pins are good. I noticed that the voltage at the ECM terminal 105 stays near 0 when the engine is rev'ed to 2,000+ rpm when it should increase to battery voltage. Seems like the procedure would direct you to the ECM after you do not get battery voltage at terminal 105 but it then directs you to an EGR solenoid harness voltage check.

I know this is a common problem, but I can not find any answers. If anyone knows, please help.

[AHall]

Someone must know something about this???

Does anyone know if the EGR and canister solenoid needs to be grounded? I noticed that the screw on the bottom fell off and the valve is not attached to the bracket that creates a ground. Is it possible that for the ground that shuts off the valve from the ECU to work that the valve itself must be grounded?

[Mrmatt3465]

Check your BPT Valve. Page 162 in the FSM [EF & EC]. If your EGR valve is not receiving vacuum it will not open.

[AHall]

Thanks Mr. Matt. I have checked the BPT, EGR and EGR and canister solenoid. For some reason the ecm is not turning the ground off and on to allow the vacuum to pass through the solenoid to the BPT and on to the EGR valve.

I will be likely force to obtain another ecm, but will either get mine rebuilt or buy new from Nissan.

[Mrmatt3465]

When my solenoid was bad it popped my ENG CONT 10a fuse under the hood. I fixed that by cleaning the connector of burnt stuff and cleaning the terminals on the solenoid itself @.@ I believe the solenoid only allows vacuum to the BPT and the EGR at around 2000 RPM. The solenoid should not allow vacuum through passages A and B at idle ie not 12v.

IAW FSM EC & EF pg 111 Step J and K

[AHall]

I will try cleaning the contacts to see what happens.

I wonder if I can substitute the PAIR solenoid for the EGR solenoid just to make sure the EGR solenoid is not the problem. But then again I do not see any change in the ground wire while rev'ing the engine when I measure voltage at the harness. It leads me back to the ecm, but would hate to drop $205 for a rebuild and that not solve the problem.

Can anyone tell me what the voltage readings are when you hook up a voltmeter to the harness that connects to the solenoid and rev the engine to 2000 rpm? Does it change from the reading at idle?