ECU Code 45 - Charge Control Solenoid

[imebgo]

Hi,

My friends stock 93 Jap RX7 developed an ECU fault and lumpy idle, we retrieved the code from the ECU which was 45, Charge control solenoid, so we took the rats nest to bits tested all the solenoids and 1 way valves and replaced all the hoses and tied them up and put it back together with exactly the same fault, we even changed the solenoids around just incase.

We cant seem to clear the fault and fix the dodgy idle, is there anything else we should try.

Can anyone also confirm the correct way to test the turbo control solenoid, the one with the Mitsubishi logo cap on it,  is that cap actually meant to be air tight becuase it leaks air our slowly. If someone can confirm I will retest this because I am unsure about how it should function.

Thanks,

James

[imebgo]

Some more info:

http://www.fd3s.net/boost_problems.html

6. Charge Control Actuator:
When closed, this prevents Primary boost from going into the Secondary Turbocharger. This valve seals the air passage the same way as the throttle butterfly valves. This remains closed until 4,500 RPM AND Secondary boost pressure is the same or more than Primary boost pressure.

I beleive this is sticking open at "idle" which is around 2,500rpm on the car at the moment, this is blowing air out of the secondary inlet.

[imebgo]

Previous post is wrong, I think the actuator is correct, it is closed at idle and that is what must be pushing the air out of the inlet ?

Still stumped as to what is causing this fault code!

[ianelvar]

Hi

Did the car idle high before you replaced the tubes? It sounds like you have an air leak, aside from a solenoid problem.

To test the solenoid, pull the electrical connector off, get two bits of wire long enough to reach from the battery to the solenoid, and touch one of them to either contact on the solenoid. you should hear a definate CLICK sound if it\'s working. Test one of the others this way for a reference to work from.

If it does click, then there\'s probably a fault with the wiring, and you\'ll need to check continuity between the sol\' connector and ECU.

If it doesn\'t, you\'ll need a new solenoid. I can probably find a spare one if you do need it.

Regarding the high lumpy idle, try this:

http://www.mazdarotaryclub.com/forums/showthread.php?t=40062

Also check for hissing noises while running, which would indicate and air leak. A neat trick is to use a piece of hose, with one end put to your ear, and point the other end in and around the inlet manifold. You\'ll soon find where the hissing noise is coming from if you have one.

HTH. Good luck.

Ian

[imebgo]

Hi, Cheers for the reply

Yea, Air leaks could be attributing the bad idle, which is something I wil triple check again, been through it plenty of times and pretty sure we dont have any leaks after the throttle body, im more concerned about the dodgy solenoid valve, its almost definitly a wiring problem because the solenoids work.

Gone through the Vac diagram numerous amounts of times and everything looks ok there, everything is tied on, replaced the gaskets between throttle body, and ACV, so i think wiring!

Im just tracing my way through the wiring diagrams and will follow the appropriate tests for finding the short circuit.

Cheers

James

[imebgo]

More info on the problem:

I took the manifold back of and tested the solenoids and wiring

1) Test solenoid connector to ensure continuity to battery and ecu, this was fine
2) Test to ensure solenoid was not active when the car ignition was on (car was not started) this was fine
3) Performed the same tests with the charge releif solenoid just for reference and it was the same.
4) Managed to clear to fault code

Reassembled and started the car and checked the fault codes at various stages to ensure it did not return and it didnt until we started the car.

Would the fault not have returned until I turned the car on without the jumping the terminals?

Im a bit stuck now, maybe im going off in completly the wrong direction! lol!

Thanks,

James

[ianelvar]

Sorry dude, I forgot to reply yesterday.

What\'s the latest?

[imebgo]

Well, i looks like it must be a short between the battery and solenoid, havent had time to confirm this yet but will be at the weekend.

Im wondering if the circuit is going to ground to early? I cant see it being anything else (maybe a knackered ECU not activating the solenoid).  Im going to try the factory manual procedure for finding the short, eg disconnecting everything and checking continuity whilst replacing each component, then I guess inspect the wiring at that point.

Good post about sorting out the idle, this is going to be a great help once I clear the fault code

Thanks Again,

James

[ianelvar]

Good luck!

Just a few more suggestions for finding the fault...

Disconnect the plugs from the back of the ECU. (Page z-32 of the 94 FSM)
Find the pin on the plug that goes to the solenoid you\'re having trouble with.
Labeled 4R. (Should be fourth from the left, on the bottom row of the largest connector if you have the clip facing up.)
Test it for resistance between the ECU plug and solenoid plug.
Then test for shorts to ground and 12V.

You\'re right, the ECU does ground one side of the relay. The other side is connected to a 12V line switched by the EGI main relay through the 30A EGI fuse.
Test to see if it\'s getting 12V when the ignition is turned on.

[imebgo]

I tried the continuity tests and there was continuity from the ecu side of the connector to the ECU connector, so no short on that side

Also, cant remember what I tested for the batter side, but I think there was continuity from the battery side of the connector to a GND terminal in the Diagnosis terminal, but that could still indicate a short?

I should probably be checking for continuity between the battery side connector AND positive battery terminal with the ignition on?

Thanks,

James

[ianelvar]

Hmmmm. Dont think it sounds right that there would be continuity from battery side to GND. This could be your problem. There ought to be between 12V and battery side of sol connector when the ignition is on, but not off. try putting the tester between +12V and the battery side of the connector, and getting someone to turn the ignition on and off. You should find that it makes a circuit when ignitoin is turned on, and not when it\'s off.

[imebgo]

Ok, im have been messing around today and I am trying to isolate the 30amp EGI circuit so I can test for shorts (using the factory manual procedure)

Can someone confirm the correct way to do this.

So far I Have:

Disconnected:

30Amp egi fuse
EGI Main Relay
Injectors
Air Pump Relay
ECU
Turbo Control Solenoid 1/2

Im having trouble locating the X-05 Common connector for the Emissions Harness to Front Harness and the Diagnosis Module, these appear to be the only things left on the circuit according to the wiring diagram at http://www.wankel.net/~krwright/files/manuals/1993%20RX-7%20FSM/_Z_Wiring_Diagram.pdf

With the ignition on I get continuity over the 30Amp EGI Terminal, I just wondered if I need to test with the ignition on or off?  I may have continuity because of the X-05 Connector and the Diagnosis module still being connected.

This is driving me NUTS!  Am I trying to find this fault correctly, or am I way way off!

May also need to disconnect X-07 (Front/Dash harness connector) also.  This seems to be in the circuit.

Thanks,

James

[ianelvar]

Sounds like you\'re having fun. I spent ages trying to find the X-05 connector myself. Don\'t forget that all the manuals are yank, so some stuff isn\'t labeled as being in the right place for our left-hand drive cars. The diagrams appear to be correct, but the component locations seem to differ in places.

The X-05, If I recall correctly, is the blue connector, down in the passenger footwell that connects the engine loom to the car loom. You\'ll have to get in nearly upside down to try and get to it, as it\'s tucked up behind all the trim near where the engine loom goes through the firewall.

with the ingnition on, you should get continuity over the EGi fuse, as the EGO relay will activate the circuit.

I think the X-07 circuit is a big blue connector underneath the stearing column, but I could be wrong about that.

Anyway, you seem to be headed in the right direction.

[imebgo]

Fun? lol

I think im missing some fundamental understanding of all of this.

The short says disconnect all the connectors in the circuit and then reattach until there is voltage going over the 30amp EGI Fuse.

So i have removed everything, injectors, solenoids, X-05, X-07.  If I Disconnect the EGI Relay I dont have any voltage over the fuse, as expected.  If I connect the relay and dont turn the ignition, theres no voltage as expected, If I turn the ignition on I get voltage over the EGI Fuse ?? thats not expected is it??  Surely for voltage to be present over those terminals the circuit must be grounded somewhere, and I cant see anywhere on the diagram to indicate this, so whats happened?

Does this mean that somewhere after the EGI Relay the circuit is shorting out?

Next question, is the only way to sort this I guess is to rip the wiring out from the fuse onwards and then inspect it all the wrap it back up again? Is there a method to isolate the fault even more? (if I was doing it right in the first place!)

Hmmm Sounds like a big task lol

Ta,

James

[ianelvar]

LOL. Arrrgghh, dude, you\'ve lost me there. I\'ll have a look in the manual and try to come up with a comprehensive list of things to check.

When I get a problem like this I always try to sit down with the manual and redraw the circuit myself with only the components I\'m interested in included. This will give you a clear view of what to expect, and helps just having the whole circuit on one page rather than two. Give it a go, and try to think about what voltages you\'d expect at various stages in the circuit, and in its various different states.

Try it and see what you come up with. I\'ll do the same.