I have the SHO ghost smh

[NoSlo]

It's hard to ultimately diagnose a fuel supply issue unless you have a remote fuel pressure gauge that can be observed while driving, so you can stomp the pedal for a 0-65 run.

A particular type of driving that illuminates the CEL and sets the code? Does the CEL cycle on and off?

If the 542 code also returns without the engine taking serious stalls or stumbles (Fuel pump open, bad ground or always on - - Power / Fuel Pump Circuits) it may be time to start believing that code.

We have to rule out sources of vacuum leak (or lack of vacuum opening when expected). The big PCV pipe is probably 25 years old. Any leak in the EGR tubing or gasket seal (if you've got one) can let in excess air (instead of setting an EGR code from the passages being plugged up). Vacuum hoses in the back of the engine are brittle. A trick is spraying starter fluid around potential leak sites to see if RPMs increase.

I had to clean out the three PCV holes in the bottom of my throttle body with drill bits, and the same with the main PCV passage, as they were completely gunked up.

Otherwise, if nothing else can be identified, injectors can be flow tested or replaced. One would expect that only one injector would initially have a problem, setting only one bank code.

 

[SHOYAY]

It's hard to ultimately diagnose a fuel supply issue unless you have a remote fuel pressure gauge that can be observed while driving, so you can stomp the pedal for a 0-65 run.

A particular type of driving that illuminates the CEL and sets the code? Does the CEL cycle on and off?

If the 542 code also returns without the engine taking serious stalls or stumbles (Fuel pump open, bad ground or always on - - Power / Fuel Pump Circuits) it may be time to start believing that code.

We have to rule out sources of vacuum leak (or lack of vacuum opening when expected). The big PCV pipe is probably 25 years old. Any leak in the EGR tubing or gasket seal (if you've got one) can let in excess air (instead of setting an EGR code from the passages being plugged up). Vacuum hoses in the back of the engine are brittle. A trick is spraying starter fluid around potential leak sites to see if RPMs increase.

I had to clean out the three PCV holes in the bottom of my throttle body with drill bits, and the same with the main PCV passage, as they were completely gunked up.

Otherwise, if nothing else can be identified, injectors can be flow tested or replaced. One would expect that only one injector would initially have a problem, setting only one bank code.

The cel cycles on and off when driving it... doesn't seem to have a particular type of driving that affects it much...but...since I put new o2s in, the light is on more consistent now.
Now, if I erase codes, then drive it, the light will start coming on after about 5-10 minutes of driving and then do it's on and off thing. If I've driven it that day and it sits for just hours, and it's cold etc and when I go to drive it again light is on right away. BUT if it sits for days and I go to drive it, the light stays off for that 10 minutes of driving. It's only immediately on if I have driven it that day. Any days of sitting, light is off for 10mins of driving.
I don't think I have any vacuum leaks cause it has the perfect 22hg at idle and reacts correctly to revving etc.
I'm going to try the fp pressure while driving it, I have access to a gauge etc so I can do that. I took for granted my fp readings that were spot on for idle and revving etc but didn't expand my investigation into while driving fuel pressure and pump all warmed up etc. As for egr, that system has been deleted, so I ignore the egr code.

 

[NoSlo]

The check engine light going on and off on a pretty regular interval is how a bad O2 sensor behaves, failure to detect switching. Since we've been switching sensors here and haven't rectified the problem, one might instead look at what else could cause such a fault.

Having other engine management missing and setting codes and illuminating the CEL will aggravate our diagnosis. We wish the ECU was aware of your non-EGR. When the EGR is commanded opened and closed, the computer can discover something is up, because it can sense even the non-response in the fuel mixture and RPMs just from having the small intake passage port plugged up. Expecting EGR could upset the learned fuel trim mapping.

Since it continues to have O2 sensor issues (rather than perhaps actually "running lean") I would ensure the harness circuits at the connector to both O2 sensors are working with a multimeter before going to more drastic measures:

1 - power from 15A fuse #5 under the dash, +12V key-on power that heats the sensor and provides reference voltage (Pink/Orange); (you would notice a fuse out, since this also runs VAPS, part of EATC, multi-function switch turn signals, defrost button control.)
2 - ground - On the three-wire sensor, O2 sensor ground is on the harness under the center of the intake manifold (black); check for continuity between harness plug and battery;
3 - continuity of "HO2S" harness wires from o2 sensors back to ECU connector. Red/black at ECU pin 29, and dark blue/light green at pin 43.

See the harness connector diagram pinouts below for ground, "ign run" 12+, and sensor pins.

 

[SHOYAY]

The O2 sensor light going on and off on a pretty regular interval is how a bad sensor behaves, failure to detect switching. Since we've been switching sensors here and haven't rectified the problem, one might instead look at what else could cause such a fault.

Having other engine management missing and setting codes and illuminating the CEL will aggravate our diagnosis. We wish the ECU was aware of your non-EGR. When the EGR is commanded opened and closed, the computer can discover something is up, because it can sense even the non-response in the fuel mixture and RPMs just from having the small intake passage port plugged up. Expecting EGR could upset the learned fuel trim mapping.

Since it continues to have O2 sensor issues (rather than perhaps actually "running lean") I would ensure the harness circuits at the connector to both O2 sensors are working with a multimeter before going to more drastic measures:

1 - power from 15A fuse #5 under the dash, +12V key-on power that heats the sensor and provides reference voltage (Pink/Orange); (you would notice a fuse out, since this also runs VAPS, part of EATC, multi-function switch turn signals, defrost button control.)
2 - ground - On the three-wire sensor, O2 sensor ground is on the harness under the center of the intake manifold (black); check for continuity between harness plug and battery;
3 - continuity of "HO2S" harness wires from o2 sensors back to ECU connector. Red/black at ECU pin 29, and dark blue/light green at pin 43.

See the harness connector diagram pinouts below for ground, "ign run" 12+, and sensor pins.

Thanks...I'll try and get to that as soon as I get some time...
When I rev the engine, is it normal for several clicking noises to emanate from the ccrm?

 

[NoSlo]

It is not normal for several clicking noises to come from the CCRM when you rev the engine. Relays inside would make noise, not that I've ever heard them, but nothing any faster than the normal cycle time of the AC system, about every 20-40 seconds, and unlike the fan, fuel pump, or PCM power relays in the CCRM, AC doesn't make noise because it is a solid-state relay.

I wonder if you are hearing ignition sparks around the coil pack. Normally you wouldn't expect that except for internal failure in the coil pack, because each of three coils runs two spark plugs, so even a bad plug wire would prefer to spark through the other plug's exhaust gasses rather than finding a spark through ground. You can see if you get shocked touching around there if you are adventurous.

There's also the evap canister solenoid below all that that could click if it was weak, when revs give higher voltage, but should only be commanded to operate after engines been running a while.

Also continuing above, you can partially check the disconnected O2 sensors by measuring between the power and ground pins. Off the top of my head, they should measure around 10 ohms. Don't measure the sensor output pin though, as it can possibly be damaged by the meter's voltage.

 

[SHOYAY]

It is not normal for several clicking noises to come from the CCRM when you rev the engine. Relays inside would make noise, not that I've ever heard them, but nothing any faster than the normal cycle time of the AC system, about every 20-40 seconds, and unlike the fan, fuel pump, or PCM power relays in the CCRM, AC doesn't make noise because it is a solid-state relay.

I wonder if you are hearing ignition sparks around the coil pack. Normally you wouldn't expect that except for internal failure in the coil pack, because each of three coils runs two spark plugs, so even a bad plug wire would prefer to spark through the other plug's exhaust gasses rather than finding a spark through ground. You can see if you get shocked touching around there if you are adventurous.

There's also the evap canister solenoid below all that that could click if it was weak, when revs give higher voltage, but should only be commanded to operate after engines been running a while.

Also continuing above, you can partially check the disconnected O2 sensors by measuring between the power and ground pins. Off the top of my head, they should measure around 10 ohms. Don't measure the sensor output pin though, as it can possibly be damaged by the meter's voltage.

I put my hand on the ccrm and rev it and you can feel it clicking internally...it feels like 3 clicks.

 

[SHOYAY]

Drove to a car show today and all same codes came back after being cleared. This week I replaced fuel pump, checked wiring for continuity on both o2s, tps, and maf and all's well. These lean codes will not disappear. I'm at a loss for what's causing it. I'm down to thinking of replacing pcm. I have a 94 mtx pcm that as far as I've been told can be used in my 92 mtx.

 

[zoomlater]

It should as long as it has X2J code on it

 

[NoSlo]

In 1992 though, we have F2DZ-12A650-AA (X2J) (1992-1995) - and F2DZ-12A650-BA (W2Z) with California emissions. With EGR delete, the 1994 or one without California should be your choice to manage the engine.

I'll let you have a look for differences in the PCM pins besides EGR.





I think the descriptions of a few pins got mixed up creating the 1992 documentation. It is unlikely that these functions below switched position. Rather, somebody got confused because IAC (intake air control) was renamed IMRC, and ISC (idle speed control) was renamed IAC.

1992: wiring diagram : Idle air control - circuit 965 LG/P - Pin 32
1994 : wiring diagram : Intake manifold runner control (secondaries) - Circuit 965 LG/P - Pin 32

1992: wiring diagram : Idle air bypass valve - circuit 68 O/BK - Pin 21
1994 : wiring diagram : Idle air control valve - circuit 68 O/BK - Pin 21​

Also 1994 has one change I know of - the AC refrigerant containment switch - it seems the ECU is only informed about that on the ATX, though.

 

[SHOYAY]

In 1992 though, we have F2DZ-12A650-AA (X2J) (1992-1995) - and F2DZ-12A650-BA (W2Z) with California emissions. With EGR delete, the 1994 or one without California should be your choice to manage the engine.

I'll let you have a look for differences in the PCM pins besides EGR.





I think the descriptions of a few pins got mixed up creating the 1992 documentation. It is unlikely that these functions below switched position. Rather, somebody got confused because IAC (intake air control) was renamed IMRC, and ISC (idle speed control) was renamed IAC.

1992: wiring diagram : Idle air control - circuit 965 LG/P - Pin 32
1994 : wiring diagram : Intake manifold runner control (secondaries) - Circuit 965 LG/P - Pin 32

1992: wiring diagram : Idle air bypass valve - circuit 68 O/BK - Pin 21
1994 : wiring diagram : Idle air control valve - circuit 68 O/BK - Pin 21​

Also 1994 has one change I know of - the AC refrigerant containment switch - it seems the ECU is only informed about that on the ATX, though.

Yea with the egr already deleted on mine I figure the non Cali emission one should work. Ccrm have to be exchanged also? One is an M and the other is a D

 

[NoSlo]

You must use the correct relay module shipped with your car for your year. The wiring harness circuits and pinout is quite different.

D for 1994-1995 and M for 1989-1993.

You can see the significant differences, note the circuit numbers (1994-95 identical diagrams; 92 depicted below while 93 uses some different terms)



The description for 94/95 pin 1 and pin 2 is wrong; circuit 181 is still cooling fan low speed power (but on different pins).

 

[SHOYAY]

So I went crazy testing last couple days again. Vacuum is right on @20-22hg...and made sure no exhaust restrictions or intake problems via vacuum gauge and all's good. Fuel pressure was @28-30 idle and jumped to 39 with regulator unhooked. Did notice while it was idling, I heard a click from the ccrm and it stalled out. Started right back up tho, but that click and stall has me thinking something else is not right...ccrm or pcm

 

[luigisho]

CCRM can be heard clicking while it is functioning normally if you listen closely. However, I agree the next place to look are those 2 places. I don't suppose you have extra used ones laying around? If the fans and fuel are funky I'd start at the CCRM. Injector firing is controlled by pcm. I assume your wiring is in decent shape? SHOs make mechanics and used parts hoarders out of many of us.

 

[NoSlo]

The CCRM module provides power to the ECU via a relay when you turn on the key. Failure of constant voltage, of either the CCRM's many power lines or grounding may cause the relay to click off. Of course, the fuel pump is also run by relay (and you previously got a fuel pump code?). Vibration from revving may aggravate loose, worn, or shorting wires, or it may be that the voltage is not maintained by the alternator from a failing internal regulator or such. Intermittent fuel pump operation may, surprise, set a lean code, if not stalling the engine.

The CCRM (IRCM) ground location is also the PCM ground, the bolt on the fender with the battery wire. The CCRM's PCM power is provided by the 30A EEC engine compartment fuse, and the key-on voltage by the 10A ignition coil engine compartment fuse and of course the key. Each also has a couple in-line connectors in addition to the CCRM plug. The CCRM harness plug found on the wire leading towards the engine latch provides PCM power.

Connectors and fuses should be inspected for corrosion, cleaned and re-assembled before pursuing the main electronics. Vibration of a poor wire connector is probably more likely than a component fault.

 

[SHOYAY]

CCRM can be heard clicking while it is functioning normally if you listen closely. However, I agree the next place to look are those 2 places. I don't suppose you have extra used ones laying around? If the fans and fuel are funky I'd start at the CCRM. Injector firing is controlled by pcm. I assume your wiring is in decent shape? SHOs make mechanics and used parts hoarders out of many of us.

Yes wiring is in decent shape. I don't have an extra ccrm with the same code.

 

[SHOYAY]

Something came to mind...is it possible that the knock sensor is detecting my wrist pin noise and therefore it's adjusting my timing making it run lean?

 

[NoSlo]

Something came to mind...is it possible that the knock sensor is detecting my wrist pin noise and therefore it's adjusting my timing making it run lean?

An interesting possibility outside the box. It's possible it's being detected, but the engine should still know how it is managing the fuel.

Either not enough fuel, or too much oxygen, or O2 sensor switching detection or engine management is failing... Or an internal engine failure - do you still get good cylinder compression numbers?

 

[SHOYAY]

An interesting possibility outside the box. It's possible it's being detected, but the engine should still know how it is managing the fuel.

Either not enough fuel, or too much oxygen, or O2 sensor switching detection or engine management is failing... Or an internal engine failure - do you still get good cylinder compression numbers?

Yes I have even, good compression thru all the cylinders. The only thing I haven't changed is the pcm... every other part possible to change, has been. I'm thinking the next thing to change out is the pcm and ccrm.
Or get a air/fuel meter in there and see if I get the right readings and finally find out if the pcm is bad

 

[SHOYAY]

Today I switched the pcm and ccrm(both non CA) from my 94mtx into the car. Codes I'm getting from this computer are
Koeo
543
556
Koer
136
172
Still lean...I'm at a total loss of what this damn lean problem is....never had the 543 or 556 before changing the pcm and ccrm
Should I have changed ccrm or put original back in?...they are different codes...one D and one M

 

[NoSlo]

You cannot switch the CCRM code. Post #31.