96 Cobra Issues

Correct me if I'm wrong but IMRC is the Intake Manifold Runner Control and if it is stuck open or closed I would think you would just have to replace it. Just my 2 cents

It's quite possible that the codes are a result of each other. It would make sense that an IMRC not opening could cause a lean condition. Perhaps if one side is still working, it's the side that's too rich. I don't know much more than basics when it comes to trouble codes and stuff, but I've heard a lot about IMRC's getting some heavy deposits over the miles and years and simply need to be cleaned and replace the actuator unit as well. There's a link in the forums somewhere that has good pix and instructions on how to get to the IMRC's and clean them.

Yes, you're going to have to take it apart and clean them if you're technically saavy, if not, try the seafoam trick, some guys have reported good results with that. Me personally, I'd rather take it apart and clean it manually, then I KNOW it's clean.

I'm pretty sure the codes are all related, just fix the obvious thing first, reset and re-calibrate the PCM, then check again. IMRC stuck closed would cause a rich condition, and then once it gets too rich, it will read LEAN because the O2 sensors cannot read liquid fuel, so they decide there is way too much oxygen in the exhaust and call it lean.. See what I mean? It can be deceiving with this rich/lean code. Just clean the IMRC's and make sure the cables aren't binding on anything and are routed correctly.

Let us know how it goes, more help can be provided if necessary, don't be afraid to just ask..

Oh sure, that's not a problem. The IMRC's sit underneath the lower intake manifold and on top of the cylinder heads. You're going to need to pull the strut tower brace (if equipped), intake elbow, upper intake manifold, coolant crossover tube (drain a little coolant before you do this, makes it a lot easier, fuel rails are going to either need to come out, or you can unbolt them from the lower intake and pull the injectors from the manifold, then swing the entire rail over to the side and out of the way (use this method if you don't have access to the fuel quick disconnect tools), then you can safely remove the lower intake manifold.

Once you go to pull the lower you're going to see the controller is mounted underneath (but attached to) the lower intake manifold itself. The IMRC's will be sitting right underneath. Make sure you take special care of the gaskets as they are all reusable. You can then take the cables off of the IMRC's, take them to the side and commence a thorough cleaning! Good luck, let us know if you need any more advice.

There is a detailed PDF of how to do it somewhere. Maybe MustangWorld? I'm sure someone has a link. Try a search.

I have it from my website

http://www.svtmustangcobraclub.com/media/pdfs/tech/IMRC_Cleaning.pdf

There we go. I'll prob do this on mine once it warms up a bit.

The check engine light won't come back on until a complete "drive cycle" has been done.

Quoted from, http://www.fordscorpio.co.uk/drivecycle.htm

Whenever work has been done on the Engine or Sensors the EEC will take time to relearn it's optimum values. This process can be speeded up by following the recommended Drive Cycle - a process designed to help the EEC-V relearn all of the sensor values. Obviously it will do so without the full Drive Cycle - it just takes longer.

The recommended OBD II drive cycle begins with a cold start (with coolant temperature below 122 degrees F and the coolant and air temperature sensors within 11 degrees of one another).

NOTE: The ignition key must not be on prior to the cold start otherwise the heated oxygen sensor diagnostic may not run.
* As soon as the engine starts, idle the engine in D for two and a half minutes with the A/C and front and rear window defrost on.

OBDII checks oxygen sensor heater circuits, air pump and EVAP purge.

* Turn the A/C and front/rear defrost off, and accelerate to 55 mph at half throttle.

OBDII checks for ignition misfire, fuel trim and canister purge.

* Hold at a steady state speed of 55 mph for three minutes.

OBDII monitors EGR, air pump, O2 sensors and canister purge.

* Decelerate (coast down) to 20 mph without braking.

OBDII checks EGR and purge functions.

* Accelerate back to 55 to 60 mph at ¾ throttle.

OBDII checks misfire, fuel trim and purge again.

* Hold at a steady speed of 55 to 60 mph for five minutes.

OBDII monitors catalytic converter efficiency, misfire, EGR, fuel trim, oxygen sensors and purge functions.

* Decelerate (coast down) to a stop without braking.

OBDII makes a final check of EGR and canister purge.

* Test complete

Obviously there may be some variances, such as manual trans, idle in neutral, etc. Just use your best judgment, try to get as close to the test as possible.

In english, well I didn't know I was speaking another language! Basically that is the "drive cycle" that Ford uses, it's just looking for daily driving, and they figured all that would justify it. This just expedites the process for troubleshooting and testing purposes where driving it for a week would not be ideal (generally for service technicians).

OBDII is the type of engine management system that exists in the 95+ vehicles, it actually is a very sophisticated system so a lot of that is not really applicable for your troubleshooting of the IMRC system. Oxygen sensors sense the amount of oxygen content in the exhaust adjusting Short term and Long term fuel trims to sustain the engine under certain conditions (rich/lean/nominal), EVAP purge and air pump are emission related components therefore not applicable to your issue, however the test must be run in it's entirety. EGR (Exhaust Gas Recirculatory) is emission related, as well as canister purge. Fuel trim is what the system uses when a combination of inputs are sensed to adjust the pulse width of the fuel injectors in an attempt to keep the engine running at a nominal level (not rich nor lean).

I know it's a lot of information and a lot of unecessary information at that, but what I was just trying to get across was the use of the drive cycle to expedite the check engine light if it was going to come back on, a lot of people see a P1000 code in the system and assume everything is OK when it's actually not, it just hadn't run a complete drive cycle yet.

In my opinion you should just remove the IMRC's clean them and be done with it. If it's doesn't solve the problem, you could quite possibly have a bad IMRC controller, in which case you'll have eliminated the possibility of it being a "stuck" plate, which would have had to have been done anyhow.

Talk to you soon I guess!

Hey you don't need to replace the gaskets, all the ones you will pull off are reusable! Don't got spending money when it will make no difference anyways, unless of course they are torn, but that's highly unlikely.

I can pull mine off and take pictures of all the steps if you'd like, my Cobra is down right now anyhow waiting on a Koni shock rebuild. Let me know if it would help!