Contour Enthusiasts Group Archives Forums Modifications Duratec Maintenance Multiple Queries!

I have a 98 with 99,000km 2.5L 5speed. It has a lack of power above 4000rpm. I would like to start working on my car myself because I am poor. I need some help with this though, I know nothing but am willing to learn. I understand that it is probably the IMRC but where is this, does someone have pics? What are the 'secondaries' and where are they located. How would I determine which one is causing the problem.

Thanks for all your help,
Mike

Tests.
http://www.contour.org/ubbthreads/showflat.php?Cat=&Board=trouble&Number=976209&page=&view=&sb=5&o=&fpart=all&vc=1

Location. Under the black plastic cover
http://img256.imageshack.us/my.php?image=cover2vd.jpg

Thanks very much...can I still drive the car like this or will it do more damage?

Shift before 4000 RPM (aka drive less aggressively, cheaper on gas too) and you should be fine.

Edit. One other thing you may want to consider checking is a plugged exhaust. A good cheap way to test is to remove the O2 sensors, in this order (and see if the performance improves). Uninstall Bank 2 lower (radiator side) to determine if main cat is plugged, reinstall Bank 2 lower and then uninstall Bank 2 upper (radiator) to determine if Bank 2 precat is plugged, reinstall Bank 2 upper and then uninstall Bank 1 upper (hardest one, close to firewall) to determine if bank 1 precat is plugged. You don't need to mess with bank 1 lower as bank 2 lower will also be a test of that issue too (if that is the issue). Negative battery terminal needs to be disconnected before uninstalling or reinstalling O2 sensors. Good luck.

Thanks for the help and I have no idea what you just said
You are going to have to bear with me as I have no clue about anything mechanically but it is about damn time I learn!! How does removing the sensors improve performance if there was an exhaust plug?

What are the secondaries?

"Lower intake manifold houses secondary runner butterfly and fuel injectors along with fuel rails. Below 3700 rpm the engine only breathes through primary runners and one intake valve. At 3700 rpm a 34 mm butterfly opens and allows the engine to breathe through both intake runners and intake valves." From SHO.com. I guessed with it being open, you get more power. If you don't understand, don't worry about it (for now). Someone, (Ray maybe) will give you a better description later.

As for the plugged exhaust (aka catalytic convertor being broken and plugging up the exhaust), sometimes, a clogged catalytic convertor can cause bad engine performance at higher RPMs. For now, don't worry about it. Just test the IMRC and go from there.

Edit. Any CEL codes?

Might be good to go to the library and pick up a car repair book or manual (Chiltons, Haynes or Popular Mechanics) to read up on how cars perform. Good luck.

Hey!
Explanation
Your lack of power at 4K is certainly evidence of either a faulty IMRC/secondary/linkage, or a faulty catalytic converter.

The engine has, as tony stated, what you can consider two "airways" it can use. one, when the secondaries are not opened, is comprised of about half of the possible airways being closed with small round plates attached to a rod.

The smaller total airway creates an increase in torque (to get you going). Once moving, the IMRC "does its thing" and pulls the round plates 90 degrees, allowing air to flow through the other half of the airway as well, thus doubling your volume and creating a surge in horsepower.

Your IMRC is a small silver box underneath the "Duratec" plastic engine cover in the front of the engine (three 7mm bolts).

The IMRC has a connection coming from the PCM (car computer) that tells the IMRC when to "do its thing" (3750ish during normal acceleration and ~3200rpm at WOT[wide.open.throttle])

When instructed to "do its thing" by the PCM, the IMRC pulls on a cable (much like a bicycle brake cable works) and the cable leads down and to what is referred to as a "secondary linkage". this is nothing more than a very tense spring (that holds the secondaries closed.. remember you need that increased torque!!) and a copper/brass colored rod that connects another "bank" or plates. The cable is pulled, compressing that spring, and rotating both of those banks of plates 90 degrees, bumping your HP up. The plates snap back shut if you ever drop below secondary operation RPM.

If your problem is a faulty IMRC, then it would never open the secondaries. This would exhibit symptoms of normal driving any time you are below the secondary operation RPM, but a loss of power (since it isn't opening those plates) at 4K (or so).

Testing:
Firstly, if the IMRC isn't operating (EVER) then you should have a CEL code stored for that. Have the codes pulled. Tony can reference a place that does it for free, even in Canada (which doesn't do it, as the US chains will).

Secondly:
You can see the secondary linkage by looking in to the engine bay from the driver's side. Look underneath the air intake for the linkage rod (copper/brass colored rod)

you can see one of the secondary bank hinges in this picture:





It is to the left of the round TB, between the TB and that black electrical connector. (its round, metal and has a black "rectangle" in the center, in that picture.

you can also get a top down view in this (disassembled version) picture:




Its the bottom right metal hinge. You can also see the "plates" I was talking about in every other hole of the LIM(lower.intake.manifold)

Anyway, rev the car above 4K (audibly) using the black pivot point to the right of the TB (in that first picture) and watch for that rod and those banks/hinges to move towards the firewall(rear) of the engine bay, then move back when you stop revving the car.

Ray

Reading it in the colors are hurting my eyes.

It could also be high air intake temps. The ECU pulls timing when the temp gets above 100 degrees. If you have done anything to lean out your AFR you may want to run a higher octane fuel. Also your C/R can increase over time (rumor, not sure) try some diff gas. Look into the engine bay, underneath the Tb. Rev the car and look to see if the secondaries are IN FACT opening!