My son has a '96 Cobra. Check engine light recently came on, codes for both banks running lean. Took it to the shop who said the IMRC is bad. This is something I'm not familiar with, but I gather it's part of the intake. Shop wants me to source the part. Who knows about these things and can recommend something? Yeah, I can Google it, but hoping someone has first hand knowledge.
Here is a very good breakdown of the system and how it works.
https://img1.wsimg.com/blobby/go/1975f84f-4935-4131-8404-5a914da1afb7/downloads/1btatmkq1_834019.pdf
MMR also sells IMRC delete plates is you wanted to remove the system completely.
https://www.modularmotorsportsracing.com/cart/index.php?main_page=product_info&products_id=699
If the code is for bank running lean how did they arrive at the conclusion that the IMRC system is bad? I would check simple things first.
Not sure I would agree with their diagnosis.
IMRC's are just a partial throttle valve in the intake to increase the tumble going into the chamber at low air flows. It being stuck open or closed does not add or subtract air. It's quite possible it is broken, but you also need to get them to be much more specific of what's broken on it. Most of them, the actuator fails in some manner, which isn't a lot of what is there.
If it's really worn out, and the shafts are leaking- *maybe* that's the source of the air leak.
It's a lot more likely that one of the rubber tubes downstream of the air meter is leaking- and there are a lot of them including the PVC and gas vapor systems.
They said the gasket on the IMRC is bad and sucking air. I'm trying to learn about it. Thanks for the link!!
If it's a bad gasket, can't they just replace the gaskets? If it really is bad IMRC housings, can't they must true the housings? If you go with the deletes, you are going to make more power up top, but lose a lot of power down low. I really had a love / hate affair with my 97 Cobra. The engine and brakes were the only things I really liked about it for what it cost. They will run if you drive it hard like you hate it. If you baby it, that engine is a real dog.
In reply to AnthonyGS (Forum Supporter) :
Agreed. You have to beat it like it owes your grandmother money.
SKJSS (formerly Klayfish) said:They said the gasket on the IMRC is bad and sucking air. I'm trying to learn about it. Thanks for the link!!
That's not a bad thing- if there's an IMRC problem. Cheap to change a gasket.
Does 6 hours labor sound right to change it? I haven't looked at the car yet, but it seems like a lot. Not sure how buried the IMRC is.
I have the three valve version, they are between the intake and heads. Mine got deleted when I went to a different intake.
They shouldn’t be that bad to replace at least not on an 08 Mustang.
I went to the Ford Racing intake and did lose some low rpm grunt but gained actual seat of the pants HP. With my cams it really screams. No I just need better valve springs so I can bump up the rev limiter.
I called the shop myself this morning to get clarification. They said the bearings inside the IMRC are worn badly, allowing the rod inside to move around and it's sucking air. A lot of it. As far as we know, the engine is stock. Now to figure out whether to buy another IMRC or go with the delete kit.
In reply to SKJSS (formerly Klayfish) :
There should be low mileage used ones for sale cheap. It's the first thing you remove when boosting these engines.
akylekoz said:I have the three valve version, they are between the intake and heads. Mine got deleted when I went to a different intake.
They shouldn’t be that bad to replace at least not on an 08 Mustang.
I went to the Ford Racing intake and did lose some low rpm grunt but gained actual seat of the pants HP. With my cams it really screams. No I just need better valve springs so I can bump up the rev limiter.
Comp VSR cams are fun. Had a set in my 05 Mustang and they produced a significant amount of power coupled with a C&L intake manifold(which i think i had one of like 10 they made) and a ported throttle body.
The car made 360rwhp on a Mustang dyno with full bolt ons, heads and cams. It ran with blower cars though so it wasnt really about the dyno numbers. Sounded insane with the cams and long tubes. I did like the Ford Racing Hot Rod cams better but they didnt produce as much power as the Comp cams.
As much as the 3 valve S197 is the red headed step child they were actually pretty great. I miss mine quite a bit.
In reply to kevinatfms :
Couldn't agree more, mine has long tubes, bolt ons, Detroit Rockers cams with a canned Brenspeed tune. Prior to the intake change it made 320 to the wheels, revs happily and freely. These are a sturdy motor 350-400 horse capable NA motor that has a unique sound, what's not to like.
I perfer the look and interior of a 05-09 and they are lighter than the 5.0 cars, it may be a keeper if not long term toy.
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