Unidentified Engine Component

mercury
sable

#1

I discovered a small, unattached metal arm on the engine of my 1999 Mercury Sable. It is the DOHC 24 valve V6 engine. I will try to attach a picture if I can.



It is just in front of and below the throttle body. I am not sure what it does other than provide a physical link with a component further back toward the firewall. It came loose when the metal clip holding it in place was mashed beyond recognition over years of operation.



This car does have some difficulty starting sometimes and I am wondering of this component not doing its job is to blame.


#2

I’ve heard the way to post a picture is to reply to your own question. In that reply is where you can link your photo.


#3

Here is a (poor) picture of the arm. Thanks in advance for any insights!


#4

So far, the best I can see ( there are no taurii in the shop just now ) it joins the right and left intake runners.
each end held on by little white plastic clips you can buy at the dealer # F5RZ-9F955-AB


#5

Thanks. I’ll look into that.


#6

With that linkage disconnected, would that cause the engine to stall out? If I’m understanding the purpose of the intake runners, they provide more or less air to the intake manifold depending on the operating situation.


#7

Yes, it will cause a choking situation and all that goes with that.
The intake runners are small butterfly valves which, I believe, default to closed.
As is, you’re probably operating just one side now.

AND, to top it off, those little clips aren’t cheap at $7.65 list each. ( we sell @ 6.49 )


#8

I’m pretty sure the butterflies should remain closed until you hit something on the order of 3500 rpms or so. They should be out of the picture at start up & idle. If they were hanging open then that would cause a problem. But it should also set an error code (is your check engine light on?), and I’m not sure how plausible it is that a loss of linkage would leave them hanging open. A lot more about the IMRC module would have to come apart for that to happen.

I think that your occasional difficulty starting is from something else. Then you only just mentioned stalling out. Is there more info you can offer about that?


#9

Usually after the engine has gone up to operating temperature, been shut off, and then is restarted it will stall out and refuse to restart (although it cranks) until it cools back down. Someone suggested the idle air controller could be at fault, and then I found this. Could be unrelated, but then cars tend to run better if all their parts are properly connected!


#10

Well, you should certainly fix this linkage whether its related to starting issues or not. But the starting issues are more likely due to other things - like maybe fuel pump problems.


#11

The way these dual runner manifolds are designed, there is only one butterfly per two runners, and there’s two runners per cylinder so there’s no way to actually “choke” the engine. When it’s idling the IMRC is at work opening the butterfly to have the longest runners for the best idle. When the RPM is above 2000 the butterfly closes to give you a shorter runner for better performance. With the IMRC disconnected it will still start, but will idle poorly. What I mean by idle poorly is to surge. If you get the RPM above 1800 it should smooth out. The IAC could be the culprit, but you would still be able to partly open the throttle when it’s a no start and that will give an idea if that’s the problem. As others have stated though, get those clips and get that part repaired and your problem may be fixed.