• Welcome to the Contour Enthusiasts Group, the best resource for the Ford Contour and Mercury Mystique.

    You can register to join the community.

Intake manifold torque specification question

K

K-Dog

New CEG'er
Joined
Feb 3, 2010
Messages
17
A couple of months ago I pulled and replaced the upper and lower intake manifold gaskets on our '97 Contour with a 2.5L V6. I retightened all bolts to spec. (book says 72 to 108 in-lbs) using a big torque wrench not really designed for lower torque values. Everything ran great for a while, then it started running a bit rough, and it finally began throwing cylinder misfire codes. Figured it was something to do with my work.

So I pulled everything off again and redid it using a new wrench calibrated in in-lbs. (I torqued to 108.) Same story: ran well, then ran rough, now misfires :mad:

Has anyone else experienced something like this? Problem seems particularly bad on very hot days (we live in Arizona, so I mean hot!) It seems to me the bolts must be loosening. Do I just go ahead and over-torque, or should I be using threadlock? Any other ideas? Thanks!
 
how do you know that the bolts are loosening? have you checked the break away torque on the bolts? they only need to be alittle more then hand tight.

if it missfires check the plugs and wires for carbon tracking. replace together as needed.

if you think that the uim is coming free check for vacuum leaks. this shouldn't however, I beleive, cause a miss fire.
 
Put on over 40 manifolds. Not 1 has ever come back with an intake leak from my garage. That being said i tq too 100 in-lbs. Nothing more is needed..you will flatten your gasket and they will fail sooner!

Your problem is not the gaskets. Do what brapple recommended. Plugs wires..even coil pack check.
 
I've recently replaced plugs, plug wires, coil pack, O2 sensors, coolant temp sensor, vacuum lines, o-rings on injectors, and cleaned the upper and lower manifolds. EGR operates fine (after cleaning out the vacuum channel right under the throttle plate -- was totally clogged!). Doing nothing else but pulling the manifold and retightening the bolts took care of the problem last time, so I am fairly confident that is where the problem lies. (In fact, before I did that I sprayed some carb cleaner around mani gaskets with the engine running and got some stumbling as a result.) And you're right, Harry -- I don't want to risk crushing the gaskets. I've been very careful about the tightening sequence, too. I suppose it's possible one of the surfaces has warped.
 
K-Dog said:
I've recently replaced plugs, plug wires, coil pack, O2 sensors, coolant temp sensor, vacuum lines, o-rings on injectors, and cleaned the upper and lower manifolds. EGR operates fine (after cleaning out the vacuum channel right under the throttle plate -- was totally clogged!). Doing nothing else but pulling the manifold and retightening the bolts took care of the problem last time, so I am fairly confident that is where the problem lies. (In fact, before I did that I sprayed some carb cleaner around mani gaskets with the engine running and got some stumbling as a result.) And you're right, Harry -- I don't want to risk crushing the gaskets. I've been very careful about the tightening sequence, too. I suppose it's possible one of the surfaces has warped.
Click to expand...
Sounds like you have a gasket problem and not a tightened down problem. Get new gaskets.
 
Sorry, I should have mentioned that both manifold gaskets are new as well (Fel-Pro) -- I double checked their condition when I pulled the mani back off. All mating services were meticulously cleaned before installation of the new gaskets. I am so not looking forward to working on this at 110 degrees!
 
Check the three electrical connectors on the passenger end of the rear valve cover.

I did some UIM/LIM work a few weeks ago and had a bad warm mis-fire afterwards. Turns out when I parted the middle connector, which carries the firing wires for the coil pack, the O-ring in the connector pulled out of it's groove and I didn't notice it. The out of place O-ring kept the connector from fully mating and I was getting intermittent firing on one coil. It would run OK when cold, but mis-fire once warmed up.
 
Thanks for everyone's input, and for the tip gmorrell; I've follow up with whatever I discover.
 
I hate to say this...but i fear you might be the 2nd person who had a similar problem. It's so rare most here wouldn't even think of mentioning it.

The bearings that the lim linkages run through on the lim. Those have gone bad on 1 persons car. Causing it to run as if his UIM gaskets were bad resulting in the light to flash and hesitation.

They can be replaced...and were honestly cheap $6.00 a piece. You can't get them at ford. They were sold some where...but i don't recall. A search of lim bearings might turn something up for ya.

Do me a favor!!! Grab a can of carb cleaner! leave the car running...and grab the can (with the red plastic straw connected) and stray deep into the bend of the UIm. On the exterior...if the leak is around the heads..(from warpage) the idle will raise quickly and the car will change rpms. Srpay little bit here...a little bit there. Keep spraying in areas where the uim meets the lim. To check all the plenum. That way you start to remove what areas could be causing the porblem. Then spray around the linkages. To see if the bearings are bad!!
 
Are these bushings the throttle shafts run in or actual bearings?? Bushings are typically used in Holley Carbs and they do wear with extended usage and high vacuum. Weber got it right and uses 5mm ball bearings.
 
You must log in or register to reply here.
Back
Top