95 SE Secondary Problem

[mjwood0]

Well, I removed the throttle body to clean it as my 95 SE throttle was sticking bad. Fixed the throttle problem completely and it is smooth as butter.

However, now my secondaries aren't opening (at least that's what I think it happening). When I rev the engine to around 4000 RPM, it just sort of stutters and won't rev any higher.

So... I know that I have vacuum operated secondaries and I know I messed with the air intake to get to the TB. All hoses are in place to the best of my knowledge. What do I check next?

I'm stumped as I have no clue where the secondary vacuum hoses even are!

Thanks,

Mark

 

[Daves95Contour]

hey

hey

Check to make sure that you secondary linkage is still intact. It is under the throttle body, right on the right side of the LIM (lower intake manifold). There are two separate white small clips that hold the little brass colored bar in to place in two separate areas. It is possible for the small white plastic clips to become brittle and break. If it is broken pull the upper intake manifold and follow the begining of the intake manifold rebuild that is located on contour.org home screen under the mods/parts section (below the forums url). Another possibility is check that the cars vacuum line that runs the seconaries and everything else that is vacuum oriented (one huge vacuum line on 95se) that connects in one piece to everthing Is NOT LEAKING! On the 95 there is no IMRC box that runs the secondaries. Instead, it is vacuum operated and when the car is off the secondies are actually open from the vacuum. Hope this helps...

 

[Ray]

You are correct, the 95's are vacuum operated, but they are vacuum CLOSED. missing vacuum is going to make them STAY open. That would make your car a DOG below 3800 or so.

Check your linkages physically, and make sure the copper rod is there that connects one bank of secondary plates to the other.

 

[mjwood0]

Thanks for the ideas!

Thanks for the ideas!

You both make very good points. I'll have to check into the linkage.

A little weird development...

I was testing them last night after I put the TB back together to make sure I didn't screw up anything with the vacuum lines. I tried with the car both in park and in neutral. Neither one allowed the secondaries to open. It was quite weird.

This morning, I got on the freeway and gunned it. Smooth transition all the way from 3000 to around 5000 rpm. Seems they work fine.

I guess my question is this -- is there not enough vacuum pressure without a load to engage the secondaries? I normally don't like revving the engine without a load, but I was being very careful last night. I wonder that if there is no load, there simply isn't enough vacuum to cause them to open?

At any rate, one of these days I'm going to have to get around to cleaning the LIM as described in that HOWTO. The car only has 47K on it but sat in my grandma's garage and was seldom used (about once a month). Cleaning out the TB was nasty and I even found a chipmunk's stash of nuts in my airbox... All is now cleaned and happy!

Thanks again!

 

[BrApple]

if you have an atx you have a park and neutral rev limiter at 4k rpm, so if you can't rev highre then that then the secondaries will not open ...


also since the vacuum holds them closed if there was a leak you would have poor driveability under 3k and it would be nice and smooth above 3 to 4 k rpm ...

 

[mjwood0]

That explains it! Thanks a lot BrApple!

It really did sound like a limiter, but when I searched, I found lots of information similar to what I was seeing being attributed to the secondaries not opening.

Problem solved! (now on to other problems...)

 

[ck42]

You are correct, the 95's are vacuum operated, but they are vacuum CLOSED. missing vacuum is going to make them STAY open. That would make your car a DOG below 3800 or so.

This has me wondering.

If the secondaries were staying open/partially open, this would allow more air into the mixture. So, wouldn't the MAF detect this increase in air flow and then have the PCM increase the fuel to compensate? I know I've gotta be missing something here.