Rough Idle & Vibrations at highway speed.

[tripplec]

Could they be related or two symptoms. New wires and plugs changed a while back. the new plugs smoothed it out them. I had to replace the leaking radiatior. I have a pretty rough idle although the tach is stable. My biggest concern is why it vibrating at 90-100km/hr and also around 110-120km/hr. If I back off the gas on the highway it actually vibrates more. I had CV shafts replaced a year ago (after market shafts).

I am not sure if the engine is doing it even without load in coasting or not.

This is a 1990 CRX w/1.5L stock power train

[anassa]

Get a alignment make sure there is nothing wrong with the alignment have good tires then make sure nothing is clogged up (for freeway vibrations)

For crap running engine:

Maybe seafoam the engine (i think that's what its called..).

Also see to make sure there is no air leaks

bleed out the coolant, make sure there are no air bubbles...

Check those one of those things could help it.

[tripplec]

Tires are good with nothing in them. They are like new, low profile and vehcile tracks fine.

I looked for air leaks but could not find any. The vacumn advance for what appear a choke flap in the intake is defective. (metal arm appear to be separated and I can move it in and out of the vacumn chamber). Found that the other day. Likely a dealer part only so I will have to order one. I have checked and bled the coolant screw an number of times, getting air out mostly when its cold. (on the thermostat housing).

Thanks for the feedback.

[tripplec]

I took the beast to my mechanic. After a test drive he said it was tires. Well he had an old balancer an we checked all the tires. Most had some rim wobble in them two were real bad, one of these two had a very noticable side wobble and theother a hop. He balanced most of the stress out of them and we put the best combos on the front.

These ABS Aluminum rims and are clean never hit the curb etc but clearly poor quality. After all this test drive again and it was radically better. The steering wheel does not shake anymore nor does the vehicle vibrate as it did before.

I am still working on the idle. This engine is not know for a smooth idle he said. My RPM's also go up in slow traffice but ok after a bit of a faster run when it gets cooler from the air flow. I am gathering it is the IAC or an air pocket in the coolant line at the IAC. I see it is part of the coolant flow path with hoses going in and out.

[drummingpariah]

It actually sounds like you have a vacuum leak on the intake manifold. It could also be a problem with the hellish DPFI system (I suggest swapping to MPFI as soon as possible to avoid future headaches).

[tripplec]

I know I have a malfunctioning vacuum control module which is mounted on the trottle body, upper back side and an arm comes out controlling the intake butterfly valve. I am unable to locate this other than at honda who say its a tandem valve. The want $100 for this vacuum control. wow

Anyone with good sources for part? I am in Canada.

[drummingpariah]

$20 plus shipping and mine becomes yours. I'm going MPFI anyway. It'll probably be a few weeks before I'm able to send it out though.

[tripplec]

Originally Posted by drummingpariah

$20 plus shipping and mine becomes yours. I'm going MPFI anyway. It'll probably be a few weeks before I'm able to send it out though.

I pm'd you but no reply. Can you send a photo of your part?

[drummingpariah]

Oh sure thing. It'll have to wait until morning though, it's dark out now. Your PM must've gotten lost in the shuffle (I tend to get a lot of 'em).