protopro88

I just recently pulled the head off of my 91 honda accord because it had two bent valves. So i got the valves fixed and just got done installing the head. When i go to start it up, the idle pulses from 1500 rpm, to 2500 rpm, back and forth. What could be causing that? also the car has a very loud squealing noise, what could be causing that? thanks

GhostAccord

Bouncing idle can be a number of things. Here are a few;
• Vacuum leak - hose or gasket
• Air bubble in coolant system - bleed system
• Dirty IAC valve, FIT valve or air boost valve - Check FAQ, there are a few good threads on cleaning/adjusting them.

As for the squealing that could be an accessory belt that is ether worn or not properly tensioned/adjusted. Or it could be your timing belt rubbing up against something. Try adjusting the tension on your alternator and power steering belts.

protopro88

Well i bleed the cooling system, and i put the car into drive and the car idles perfect, just a little high at 1500 rps. What could possible be wrong?

GhostAccord

Sounds like it could be a vacuum leak.

protopro88

The only things that it could be would be the exhaust manifold and intake manifold. I didnt really disconnect anything else when i took the head off. Would an exhaust leak from the section where the upper and lower part of the manifold meet cause the idle to surge?

GhostAccord

A leak in the intake manifold gasket would do it. Or a crack that may have occurred in one of the hoses while you were moving things around.

protopro88

Ok. well ill check the make sure the nuts on the intake manifold are tight tomorrow. Also i had to remove the thermostat housing to get to a bold on the intake manifold. Would that cause a idling issue>

holmesnmanny

Assuming it's steady at 1500 when cold started and it hasn't warmed up yet, you sure it's simply not a cold start idle? Does it come down after it's warmed up?

protopro88

its only a steady 1500 rpm with its in drive. I let it sit in drive with my foot on the brake for probably a minute, and no change. Do you think it would be safe to drive it to warm it up?

protopro88

Im going to clean the iacv and fit valve tonight to see if that does anything

StreetsideStig

It should be safe for easy driving if it's revving a little high. I would agree that it's probably a vacuum leak, a pretty common problem, especially after that type of work.

protopro88

well i sprayed carb cleaner around the intake manifold gasket, tb gasket, iacv, fitv and nothing jumped in rpm. I also cleaned the iacv and fitv and it seemed to help a little bit. Now the car idles normal in park until i put it in drive and back to park then the idle starts to bounce around again.

holmesnmanny

It's very easy to spring a leak around the injector passages. Also, I like to use a fine mist of water to find vacuum leaks. I think it works better since it doesn't burn off so easily.

teamLegendz_sd

I you do a valve adjustment? it's a must do if you removed the head, adjust your valve clearance first, check timing, and so on...

protopro88

yea i tried to do a valve adjustment on it but the car didnt have any oil in it at the time so there was no oil pressure causing the rocker arms to be very sloppy and not hold the the clearence i set them to. Im going to do a valve adjustment tonight. Would that cause a bouncing idle and sluggish acceleration

chikin pickle

No, and the rocker arms are mechanical, oil pressure does not affect them at all. There isn't any oil pressure in the car even with oil in it anyways, there is only oil pressure when the oil pump is spinning.