rebuilt head now no idle

[jmorton]

Okay, any of you foks that have rebuilt your m30 cylinder head - mine's together, she starts, she runs OK as long as I have my foot on the accelerator, but she dies as soon as I take my foot off, even at regular operating temperature. I checked the fault codes using the stomp on the pedal five times routine, and it's showing no faults, not even a idle actuator valve fault - so what gives? Any ideas? I'm lost at this point . . .

[zygoteer]

After I did my head gasket over a summer weekend the Idle Control Valve gave a problem on reassembly... would only run above 1500 rpm with foot on throttle, so I cleaned the ICV and it gave a lovely smooth 800 rpm idle.
I had no codes either, I figured the aluminium oxide surface deposits it gets probably dried and made it stick a lot.

Its worth a try ... just use carb cleaner and an old toothbrush to get in the opening ... takes half hour tops, but make sure the valve rotates inside smoothly.

(I assume the shaped hoses that connect to it are not leaking air)

[Jeff N.]

1 - check to make sure your throttle position sensor is triggering the idle circuit when you release the throttle.
2 - vacuum leaks, got any? recheck all the hoses to the intake manifold,
especially the ICV hose, booster hose and the 3mm hoses under the intake.
3 - cam timing. are you sure you have it right? not on tooth advanced or retarded?

That's where I would start.

Jeff

[jmorton]

Thanks, for the fast replies, I know I'm spot on with the cam gear and chain, I've had the upper timing cover back off to check it. The 3mm vacuum hoses are all new and connected. I'll continue to search for vacuum leaks, and I'll take the ICV off and clean it out. How do I check the throttle position sensor?

[octanejunkie]

The throttle position sensor should make a little "click" as soon as you touch the throttle. Check this in the engine bay and adjust with the little screws on the tps mounting.

[Bill R.]

carb cleaner, i would use throttle body cleaner. Carb cleaner can damage electrical components , I would triple check the cam timing again and verify that its not off... and then i would check one more time for vacum leaks since that what it sounds like is the problem.




1 - check to make sure your throttle position sensor is triggering the idle circuit when you release the throttle.
2 - vacuum leaks, got any? recheck all the hoses to the intake manifold,
especially the ICV hose, booster hose and the 3mm hoses under the intake.
3 - cam timing. are you sure you have it right? not on tooth advanced or retarded?

That's where I would start.

Jeff

[genphreak]

Check if the air is the root cause by temporarily blocking off the recirc pipe going into the afm-throttle body pipe... if the engine idles, you will know if the leak is there, or in the inlet manifold...

If you feel it is air leaks, have you checked the non-return valve take-off? It often breaks off giving you a leak through the brake booster pipe.. check the timing and head cover gaskets are all nicely sealed (Hylomar is the best stuff to use).

[jmorton]

After I did my head gasket over a summer weekend the Idle Control Valve gave a problem on reassembly... would only run above 1500 rpm with foot on throttle, so I cleaned the ICV and it gave a lovely smooth 800 rpm idle.
I had no codes either, I figured the aluminium oxide surface deposits it gets probably dried and made it stick a lot.

Its worth a try ... just use carb cleaner and an old toothbrush to get in the opening ... takes half hour tops, but make sure the valve rotates inside smoothly.

(I assume the shaped hoses that connect to it are not leaking air)

Genphreak - you were right, some throttle bottle cleaner, a tiny brush, and my baby runs good as new. I've been driving my wife's Acura TL sport AT. Lord, am I happy to have my five speed, rear wheel drive, "ultimate driving machine" back!

Thanks to all for the good advice!

[jmorton]

Genphreak - you were right, some throttle bottle cleaner, a tiny brush, and my baby runs good as new. I've been driving my wife's Acura TL sport AT. Lord, am I happy to have my five speed, rear wheel drive, "ultimate driving machine" back!

Thanks to all for the good advice!

Woops, sorry Zygoteer, it was you who was right - genphreak, is that a trailer hitch sticking out of your rear, or?