'93 N* Ear piercing whistle - Continuing glitch

[Mountie]

Continuing my troubleshooting, I repaired a broken vacuum connection to ( what I believe) is my Fuel Pump Relay ( next to EGR?). The vacuum from top of Throttle Body ( triple connection) to the FPR. My idle is still at about 1,200 rpm after repair.

I hear an ear piercing whistle above the FPR area. It's not loud, just piercing.

Anyone familiar with this? I shot some carb cleaner but no reaction.

> I want to receive e-mail notifications from this thread, but I can't seem to up-date my e-mail address.< I've tried, but no luck.

Also help

[Ranger]

You have a vacuum leak. There is no vacuum to the relays. They are electrical. Check the over pressure relief valve in front of the manifold. Opposite the TB.

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[Mountie]

Originally Posted by Ranger

You have a vacuum leak. There is no vacuum to the relays. They are electrical. Check the over pressure relief valve in front of the manifold. Opposite the TB.

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Thanks Ranger..... I'll keep checking ( a lot of crap around there)

Uh, my e-mail needs to be changed, but somehow I can not get success even though I try to go through the steps.

I can change my 'Mountie', & password, but not e-mail....

[urbanski]

pm me

[Mountie]

Originally Posted by Ranger

You have a vacuum leak. There is no vacuum to the relays. They are electrical. Check the over pressure relief valve in front of the manifold. Opposite the TB.

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Up date......

Now what??? When I turn off the engine I heard 'another' noise. Upon poking around, a 'click-click' & little gear noise. I research the component and it's the Idle Speed Control bumping the Throttle Body Lever Assembly for about 30 seconds- then stops.

When I replaced the engine I have a spare Injector - throttle assembly for parts. ( I can hear the suggestion coming....)

[submariner409]

You hit it.....The ISC needs calibration. There were a few threads on this last summer and in the fall of 2006.

I think the starting point is a good cleaning with throttlebody spray and brushes and fuzzy pipe cleaners, but after that you're in our GM Tech territory.....sorry.

[Mountie]

Originally Posted by submariner409

You hit it.....The ISC needs calibration. There were a few threads on this last summer and in the fall of 2006.

I think the starting point is a good cleaning with throttlebody spray and brushes and fuzzy pipe cleaners, but after that you're in our GM Tech territory.....sorry.

Are you saying to remove the ISC and do said cleaning? It looks all electrical.

( No such thing as a stupid question when there's so many parts)

[Ranger]

No need to remove the TB. Just open the throttle plate and spray it with TB cleaner, scrub with a toothbrush and wipe with a towel till it is clean. Don't forget the backside of the throttle plate and it's perimeter. Then with the engine warmed and at idle, press on the ISC plunger till it retracts. When it bottoms out, pull the connector and adjust the gap to .060.

[Mountie]

Originally Posted by Ranger

No need to remove the TB. Just open the throttle plate and spray it with TB cleaner, scrub with a toothbrush and wipe with a towel till it is clean. Don't forget the backside of the throttle plate and it's perimeter. Then with the engine warmed and at idle, press on the ISC plunger till it retracts. When it bottoms out, pull the connector and adjust the gap to .060.

I have a spare injector assy. Including the entire throttle body / components.

WHAT IF... I change out the TP?? Then the ISC, if the TP isn't the problem?

Learning as I go, I can remove / inspect the parts on my spare assy. before I attack the one on my car.

I also will be replacing the vacuum manifold on top of the TB (cracked) > would that be a culpret? I did do a temp patch - but I suspect it leaks a bit.

UPDATE-Upon looking at the owners manual, I see (6C-58) that there is a "TP Sensor/Idle Learn procedure after r&r.
Is this a Dealer thing?

[submariner409]

Mountie, Any vacuum leak in a Northstar (vacuum manifold on top of TB) is a prime suspect for rough idle, erratic idle, whistling noises, and code sets. Any vacuum leak must be repaired before trying other remedies because the leak itself will throw accurate diagnosis out the window.

[Mountie]

Originally Posted by submariner409

Mountie, Any vacuum leak in a Northstar (vacuum manifold on top of TB) is a prime suspect for rough idle, erratic idle, whistling noises, and code sets. Any vacuum leak must be repaired before trying other remedies because the leak itself will throw accurate diagnosis out the window.

Yup....... I'm going to see where I can get replacement vacuum parts, first.

I find this stuff as I poke around the engine.

When I replaced the N* I restored anything that was going to be hard to get at. These other parts on the top are original.

The idle is slow to come down & sits at 1,200 at the moment.

I REALLY appreciate all these suggestions. ( Owning the OEM manuals are a big help too!)

[Mountie]

[quote=Ranger;1651996]You have a vacuum leak. There is no vacuum to the relays. They are electrical. Check the over pressure relief valve in front of the manifold. Opposite the TB.

I was lucky ...found nearly new vacuum manifold ( on top of TB)

The idle is still wrong. Uh, the ISC..... I'll see if I can understand how to adjust it ( 60 thousands gap) Is this between the 'bolt' stop & the cable pully?

I have a second ISC, can I just replace it?

I hope the high water temp ( 240) is due to high idle? Driving around the neighborhood? The high temp does come down, but it makes me nervous!! To say the least!!

[Ranger]

The .060 gap is from the plunger tip to the throttle linkage. I think we are saying the same thing in different terms.

[Mountie]

Originally Posted by Ranger

No need to remove the TB. Just open the throttle plate and spray it with TB cleaner, scrub with a toothbrush and wipe with a towel till it is clean. Don't forget the backside of the throttle plate and it's perimeter. Then with the engine warmed and at idle, press on the ISC plunger till it retracts. When it bottoms out, pull the connector and adjust the gap to .060.

Sorry for being "so testy".... I warmed up the engine, the plunger doesn't really retract. It does 'push' against the throttle surface and the throttle keeps pushing against it. I use a 9mm to turn the plunger/bolt? But the throttle still pushes against it. I never get a "gap" between the throttle & plunger. WHERE is the 0.60 gap?

The owners manual states it (ISC) is "not servicable".. How about I just swap it with the other ISC that was on the original engine?

I appreciate your patience.

[Ranger]

Press on the plunger. It should retract. When it bottoms out, unplug it. The RPM should drop to about 450 and may stall. NOW adjust the gap to .060. Then plug it back in and you are set unless the ISC motor is bad.