has anyone ever solved the post intake refresh whistling mystery?
I can't believe how many people had this similiar problem.

 

You have several dozen 'post intake refresh' threads that you've started in the past several weeks with various issues that you've run into. I don't see any of them getting resolved.

Do you have a copy of the test plan? There is a very methodical list in there for eliminating all of the things that can cause problems with the way your car runs.



I'm not trying to be an a-hole here, but if you want help you're going to have to do what people suggest and report back on your progress. Just asking for suggestions doesn't help if you don't do anything about it.

Your intake has a leak, probably several of them. Take my word for it. Once you eliminate the source of unmetered air you may find that your problems are solved or you may have a whole raft of other issues to deal with. The intake is a can of worms that can introduce a million different issues and the only way to get through them is one thing at a time and making sure they are reading perfectly back to the LH/EZ.

Sorry if this seems harsh, I'm really trying to help you here. I just feel like I'm wasting my time because you keep asking the same question different ways trying to find an answer you like.

 

i am just getting frustrated
I dont want to take the intake off again

I was thinking of trying steam or cigar smoke into the intake, or unplugging the mas

 

Best bet is to get in there with a mechanics stethescope (autozone/sears etc) and search for it. I've had it come up a few times on 85/86 intakes and it is almost always some boot/gasket that is not sealing right. There are so many to search on those years it can get frustrating.

The one I found the most amusing was an intake runner [||] rubber that was slightly folded over, underneath were you could not see it, but could hear the whistle when it was cold. Engine hot you'd hear nothing and it actually sounded like it was coming from the bottom of the V. Once I decided it would be smart to remove everything to find the damn leak, once I pulled that inlet side off I could see what I did.

Don't give up, all of these cars take some time and love to get them where we want them.

 

I can hear your frustration and I sympathize with you, I seriously do.

The only way out is through though. You need to pick one of these threads where you've gotten a lot of advice and work through ALL of the solutions suggested.

There is a test plan in the WSM. I keep suggesting it because it works. You will eliminate each possibility before moving on to the next possible issue and when you're done you will know what works and what doesn't work.

Test all sensors all the way back to the LH and EZ.
Test entire top end for vacuum/holding pressure.
Verify all grounds are clean.
Make sure all connections are clean.
Make sure all fuel lines are in good shape and you have proper fuel pressure in the rail.

There are no shortcuts.

But if you work through each step logically and methodically we'll work you through it. Just keep us posted on what you've done to try to isolate it and we'll talk you through it step by step.

 

I know building the pcv pressure tester is a good way to go, but I have to be honest I am not familiar with the plumbing components needed.
I have been reading all the vacuum leak posts, and saw something about an inner tube method.
I thought this might be simpler. I did not find a pic.
I have an air compressor.

This may sound stupid, but I have a fog machine.
I was thinking about using my old rubber sleeve and making something to pump the fog into the mas.
I am not sure if this would be bad for the mas.

 

You're not alone on that one. I did it once and my car had a lumpy idle and stalled at intersections when warm for a few days until I went in to find the problem. Then felt like an idiot when I did.

The OP has vacuum-related idle issues and now he hears a whistle. The two are almost certainly related. My suggestion is not to assume anything is correct and start looking. If the intake boots are on, get the engine warm and tighten them again. Check all the vacuum hose elbows and connectors. Make sure the hoses are seated, make sure the connectors aren't cracked. Check the oil vent hose to the intake, make sure it's tight. Make sure the MAF is seated. Check it all. You'll find it.

Matt

 

Get four feet of 1/4" clear plastic tubing. Stick one end in your best ear. Use the other end as a probe to locate the source of the whistling.

 

This is how I found my whistle. It was two things, an ill-seated intake rubber gasket (as Sean suggests) and the o-ring in the idle screw adjustment in my throttle body.

 

mike,
on your test unit
did you drill with a 1/4" bit, before tapping with the 1/4" tap
or go with a slightly smaller bit?

 

The 1/4" NPT thread requires a hole much larger than a 1/4". The ID of the pipe is 1/4" but the OD is probably closer to 1/2" or even larger.

You'll probably have to get the 1/4" NPT thread tap and then figure out what size drill bit to use, I'm afraid I don't remember exactly what size it was.

 

pic
last stupid ques,
the 10 psi schrader valve hooks into a compressor?

 

A 1/4" NPT tap requires a 7/16 drill bit. It's 18 threads per inch.

 

That's the stuff.

This is the tricky part. You'll have to let the compressor fill up and the shut off (so it's quiet in the shop). Might even want to turn it off at this point so it doesn't kick on while you're working.

Then wedge something in on top of the test cap you've made out of PVC so it doesn't pop off when you apply some pressure. I think I used some cardboard or something but you might be able to rig up some bungee cord or something to keep the MAF seated where it belongs under your test jig. The whole thing will try to pop off when you add pressure.


Then hit the shrader valve with the air and pump it up a few PSI and see if it leaks (more like where it leaks from most).

If you can hear it but don't see it you can spray soapy water depending on where it is or else get some of that blue leak detector and spray it around there. Most likely you'll hear it pretty easily though and you won't have to spray anything.


Don't be surprised if you have leaks all over the place but once you isolate and fix them all your car should run much better.

 

Hey PC-85,

Any luck with this? Haven't heard from you in a while. Let us know how it's going, OK?