jbrob007

My shark is a 86.5 / 5.0 / 32 V with a noticable vac leak under the intake - where I'm not sure yet - we start tearing down the intake next weekend. I have a vac line replacement kit from Roger, but no directions. I've searched for vac line testing & replacement directions with no luck. I did find Dewaynes HVAC tutorials for 87 and later which I'm sure most of the HVAC lines are similar. I wish he owned an 86

Can someone point me in the right direction, provide a link to another thread, etc, that addresses how to replace the vac lines under the hood on a 86...??? Really hoping I dont sound TOO ignorant in this regard...

Thanks in advance,

Joel

SMTCapeCod

Erm, go to Roger's web page, Downloads tab, vacuum line diagram. It shows the kit superimposed on the OEM routing.

rexpontius

What are the symtoms of your vac leak (no cruise, hvac not operational, bad running)?

The vacuum system looks pretty complex but is actually pretty straighforward if you remove the air cleaner box, and the two intakes. When they are removed you get a much better view of what goes where.

jbrob007

Thanks guys! Believe it or not, Roger wrote me (on his day off) and sent me the diagram. Now THAT is customer service at its finest!!! Roger is Da Man!!!

The cruise control will slowly let the cruise fall off and you have to bump the throttle, but its primarily a running issue... it's sucking air & whistles so loudly it almost sounds like a supercharger under there... and, its beginning to lurch forward & aft in light throttle (sometimes in all gears) - I've been told that symptom is typical of running lean... NOT GOOD. This may be a combination of issues so I'm starting with the vac lines. Could also be a throttle body adjustment issue, breather hose leak, etc... Frankly we wont know until we get in there... I HOPE its as simple as a leaking vac line or vac operated valve and nothing more serious.

Hard to do a proper evaluation over the net, but I appreciate all recommendations, input, ideas, prior experiences and guidance!! I can use all the help I can get

joel

SMTCapeCod

Could be one of the vacuum lines- or one of the seals around the MAF.
Any correlation with recent work done on it?

jbrob007

SMT, No... but its just getting worse... It whistled a little when it HAD 41K miles when i bought it. I've put 17K miles on it since February - I LOVE THIS CAR!!! Its getting pretty loud so I'm thinking a seal or something larger than a vac line but I'm sure the vac lines could use a refresh as well. Now that the weather is getting crappy its time tear it down and get this fixed

PorKen

Have you tried adjusting the idle speed (up)? The sound may be from the idle control valve.

The plenum connector 'T' is often very difficult to fit into the hose to the throttle body properly with the entire intake installed.

Loosen all of the plenum hose clamps, then center the hoses. While pushing the plenum towards the intake tubes as hard as possible, tighten all the clamps.

jbrob007

Ken, It could be as simple as not putting it all together correctly - someone was in here before I bought the car as the PO had reciepts for valve cover gaskets and other top side stuff including new plenum rubber hose connectors. I took a lot of time to make sure the plenums & the rubber hose connectors were lined up & tight when I put in your Torque Tubes. It looks like the rubber hose connectors on each intake tube is aftermarket black silicon or something... very pliable and hard to keep under the hose clamps (wants to squeeze out when you tighten them). Might need to get a new set of OEM from Roger as well - although it was sucking air before and after the install - no change in that regard. I'll make sure we pay close attention to the 'T' hose & throttle body fitment when we put it all back together.

Now, without sounding like a complete moron... How do I adjust the idle speed (up) without taking all this apart? Where is the adjustment screw located & how do I get to it??? And, how can I tell if the idle control valve is faulty???

I'm ignorant as to how this is set up since this will be my first time inside the "valley of death" Thats gonna change in about a week!

Thanks again for all your help! Joel

SMTCapeCod

One of the 40 returns for a search of "86" and "adjust the idle":

https://rennlist.com/forums/1445983-post1.html

jbrob007

Thanks! I also found a few including input from Ken when he had this same problem. So the adjustment screw is actually a 8 mm nut that I will be turning? I noticed one right off of the throttle body partially covered by a vacuum hose. I also read a few posts indicating the leak/whistle could be at the throttle body & "T" connection (as Ken mentioned)... looks like it may be a combination of minor issues.

My idle is less than 700 rpm so tomorrow I'll crank her up to 700 or so and take another look at the Big 'T' and TB connection (after she's warmed up). I'm still gonna refresh the vac lines, but I'd really like to get this resolved especially if she's running lean.

All of this brings up one other question - My car has the airpump delete. The blue hose that goes to an actuator between the airpump and the cats was removed and the steel pipe to the cats has been disconnected for a LONG time. There is a vac line that runs from the top of that actuator and goes under the intake - where does that go and can I plug it (since the actuator doesnt DO anything) without any negative effects?

I'm still looking at various threads.... Thanks in advance.

Thanks!

Joel

PorKen

7 mm socket for the idle speed.

I don't like the silicone hoses for the plenum. I use the factory rubber ones.

Plug 'em all!

Mike Frye

If you have a loud whistling you might be able to isolate it by putting a piece of hose up to your ear and moving the other end around underneath the hood with the car running and see if that points to the source of it.
Or...
Check out this thread on intake leak checking.

I built a jig out of some cheap Home Depot stuff and was able to identify and fix all of the leaks in my intake.


Also, I agree with Ken, those aftermarket silicone intake boots are a PITA to deal with. Even with the stock ones though I've had to put them on, then get the car up to operating temp and adjust them again. You can't just put them on cold and expect them to stay where they are unfortunately.

Don't be fooled into assuming it's on the vacuum side though, could be unmetered air and that will mess with the running of the car and give that whistling sound.

I'd recommend going through the test plan (it's part of the manuals an also is included separately on the CDs Roger sells.) The first time through it you will want to skip to the part you think it is, but after you go through the whole thing one time you'll see the value of it. Most likely you have more than one thing wrong and going through the test plan will ensure that you've got good readings everywhere until you find the things that are wrong.

jbrob007

Thanks again... I'll get her warmed up... adjust the idle... and make sure all my plenum boots are installed correctly & retightened Next weekend it all comes off and I'll do a comprehensive eval of all connections. Looks like I'll need to call Roger for OEM plenum boots, amoungst other assorted parts yet to be identified...

Joel

4losi

Hey Joel, Randy in Columbus here, I saw the 928 buckeye land shark web site.......tried the email address to join you guys...and it keeps getting kicked back....can you give me an address where I can sign up or one of the head "drivers"....Thanx.... rvia@wowway.com

Jchiodi

Joel, just got my 86 buttoned up, after intake refresh. I will def try to be there! It is a pretty scary looking bunch of hoses, vac lines, and wiring harness, not to mention the plug wires. You can tell these cars are hand made. No way machines could weave it back together!

Also got into the evaporator to clean, wasn't quite as bad as I thought.. looking forward to seeing other sharks and owners!!

Jchiodi