doug928

Fortunately, my shark is safely in my garage since the snow dumping here in NY (about 10" deep) happened yesterday. On friday I was able to reassemble the intake manifold and start'er up before the big snow. The car is running a little rough and I haven't been able to rev above 3000rpm and the flappy doesn't seem to open. I've ordered a mity-vac because I am assuming I have a vac leak somewhere. I'm also going to try the innertube trick. But I have a few questions that I thought someone might be able to answer.

Before I started on the intake system rebuild, the car was running pretty well. I found upon disassembly that the front knock sensor wasn't hooked up. I have installed all new hoses, knock sensors and idle regulator. Could the reinstallation of the front knock sensor be affecting the car? Besides checking all the vac lines is there anything else I should be looking for or testing?

shaaark89

doug,
did you check the flappy actuator when the intake was off? if you did and it was good then you definitely have a vacuum leak somewhere which could affect the idle. also need to look at all the breather hoses and attachments. it's not hard to knock one loose when reinstalling the intake. check to be sure the throttle body portion is tight against the intake portion if you had it separated while off (4 bolts as i recall). lastly, if you installede a new idle regulator, make sure the connections to it are good.
i don't think the knock sensor will give you these symptoms.

worf928

The only way I can think of that the knock sensors could be a problem is if you didn't torque them to spec.

For the rest - you need to check every connection that you disconnected when you R&R'd the intake. Lot's of stuff was disconnected on purpose - something could have been accidentally disconnected. If you are an OC member there's a write up in The Journal section of the OC website. Otherwise Tony (v1uhoh) has a write-up too.

Sounds like you might have three problems:

- flappy : check vacuum and electrical connections at the vacuum valve on the left-side t-belt cover

- rough idle: false (unmeasured-by-the-MAS) air due to a vacuum line or breather hose not properly connected. MAS's rubber elbow. Or, idle actuator not re-connected electrically. Injector connections? Plug wires? Coil wires?

- >3000 rpm: does it want to die? or is it really, really rough?

Regardless of your answer to the above I would start by very carefully going over the installation phase. Occam's Razor (the simplest explanation) says that you missed reconnecting something. Do the double-check before you start worrying about other stuff.

doug928

Tom,

When the intake was off I did check the flappy and it moved fine. I know it SHOULD move if it was getting the right signal. I was able to rev the engine up to 4000 rpm today and no perceivable movement on the flappy.

David,

I did torque the knock sensors to spec, and the car is only 'slightly' more rough than before the intake rebuild. Today I had it running for about 15-20 minutes and after it warmed up it was idling at about 550rpm ( which is where it was b4 the rebuild). But I was wondering what the electrical signal should be to the flappy control actuator? Also, I read somewhere that the flappy doesn't start to open until about 250mm HG - is this correct? Do you happen to know at what vacuum hg the system should maintain under normal operating conditions? Lastly, regarding the coil grounding, I couldn't remember how my coil ground was attached to the plug wires, so I attached it to the connector which holds the wires to the cam cover. Would it work properly if the ground strap was secured to the bolt through the plastic strap or should it be attached directly to the cam cover?

I was also considering changing out all the vac lines to silicone - but I cannot find the various sizes for these lines. Anyone know the various sizes I would need to order?

Thanks.

ErnestSw

Doug,
You should be able to move the flappy by sucking on the vacuum line that goes to it. The line is connected to a solenoid that gets an opening signsl at 4K rpm and transfers vacuum to the flappy line. It's on the front of the engine on the driver's side under the cross brace.

shaaark89

also make sure you have the vacuum lines for the flappy connected properly to the solenoid at the front of the drivers side cam cover. the line to the flappy should connect to the port pointing up and to the left. the line from the vacuum source connects to the port pointing down. i've seen these reversed and the car didn't run well and obviously had no flappy action.
the other thing is that the flappy won't open just because you go over 4000 or 3500 rpm. it has to be an aggressive acceleration to generate the signal. of note, the flappy should open briefly whenever the motor is started.

doug928

Ernest,

I did do the "sucking" test and the flappy worked ok.

Tom,

Thanks for the heads up. I may have the two vac hoses reversed. I'm going to check now!.

I'll fill you in after I check these out.

doug928

Tom,

I had them reversed. Changed them and started the car up. I didn't notice any major difference and I didn't notice any movement in the flappy upon start-up or after reving to 4000 rpm. Which connection should the bottom vac connection of the electronic flappy actuator go to? I have it connected to the air pump damper.

Unfortunately, due to some heavy snow I cannot do a test drive to see how the car really operates.

shaaark89

doug,
the vacuum line from the brake booster, through the check valve, then through the 4 way splitter that goes along the drivers side injector rail is the one that goes to the bottom of the flappy solenoid. if it's hooked up right and the flappy doesn't open on startup then either you have a vacuum leak or the solenoid is not working. not sure what you're referring to as air pump damper.

doug928

Tom

I labeled all the vac hoses prior to removal, but I the po had all the work done by his mechanic (i.e., they may not have been put on correctly). But the bottom vac connection off of the flappy solenoid was connected to the passenger side air pump dampener ( the one that is towards the rear just under the filter box, it looks similar to the fuel dampener and has a port on top for a vac hose. If this is incorrect, where does this line go to and does the line off the 4 way splitter just travel under the fuel rail to this port?

I guess I could have more than one incorrectly attached vac hose.

P.S. I have tried to follow the vac diagram on the hood but it's not that clear.

doug928

After looking at Tony's site with the great pictures, I realize that I definitely have some wrong vac connections. I need to know where the vac line from the passenger air pump dampener gets connected to and I must have a line off the 4 way splitter incorrectly connected also.

ErnestSw

There are two vacuum lines on the passenger side if I remember correctly. The rear one, under the air filter, is routed into the back of the intake and goes to the bottom-most connector on the intake. The one in front of that is routed forward, between the two front legs of the intake, and back toward the forward facing of the twin connectors. The backward facing one goes to the 6 way splitter under the MAF.
HTH

shaaark89

doug,
your lines are all off.
here's how they should go:
line off brake booster through check valve to 4way splitter.
a) one line (usually black) goes through the firewall to the climate control.
b) second line goes through the drivers side fender to the vacuum reservoir located aft of the drivers front wheel.(usually clear)
c) third line (gray?) goes along the fuel rail on drivers side to the flappy solenoid.

second set of lines:
main one comes off the top of the throttle body and is attached to a 5 way spitter under the airbox on the drivers side near the rear fuel damper (what you refer to as air pump dampener. the s4 has 2 fuel dampers)
out of the 5 way splitter are the following:
a) short line to rear fuel damper
b) second line that runs along drivers fuel rail to front fuel damper
c) third line to fuel pressure regulator under passenger side of airbox
d) fourth line to auto trans runs along top of bell housing along top of torque tube.

there is a third line that comes off the bottom of the throttle body and out the rear under the fuel pressure regulator and to the smog control valve bolted to the side of the passenger side cam cover.

fourth line comes from under the intake and out the passenger side between the front two intake plenums under the fuel rail and to the gas tank vent valve on the passenger side fender wall.

the rest are breather hoses:
passenger rear cam cover goes to the side of the throttle body where there's a splitter that inserts into the throttle body boot. the second line off this splitter goes to the oil filler neck.
passenger front cam cover goes to the oil filler neck.
drivers side off the intake splits with one side going to brake booster. second side goes to the throttle body boot into a splitter. second line off here goes i believe to the idle stabilizer.
breather off oil filler just below the cap goes has two ends. one goes under intake front and can't remember where that connects. the other half of it connects to a vacuum solenoid at the front passenger side of engine.

hope that gets it for you.

doug928

Tom

This description is great. Thanks a million. The dampener I was referring to in the previous post was the smog control valve. I don't know how it ended up attached to the flappy solenoid but it must have been connected there from a po? I think I'll try and put a flow diagram together for future reference and post it.

Tomorrow I will attempt to rearrange my vac lines w/o removing the intake and see how it goes.

I'll keep you informed.

Thanks

Doug

UKKid35

Tom's description is great, the diagram from the workshop manual on Pirtle's site is really helpful too

http://members.rennlist.com/pirtle/svc_intake_2.jpg