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Ok so I finally got my 350 tpi running and I have a couple questions about the vac lines on the intake manifold and the throttle body it's self. Question one: on the intake manifold drivers side rear is a fitting going into the manifold, what's it supposed to connect to?
Question two: on the throttle body passenger side is two lines, the one on top doesn't seem to have air coming or going and the one on the bottom is a suction and if I put my finger over it the engine dies right now, what goes on these two lines? I'm sure once I have these hooked up I'll have a reliable idle but for now it doesn't idle at all unless you are on the throttle before it dies.
It's an 89' Iroc z28 with an 89' 350 tpi engine in it. If that helps any with a smog pump and EGR delete done by Brian with tuned pro. I have 22# injectors and a distributor out of a vette from a member of the forum.
Any help on the vac lines would be awesome and I need to give a big thanks to everyone that has helped me out on this build. If it wasn't for the people here helping me I don't know if I could've figured out half of this mess I bought into. So thanks everyone for all your time and knowledge.
Clint
On my speed density 91 manifold, the vacuum lines are as follows: There are three ports on the rear passenger's side. Rearmost one connects to FPR, one in front of it connects to MAP sensor, and the one in front of that one connects to vacuum for cruise/hvac. On the rear driver side is the fitting for the brake booster vacuum. Throttle body has one line underneath that goes to EGR if I remember correctly. Then there's the inputs for the coolant for keeping the plate from freezing, a vacuum line for the canister purge, and a line for the PCV valve that doesn't get vacuum if I remember correctly (it dumps right before the throttle plates, so no vacuum).
Question two: on the throttle body passenger side is two lines, the one on top doesn't seem to have air coming or going and the one on the bottom is a suction and if I put my finger over it the engine dies right now, what goes on these two lines? Top hose on TB goes to rear pass valve cover.<br/>Lower port canister,
Awesome Bob88GTA thanks for the help! Thats exactly what I was needing. I also have a issue with the idle going up to about 2200 and staying there now and it happened when I put my finger over the vac line for the brake booster and when I pulled my finger off it stayed at about 2200. Do I have an issue with my throttle position sensor or is there something else I can check? Any ideas?
Once again thank you and I will do this as well. Can you tell me what ALDL stands for? Is that the plug that connects to the tps? I surely wouldn't wanna cross the wrong plug and have a real big issue. Lol
These come from the passenger side fuel injector wire harness and don't have enough length to go much past the back of the A/C pump. I've looked at the smog system that I had deleted but those parts don't have any plugs on them so I'm at a loss with what these go to. I don't see any other plug sockets on the intake plenum that they would go to either.
Okay Bob88GTA I did the iac and TPS adjustments and it didn't change the rpm but maybe 500 it's down to about 1000-1500 or so and that's as low as the adjustment will go so do you think I might have a vacuum leak on the plenum or runners that would be causing it to not idle down?
Okay Bob88GTA I did the iac and TPS adjustments and it didn't change the rpm but maybe 500 it's down to about 1000-1500 or so and that's as low as the adjustment will go so do you think I might have a vacuum leak on the plenum or runners that would be causing it to not idle down?
hi
if you did the adjustment procedure and it didnt come down, you have a vacuum leak. Check around the throttle blade shaft on both ends and all plenum/runner/intake connections.
When you started the procedure, and if you had no leaks, the engine should of had a rpm around 500 rpm. Is the IAC and good or is it just letting tons of air in, as in STUCK OPEN or fully retracted.
in your pic above, do you have the top port on the TB going to the passenger valve coveR and bottom port going to the canister? Looks like your top port is open
Top port is open, bottom port is going to the charcoal can on the drivers front fender. I wasn't sure what to do with the top one beings I've plugged it with my thumb and felt no vacuum or pressure. Didn't know it needed to go to the valve cover. I will do this tomorrow.
The iac looks to be functioning according to the vot meter. How can I check for vacuum leaks? I don't wanna spray starting fluid around it at all. Is there something else I can use that might choke it out if it pulls it into the intake?
Top port is open, bottom port is going to the charcoal can on the drivers front fender. I wasn't sure what to do with the top one beings I've plugged it with my thumb and felt no vacuum or pressure. Didn't know it needed to go to the valve cover. I will do this tomorrow.
The iac looks to be functioning according to the vot meter. How can I check for vacuum leaks? I don't wanna spray starting fluid around it at all. Is there something else I can use that might choke it out if it pulls it into the intake?
Use one of those long Bic lighters for charcoal grills. DON'T LIGHT IT!!!!!!!!!!!! Just press the button to let the gas come out and follow all the joints. Engine will rev HIGHER THAN IT IS NOW when you find the leak
By god I will read this info 12 times if that's what it takes to keep it all retained. That's what I get for not touching the car all weekend and helping a friend move, I lost where I was at and lost all the info you had given to me. I will go back and read this again and make sure I have done everything and I will do the bic lighter test and see what comes of it. I have a feeling I'm gonna be replacing the plenum gaskets.
I use an unlit propane torch to find vac leaks. I had some erratic idle issues with mine that turned out to be a lot of slop in the throttle body shaft. It was causing my butterflies to stick open a bit sometimes. There was probably air sucking in from the ends of the shaft too. I had it rebuilt. Not the standard gasket rebuild though. There is a vendor called Mr Injector that takes them apart, drills out the shaft holes and installs brass bushings to remove the slop.
Well after doing these vac tests I found that I had a bad gasket on the bottom of the drivers side runner, replaced all the plenum gaskets and the water pump decides to take a dump on me so I replaced it and it's running at about 850.-950 rpm. I also found a vac line under the plenum on the drivers side rear that's not hooked up so I'm trying to find where it's supposed to go, this vacuum issue with all these little ports is gonna get the best of me!
Already got the break booster hooked up to the one on the manifold, drivers side rear part of the intake manifold. This one is on the plenum it's self at the drivers side rear.
Ok,the REAR port on the plenum is for the booster, the place where you hooked the booster to is for the PCV.
Driver side of the plenum on the back goes to the brake booster.
The vaccuum beside where your cold start injector would be (you don't have this), is your pcv valve.
Awww okay well that's done now and I have another little valve or something on the back of the engine that has one electrical plug going to it and two little vacuum lines coming out of it, I'll have to get a picture of that tomorrow morning after work and see if you might know what it is and where the lines might go. Other than that it's all together thanks for your help on that and I believe it's ready for the road.
Sounds like your EGR Solenoid. The BLACK port goes to EGR Valve, the other goes to the little port on the pass side rear of plenum. It shoud have a T in it and a check valve, the other line goes to the vacuum Ball in Drivers fender and T s to cruise. The other port on plenum goes to Fuel Pressure Regulator. O MY, VACUUM SUCKS! Right above my finger to the left it elbows over to the EGR Solenoid. The line by the check valve is the line that goes over to the drivers fender vacuum ball
I did a EGR and smog pump delete on this car per Brian with Tuned performance but the little thing is about a one inch square and looks like it has a really small filter on it. I'll have to get a pic of it. For the cruise line and the ball I guess I don't see a ball on the drivers fender anywhere and the only vac line I have going over to that area came off the lower fitting on the throttle body to the charcoal can.
Your brain is in over load? Yeah I hear that one cause this is driving me crazy. Seem like I get one thing done and 5 more come up! Thanks for your help thought! I really do appreciate it!
the little square with the small foam filter on it is the VENT for the EGR Solenoid.
The vacuum ball is INSIDE the driver fender, towards front
Just disconnect the line to the EGR Solenoid since it was programmed out.
When you find the ball, right before its connection should be a T that goes over to the cruise. Then back over to the rear pass side of plenum to that check valve. Just cap the check valve port that goes to the solenoid.
Is the 2 hard plastic lines coming out of the harness on the firewall connected. They control the heater control valve and the heater controls on the dash inside. See diagram...Its for a 91 IROC, but the vacuum lines(BOLD BLACK Lines) at top are the same.
The one line comes off that t and goes into a wire harness and I can't see where that come out of but the harness doesn't appear to have been tampered with so I'm not gonna chase anything in that.
This is the little valve or solenoid that I was talking about and you say it goes to the EGR and can be removed.
All the pollution control crap I've taken off has gone into a box for a later date, not that I would expect Wyoming to start doing inspections but you never know so I'd sell it to you and with the way our government and EPA is working id need it tomorrow. I do wish there was something I could do for you and everyone else that has taken there time to help me out on this. I can't thank everyone enough and I feel like **** for doing nothing in return.
Its cool. Don't worry about it. As long as we all give our expertise and help someone out, is all that matters. You may return the favor later on...ya never know. I get the thanks from when it's all done and the guys car actually runs then. I've spent over an hour on the phone one Friday night helping a guy out with his 83-84 Cross Fire T/A. We finally got it dialed in. I was about to fly to Seattle! Just Kidding.
As far as the solenoid goes, I don't need it. I have a spare and the one on the car works. Just ribb'n ya!
Well thanks again for all your time and help. I just figured out how to post pics on here so maybe when I get tags and the exhaust done I'll have to figure out how to post a video. It sounds amazing but still idles a little high. Might look into a new tps and see if that helps it.
Yeah they are closing all the way. I also backed the idle screw out about 2 1/2 turns. I noticed yesterday when I pulled it out of the garage my idle was perfect, right around 6 to 700 in drive and when I put it in park it stayed there and just idle but when I flipped the throttle by hand it came back up to about 1000 and stayed at that point till I backed it back in the garage.
in my dealings, and even when it was under warranty, EVERYTIME i took the car in for stumbling,high, weird idle, and such....they always changed the IAC. It controls the Air running around the butterflies. Too much air....to high of Idle.....so....thats just me though. If you buy either.......GET AC DELCO OR BWD. no other. 1st choice would be AC Delco
07-23-2015, 11:27 PM
