z34_nut Posted July 25, 2005 Report Posted July 25, 2005 perhaps you didn't get the timing right? hell, how long did you let it idle? if you didn't allow it to to the idle re-learn. The idle re-learn occure when you disconnect the battery for about 2-3 hours, then start the car. they computer needs to re-learn the idle. This could be your problem. i would say start over again. Disconnect your battery tonight and let it sit. In the AM attatch your battery again, and start it up. the idle should be all over the place, but after a couple minutes it should re-set and be ok. Quote
1990lumina Posted July 25, 2005 Report Posted July 25, 2005 Holy I'd be scared dropping it into drive with the revvs that high. Anyway good luck man, hopefully z34 nut is right! Quote
slick Posted July 25, 2005 Report Posted July 25, 2005 Intake Leak somewhere. That or vacuum leak. Quote
Aaron Posted July 25, 2005 Report Posted July 25, 2005 perhaps you didn't get the timing right? hell, how long did you let it idle? if you didn't allow it to to the idle re-learn. The idle re-learn occure when you disconnect the battery for about 2-3 hours, then start the car. they computer needs to re-learn the idle. This could be your problem. i would say start over again. Disconnect your battery tonight and let it sit. In the AM attatch your battery again, and start it up. the idle should be all over the place, but after a couple minutes it should re-set and be ok. It is not the cam timing, there is no way it could cause a high idle. It is not an intake leak either, and he used all new gaskets and properly torqued the intakes. It is a vacuum leak, and over at 60* we are fairly certain it is the brake booster line, but he swears he connected it, this before asking what the brake booster is and where it goes Quote
Rabbi Posted July 25, 2005 Author Report Posted July 25, 2005 i was missunderstood at 60 degree v6, i meant where does the other side of the break booster connect to. I have the big hose on the backside of the plenum attached tight as hell. But where is the other side go? z34 nut, my car sat without a battery in it for about 2 months. Maybe this is the problem? Im going to replace my serpintine belt tensioner tommarow and then see what happens when i let the car sit for a few mins. Will idling at 3000 hurt the car? Im asuming the rev limiter is at 3000 to prevent engine damage (obviously) but will it idling at 3000 for 5 mins damage anything? thanks Quote
slick Posted July 25, 2005 Report Posted July 25, 2005 i was missunderstood at 60 degree v6, i meant where does the other side of the break booster connect to. I have the big hose on the backside of the plenum attached tight as hell. But where is the other side go?thanks Into the brake booster. You should see a nice sized "nozzle" where it would slip over. Quote
bartonmd Posted July 25, 2005 Report Posted July 25, 2005 I have only seen them idle THAT high when the IAC connector is disconnected... That leaves the IAC completely open, and therefore, the throttle effectively fairly open... Mike Quote
DaveFromColorado Posted July 25, 2005 Report Posted July 25, 2005 it sounds like the throtle may be stuck open too, or something along those lines - For some reason there's a massive vacuum leak, and the computer is sensing to add more fuel - I'd re-check your plenum gaskets and your throtle cables. (just an idea) --Dave. Quote
z34_nut Posted July 25, 2005 Report Posted July 25, 2005 Doesn't sound like idle re-learn if it stays at over 3k... How-ever it does sound like you got a major vaccum leak. A common problem with my vaccum lines would be the "T" fitting just behind the plenum on the drivers side. Also, your brake booster vaccum, if it were disconnected, would have a very rough idle, not so much as high... When I diconnected the brake booster on my z34, a 89 GMC, and a 01 ranger, they all had rough idles, but mostly low idles. It wasn't untill the vaccum line was re-connected that the idle shot up. Quote
Aaron Posted July 25, 2005 Report Posted July 25, 2005 The brake booster line disconnected makes both of my Z34s idle at 2600rpm, exactly. There is no way that line being disconnected would make it rough, but not high. That much air through a 5/8" opening? No way the IAC can accomodate that. A disconnected brake line would cause your idle to be around 2500-3000, which is why I suspect that. That "T" fitting you mention behind the plenum isn't a vacuum source. Well it is, but not the one causing his problem. That line is for the breather assembly, one line comes from the front valve cover, T's with the short line from the rear valve cover, then that line goes into the airbox, before the throttle blade. Therefore if it were disconnected, he wouldn't notice a thing. It would not affect drivability, or anything. You might get very little amounts of oil shooting out, but nothing else. It seems I need to disclose here that there was another comment I had typed before editing it. It was me telling Z34_nut to stop posting after he posted 2 blatantly incorrect statements. There Quote
bartonmd Posted July 25, 2005 Report Posted July 25, 2005 When we forgot to hook the IAC back up on the racecar, it idled at 3500rpm... Remember, it doesn't take much power to push idle up... The engine's not loaded or anything... I don't claim to be the end all for answering technical questions or anything, just something to try... Probably one of the first things to look at too, asside from vacuum lines and such... Mike Quote
Robby1870 Posted July 25, 2005 Report Posted July 25, 2005 Im gonna go with brake booster after reading this thread Quote
jeremy Posted July 25, 2005 Report Posted July 25, 2005 Maybe Z34_nut should go hide and stop posting... There is no need for posts like this. Everyone here is just trying to help. Quote
z34_nut Posted July 25, 2005 Report Posted July 25, 2005 Yup Aaron, you are always right. Why would any-one share other possible situations in this case? Could some-thing happen other then what you have expereienced? Nope! I'm a complete moron. I have never worked on any cars in my life, and all the experiences I have encountered are completely false. I am never right. I'll take your advise Aaron. In all honesty, I am simply approching the problem from a different angle. Please don't neglect my advise. No need to bash, but you have always found a way to weasel yourself out of corners you've backed your way out of. ...260whp, your headers are the best for a 3.4, LT5 is a modified 350....the list goes on buddy. Quote
Robby1870 Posted July 25, 2005 Report Posted July 25, 2005 And he edits his original post. Slick. What'd you expect? Quote
bartonmd Posted July 25, 2005 Report Posted July 25, 2005 HAHA, I LOVE that!!! Just editing the original without saying "edited to take out XXXX material" or anything, or even an "I'm sorry, I took it off" post at the end of the thread... Awesome! Mike Quote
Aaron Posted July 25, 2005 Report Posted July 25, 2005 Wow, get on my case about me editing that part out? Jeremy told me there was no need for that, I took it out, simple as that. If you'd like I can add it again Z34_nut, go. Give me a reason why a 5/8" hole in the intake manifold would not raise the idle. Approach it from a technical standpoint. Prove it. As I said over at 60*, everytime I put back on the intake, I forget the brake booster line. Then I start the car, and it idles way up at 2500rpm. It doesn't idle at 800, and it isn't rough. There is no way it could hold itself at 800, or even 1500 with that much air getting sucked in. And about that T, it isn't a vacuum line, therefore could not cause a high idle. I mean it is vacuum in a sense, but it is before the throttle plate, therefore it could have no effect on idle. That'd be like saying removing the air filter will raise your idle significantly... Quote
Aaron Posted July 25, 2005 Report Posted July 25, 2005 And the LT5 is a small block Chevy. I was unaware the bore/stroke were different, but as I said over there, its basic design is a small block. It will bolt right into a 1992 Camaro, or a 1988 truck, or hell a 1955 Bel Air. Its mounts are all typical SBC, its bell housing pattern is SBC, and its internals are very SBC related. Like I said, it is to the SBC what a 3.4 DOHC is to the 3.1. Essentially the same block, but with differences. The 3.4 isn't identical to the OHV 660 blocks, but it is close in many respects. It is based off of a OHV block. Quote
GP1138 Posted July 25, 2005 Report Posted July 25, 2005 Z34_nut, go. Give me a reason why a 5/8" hole in the intake manifold would not raise the idle. Approach it from a technical standpoint. Prove it. As I said over at 60*, everytime I put back on the intake, I forget the brake booster line. Then I start the car, and it idles way up at 2500rpm. It doesn't idle at 800, and it isn't rough. There is no way it could hold itself at 800, or even 1500 with that much air getting sucked in. There's a difference. The IAC hasn't had time to react and learn the idle. When you remove the brake booster when the engine is running, it's going to react differently. Also, this thread is not about your car. This thread is about his car. Maybe there's something about HIS CAR that is different than yours, and causes it to react differently. And about us getting on your case. That would be like me being an ass to someone, and having them react, and they reply being naturally pissed because I said something offensive to them. Removing what I originally said takes their reaction out of context, and it makes me look like even more of an ass than I did before. Quote
z34_nut Posted July 25, 2005 Report Posted July 25, 2005 And the LT5 is a small block Chevy. I was unaware the bore/stroke were different, but as I said over there, its basic design is a small block. It will bolt right into a 1992 Camaro, or a 1988 truck, or hell a 1955 Bel Air. Its mounts are all typical SBC, its bell housing pattern is SBC, and its internals are very SBC related. Like I said, it is to the SBC what a 3.4 DOHC is to the 3.1. Essentially the same block, but with differences. The 3.4 isn't identical to the OHV 660 blocks, but it is close in many respects. It is based off of a OHV block. no-one cares Quote
Aaron Posted July 25, 2005 Report Posted July 25, 2005 Z34_nut, go. Give me a reason why a 5/8" hole in the intake manifold would not raise the idle. Approach it from a technical standpoint. Prove it. As I said over at 60*, everytime I put back on the intake, I forget the brake booster line. Then I start the car, and it idles way up at 2500rpm. It doesn't idle at 800, and it isn't rough. There is no way it could hold itself at 800, or even 1500 with that much air getting sucked in. There's a difference. The IAC hasn't had time to react and learn the idle. When you remove the brake booster when the engine is running, it's going to react differently. Also, this thread is not about your car. This thread is about his car. Maybe there's something about HIS CAR that is different than yours, and causes it to react differently. The ECU will read that there is too much air, idle is too high, and it will close the IAC, all the way. But there is still the opening, and the MAP will read all the airflow, and it will idle really high. There are differences, but not that will cause it to react different. It is a hole in the intake manifold, every 3.4 will react the same. Quote
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