Guest benjlv Posted July 29, 2003 Share Posted July 29, 2003 take a unlit propane torch and go over all the areas where a vacuum leak could be. When you find it the RPMs will go up.... Did you ever pull the plugs and see what they look like? check out grumpies links...one of them has to contain some info http://www.idavette.net/winback/lt115.htm http://www.afrashteh.com/guide/install.htm http://www.corvettefever.com/howto/36501/ http://www.protechmachine.net/lt4/lt4.html http://www.thunderracing.com/lt1inteng.htm#CNC http://phil.tobin.net/Hoover/index.html http://www.gmmodernmuscle.com/383/383build.html http://www.h-body.org/people/projects/building_lt1/lt1%20info.html http://www.automotiverebuilder.com/ar/ar99928.htm http://www.hashmarks.com/dyno_page.htm http://www.mochevracing.com/Corvette/lt1lt4.html http://www.lt1motorsports.com/396LT1.htm http://www.lt4.com/story.htm http://www.malcams.com/legacy/misc/headflow.htm http://www.kendrick-auto.com/lt_1__gm_head.htm http://www.charm.net/~mchaney/optisprk/optisprk.htm http://www.fierolt1.com/lt1_95_up_OptiReplace.htm http://www.noid.org/~muttvette/opti.html http://www.gulicks.com/vette/projects/opti/index.html http://www.houston-f-body.org/tech/optispark/ http://www.dynotech-eng.com/dynaspark.htm http://www.corvetteclinicinc.com/ http://www.corvettefever.com/howto/16758 Quote Link to comment Share on other sites More sharing options...
Mudge Posted July 29, 2003 Share Posted July 29, 2003 Have you tested TPS per Chiltons? Have you looked at the IAC counts? For a stock car it should idle in the 40s or so. Quote Link to comment Share on other sites More sharing options...
80LS1T Posted July 29, 2003 Author Share Posted July 29, 2003 Yes I have tested the TPS with a voltmeter like ALLDATA says to but it all comes out fine? When I followed the diagnostic procedure on ALLDATA, it came up with bad TPS or bad connection? I just bought a new TPS and it does the same thing? The connection looks fine and its not shorted to ground? I have to do some work on it tonight cause idleing at 1500rpms is driving me nuts! I forgot about that propane "trick" I really do need to pull the plugs and the O2's to see what they look like. Guy Quote Link to comment Share on other sites More sharing options...
80LS1T Posted July 30, 2003 Author Share Posted July 30, 2003 Well I went out and pulled the plugs and the o2's... The drivers side is deffinetly running rich. The passenger side has me confused...the plugs have a lite carbon deposit on them but the o2 is is white, like its running lean? Could these conditions be caused by my code 22(TPS)? Oh and I also found some more bad news while I was under the car...my rear main seal is leaking! I am 90% sure that is the rear main but I guess it could be the pan. I am going to pull the inspection plate tommorow to see if I can tell which is is. I really hope its just the pan. Yeah right, I know Im going to be dropping that tranny but theres always wish full thinking! Hopefully my $500 clutch/pressure(Center Force Dual Friction) plate is not oil soaked! That would really piss me off! I dont want to have to buy another one. Money doesnt grow on trees you know. I was going to put it on the scanner today but I couldnt find the right cartridge for the SNAP-ON Scan tool. I will try again next week. This idleing at 1500rpms is really annoying. Sometimes it drops down to 1000rpms and thats not soooooo bad but I would like to get it down to about 850rpms. I also think I have a bad left front wheel bearing. Oh well just another thing to fix. So this is what its like to get a Hybridz "tuned and ready to go" LOL Its all part of the fun I guess Guy Quote Link to comment Share on other sites More sharing options...
Mudge Posted July 30, 2003 Share Posted July 30, 2003 Sounds like lean and hot on that side... Quote Link to comment Share on other sites More sharing options...
80LS1T Posted July 31, 2003 Author Share Posted July 31, 2003 Well I think I fixed my code 22(TPS Signal too low). I enlongated the holes on the TPS sensor so that at closed it would read .350 Volts instead of the .090 volts that it was reading. So far so good, no engine light is on but I cant go for a drive because its raining like a son of a gun here. I might be able to drive it tommorow but I think is going to rain all day Hopefully this will fix my code 44 and 65 too! My idle also came down but I need to clean my throttle body because it is sticking at the closed position. I spilled a little coolant in it when I took off the thermostat cover last week when I was dicking around with my temp sensor. I think thats why its sticking. Guy Quote Link to comment Share on other sites More sharing options...
Kinked_Chrome Posted August 1, 2003 Share Posted August 1, 2003 I had the exact same problem on my LT1, high idle, couldn't get it to go away. Turns out that I had a massive vacuum leak. I forgot to plug the vacuum port on the throttle body for the fuel canister, it's the port right in the middle on the throttle body on the passenger side. Quote Link to comment Share on other sites More sharing options...
dmyntti Posted August 1, 2003 Share Posted August 1, 2003 It sounds like a vacuum leak on the passenger side of the intake. Use the porpane torch trick concentrating on the passenger side intake manifold gasket. If one side of the intake gets a leak and goes lean then the computer will richen up the mixture for all cylinders making the other side too rich. Also check for vacuum leaks around the injectors if one of the o-rings got damaged it could cause a problem. Quote Link to comment Share on other sites More sharing options...
Mudge Posted August 1, 2003 Share Posted August 1, 2003 Vacuum leak should show up as very high map, if its an LT4 Hotcam it should probably idle around 50 MAP, if its 60+ something is amiss. There is also a HIGH MAP code when its pretty bad. Quote Link to comment Share on other sites More sharing options...
Guest tom sixbey Posted August 1, 2003 Share Posted August 1, 2003 sorry for the confusion, by egt sensor - i meant 02 sensor - pretty much the same thing.. my concern was that the 02 sensors might be getting significantly different readings because of their different locations in the exhaust stream and the materials that they are mounted in (due to having different manifolds on each side of the car). i wouldnt imagine that it would cause too much of a problem, but its just a suggestion... later Quote Link to comment Share on other sites More sharing options...
Mudge Posted August 1, 2003 Share Posted August 1, 2003 Amazingly even the stock setup does ok with the different O2 location, EGT is an exaust gas temp sensor Quote Link to comment Share on other sites More sharing options...
Guest benjlv Posted August 2, 2003 Share Posted August 2, 2003 i would go out and do the propane trick. i bet youll find something Quote Link to comment Share on other sites More sharing options...
80LS1T Posted August 4, 2003 Author Share Posted August 4, 2003 Well heres whats going on now.... I have my idle down to about 900-1000rpms. I checked to see that the vaccum port on the side of the throttle body was plugged and it is. I think I that my throttle plates are actually sticking because when ever I have the engine off and pull on the throttle it kind of sticks right off the closed position? My biggest problem is that it seems to still run rough under 2500rpms but there are no codes present? I did a fuel injector flush on friday but I didnt get a chance to put in on the scanner at work. I would think that if it were misfiring that there would be a code or 2.......right? Oh and the O2's are mounted the exact same distance from the heads on both sides. They are not mounted it the header or manifold. So I dont think that is the problem. I have to pull my crappy header off the passenger side again because it is leaking out of the gasket area! I really need to get some nice header that dont leak cause this is causing me quite the headache! Anybody want to give me the $800-$1000 for set of custom coated headers? I really need to get this stuff taken care of so that I can finish the car. The guy that ported my heads and intake wants to use my car for his websites promotion in the "project cars" section! I dont want to send him pictures without it all painted up though! I was really excited to get that email! 8) Guy Quote Link to comment Share on other sites More sharing options...
Mudge Posted August 4, 2003 Share Posted August 4, 2003 Ideally they should be mounted in the header, unless they are block huggers. Quote Link to comment Share on other sites More sharing options...
80LS1T Posted August 4, 2003 Author Share Posted August 4, 2003 Yeah I know that they should be as close to the heads as possible but I want to make sure that they were even on both sides. I dont have a mount for a O2 in the stock manifold and the header didnt have one either. So I have them mounted about 1 1/2 feet from the heads. This is so that they are easier to check also. They are still close enough to take an accurate reading. Guy Quote Link to comment Share on other sites More sharing options...
Mudge Posted August 4, 2003 Share Posted August 4, 2003 Thats not bad, the stock passenger manifold on the OBD I cars has an O2. Quote Link to comment Share on other sites More sharing options...
sweetride2go Posted October 3, 2007 Share Posted October 3, 2007 this is a bit of a resurection, but heres my .02 for this peticular thread.... i had a similar problem on my 95 lt1, with a high ilde and low power... we chased it down to the 'idle air control valve'... after changing that and a broken spark plug(the doner car was wrecked) it ran like it was sapose to... for 6 months anyhow, haha, now i got a new problem... ryan~ Quote Link to comment Share on other sites More sharing options...
80LS1T Posted October 4, 2007 Author Share Posted October 4, 2007 I think I actually answered this in another thread but I will in this thread too. My problem end up being a couple of things... 1. the previous owner of the engine harness had the left and right bank o2 sensors crossed so the left bank was controling the right bank and vise versa. 2. the IAC valve was not wired correctly for my 1993 IAC vavle, the previous owner was running a 1996 IAC so I just had to swap a few wires around and the idle came right down where I wanted it too. 3. I also found that I didn't have enough a good enough engine ground which didnt really seem to effect the running of the engine but it made it hard to start sometimes. I ended up making to extra grounds straps out of wire from jumper cables(0 gauge). One is hooked from the framerail on the passenger side to one of the starter bolts and the other is hooked from the framerail to the drivers side engine mount. No starting problems since. 4. I did find a couple of spark plug wires that burned through even though I had those high temp covers on them. I have since rerouted the wires and haven't had a problem with them burning up. The engine is now running great and no issues to speak of! Guy Quote Link to comment Share on other sites More sharing options...
MoNkEyT88 Posted October 4, 2007 Share Posted October 4, 2007 Good job..! Quote Link to comment Share on other sites More sharing options...
piston Posted October 4, 2007 Share Posted October 4, 2007 wow, i havent been on here for 2 months. anyways, when you find out why its at 1500rpm, let me know because mine is at 1500 rpm also. but i think its just my tach because it redlines at 7500. man, this tunercat tool section gets me lost. i think it runs good already the way mine is, its just not full potential. anyways, hopefully you find your problem and dont hesitate too much. at least your in beter shape than me. my z has a check light 24/7 and the fans turn on at all times. it idles and runs fair. but oh well, i havent gotton the chance to even undersatand the tool section in tuner cat yet and have no idea about how to mess with the tool section tunercat offers. Quote Link to comment Share on other sites More sharing options...
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