WhiteOut Posted March 22, 2004 Report Share Posted March 22, 2004 Alright. Its nearly spring and its time to start fixing the little things on my car. First of which is a high idle problem. The car idles between 1050-1150 RPM and will go 30-35mph by itself if put into gear. I think thats a bit high myself, so I'd like to get it down to where everyone else is (600-800 RPM) problem is I have no idea whats causing it. The idle is stable from both cold and warm starts and there's no surging, and I did the intake gaskets last fall so I know thats not the problem. I cleaned the IAC off last fall as well, but that didn't do anything to fix the problem. Could I possibly need a new IAC, or TPS? Is there a way to tell? Where does everyone else's 3.4 idle at? I'm curious as to what the 70 mph cruise RPM is too for everyone else, my car usually pulls 2750 RPM or so on the freeway at 70. Quote Link to comment Share on other sites More sharing options...
pblunt_ Posted March 22, 2004 Report Share Posted March 22, 2004 My 3.1 Euro idles at 800-900 anything less will shut off my euro. I can't remember my rpm @ 70 mph I'll check tomorrow morning on my way to work. Quote Link to comment Share on other sites More sharing options...
pblunt_ Posted March 22, 2004 Report Share Posted March 22, 2004 Okay I checked 3.1 = 2100RPM @ 70 mph Quote Link to comment Share on other sites More sharing options...
sonyman87 Posted March 22, 2004 Report Share Posted March 22, 2004 Alright. Its nearly spring and its time to start fixing the little things on my car. First of which is a high idle problem. The car idles between 1050-1150 RPM and will go 30-35mph by itself if put into gear. I think thats a bit high myself, so I'd like to get it down to where everyone else is (600-800 RPM) problem is I have no idea whats causing it. The idle is stable from both cold and warm starts and there's no surging, and I did the intake gaskets last fall so I know thats not the problem. I cleaned the IAC off last fall as well, but that didn't do anything to fix the problem. Could I possibly need a new IAC, or TPS? Is there a way to tell? Where does everyone else's 3.4 idle at? I'm curious as to what the 70 mph cruise RPM is too for everyone else, my car usually pulls 2750 RPM or so on the freeway at 70. the final drive ratio in the 3.4dohc 4t60e is not the same as the 3.1 4t60e. your 70mph rpm seems to be close enough.. i was going to say about 2600rpms. Your idle should be about 900rpms with the LQ1 a little lower when not moving in drive. In drive and moveing even if its 1mph your idle should be at 1100rpms to 1300rpms and that will be normal. just a few quick tests for you to make sure everything is good Turn your car on without starting the motor and look where your Tack its reading. If its not directly on 0 rpms then your tack is off. the distance to 0 will be even threw the entire range. You have to imagine a needle that distance away from the actual needle to figure your rpms more acuratly. IF you still have a High idle problem then look for a vacume leak. Does your car stall when it tries to go below 1000rpms? if so then your sparkplugs could be fouled out or you have a leaky inake gasket you should be able to go up a hill after the car is warmed up a little in 4th gear at 55mph at ~2000rpms without a problem (depending on how steep of a hill) i can get my car to go up a hill at 45mph at 1800rpms but if im not gentle enough with the peddle it downshifts. i hope this helps. let us know how it turns out Quote Link to comment Share on other sites More sharing options...
WhiteOut Posted March 22, 2004 Author Report Share Posted March 22, 2004 Super helpful. Thanks for taking the time to write all of that. Turns out my tach IS off by about 150-200 RPM or so. Is there a way to fix/adjust this. I know its probably based off of a speed sensor in the tranny somewhere. Could this have been caused by the Trans shop messing up when they rebuilt my transmission? Quote Link to comment Share on other sites More sharing options...
sonyman87 Posted March 22, 2004 Report Share Posted March 22, 2004 Super helpful. Thanks for taking the time to write all of that. Turns out my tach IS off by about 150-200 RPM or so. Is there a way to fix/adjust this. I know its probably based off of a speed sensor in the tranny somewhere. Could this have been caused by the Trans shop messing up when they rebuilt my transmission? Simply pull the needle off i believe and just put it back on pointing at 0rpms instead of the 150-200rpms off. I need to do this with mine also and just havent taken the time to do it. be sure when you put it at zero that the ignition is on and the motor is off. like you did your test Quote Link to comment Share on other sites More sharing options...
EurosportZ34 Posted March 22, 2004 Report Share Posted March 22, 2004 My Z idles at 900-1000RPM, but I'm not sure at 70MPH, I'll have to check sometime and reply back EDIT: 2100RPMs at 70MPH Quote Link to comment Share on other sites More sharing options...
maybe2fast Posted March 27, 2004 Report Share Posted March 27, 2004 vacuum leak??? sounds like one Quote Link to comment Share on other sites More sharing options...
WhiteOut Posted March 27, 2004 Author Report Share Posted March 27, 2004 I don't think there's a vacuum leak. I tested it and its a steady 18 in. of Hg at idle. Plus the idle is VERY stable with no fluctuation, so I doubt its a leak of some kind. My tach was off by about 100-150 RPM though, but thats fixed now, idle is still around 900-1000 RPM though. Maybe thats normal for this engine, it just seems odd since my Trofeo idled at 600 RPM. Quote Link to comment Share on other sites More sharing options...
joey b Posted March 28, 2004 Report Share Posted March 28, 2004 check the cable from the cruie control. Quote Link to comment Share on other sites More sharing options...
chree Posted March 29, 2004 Report Share Posted March 29, 2004 I also have a high idle (1200-1500rpm in gear) on my '95 Cutlass with the 3.1L. I've replaced the temp sensor and the tps and scanned it with an AutoXray (no obvious problems). I'm stumped. I tried spraying WD-40 around the intake gasket - but saw no change in rpm. I don't have a problem changing the intake gasket - I just want to be sure that's the problem! What AutoXray readings should I look at? Thanks, Chris Quote Link to comment Share on other sites More sharing options...
zachismisit Posted March 30, 2004 Report Share Posted March 30, 2004 well, im not a genius car guy but couldn't the pcv valve (i think thats the right order) cause some weird rpm stuff if it clogged up Quote Link to comment Share on other sites More sharing options...
chree Posted March 30, 2004 Report Share Posted March 30, 2004 I'm starting to think it has to be a vacuum leak. What else could it be? The ecm doesn't raise the idle speed does it? (At least not for anything but startup?) The question is how to confirm the leak. The Cutlass will do a nice steady 50mph with no throttle input! Chris Quote Link to comment Share on other sites More sharing options...
WhiteOut Posted March 30, 2004 Author Report Share Posted March 30, 2004 Wow, mine doesn't quite do 50mph but it will idle along at about 30mph. I guess I'll just learn to live with it. It doesn't really effect drivability since the idle is stable, I just wondered what the hell was going on since it seemed really high compared to my last car which idled at about 600-700rpm. Quote Link to comment Share on other sites More sharing options...
chree Posted March 30, 2004 Report Share Posted March 30, 2004 50mph is a bit ridiculous, but I've been living with it because I mainly commute to work in the car and my commute is almost all highway. I am worried about the transmission though, it slams into gear pretty hard. I read that a smoke source (like a cigar) could draw into the vacuum leak to locate it. I guess that would only work if the fans were off. How hard is an intake gasket swap on the 3.1? Chris Quote Link to comment Share on other sites More sharing options...
WhiteOut Posted March 31, 2004 Author Report Share Posted March 31, 2004 Not sure about the 3.1 but my 3.4 was a PIA. I've heard people say the 3.1 is easier since there's simply not as much crap in the way though. Quote Link to comment Share on other sites More sharing options...
chree Posted April 11, 2004 Report Share Posted April 11, 2004 I feel not so bright that the cause of the high idle was so obvious... Many people have suggested it was due to a vacuum leak - and I was pretty certain that was the problem. All the sensors were reading correctly, so a vacuum leak would be compensated for by the map sensor (no maf). I started spraying throttle body cleaner around the intake and was also poking around the vacuum hoses. All of a sudden I hear the telltale hiss when I bump the pcv hose. It is a hard plastic line and the "T" that plugs into the intake is partially covered by the throttle cable bracket. As I move it I see that there is a flange on the hose that is the same diameter as the hole in the intake - but when I wiggle the line I see there should be a grommet in the intake... Where is the grommet??? To sum up: a 1/2" section of 3/8" hose substitutes the MIA grommet perfectly. The idle returns to normal, I disconnect the battery to clear the code and go pass an emissions test. I'm a happy camper. I can't believe it was so simple! I only spent $180 in sensors and testing equipment trying to find it! Chris Quote Link to comment Share on other sites More sharing options...
Cueman Posted August 19, 2004 Report Share Posted August 19, 2004 Does anyone know if there really sholud be some kind of grommet in there, where the "t" connects to the intake under the throttle bracket. I have discoverd the same "missing " part...don't wanna just put a piece of hose in there and have it melt..any suggestions?? Quote Link to comment Share on other sites More sharing options...
chree Posted August 19, 2004 Report Share Posted August 19, 2004 I suggest... a 1/2" section of 3/8" hose. It's fuel hose so it's made to hold up in the underhood heat. Four months later it's working fine on my '95 (in Atlanta with 100 degree weather!). I feel confident there was some type of grommet there - I'd guess it's $20 at the dealer. Maybe HELP! brand carries it at the local parts store? Chris PS: Anyone in the southeast have a hood for a '95 2 door? Email or PM me please. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.