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| Idling Issues! Super frustrated. | |
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| Tweet Topic Started: Sep 16 2013, 10:31 AM (2,197 Views) | |
| macuserman | Sep 16 2013, 10:31 AM Post #1 |
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I recently had the head rebuilt on my little green 91 hatchback. I was very pleased with the work that was done and it seemed that it was all running very well. My new mpg is 44-46mpg around town with some ac use thrown in. Compression is 195 on all cylinders and it was running stronger than ever. However about a week after I got it back from having the head job done it started idling horribly... as in it would shake the whole car. I fiddled with it a little bit and finally took it to a local mechanic to have it looked at. They replaced the sparkplugs wires with fancy new one's and did a "tune up" not sure what all that entails did an additional compression test and said it was running great. I paid 127 bucks for them to do whatever it is they did and now once again two days after the work it is doing the nasty shaking again! I'm so frustrated with this whole process, it doesn't do it everytime I stop but it seems to get worse over time, when it first started it got worse and worse until I finally took it in and it seems to be doing the same again. As long as I keep my foot on the gas just barely it doesn't have any issues however it is tricky sometimes to keep your foot on the brake and gas at every stop and probably horribly unsafe. I'm not sure if its relevant or not but it seems to be less peppy since I got it back from the mechanic this time I'm not sure how they "tuned" it but it is significantly less powerful than before. Any input would be greatly appreciated at this point. I don't really want to throw down more money without having a pretty good idea that this will fix it. Please help!! P.S. Sorry for the rant sometimes you have to get it out of your system. |
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| Vkhelldog | Sep 16 2013, 10:52 AM Post #2 |
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Of course. Sounds like the tps may be set wrong or maybe you have a bad vacuum leak? Hopefully whoever worked on it did not touch the tps so it's not set wrong... check for vacuum leaks first or get new lines unless done recently. |
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| macuserman | Sep 16 2013, 12:58 PM Post #3 |
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I'm pretty sure it isn't a vacuum leak. I have sprayed starter fluid around the hoses and it doesn't seem to change anything. How would I go about checking the TPS? |
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| macuserman | Sep 16 2013, 01:05 PM Post #4 |
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I just found this thread I need to spend some time reading it hopefully I'll be able to check the TPS sensor and determine if there is an issue there. I'll report back what I find, if there are any other suggestions I'm still wide open to those as well. |
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| geogonfa | Sep 16 2013, 01:19 PM Post #5 |
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just for peace of mind...check and clean the grounds...especially the ones right below the TBI on the back side of the Intake manifold...and the one near the distributor... |
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| Memphis metro | Sep 16 2013, 01:44 PM Post #6 |
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Do not fool with the TPS. Too many people fiddle with it when it does not need it. Who replaced the head? What is the timing set at? What is the idle speed when engine is hot and all accessories are off? Do you have a tach gauge? Just for the fun of it, check the spark plug wire routing on the distributor cap and make sure they are correct. |
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| truckjohn | Sep 16 2013, 04:05 PM Post #7 |
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I would go through all the vacuum hoses again... just to make sure.... Had a similar issue on my '94 (Before I blew the head gasket).... Turns out that the funny shaped breather hose that connects the Head, Intake, and air cleaner assembly was missing the hose clamp on the intake... Created a huge vacuum leak.... Idle was horrible.... $0.54 hose clamp fixed that.... Next one that did *Exactly* what you are talking about was the Alternator.... First - the alternator was dead... Idle went horrible as the battery started going down and the Alt only put out 9 volts..... Next was with the New alternator with the old belt.... Same exact thing, except way more belt squealing at higher speeds.... Weird bit was no belt squealing at idle.... but it only put out 9v... Check your battery voltage at idle - if it's reading 12-something volts - check that alternator belt is still tight.... Next one that did it for me was my blown head gasket.... With a beat up non-pressurizing radiator cap - it doesn't blow white smoke.. but the idle was terrible.... Thanks |
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| Kevin L | Sep 16 2013, 04:23 PM Post #8 |
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check grounds, check vac lines check timing. don't mess with tps but you can count the turns in on the idle screw and then see if turning it out makes a difference good luck! |
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| 1Liter.love | Sep 16 2013, 07:33 PM Post #9 |
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I may be wrong about its potential for issues but also the egr line routing is important. I observed idle issues with my 3/5 when the vacuum lines were routed improperly to the egr pressure transducer. This is the thing located to the right of the air cleaner, round, about as round as a soda can. Your metro should have a vacuum routing diagram on the underside of the hood. Best of luck! Do you know if your engine is appropriate for its year? |
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| 1Liter.love | Sep 16 2013, 07:35 PM Post #10 |
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DON'T LISTEN TO THAT GU ABOVE ME. DO NOT ADJUST THE IDLE SCREW. THIS IS ADJUSTED AT THE FACTORY AND WILL CAUSE YOU PROBLEMS. |
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| Memphis metro | Sep 16 2013, 07:49 PM Post #11 |
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Actually on a 91 model, base idle can be adjusted. Throttle plate opening has a adjustment screw as well but usually should never be touched, but idle speed can be tweaked using the correct idle adjustment screw. |
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| macuserman | Sep 16 2013, 10:44 PM Post #12 |
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Wow thanks for all the input, I have several things to check now. I'll try to see if I can find a different culprit before I mess with the TPS. I would like to verify at some point that the TPS has not been messed with, I am not the original owner and I think there have been quite a few shade tree mechanics under the hood before me. Just to answer a couple of the questions, the head job was done by a mechanic that my uncle really likes, I had him put in 3tech stainless steel valves that I bought and the nonstretch reusable head bolts, he also cleaned my lifters which got rid of some noise I was having before from lifter clack and I was pretty pleased with the work he did. To my knowledge the engine is the original motor, I do not have a tach yet I have purchased one, but it is taking forever to arrive (several months), I don't have a clue how to set my timing or even check it, the spark plug wires look like they are hooked up correctly to me. Sounds like I need to make absolutely certain there isn't a vacuum leak. Is there official way to test that is perhaps more of a sure thing than spraying starter fluid around? |
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| macuserman | Sep 17 2013, 07:24 PM Post #13 |
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Discovered the wire to the O2 sensor was just hanging down not connected while poking around today. Seemed to run quite a bit better after plugging it back in although its still not quite doing the trick. I wasn't sure how big a deal it was to have it unplugged but figured it couldn't be a bad thing to plug it back in right?
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| Deleted User | Sep 17 2013, 07:40 PM Post #14 |
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If your 1991 has a manual transmission, you do not have a TPS. It is a TS, which translated into English is a Throttle Switch. It's a fairly harmless device that enrichens the fuel mixture at an idle and near full throttle. If you mess with it, and you now have a surging idle, I'm pretty sure someone said to not mess with it. I'll take the time to talk you through the de- ing process. The Factory Service Manual has the procedure, but it's not quite right.Also, the throttle plate adjustment screw is one of the least likely to ever need adjustment. I suspect that your engine is shaking at idle because the hydraulic units in your valve lifters have become contaminated with sludge, or for some other reason, have begun to stick. Were the lifters cleaned or replaced during the head repair? How dirty is your oil when you change it? Clean enough to donate to your favorite cheap buddy for continued use, or so black that . . . Also, does the rough idle go away after driving for a while? |
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| macuserman | Sep 18 2013, 11:32 AM Post #15 |
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I do have a manual transmission, I haven't touched it all myself but thats no guarantee it hasn't been messed with by someone else. I payed the mechanic who did the head job to clean all the lifters and I was def charged for that, I had been having some lifter clacking so I had him clean them which seems to have taken care of that problem. I haven't changed my oil since the head job which was only a couple weeks ago, so I'm not sure what the oil looks like should I change it again so soon? The car uses a bit of oil so I add oil regularly. I have added a quart since the rebuild. The rough idle doesn't seem to be affected by how long I drive it if anything it gets worse the longer I drive it. I did some experimenting and while its warming up when you first start it if you just leave it idling it purrs like a kitten until it gets up to temp and thats when it starts acting a little bit funny. |
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ing process. The Factory Service Manual has the procedure, but it's not quite right.
2:17 PM Jul 11