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| '90 Automatic 18MPG; Running like crap | |
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| Tweet Topic Started: Sep 16 2012, 02:55 PM (1,591 Views) | |
| pasotx | Sep 16 2012, 02:55 PM Post #1 |
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1990 Geo Metro 4dr automatic unknown mileage as previous owner transplanted motor from other car. Compression: 132/175 130/160 135/175 replaced vacuum lines and checked for / repaired leaks. new plugs/cap/rotor/wires put in two different shops and they said they could not find anything wrong. plugs are very black and tried holding a paper in front of exhaust and it was covered in black in a couple of seconds. Looks like it is running very rich. I know the check engine light works because there was a vac leak at the air cleaner and it went off when I fixed it. Ck engine light not on. When I first start the car it accelerates fine but after a few short minutes it will not accelerate from a stop once it gets up to 5 mph, it picks up and runs ok. I did put seafoam in the tank and sprayed a BUNCH in the throttle body while it was running. No help. None of the auto parts places around here have a manual for it. What the heck is making this car run so rich? For all I know the previous owner put the wrong throttle body on the motor when he did the swap. I can smell the unburned fuel when driving. |
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| Memphis metro | Sep 16 2012, 03:02 PM Post #2 |
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Put a gauge on it and check the fuel pressure. Defective fuel pressure regulator can cause running rich condition as well as a defective injector. Engine transplants always concern me. |
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| Old Man | Sep 16 2012, 03:15 PM Post #3 |
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good deal on a 1990 manual: http://www.ebay.com/itm/1990-GEO-Metro-Service-Shop-Manual-SF-2427-/271054756311?pt=Motors_Manuals_Literature&hash=item3f1c1f59d7&vxp=mtr |
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| bennie442 | Sep 16 2012, 03:18 PM Post #4 |
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The poor compression numbers are not helping either. They are quite a bit lower than factory service limits. That's a great deal on the factory books, for sure!
Edited by bennie442, Sep 16 2012, 03:21 PM.
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| Memphis metro | Sep 16 2012, 03:19 PM Post #5 |
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Heres how to test fuel pressure in post 41 here, http://geometroforum.com/topic/4464045/3/ If it is indeed running rich and goes too long in that condition, you will find yourself needing a catalytic converter as well. |
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| clarkdw | Sep 16 2012, 06:37 PM Post #6 |
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Were the compression readings done with wide open throttle? If yes then you have low compression and probably low vacuum. Low vacuum at the MAP sensor makes it think the throttle is wide open so it goes rich. To get a good read on what is going on make sure the compression test is done with wide open throttle and get a cheap vacuum gauge to hook in to the hose that goes to the MAP sensor. It will make troubleshooting much easier than guessing. |
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| pasotx | Sep 16 2012, 09:08 PM Post #7 |
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Done at WOT. Had a vac gauge and tested that since I don't have a fuel pressure tester. Located MAP. Shows 15 on the dial. Same at the distributor advance. I know the compression is low and if I can get some other things figured out, might rebuild since the interior is and the stupid car kind of grows on ya. I have sprayed and sprayed around the motor looking for vac leaks and can't find any more. Replaced several vac lines in the process. The thing idles about 1500 RPM. (just a guess but sounds that high) Is there a way to idle it down? While I was messing with it with the air filter and cover off, bumping the throttle makes it act like it is starving for fuel. Then it picks up and will level out. Does anyone know of a person in Central Texas who has a clue about these little cars? Two mechanics I have been to did great work on my Camry and Ram but don't have a clue about this thing. They almost acted like they did not want to work on it. I have a guy 130 miles away that works on my VW diesels. I don't think this car is ready for the bone pile yet. |
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| pasotx | Sep 16 2012, 10:21 PM Post #8 |
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So if the fuel regulator has failed, the reading will be below 20 psi because it is not providing resistance. Is that correct? The top of the pistons have a sludge on them. |
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| Old Man | Sep 16 2012, 10:25 PM Post #9 |
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go to the "available geo mechanics" thread at http://geometroforum.com/topic/1644179/1/#new post #41 is a mechanic from Austin Post #49 is a mechanic from Houston |
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| Memphis metro | Sep 16 2012, 10:30 PM Post #10 |
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You can also check for a restricted or kinked fuel return line back to the gas tank. Since someone has put an engine in it, its possible they could have kinked the return line. |
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| pasotx | Sep 16 2012, 11:57 PM Post #11 |
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| pasotx | Sep 16 2012, 11:58 PM Post #12 |
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So if there is a restriction or the regulator is closed, the pressure would be very high. |
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| Old Man | Sep 17 2012, 08:18 AM Post #13 |
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best monies you will ever spend on your Metro |
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| pasotx | Sep 22 2012, 10:40 PM Post #14 |
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I checked the fuel return line for kinks and it appears to be OK. I disconnected the electrical to the MAP sensor and the idle returned to normal and the nose dive on acceleration went away while driving it with the sensor disconnected. Have not been able to get a fuel pressure reading on it yet. @Old Man, the manuals came in on Friday and were helpful. Lots to digest. Still can't find what the vac should be even though the manual shows the tool and says it is for testing vac. I hate to spend $171 on a MAP sensor if that is not the problem.
Edited by pasotx, Sep 22 2012, 10:42 PM.
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| pasotx | Sep 23 2012, 11:12 PM Post #15 |
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FIXED!!! I was a little frustrated at no reply so I was reading other topics and ran across the one where a guy put in a cam and could not get it running. He took it to a mechanic. I think I posted earlier this car has been to two different mechanics who did great work on my Camry and Dodge in the past. They mostly gave up on this little car. Soooo... On the other post I found geogonfa who live about 60 miles down the road from me. In utter frustration I sent him a PM. He called me in less than an hour and invited me down to have a look at it. He said he could smell the unburned gas when I pulled in and in two minutes decided it was the coolant sensor. He just happened to have one. He installed it and reconnected the MAP sensor and the thing purred. No more eyes watering from unburned fuel, no more 1500 RPM idle. No more nose dive on acceleration. Even if he had told me to replace the sensor, I would have screwed it up trying to get it apart. He also showed me how to release the wire retainers. He has an awesome XFI and took the time to show me how to fix the window regulator and was basically a wealth of knowledge. I am dang sure going back down there to get his help with the tie rod ends. I hope next time I get to see his vert. Long story short. Get with someone who knows the cars. Taking it to a mechanic is probably a waste of time and money. Thanks geogonfa and geometroforum. |
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That's a great deal on the factory books, for sure!
7:11 PM Jul 10