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98 metro wont start??; Starting problem
Topic Started: Jan 23 2010, 06:05 PM (1,124 Views)
jodyf
New Member
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I have a 98 metro with 1.0L. It ran fine. Then check engine lite came on and stayed on. I checked owners manual and it said if the light stayed on it was probably a sensor and not serious. I drove it to work the next day, worked fine. Drove home, parked it in the garage for the weekend. Two days later I go out and it wont start. Put on new plugs, wires, cap, and rotor. Checked fuel pump, checked timing. Has fuel and spark. I took it to a mechanic. On the way I let out the clutch and it started right up. It idled fine but if I stepped on throttle it wanted to stall. If I slowly pushed throttle I could get rpms out of it, but a little too much, it would stall. Mechanic put it on scanner, and it said I needed an airflow temp. sensor. Replaced this, no change. He said he put an air vent on it and it blew out the exhaust at TDC, so he thought an exhaust valve was shot.
Before I pay to have the head done, I would like to know if anyone agrees with this. It seems odd that it ran fine, and then suddenly I park it for 2 days and then the valve is shot when I go back out. If anyone has an opinion on this it would be appreciated. Thank you!
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jellybean


did he do a compression check and is the timing right ?as for the light what codes does it have Just my $0.02
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jodyf
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The mechanic said the middle cylinder was a little low but not too bad. He thought it was because the exhaust valve was stuck open. Timing is good. I gave it a sea-foam treatment and now I can start it but It still dies when you step one the throttle.
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Bad Bent
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Facetious Educated Donkey

Welcome to the forum, jodyf! :coffee

It would be nice if we had numbers. The OBD Code is P0100 through P0107 for Mass or Volume Air Flow Circuit Malfunctions.
If an exhaust valve was leaking then fuel would be going into the exhaust and it could fry the Catalytic converter. That being clogged you would get less power. It is cheaper than a head but the valve would be the cause.

If the manual is correct it's a common fix to replace one of the O2 sensors, depending on the OBD Code. You can get a OBDII code reader for $35US on eBay. It's a simple plug-in to the socket above the driver's right knee, key-on and push some buttons per instructions.

The compression is good above 155 psi. and is usually done dry and wet. How to - Compression Test.

Seafoam it again. ;)
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jodyf
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I dont know the code number, but he said it was Intake Airflow Temp Sensor. If the exhaust valve was stuck open would this lower compression on one cylinder?
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Murf 59
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If a valve were stuck open. He would not get a compression reading. If the valve is open. The piston has nothing to compress the mixture against. I am not sure what the exact problem is. But I smell a rat.
Sorry I forgot. Welcome to our little home on the range :thumb
Edited by Murf 59, Jan 23 2010, 11:53 PM.
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starscream5000
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Got 70 MPG?

Unicron had a similar problem with his car. He bought it, drove it home (about 5 miles). Goes to start it up a few days later, no start. We tried several things. We pulled the motor, came to find out that the exhaust valves were burnt up to some degree on each cylinder.
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Johnny Mullet
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Fear the Mullet

I would do the compression test yourself and post the readings here
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StevieC
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:gp

+1 on the compression test. Don't just go out and buy parts, something I've come to learn is too easy to do. Get yourself a compression tester and the guys here will have you on your way in no time! :)
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mwebb
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FOG

...."He said he put an

air vent

on it and it blew out the exhaust at TDC, so he thought an exhaust valve was shot."......


========================
an air vent ? makes no sense

maybe what he used was a pressure transducer in the exhaust synced to spark
and he had a pressure pulse in the exhaust that synced to TDC or spark which is very close but 8 degrees before which in the scope screen ?
(at idle)
would be very close to TDC

i can interpret a screen cap of that waveform if you provide it , i would like to see at least 720 degrees of engine rotation
in the waveform and i can post examples if you wish

if what i posted above makes no sense to you , it's ok.
then
we will need compression values and intake vacuum values at hot idle and hot 2k rpm , if possible
BUT
cylinder leak down values performed with a leak down tester
would be infinitely better

==============================================
regarding scan data
after the car sits overnight , use the scan tool to compare coolant temp and air temp values
KEY ON ENGINE OFF
without starting the car , the values should MATCH exactly AND both should be at ambient temperature at the time ...
if one or both values do not match ambient temperature , you may have a bad sensor ground or
voltage drop in supply or ground to the ECM , report your test results
...............
and
you should have a misfire code , it will be
P030X where X is the misfiring cylinder and possibly a P0300 as well
P0300 is random misfire Mr ECM does not know when the misfire occurred ,it usually sets with a P030X DTC.
Edited by mwebb, Jan 24 2010, 09:41 PM.
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jodyf
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I got it going!!!! A buddy came over and we adjusted the timing. We had to move the belt two notches and then it ran fine. Guess I took it to a poor mechanic. Thanks to everyone for the advice! This is an awesome forum. I'll be sure to come back often. Thanks again!!!!!!!
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Woodie
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It's not fixed, it's patched. Cam timing should not jump like that. You've either got a timing belt about to let go or the crankshaft key is sheared and the sprocket is slowly walking around the shaft.

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billy508
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billy508

:gp :gp What Woodie said. Please find the reason the belt jumped. :banana :banana :banana
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undgsx-R
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Self Certified Garage Mechanic

Could the timing belt tensioner be going bad?
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