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problems with my lumina?


kskwsde's Avatar
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12-27-04, 10:42 AM   #1  
problems with my lumina?

I have a 1998 Chevy Lumina LTZ with the 3.8 liter V6 (eng. code K). I just recently had the lower intake manifold gasket replaced, the EGR valve gasket replaced, and the upper intake plenum replaced. As part of that process obviously, the fuel rail and injectors had to be temporarily removed. Everything is ok with that, there are no oil or coolant leaks now. I drove the car after the repair fine without any incident for about 1 month.

However, just recently (with the last week) the service engine soon light has come on and stayed on. It is not flashing, just continually on. I have also noticed that I am getting poor gas mileage, I usually get 26-27 mpg but am now only getting around 18-19. Otherwise, the car is running fine, there is nothing else noticeably wrong.

Any ideas about what could possibly be the culprit without knowing an error code? I'll take it in if I have to, just wanted to see if anyone knew any possible causes for this. Is it possibly related to the recent repairs?

Thank you,
Kevin

 
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12-27-04, 12:27 PM   #2  
Anything is possible. You have to read the code to get started in the right direction.

 
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12-27-04, 02:08 PM   #3  
That light can come for over 100 different reasons. have the codes read and post the numbers here. We'll try to help then.

 
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12-28-04, 10:26 AM   #4  
re: lumina mileage problem

Ok, i took the car in and had the codes read, and this is what came up for codes:

P0107 - map or baro pressure signal low
P0108 - map or baro pressure signal high

P1106 - map sensor ckt (<-sp?) intermittent high
P1107 - map sensor ckt (<-sp?) intermittent low

P1133 - HO2S S1 insufficient switching

The place that read the codes just does diagnostic,they do not do engine repair work. The guy who did it though said that he thought it wasn't necessarily related to a sensor, but something that relates to and affects the sensor(s). Could this be related to the work that was done (see previous post)? Could there be a gasket that is not keeping pressure? And can this be checked without having to completely re-do the gasket work that was done? Please let me know if you need any more information to give me an opinion. Thank you for the advice,

kevin

 
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12-28-04, 01:52 PM   #5  
It's not a vacuum leak or pressure leak.The only thing I can think that would cause hi and lo map circuit codes would be a faulty map sensor,faulty pcm or more likely a broken wire or poor connection from a spread terminal.The map sensor connection or pcm connection could be at fault so check both.If I was the one working on the car the map sensor connection or wires real close to the connector would be my first place to go.You may have to pull on the wires to check for a weak spot.One note worth mentioning sometimes the wire breaks where it's crimped on and can be hard to find without just replacing the terminals in the connector.

 
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12-29-04, 10:08 AM   #6  
Posted By: davo It's not a vacuum leak or pressure leak.The only thing I can think that would cause hi and lo map circuit codes would be a faulty map sensor,faulty pcm or more likely a broken wire or poor connection from a spread terminal.The map sensor connection or pcm connection could be at fault so check both.If I was the one working on the car the map sensor connection or wires real close to the connector would be my first place to go.You may have to pull on the wires to check for a weak spot.One note worth mentioning sometimes the wire breaks where it's crimped on and can be hard to find without just replacing the terminals in the connector.
I guess that's good news...I was worried that a gasket had failed someplace where they had to replace gaskets when this repair work was done. One of the first things I thought of was that the EGR had to be temporarily removed when they replaced the intake gasket(s). So that EGR gasket was also replaced. I will take this information, along with the codes, to an engine shop and see what they can find out. I just thought it was odd that this happened after that repair work was done. Of course as part of that work, a lot of those sensor connections were unplugged and then plugged back in, so maybe one of those connectors was damaged.

Would it be worth a try to just unplug and re-plug in all of the different electrical connectors? Maybe on the chance that something just wasn't plugged in securely enough... If there was a damaged connector or a loose connection, how long would it take for that to register as an error code?

Thanks for all the great advice, I'll post back with more info as I get it - any other help is greatly appreciated

Regards,
Kevin

 
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12-29-04, 02:14 PM   #7  
You could unplug the map sensor and then plug it back in but I wouldn't hold my breath.I would think if the problem was induced by the manifold/gasket repair it would have been right away.Even so a hi circuit and lo circuit code doesn't really jive except as I mentioned so I don't feel if the repair was done wrong you would have hi and lo codes.Unless they set the codes during the repair but you said the light just came on so I will assume the light was off and no codes were stored when you picked up the car.Have you had the codes cleared to see if any reset?Try that and see if the light comes back on and let us know.If it does have the codes read again and if any reappear.Autozone will do it for free and low cost readers can be had for a small amount these days.

 
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12-29-04, 06:03 PM   #8  
Yes the light did just come on, well actually about 1 week ago now. But the gasket work was done about 6 or 7 weeks ago... I could try resetting the map sensor to see if the problem goes away, However, in addition to the error codes, I am also seeing a noticeable decrease in mileage, only getting about 19 mpg, whereas I usually get around 26-28 mpg. Would resetting the map sensor possibly take care of this? Thanks for the help thus far, I'll post back with more info later if possible. Any help is appreciated, thank you

kevin


Last edited by kskwsde; 12-29-04 at 07:13 PM.
 
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