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My Buick is acting up


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jackx
User

Mar 2, 2015, 3:50 PM

Post #1 of 23 (1148 views)
  post locked   My Buick is acting up  

I got a 1999 Lesabre. It has been throwing a P0135 trouble code. I looked it up and that's a
upstream O2 sensor code. I cleared the codes and ordered a new O2 sensor.

Now its runs fine but every so often it will die. It always starts right up when I hit the ignition.
It died twice today when I was slowing down at a stop light. Then it died as it was just coasting
along at about 30 mph.

Its not throwing a code and its got 1/2 tank of gas. I guess it could be the fuel pump not putting
out enough pressure. I'm not sure how to determine what the pressure is when it is acting up. I hate
to just drive it till it is obvious it does not have enough fuel pressure by waiting until it won't start.
It primes with my fuel pressure showing 45 pounds of pressure and after it starts my guage shows
41 or 42 pounds of pressures. When you give it gas the pressure will go back up to about 45 pounds.

I looked up what the pressure has to be in order to start the motor. I found it won't start unless it has
48 pounds of pressure. Since my car starts ok it must be getting 48 pounds of pressure and I guess
my guage is 3 pounds off. So, since is starts I guess the fuel pressure may be ok.

I guess it could be the crankshaft position sensor. Maybe its needs to be cleaned or replaced. It's not
throwing a code.

I guess it could be a ignition problem but I don't know what could be the problem since its not
throwing a code.

Any body got any suggestions as to how to determine why its dying.


(This post was edited by jackx on Mar 2, 2015, 5:38 PM)


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Mar 2, 2015, 5:29 PM

Post #2 of 23 (1136 views)
  post locked   Re: My Buick is acting up  

This is one of the hardest problems to resolve. What has to be do is you have to hook up diagnostic tools to monitor spark, injector pulse and fuel pressure and you have to be watching them at the exact moment the car dies and determine which one cut out first.


In the meantime I would at least clean the throttle body.

. Remove the intake snorkel, have someone hold the throttle wide open for you and scrub the back side of the throttle plate and surrounding bore with an old tooth brush and some carb cleaner. Be sure to spray some into the small holes next to the throttle plate.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



jackx
User

Mar 2, 2015, 5:56 PM

Post #3 of 23 (1132 views)
  post locked   Re: My Buick is acting up  

Yeah if that is what you have to do then I am in trouble.Unfortunately it only stalls now when you are
rolling down the road.

I will clean the throttle body and see if it stops stalling.

Its got the same fuel pump and crank shaft position sensor it had when I bought it. That was
5 years ago and it only had 63,000 miles on it then. Since it has 109,000 miles on it now and those
parts were probably the same ones that came on it from the factory I may have to replace
them unless the problem becomes not a intermittent problem. At least that gives me an idea of
how much this could cost to fix if I can identify the problem and these components need to be
replace. Probably a $200 problem.

I'll just drive it and maybe store the local tow truck number in my cell phone....At least it starts
when it dies.....

I may take it to a shop after I drive it a few more days. A shop can probably can give me an idea
on what they find is usually the problem and I will take it from there. Unfortunately they may just
have to start replacing parts. I hate it when they want to do that.

All I know is you basically need 3 things to get a motor to run.
fuel
spark
compression

If its the pump then its "fuel'
and if its the crank shaft position sensor its "spark"


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Mar 2, 2015, 6:00 PM

Post #4 of 23 (1130 views)
  post locked   Re: My Buick is acting up  

No, a Crank sensor will take out spark and fuel.

I might gamble on changing a Crank sensor but i doubt the fuel pump is the issue here. It could even be a computer or maybe cleaning the throttle bold will resolve it.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



jackx
User

Mar 2, 2015, 7:01 PM

Post #5 of 23 (1122 views)
  post locked   Re: My Buick is acting up  

Thanks for the help.

Been checking and it only takes 45 pounds of pressure to start a lesabre.
So, my gauge is probably giving me the right number and the pump is probably not the problem.

If cleaning the throttle body with some carb cleaner does not solve the problem then I am thinking
I will pull the connector off the crank shaft position sensor and see if it needs some electrical
cleaner.


Discretesignals
Ultimate Carjunky / Moderator
Discretesignals profile image

Mar 2, 2015, 8:27 PM

Post #6 of 23 (1113 views)
  post locked   Re: My Buick is acting up  

They can start on 14 lbs of fuel pressure, but they'll bog out when you rev em. This doesn't have poppet valves that require a certain amount of pressure to open them.

Like HT stated, accurately diagnosing an intermittent stall and restart issue is very difficult. Sure you can get lucky changing parts out, but how much you will to spend on guesses and what happens if it is a circuit issue?

Someone is going to have to monitor systems to see what fails when the glitch occurs. Even professionals with years of drive-ability experience can find those challenging.





Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.


jackx
User

Mar 3, 2015, 9:04 AM

Post #7 of 23 (1097 views)
  post locked   Re: My Buick is acting up  

I pulled the snorkel off the 3.8 motor. I also pulled the MAF sensor out of the housing that the
snorkel mounts on. There is a screen over the snorkel opening and you can't actually see the butterfly
valve. I squirted Berryman B12 through the Screen and moved the throttle linkage so the
Berryman should have squirted on both the top and bottom sides of the Butterfly. I also squirted
some Berryman down the hole I pulled the MAF sensor out of. I was careful not to get any
Berryman on the MAF sensor and I cleaned it good with CRC MAF cleaner. Then I started the
motor. I had to push the pedal to the floor because it was flooded. It started. I then pulled the
vacuum hose off the brake booster, turned the linkage to rev it up and I poured 1/2 a can of Seafoam
slowly through the vacuum hose. I poured the remaining Seafoam in the tank.

I drove it around the block a few time and the throttle seemed more responsive and it did not
stall. This is good because earlier when I went to autozone to get the Berryman and Seafoam it
stalled on the way home at a stop sign. I guess after I drive it a few days I will know if it is
good to go. I will update you then. I will keep my fingers crossed. If it doesn't fix it I will take the
housing off so I can actually see the butterfly and again try to clean it with the Berryman. Hopefully
I cleaned it enough that it won't stick again.

Thanks for you help.


Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Mar 3, 2015, 12:25 PM

Post #8 of 23 (1087 views)
  post locked   Re: My Buick is acting up  

Agree with the guys this type thing is a pest on techs and people. Great - runs new then nothing for no reason then runs new again and everything checks out - arrr!


Done with this game mostly but not that long ago same bull same basic set up you have for a Winter beater car pulled that. OK, ready now with fuel pressure gauge on it and spark presence thing inline plus a momentary push button (think they still sell those) to trigger starter with key left on such that in that case you see what's missing IF IT DOESN'T START RIGHT UP!


No fuel and now spark like you. No codes to help on that one either. I think it was a crank sensor and still wouldn't know like you for sure without a period of time of it not happening or toss any possible thing that could do that.


Too late as car was free and worth as much as scrap as playing with it so to the bone yard it went and regret it now as it was a totally legal good running worst looking thing though car to just use up. It's not amusing with those sudden "I'm not running right now no matter how inconvenient it is with no warning" so sit there and I'll think about it to get you home - didn't cut it with me but should have gone for it.


I/we hate the parts toss game but if car is nice enough count that expense vs the royally annoying surprise strandings!


T



jackx
User

Mar 3, 2015, 4:05 PM

Post #9 of 23 (1082 views)
  post locked   Re: My Buick is acting up  

Drove it and it died about 3 times and as I rolled up the drive and it died again ......

I started it and blipped the throttle. I noticed it would only rev up so much and then it would start
to heave and surge. Tried it again and the same thing.

I went ahead and pulled the housing off the snorkel buckles up to so I could get to the butterfly
valve. Four bolts and it came off and whow the butterfly and the inside of the housing was coated in
thick black muck.

I got my Berryman B12 and hosed her down. I used the toothbrush just like Hammertime said to do
and finally got it clean. I did clean both sides of the butterfly valve.

I had pulled the MAF out again before I hosed it with B12 and hosed it down with CRC MAF cleaner.

I don't know if its fixed but now no more surging when you blip the throttle.

I got to drive it back the same route as I went this afternoon again tomorrow and I guess I will
see if its fixed or not....Got my fingers crossed.

Thanks for the help.


Discretesignals
Ultimate Carjunky / Moderator
Discretesignals profile image

Mar 3, 2015, 5:20 PM

Post #10 of 23 (1080 views)
  post locked   Re: My Buick is acting up  

Really don't think your out of the woods.

You'll probably need to fix the O2 sensor code. Check the O2 heater resistance. If it is open, replace the sensor. You'll need an accurate sensor to look at O2 voltages and fuel trims when it comes to that time.

Another possibility is the O2 could be sticking rich which causes the engine computer to lean out the fuel. It really easy to see this with a scan tool. On some of the early ones, the programming wasn't smart enough to stop trimming when an O2 sensor was stuck. They would actually lean or rich the engine out so much it would cause stalling, rough running, lack of power, etc. Dodge and GM were really bad about that in the early days when O2 sensors stick.





Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.

(This post was edited by Discretesignals on Mar 3, 2015, 5:28 PM)


jackx
User

Mar 3, 2015, 5:51 PM

Post #11 of 23 (1073 views)
  post locked   Re: My Buick is acting up  

Well I agree.

I just went to the store and on the way back it died just going down the street. I put it in
neutral and it started back up and I made it back home.

I know it needs a O2 sensor but I will have to wait until it gets here. It cost half as much as the same
one at Autozone but I won't get it til the 10th.

Can you explain how I can use a volt meter to test the O2 sensor to see if it is bad. It has a square
female connector. It is the upstream sensor. I know there is a signal wire and a ground. I also know
two of the wires are the same color and they go to the heater circuit of the sensor.

I erased the P0135 O2 SES code. I didn't think it would be a problem until it was driven long enough
for the computer to do its diagnosis and then it would throw a code again. Its thrown this code before
and it did not do what it is doing now.

I've considered disconnecting the MAF to see if would run right not using the MAF to regulate the
fuel injectors. I can do this to see if it cures the problem because it will be a while before I get that
new Bosh O2 sensor. I know it will throw a code but I can always erase it.

I've also wondered if the MAP could cause it to die like it is doing. I've got the same one in my pickup that I could
put in the Lesabre to see if it cures the problem. What do you think?

I guess after I eliminate these as possible cures I will end up probably deciding the crank shaft position
sensor is the problem. I will start looking for some utube video on how you remove and replace one of these
sensors. I have been putting that off.

I sure wish they would throw a SES code so I would know what the problem is.


Discretesignals
Ultimate Carjunky / Moderator
Discretesignals profile image

Mar 3, 2015, 6:06 PM

Post #12 of 23 (1071 views)
  post locked   Re: My Buick is acting up  

MAF sensor can cause stalling, hesitation, and loss of power. MAP sensor won't do that.

If the computer is receiving a MAF signal and not coding some type of MAF code, MAP sensor isn't even being used by the engine computer for load calcuations. The MAP is used for BARO readings, to see if EGR is flowing, and as a back up if the MAF goes kuput.

You could unplug the MAF and go into back up mode, to see if your stalling goes away. If your stalling stops, it could be MAF or MAF circuit issues. It will code for a MAF circuit issue when you unplug it.

The O2 sensor wires that are the same color are the heater circuit wires. Just probe those two terminals for those wires in the O2 sensor connector cavity with an ohm meter. If you have an open circuit, O2 heater is shot and needs a sensor.

As your stated the other two wires are signal and sensor ground. You can actually see the O2 sensor voltage back probing the connector on the signal wire. The voltage will swing between 0-1.0 volt when the sensor is operational. It is a lot easier to see this on a scan tool though because you can see how the computer reacts to the voltage the sensor produces.





Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.


jackx
User

Mar 3, 2015, 6:22 PM

Post #13 of 23 (1067 views)
  post locked   Re: My Buick is acting up  

Well disconnecting the MAF was a bad idea. It would barely run. I cleared the
code.

I'll wait on the O2 sensor. maybe it will get me around til then.


Discretesignals
Ultimate Carjunky / Moderator
Discretesignals profile image

Mar 3, 2015, 6:27 PM

Post #14 of 23 (1065 views)
  post locked   Re: My Buick is acting up  

Did you unplug the MAF with the engine running? Unplug it with the key off. Then start the engine.





Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.


jackx
User

Mar 3, 2015, 6:45 PM

Post #15 of 23 (1063 views)
  post locked   Re: My Buick is acting up  

      I unplugged the MAF and it would not idle right and would just barely run.

I plugged it back in and cleared the code.


I thought it would run ok and it doesn't make sense that it would barely idle.

Maybe the sensors that provide it input to know how much fuel and air are

needed are bad but aren't throwing a code. I know the MAP and Throttle Position

sensor are use to make it run if the MAF is disabled. Maybe the MAP sensor is

causing the O2 sensor to throw a code. I also suspect the TPS sensor could cause

it to die too but since it's not throwing a code and isn't a factor when the MAF is

connected it is probably not the problem.


Discretesignals
Ultimate Carjunky / Moderator
Discretesignals profile image

Mar 3, 2015, 6:50 PM

Post #16 of 23 (1062 views)
  post locked   Re: My Buick is acting up  

That is strange. Once it reverts to back up mode, it shouldn't run like dog crap. Your going to need to look at scan data.

TPS usually doesn't cause stalling unless it is shorting the 5 volt ref to ground.





Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.

(This post was edited by Discretesignals on Mar 3, 2015, 6:52 PM)


jackx
User

Mar 3, 2015, 7:13 PM

Post #17 of 23 (1057 views)
  post locked   Re: My Buick is acting up  

It was not running and the switch was not on when I disconnected the MAF sensor.


jackx
User

Mar 3, 2015, 7:24 PM

Post #18 of 23 (1057 views)
  post locked   Re: My Buick is acting up  

    Yeah it was all over the place after I started it up.

It revved up and then it idled back down and started to

try to die and then it would rev up again. Weird.....

I have a new O2 sensor that I can put in tomorrow but I

will have to put a square connector on it. I got the

one for a lesabre but it did not fit because during the

year they switched to a square connector. Its been setting

around for a year or so. I'll go to Ace hardware and get some

butt splice connectors and install it tomorrow, Then maybe

I will have a good O2 sensor that may be my whole problem. I

really hate to suffer with this thing til the 10th when the

one I ordered gets delivered.


(This post was edited by jackx on Mar 3, 2015, 8:02 PM)


jackx
User

Mar 3, 2015, 9:21 PM

Post #19 of 23 (1047 views)
  post locked   Re: My Buick is acting up  

I may have got some Berryman B12 on the TPS when i was cleaning the throttle body. If I did
that probably caused it to give a bad signal to the ecm. That could make it cause the wild i
dle when I removed the MAP and it could also make it die. I will let it dry tonite. I will check
it again tomorrow to see what happens when I disconnect the MAF again.



If it still idles crazy I may need a new TPS. I found this on a website I googled up for :
" can a tps cause a lesabre to stall"

"ENGINE STALLING

This generally occurs when rapidly decelerating to a standstill, though it can also happen while idling. Again, without accurate information, the computer cannot deduce how much fuel to inject, so it averages the amount used in the last few moments of operation. When the throttle suddenly snaps shut, the engine is starved of air while the injectors are still delivering part-throttle amounts of fuel. The effect is very similar to rapidly closing the choke on an old manual-choke equipped truck."

link deleted ....................... not allowed

A bad TPS would also explain why it won't idle when the MAF is disconnected

I may get one tomorrow.


(This post was edited by Hammer Time on Mar 4, 2015, 3:07 AM)


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Mar 4, 2015, 3:09 AM

Post #20 of 23 (1038 views)
  post locked   Re: My Buick is acting up  

I think your theory about getting cleaner in the TPS is all wet. There is really no path for that to happen from inside the throttle body.

It's pretty asy to simply test the TPS if you have any doubts. If you have a reader with data you can monitor that or you can just use a DVOM



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



Discretesignals
Ultimate Carjunky / Moderator
Discretesignals profile image

Mar 4, 2015, 5:45 AM

Post #21 of 23 (1031 views)
  post locked   Re: My Buick is acting up  


Quote
This generally occurs when rapidly decelerating to a standstill, though it can also happen while idling. Again, without accurate information, the computer cannot deduce how much fuel to inject, so it averages the amount used in the last few moments of operation. When the throttle suddenly snaps shut, the engine is starved of air while the injectors are still delivering part-throttle amounts of fuel. The effect is very similar to rapidly closing the choke on an old manual-choke equipped truck."


Stalling can occur at any engine speed and any throttle position. That statement is inaccurate. When the throttle is snapped shut the IAC or ETC acts as a dash pot to bring the idle down.

Maybe it is time for a shop that specializes in drive-ability to have a look at it. I don't see any testing going on, only wild guesses and part swapping idea.





Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.

(This post was edited by Discretesignals on Mar 4, 2015, 5:49 AM)


jackx
User

Mar 4, 2015, 7:13 AM

Post #22 of 23 (1022 views)
  post locked   Re: My Buick is acting up  

I let it set overnite. I was still was thinking the TPS had B12 on it. I wanted to let it dry out some.

I pulled the MAF connector off. It did not rev up or anything this time. Lots better. It seemed to idle ok but
when you blipped the throttle it acted like it was missing. I turned it off and replaced the
MAF connector and cleared the code. Started it and it sounded great. I did notice that the
MAF and TPS have the screws in them that require a special screwdriver that I don't have. Nuts.....
I used a pair of pliers to take those screws out of the MAF but I can't get the pliers on the
ones on the TPS.

There is another sensor mounted back and under the MAF sensor that does not have those screws.
I pulled it off. It had a plunger on it that was dirty, I cleaned it off with B12 and put it back on. I
suspect it is the Idle control module. Under it is what appears to be the TPS. Since it had those
screws I left it alone.

Later today I will go ahead and rewire the pigtail on the new O2 sensor and put it on. I will
drive it some and see if still dies when I am coasting along or stopping. I do know cleaning that
butterfly really did make it respond a lot better to the throttle but there may be other problems
that also need to be addressed.

I don't have the testing equipment and I think I will take descrete's advice and start looking for a shop that
can fix this thing by performing whatever tests are necessary to determine what is actually
causing the problem. All these parts are expensive and I sure don't want to buy any that don't
actually need to be replaced.

Its always possible that since the TPS seems to be working better this morning
that it may be ok now. It could have been that ecm can't read the MAF sensor sometimes
when I am slowing down and when it reverts to the backup system the bad TPS caused it
to die. Its possible I guess that the TPS could even be causing the problem even if the
MAF sensor system was being used by the ECM. I really don't know what component or components are
bad but I am sure someone out there will be able to figure it out if I can just find them.

Thanks again for you help.


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Mar 4, 2015, 1:14 PM

Post #23 of 23 (1015 views)
  post locked   Re: My Buick is acting up  

I think this thread has run it's course as DS pointed out. Advice isn't being followed and no actual testing is being done.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.







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