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Old 04-01-2005, 07:33 PM   #1
vwnut
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Question 87 buick surges!!

Im working on my brother in laws 87 buick, 3.8l. its surging terribly in drive, but revs great in P or N. I thought cat converter, but took it off and no change. I also checked EGR valve function and vacuum lines for leaks to no avail. Anyone have any ideas ??...Id really like to get it going for them, they cant afford to take it in and need it for work.
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Old 04-01-2005, 08:48 PM   #2
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Quote:
Originally Posted by vwnut
Im working on my brother in laws 87 buick, 3.8l. its surging terribly in drive, but revs great in P or N. I thought cat converter, but took it off and no change. I also checked EGR valve function and vacuum lines for leaks to no avail. Anyone have any ideas ??...Id really like to get it going for them, they cant afford to take it in and need it for work.

any code's service engine light check the mass air flow sensor
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Old 04-02-2005, 12:48 PM   #3
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There is also an idle air speed motor or valve that may be bad.
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Old 04-03-2005, 03:23 AM   #4
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Quote:
Originally Posted by osborste
any code's service engine light check the mass air flow sensor
The check engine light comes on intermitentlt, but no codes are being stored..at least none that ive been able to retrieve. All I get is the code 12, that the manual says indicates yhat the system is funtioning.
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Old 04-03-2005, 03:26 AM   #5
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Quote:
Originally Posted by srober32
There is also an idle air speed motor or valve that may be bad.
Checked the idle air valve and its funtioning properly. Replaced some vacuum lines and adjusted the idle speed and its a little better. Only seems to surge badly at part throttle now, but still not quite fixed.
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Old 04-03-2005, 09:21 AM   #6
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i had same thing

Quote:
Originally Posted by vwnut
Checked the idle air valve and its funtioning properly. Replaced some vacuum lines and adjusted the idle speed and its a little better. Only seems to surge badly at part throttle now, but still not quite fixed.
i have a 89 olds 98 3.8 litre did the same exact thing.it is the
sensor on the air intake assembly.i smacked it a few times.if you remove the cat,the backpressure is wrong and it will run wrong too.now full power.my neighbor is a gm service manager,says a plugged cat will do that too.if the maf sees wrong backpressure it shuts down under load.revs fine,no load....
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Old 04-03-2005, 05:02 PM   #7
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Quote:
Originally Posted by the lobster
i have a 89 olds 98 3.8 litre did the same exact thing.it is the
sensor on the air intake assembly.i smacked it a few times.if you remove the cat,the backpressure is wrong and it will run wrong too.now full power.my neighbor is a gm service manager,says a plugged cat will do that too.if the maf sees wrong backpressure it shuts down under load.revs fine,no load....
Hate to break this to you pilot boy, but... The MAF reads MASS AIRFLOW into the engine. You can drop the entire exhaust system after the O2 sensor and Y-pipe and it will run just fine. The ECM can more than compensate for a minor change in backpressure and therefore engine vacuum.

PLEASE STOP SPEWING YOUR OWN SPECIAL BRAND OF BULLSHIT AND CONFUSING PEOPLE IN NEED OF HELP.
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Old 04-03-2005, 07:15 PM   #8
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Vwhobo Is A Poser

You know, VWHOBO,

the registered users of this website tire of your constant outlandish claims of superiority and supremacy. if you have nothing positive or constructive to add (which is why this site exists in the first place) then why do you take your pseudo-overly-educated and snide remarks and shove it?
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Old 04-05-2005, 07:34 AM   #9
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Exclamation okay..Ive got it narrowed down

Quote:
Originally Posted by vwnut
Im working on my brother in laws 87 buick, 3.8l. its surging terribly in drive, but revs great in P or N. I thought cat converter, but took it off and no change. I also checked EGR valve function and vacuum lines for leaks to no avail. Anyone have any ideas ??...Id really like to get it going for them, they cant afford to take it in and need it for work.
I think ive narrowed it down to the fuel pressure.. it starts our at 40-45 at start up, then jumps to 60 if I clamp off the return line like the manual says to. If I then release the presure via the gage, it drops to 0, and when I represurize, ie..release thr presure release valve, ony goes back up to about 20. I dont think its holding fuel pressure.(if im judging this right.) Im thinking fuel filter, pump, lines, or presure regulator. Ive been told that the if it is the presure regulator, the presure will fluctuate when the return line is clamped off..it doesnt. It remains at the above values pretty consistantly.
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Old 04-06-2005, 03:30 AM   #10
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Seems like the fuel filter may be the problem, but I am not sure if you want to replace it and have that not be the problem. Maybe VWHobo has better advice on this.
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Old 04-11-2005, 11:18 AM   #11
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your royal highness

Quote:
Originally Posted by vwhobo
Hate to break this to you pilot boy, but... The MAF reads MASS AIRFLOW into the engine. You can drop the entire exhaust system after the O2 sensor and Y-pipe and it will run just fine. The ECM can more than compensate for a minor change in backpressure and therefore engine vacuum.

PLEASE STOP SPEWING YOUR OWN SPECIAL BRAND OF BULLSHIT AND CONFUSING PEOPLE IN NEED OF HELP.
listen here you know it all.i own one of these cars and you do not.my neighbor is a GM SERVICE MANAGER AND HE HAS FORGOTTEN MORE THAN YOU KNOW.first of all,not all cars have only one o2 sensor,so YOUR idea is bullshit.the backpressure is an issue.the fuel filter on this car is on the drivers side,near the jack up point.
it is a huge cannister.if you smack it hard sometimes the problem goes away.GENERAL MOTORS SELL TONS OF THESE.
the vacuum lines on the throttle body can be loose and cause trouble,and just because you said on A PREVIOUS POST THAT THE 3.8L DOES NOT BLOW HEAD GASKETS,YOU ARE A RETARD.o.k.?i know what a mass airflow sensor is and what you do not know is that if you hit it with freeze spray and its bad it can act up.CALL GENERAL MOTORS AND ASK HOW MANY CATALYTIC CONVERTERS HAVE BEEN DONE ON THIS MODEL OF CAR.TAKE A LOOK BACK AT HOW MANY POSTS I HAVE NAILED DOWN,I CANT BE THAT STUPID YOU GOOF...AND YOU SPEND MORE TIME ARGUEING WITH PEOPLE THAN WHAT YOU ARE WORTH.my neighbor says that the MAF can be misled by a plugged CAT ,and considering that he has done HUNDREDS of these,i believe him...o.k.?your royal highness.

Last edited by the lobster : 04-11-2005 at 11:26 AM.
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Old 04-11-2005, 11:31 AM   #12
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change the fuel filter

Quote:
Originally Posted by vwnut
I think ive narrowed it down to the fuel pressure.. it starts our at 40-45 at start up, then jumps to 60 if I clamp off the return line like the manual says to. If I then release the presure via the gage, it drops to 0, and when I represurize, ie..release thr presure release valve, ony goes back up to about 20. I dont think its holding fuel pressure.(if im judging this right.) Im thinking fuel filter, pump, lines, or presure regulator. Ive been told that the if it is the presure regulator, the presure will fluctuate when the return line is clamped off..it doesnt. It remains at the above values pretty consistantly.
they are 12 dollars.get the gm part.looks like a beer can ,if the buick is anything like the olds.it is a real monster to get out if it is the original.sometimes if the sediment gets in it and you hit it hard a few times,if it is the source of the surge,it will go away,temporarily.
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Old 04-12-2005, 02:51 PM   #13
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off topic

I have a 92 buick centry and the compter is saying i have a bad cooling temp sensor i have a new one but cna anyone tell where it is located at so i can switch them out.
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Old 04-13-2005, 12:52 AM   #14
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Quote:
Originally Posted by sweetkim
I have a 92 buick centry and the compter is saying i have a bad cooling temp sensor i have a new one but cna anyone tell where it is located at so i can switch them out.

here we go once again
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Old 04-13-2005, 01:00 AM   #15
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Quote:
Originally Posted by vwnut
Im working on my brother in laws 87 buick, 3.8l. its surging terribly in drive, but revs great in P or N. I thought cat converter, but took it off and no change. I also checked EGR valve function and vacuum lines for leaks to no avail. Anyone have any ideas ??...Id really like to get it going for them, they cant afford to take it in and need it for work.

just try tapping the MAF w/ a screwdriver handle (but not hard--tap) and see if it dies or stumbles worse. that would be a bad MAF. in my experience, you can also unplug the MAF (w/ the engine off) and the engine should run smooth if the MAF was the problem. that's the experience i've had w/ V6 firebirds, but it may be different w/ a 3.8...
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