87 buick surges!!

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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. :banghead: 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.

posted by  vwnut

any code's service engine light check the mass air flow sensor

posted by  osborste

There is also an idle air speed motor or valve that may be bad.

posted by  srober32

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.

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.

posted by  vwnut

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....

posted by  the lobster

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.


posted by  vwhobo

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? :hi:

posted by  kennyg

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.

posted by  vwnut

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.

posted by  srober32

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.

posted by  the lobster

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.

posted by  the lobster

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.

posted by  sweetkim

here we go once again :mrgreen:

posted by  BanffAutoSpa_ap

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...

posted by  dodger65

actually any american car after 1996 has to have more than 2, i think vwhomo as well as everyone else around here knows this.
one of my pet peeves is when people know someone that knows what they are doing and speak for them second hand. get your neighbor on this forum, he could probably help a lot of us out.

posted by  carls47807

Okay Twinkie, I didn't see this crap earlier so let's take the time to go over it one bite at a time right now.

Okie dokie dumbass.

Are you sure about that? Why not, because my name is vwhobo? I know, because it's obvious I'm not stupid enough to buy one... Like you.

Again I ask, are you sure? Do you know why people are service managers? Because they are managers, not because they know anything about repairing cars. Over 50% of service managers nationwide (industry statistic for North America) don't even come from a technical background. So the things he's forgotten I probably don't even care about... Except that I have a degree in management so I know more about both ends of the business than he does.

Get outta here! No shit! You mean my wife's Ram Hemi with four H2OS's has more than one. Must be the new math. I was so confused looking at EVERY TYPE OF CAR SOLD IN THE US SINCE 1996 (OBD II) WITH AT LEAST TWO H2OS's. I just thought I needed new glasses. And just out of curiosty, when did I say they did?

What I said was not an idea, it was a fact. But you finally got something right. BACKPRESSURE is an issue, unfortunately you said;

That, dumbass would be a LACK OF BACKPRESSURE.

The "jack up" point? You can jack you car wherever you want to stick jockey.

The fuel filter is 3" long and 1.5" diameter. You probably have your wife convinced (or at least yourself) that your four incher is a foot long.

Oh baby, talk dirty to me too.

Will the same thing work with you? Smacking the fuel filter to clear up a drivabilty concern is one of the most ludicrous things I've ever heard. Did you think that one up or did Service Manager Man put on his cape and tell you about that?

Yep, so does every car parts store in the country. Ya see, they're called a MAINTENANCE ITEM. They should be changed every 30k miles. What a freaking concept.

Call today a national holiday. He mede two correct guesses in the same post. Congratulations.

I did? Can you refer us all to that post? I think not Dipshit.

Speak into the mirror.

Good for you, so does my 75 year old mother... But then she's not a pilot so it doesn't seem as impressive.

You and your magic freeze spray. I prefer to use proper diagnostic techniques.

I just did, and GM said they don't keep records on that type of thing. They did say that some jerkoff who claims to be a pilot and live next door to a service manager has been harrasing them and telling them they need to shoot freeze spray on things if they really want to get them fixed right.

Can't find one.

I vote for stupider.

When's the last time you had your blood pressure checked?

He's right, but are you smart enough to tell us exactly why... Without asking someone or researching it? I bet not but I'll give you a chance. On the honor system.

Hundreds? Are you sure? That seems like an awful lot, especially for a service manager.

Sure your Royal Dumbass.

posted by  vwhobo

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