The Unsolvable Miss at Idle....

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Tim Payne wrote:


My car didn't register a single code for a busted MAF *or* PCV system - just a cryptic "do not drive" message on the tester/probe.
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"Tim Payne"

MAF sensor. fuel supply. ignition system.
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: > Rommel wrote: : > : > > If you had your car at a dealer for $2600 of repiars and they couldnt fix : > > a stupid miss I'd say you have an extremely shitty mechanic. : > : > I agree. the EGR valve and MAF are the firt things that any : > competant mechanic should check, then the timing chain, then : > the camshaft sensor. : : They wanted to charge me $2600 for a few repairs... like $1000 for the : intake gasket! Needless to say, it didn't quite happen.... : : Also, I have replaced the PCV valve. The cheap $2 valve was one of : the first things tried. : : I did pull off the EGR today and I noticed some drops of watery : condensation in it. Other then that it didn't look like there was any : sort of EGR part to clean. But I'm going to look into it tommorow : again. : : I don't know about the MAF, since it's not sending any engine codes... : but you never know. : : The fuel pump or fuel pump regulator seems possible based on some : other posts I've read. The best bet may be to bring the car into : somebody and have them diagnosis it.... any other ideas?
That watery substance is a mix of water and distilled alcohol/gasoline/oil. Probably more water than anything else really.
Again, I this doesn't sound like a recirculation problem or a MAF sensor problem. But hey...what do I know.
Martin '01 Formula - MTI Air Box Lid, K&N Filter, Hurst-6, SLP Cold Air Induction & Smooth Intake Bellow Corsa Catback w/Premium Tips '83 V45 Magna
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Original poster:
Throw out your Haynes manual. Useless book for any serious repair. Up the ducks and get a GM shop manual.
With that being said:
1) Your MAF can be checked by any parts store that deals in remanufactured electronics. It can be sent out to their supplier for testing and functional checking if you suspect a MAF problem.
2) A shitty air filter will cause MAF problems with paper dust insulating the MAF and causing all sorts of trouble. Many times, you can use electronics spray to clean it gently.
3) GM EGR valves on this and many models flat out stuff up and clog. The 4.3 Vortec GM engines as used in Blazers of the S10 variety are notorious cloggers, code setters and stallers.
Many GM cars and trucks have EGR base plates that must be cleared out when doing an EGR service as they will either cause problems or reset a light again.
Fuel pressure should be checked with a reliable hand-held gauge before you damn any parts being bad back there. This is an expensive and frustrating mistake if you change a fuel pump that is not the problem.
With that being said, start here and tell us what you find.
Joe--ASE Certified Parts Specialist & 10th Ann.Club Tech Director '80 Carousel Red Turbo T/A, 26k orig. '79 "Y89" 400/4 speed 10th Ann. T/A, 57k orig '84 Olds 88 Royale Bgm 2 dr, 307 "Rocket" (lol), 141k and still going.... '80 T/A project car...
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: > : > Rommel wrote: : > : > : > : > > If you had your car at a dealer for $2600 of repiars and they : >couldnt fix : > : > > a stupid miss I'd say you have an extremely shitty mechanic. : > : > : > : > I agree. the EGR valve and MAF are the firt things that any : > : > competant mechanic should check, then the timing chain, then : > : > the camshaft sensor. : > : : > : They wanted to charge me $2600 for a few repairs... like $1000 for the : > : intake gasket! Needless to say, it didn't quite happen.... : > : : > : Also, I have replaced the PCV valve. The cheap $2 valve was one of : > : the first things tried. : > : : > : I did pull off the EGR today and I noticed some drops of watery : > : condensation in it. Other then that it didn't look like there was any : > : sort of EGR part to clean. But I'm going to look into it tommorow : > : again. : > : : > : I don't know about the MAF, since it's not sending any engine codes... : > : but you never know. : > : : > : The fuel pump or fuel pump regulator seems possible based on some : > : other posts I've read. The best bet may be to bring the car into : > : somebody and have them diagnosis it.... any other ideas? : > : > That watery substance is a mix of water and distilled : >alcohol/gasoline/oil. Probably more water than anything else really. : > : > Again, I this doesn't sound like a recirculation problem or a MAF sensor : >problem. But hey...what do I know. : > : > Martin : > '01 Formula - MTI Air Box Lid, K&N Filter, Hurst-6, : > SLP Cold Air Induction & Smooth Intake Bellow : > Corsa Catback w/Premium Tips : > '83 V45 Magna : > : > : > : > : > : > : > : > : > : : Original poster: : : Throw out your Haynes manual. Useless book for any serious repair. Up the ducks : and get a GM shop manual. : : With that being said: : : 1) Your MAF can be checked by any parts store that deals in remanufactured : electronics. It can be sent out to their supplier for testing and functional : checking if you suspect a MAF problem. : : 2) A shitty air filter will cause MAF problems with paper dust insulating the : MAF and causing all sorts of trouble. Many times, you can use electronics spray : to clean it gently. : : 3) GM EGR valves on this and many models flat out stuff up and clog. The 4.3 : Vortec GM engines as used in Blazers of the S10 variety are notorious cloggers, : code setters and stallers. : : Many GM cars and trucks have EGR base plates that must be cleared out when : doing an EGR service as they will either cause problems or reset a light again. : : Fuel pressure should be checked with a reliable hand-held gauge before you damn : any parts being bad back there. This is an expensive and frustrating mistake if : you change a fuel pump that is not the problem. : : With that being said, start here and tell us what you find. : : : Joe--ASE Certified Parts Specialist & 10th Ann.Club Tech Director : '80 Carousel Red Turbo T/A, 26k orig. : '79 "Y89" 400/4 speed 10th Ann. T/A, 57k orig : '84 Olds 88 Royale Bgm 2 dr, 307 "Rocket" (lol), 141k and still going.... : '80 T/A project car...
Good point Joe. Oil film on the sensor(s) can also cause problems.
Martin '01 Formula - MTI Air Box Lid, K&N Filter, Hurst-6, SLP Cold Air Induction & Smooth Intake Bellow Corsa Catback w/Premium Tips '83 V45 Magna
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i agree with martin it doesn't sound like the maf.. when my maf went bad it would change the idel while driving it would rapidly go up and down until you started driving again... this is something that is happening at start up...
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i don't see that that little oil drip is gonna cause a miss and your theromstat will solve your heat problem more than likely but again i don't see where that would have anything to do with a miss in the moter
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snipped-for-privacy@ncf.edu (Tim Payne) wrote in message
<snip>
Hi Tim,
Let me add one more thing to check. It might me a long shot but I've seen it on two Camaro's like yours with the 3.4L.
Crankshaft thrust bearing worn causing erratic crank sensor signals. Its easy enough to check. Just use a small prybar to see if there is any endplay in the crankshaft. The hard part is - this is a major repair.
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One cheep thing you should do, especially if you have over 50K miles is change the inline fuel filter. They cost any where from $6.50 to $25. Then try a good fuel system cleaner. STP makes a good one called "Complete fuel system cleaner". It smoothed out the idle on a 160K 93 Olds Cutlass (3.1) that I had. I run 4 bottles thru it in one month (I was being lazy). You could also have (don't laugh) dirty fuel injectors. Allot of shops will claim that as a last resort thing, but at times it actually does occur.
Other people have given good advice, and I'm not saying to do this over theirs. Yet a the fuel system could have low flow at low RPM's and not be notable, or bad enough to affect WOT or part throttle acceleration.
Charles
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I haven't looked at the MAF, but I did replace the Oil Sending Unit which has seemed to help the idle a bit, as a mechanic who I talked to said it would.
I just noticed that my brake pedal is making a bit of "whoosing" noise when I push it. That seems like the most likely culprit for a vacuum related problem. I don't know why I never thought of the braking system.
My brake pedal is spongy from the top and then gets really hard after a little bit of movement. Does that mean I should look into the master cylinder or is the brake booster? Or could it be a hose is mucked up back there?
Thanks, Tim-
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Brake booster or the check valve/hose coming from it to the intake.
You're onto the source of the problem. That will DEFINITELY give you idle problems like that if something is cracked. Joe--ASE Certified Parts Specialist & 10th Ann.Club Tech Director '80 Carousel Red Turbo T/A, 26k orig. '79 "Y89" 400/4 speed 10th Ann. T/A, 57k orig '84 Olds 88 Royale Bgm 2 dr, 307 "Rocket" (lol), 141k and still going.... '80 T/A project car...
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well tim i have an 87 firebird that has the same thng happen but it only does it when it is cold... if you give it about 15 or so minutes to warm up the engine should be running smooth by then... and the sluggish feeling should be gone.... but my car has almost 170,000 miles on it and it still runs hard... you may also wanna try running high test gas and octane booster with some injector cleaner all at the same time and take it out and open it up on the high way to clean out your injectors good and see if that helps any.... i also upgraded to a set of 8 mm accell plug wires you can get them at advance auto for 24 bucks but most have to next day order them....
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