LT1 Based Engine Tech 1993-1997 LT1/LT4 Engine Related

Hesitation off idle

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Old Nov 17, 2002 | 10:16 PM
  #286  
smacz28's Avatar
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How does one go about checking the egr? Where is it located, etc? Is the a link on a site somewhere?
Old Nov 17, 2002 | 10:23 PM
  #287  
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turbo_z thanks for the suggestion but I have already snaked a gauge threw the cowl and checked the pressure at WOT. It stayed around 42 or so.

I think the next thing I’m going to do is change the plug gap to something around .04 or so. It’s at .06 right now. What do you guys think would be a good plug gap to try to get rid of high map hesitations with an accel coil and msd 6a?

I’m also going to do a compression check, but I don’t think that’s my problem. My car only has 70k on it, doesn’t use any oil, and its fine in the mid rpm range.
Old Nov 17, 2002 | 10:55 PM
  #288  
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I think i have the answer! Sort of...... My car has the same problem, but only for the firt 10 min of driving. I notice this is the same time the air pump is on....I unplugged the pump, and although it throws a code, i no longer have the hesitation! Try it and see how that works for you guys!
Old Nov 17, 2002 | 11:03 PM
  #289  
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I am all but positive that mine is not related to the AIR pump. Mine was recently replaced under the recall. I double checked for vacuum leaks today and that is not the issue. Tomorrow I will make sure my IAC is not full of carbon deposits by blowing some throttle body cleaner in there. After that I will try Fuel injectors and fuel filter. The fuel filter has about 18000-20000 on it and even tho the injectors were serviced about the same time, my service tech said they could use replacing for more efficiency. I am trying to do things one at a time to see what my fix will be. Alot of people that have found their problem fixed 3 or 4 things all at once. I would like to know more about the EGR idea.

Shawn
Old Nov 18, 2002 | 12:08 AM
  #290  
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Maybe this will help someone...I have'nt read all the pages so I dont know if this was already covered, but here it goes. I had a hesitation/stutter at part thottle under 2000rpm. I changed the map sensor listening to someones advice on this board, no luck. Then changed EGR valve(It didnt pass the squeeze the diaphram at idle test, or so I thought) $50+ bucks down the tubes.. After some brain storming I disconnected the vacume line to the FPR. Wow thought this fixed the problem. So I replaced theFPR. This did fix my problem half way, I was getting an intermitent bucking under 2000 rpm. This went away but their was still a stutter, except at wide open throttle and at speeds higher then 50+ MPH. Well the opti was next on the list, unfortunately it was another waste of $. Lastly I realized my exhaust was running super rich and it occurred to me the o2 sensors could be the problem. I never considered the o2 sensors before cause they had about 7000 miles on them. I had blown both head gaskets a while back and at the time I didnt realize that coolant destroys o2 sensors. Anyway I changed them out and my problem is now finally solved. My car runs perfectly . Hope this is of help to some of you I know how discouraging and difficult diagnosing and repairing our cars can be at times.
Old Nov 18, 2002 | 12:47 AM
  #291  
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Humm i had my head gasket gone not too long ago.... and i was getting some stutter ... I'll have to try this.. sounds encouraging! =)
Old Nov 18, 2002 | 04:40 PM
  #292  
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So what do you guys think about spark plug gaps? Do you think I should make them smaller ex. .04? Do you think this would help under load? I'm at .065 right now?
Old Nov 18, 2002 | 06:14 PM
  #293  
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my old plugs were gapped at .04

my new plugs are gapped at stock (.05)

no change at all
Old Nov 21, 2002 | 09:27 PM
  #294  
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GRRRRRRRRRRRRR

There has to be an answer to this problem... Holly crap! I cant afford to keep replacing part after part when the parts im replacing are just fine. I dont know where to go from here. How about a new car?!? yeah, that sounds good! - I wish......
Old Nov 22, 2002 | 01:59 AM
  #295  
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Well no one answered about how to check egr. Also I noticed that tonight I used my defroster( I know I lied about the atmospheric controls) First time since I have had the problem that I have used any creature comforts. I turned on the defroster so I could see out my window, and the hesitating and surging appeared. I turned it off and only once did I feel a surge. Turned it on and off about 3 or 4 times. Way more noticeable. Are these tied together in my problem or does running the defroster just make it more noticeable and not actually cause it? Any suggestions as to where this points my search next? Like I said I have had my low coolant light come on and off randomly since the problem. Please help
Shawn
Old Nov 22, 2002 | 04:13 AM
  #296  
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checking EGR is easy, take it out, put one of those little hoses off the FPR to the EGR when its in your hand, have it pluged into the egr, suck on the little hose, & when you do that look at the diaphram it should move inwards when you suck on the little hose, when you suck on it, you can also quickly put your finger over the hose to keep the diaphragm open then try blowing with your mouse onto the upper opening of the EGR, while blowing release the finger off the little hose & keep blowing it'll get harder & harder & then you can't blow no more, that means the EGR is good ussually you noitice it bad right away when you try & suck on the little hose & you can't because no matter how much you suck its free & nothing happens as in the diaphragm doesn't retract at all thats bad
Old Nov 22, 2002 | 08:16 AM
  #297  
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Originally posted by smacz28
Well no one answered about how to check egr. Also I noticed that tonight I used my defroster( I know I lied about the atmospheric controls) First time since I have had the problem that I have used any creature comforts. I turned on the defroster so I could see out my window, and the hesitating and surging appeared. I turned it off and only once did I feel a surge. Turned it on and off about 3 or 4 times. Way more noticeable. Are these tied together in my problem or does running the defroster just make it more noticeable and not actually cause it? Any suggestions as to where this points my search next? Like I said I have had my low coolant light come on and off randomly since the problem. Please help
Shawn
turning on the defroster enguages the A/C clutch if i recall correctly...

and the low coolant light means nothing, just unplug the sensor after you check the level of the fluid.
Old Nov 22, 2002 | 12:59 PM
  #298  
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has anyone read all the replies???
Old Nov 22, 2002 | 03:17 PM
  #299  
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Originally posted by Farfrominnocent
has anyone read all the replies???
Yep, sure have.... I havent done all of the things people have mentioned though...
Old Nov 22, 2002 | 11:20 PM
  #300  
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From: $#&!@$
I had the same problem in my car when I first bought it. It ran rough as hell and didnt wanna stay below 2k. 2 weeks later the thing just started hesitating in every gear as soon as it got hot. Finally got the time to look under the hood and just for the hell of it, I pulled out the number 6 spark plug wire, what would you know, the thing was burnt to crisp and the wires running to the dist. were touching the headers and when the car got hot, it made my dist. malnifunction. I replaced this wire and it solved everything. Funny thing is, the guy before had the dealer put on the wires not more than 15k miles before I bought it.

Check all those wires again, you never know if you really have a burn wire anywhere. I never knew mine was burnt, looked fine under the hood until I actually got it off is when I noticed it was burnt.

Hope this helps for any of you guys.



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