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Passed the anger, Now Im just depressed :-(

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by ChevyTrucker, Mar 12, 2003.

  1. ChevyTrucker

    ChevyTrucker Registered Member

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    Can someone please shed some light on this problem/forums/images/graemlins/confused.gif
    Here are the facts :
    1987 GMC Jimmy, 1/2ton 4x4, 5.7ltr 350, Auto trans, Fuel injected, stock ignition coil, NON HEI distributor.

    My problem startes last friday. She was running like a well oiled machine up until that point. The engine feels like Michael J. Fox making love to Liz Taylor. ITS SHAKING A LOT at idle speed !! I admit that I ran it a lil hard for about 3 minutes. Went from 65mph to 85mph for about 2 miles. Then, I dropped back down to 65mph(My usual highway speed).
    I noticed the shaking when I pulled into a toll booth. The truck runs almost normal at any speed above idle. WHAT GIVES ?!?! I am a good back yard mechanic with above average troubleshooting skills. But this problem has set me back a bit. Here is a list of the parts that I replaced in order of installation...

    Fuel filter, Spark plugs (ACD Rapidfires), Cap & Rotor, Ignition coil(Standard type), EGR Valve, PCV valve, and Oxygen sensor. I installed these parts after thoroughly inspecting for vacuum leaks and intake manifold leaks, and NOTHING ! She still got the shakes at idle. Very frustrating indeed /forums/images/graemlins/frown.gif
    This problem was much worse before I installed these new parts. But the problem still persists. Any good advice ?

    I took the truck to a general mechanic, but, I was not about to dish out another $65 bucks just so he can tell me to change a $20 part. Or better yet, let him tell me that all I need was to adjust X & Y..cause then I would be really pissed and then I would do something stupid like kick the truck /forums/images/graemlins/angryfire.gif

    Any good tips or advice would be greatly appreciated. Thanks. /forums/images/graemlins/k5.gif Keep Blazin (I'm tryin to get my project started) Help me keep hope alive ! /forums/images/graemlins/smirk.gif
     
  2. Shaggy

    Shaggy 3/4 ton status

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    <font color="green"> I have to ask the simple question - Did you check the timing? /forums/images/graemlins/crazy.gif </font>
     
  3. Langosta39

    Langosta39 1/2 ton status

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    Um, you said you changed the plugs, how about the wires? You can check to see if all the cyls are firing by squirting a little WD40 on the exh. manifolds right by the head and if one cyl doesn't burn off as fast as the others you know which one is off. You can also pull plug wires and keep starting it to find out which one doesn't cause it to run any worse.

    I dont see how driving at 85mph would throw off timing, but the extra heat could cook something.

    just my .02
    andy
     
  4. jc71355

    jc71355 1/2 ton status

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    If everything smooths out after idle you might want to check the Idle Air Control Valve (IAC). It controls the amount of air that goes in the TBI at idle and will cause it to run rough at idle. Also are you getting any codes?
     
  5. ChevyTrucker

    ChevyTrucker Registered Member

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    I did check for the code with a code key that I picked up for free at the auto parts store..The Check Engine Soon light blinks 4 times, then 5 times..(dont quote me on that) But as I remember from last night..accordint to the Haynes manual..it said to check the evaporator canister for fuel odor (duhh) or replace the Oxygen sensor. I did the latter. and no sale !! /forums/images/graemlins/frown.gif I will try the tips you guys gave me..in a bit..I will update when i get back in..Thanks a million.
     
  6. DieselDan

    DieselDan 1/2 ton status

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    Check to see if your EGR valve is still working. I split the diaphram in the EGR on my ('86) Vette, run like crap /forums/images/graemlins/angryfire.gif One of those handheld vacume pumps (mityvac) works slick here.
     
  7. Grim-Reaper

    Grim-Reaper 3/4 ton status Author

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    It sounds like the EGR is stuck open. EGR should be closed at Idle.
    Dissconnect and plug the line at the EGR while it's Idling. If the idle improves that's it.
     
  8. Gary 86 K5

    Gary 86 K5 1/2 ton status

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    Sounds to me like you have an ignition problem somewhere. What I would do is unplug each plug wire at the spark plug one at a time and observe how its running. Each time you unplug a good cylinder you will definetly be able to tell by the way it runs, but once you unplug the bad, you'll know cuz it wont change the way its running. You may also want to check fuel pressure. /forums/images/graemlins/k5.gif
     
  9. Thunder

    Thunder 3/4 ton status

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    Sounds like an EGR problem to me too. A code 45 means 02 sensor senses lean air fuel mixture. The EGR valve stuck open will lean everything out, it will also cause a rough idle. Sometimes all you have to do is pull the EGR valve off and clean all the carbon off it to stop it from sticking. But if you have a bad diaphram you will need to replace it.
     
  10. ChevyTrucker

    ChevyTrucker Registered Member

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    Hey fellas..err..I did change the EGR valve. Just did so 2 days ago as I mentioned in my first post. But I do welcome your advice very much. Lemme be more direct this time..

    I changed the following parts : (1)Fuel filter (2)Spark plugs (3)Cap &amp; Rotor (4)PCV Valve (5)EGR Valve (6)Oxygen sensor and lastly. I inspected the intake manifold and surrounding area for vaccum leaks. (No vac leaks)

    The truck is running a lil better. But it still is shaking like if its got bad case of the chills /forums/images/graemlins/frown.gif Not cool !!

    I followed some of your previous tips and advice on inspecting the spark plug wires by spraying some WD-40 on the exhaust manifold to check for heat being generated by the corresponding cylinder. Well lemme tell ya..Cylinder #1(First spark plug on drivers front side of engine for you rookies) is not firing as it should. The WD-40 just stayed there like a sperm soiled panty found in Monica's dresser. So, tomorrow I will ONCE AGAIN try to replace the spark plug wires. Cylinder #3 was not burning as hot as it should also upon inspectio. So, with any luck..you guys were right. I will be just jolly if she runs like a stallion like she did prior to this annoying problem. You guys have been much help. Thanks ! I will be posting in this forum more frequently with updates on project G-Machine. Pics are also on the way. I have been very happy with this truck thus far. I just bought the damn thing 2 months ago. I was very pleased. For an '87 she looks and runs darn good I tell ya. Stand by for an update on this current problem. Thanks again /forums/images/graemlins/k5.gif
     
  11. Grim-Reaper

    Grim-Reaper 3/4 ton status Author

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    [ QUOTE ]
    Hey fellas..err..I did change the EGR valve. Just did so 2 days ago as I mentioned in my first post. But I do welcome your advice very much. Lemme be more direct this time..

    I changed the following parts : (1)Fuel filter (2)Spark plugs (3)Cap &amp; Rotor (4)PCV Valve (5)EGR Valve (6)Oxygen sensor and lastly. I inspected the intake manifold and surrounding area for vaccum leaks. (No vac leaks)

    The truck is running a lil better. But it still is shaking like if its got bad case of the chills /forums/images/graemlins/frown.gif Not cool !!

    I followed some of your previous tips and advice on inspecting the spark plug wires by spraying some WD-40 on the exhaust manifold to check for heat being generated by the corresponding cylinder. Well lemme tell ya..Cylinder #1(First spark plug on drivers front side of engine for you rookies) is not firing as it should. The WD-40 just stayed there like a sperm soiled panty found in Monica's dresser. So, tomorrow I will ONCE AGAIN try to replace the spark plug wires. Cylinder #3 was not burning as hot as it should also upon inspectio. So, with any luck..you guys were right. I will be just jolly if she runs like a stallion like she did prior to this annoying problem. You guys have been much help. Thanks ! I will be posting in this forum more frequently with updates on project G-Machine. Pics are also on the way. I have been very happy with this truck thus far. I just bought the damn thing 2 months ago. I was very pleased. For an '87 she looks and runs darn good I tell ya. Stand by for an update on this current problem. Thanks again /forums/images/graemlins/k5.gif

    [/ QUOTE ]


    Maybe it's what controls the EGR. If it's open then the EGR would be working unless it stuck open. THere is a control circuit for that. On the old one is't a timed vac port on the carb through a control valve on the water neck or intake (so it done's come open till it's warm). So you might have a mis routed vac line.
    While the engine is running unplug the hose going to the egr and stick your finger over the hose. If it starts to idle right and you have vac at the hose to it at idle that's your problem.
     
  12. ChevyTrucker

    ChevyTrucker Registered Member

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    I just got home from work..I just followed your advice by disconnecting the EGR vacuum hose and putting my finger on the hose to check for vacuum. I have no vacuum at all coming from that hose /forums/images/graemlins/frown.gif IAC valve go sour ? I hope it is the problem so that I can get on with my project G-Machine. I dont plan on buying a new IAC valve until Im possitiviely sure thats the problem. Here's my plan..I know a salvage yard that has a 1990 Chevy K5 with a complete engine just laying around. Hopefully, I can get to the engine before someone else does (I will go there saturday morning) I will remove the IAC valve from the above mentioned truck and test it on mine. If that's the cure to my problem..then and ONLY then will I buy a NEW IAC control valve. You have been a great help to me thus far..Thanks again for being prompt with your answers. /forums/images/graemlins/thumb.gif /forums/images/graemlins/k5.gif /forums/images/graemlins/usaflag.gif
     
  13. Doug M

    Doug M Registered Member

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    [ QUOTE ]

    While the engine is running unplug the hose going to the egr and stick your finger over the hose. If it starts to idle right and you have vac at the hose to it at idle that's your problem.



    [/ QUOTE ]

    What this says is you should not have vacuum at idle. No EGR at idle.
     
  14. ChevyTrucker

    ChevyTrucker Registered Member

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    That just doesnt make sany sense to me. /forums/images/graemlins/crazy.gif Doesn't the EGR valve receive vacuum from the hose at idle ? Is that not the way the valve works ?? I'm fed up of buying parts for such a simple problem for which I am sure is very common among GM cars and trucks of that era. I took it to a mechanic for an estimate to correct the problem. He had the nerve of looking me straight in my face and told me that it would cost me $450 !!! WTF happened to honesty ? I wanted to rip his head off when he told me that..but I chose to walk away instead. Im in no mood to be taken as a sucker by some half fast mechanic. Which is the main reason I plan on opening my own shop soon with my dad. Mechanics like that one give ALL good mechanics a bad rep. BTW..at idle i get NO VACUUM from the EGR hose at idle.

    I will be taking a trip to my dads house tonight to meet with his friend...I am almost certain he is gonna make me feel stupid in about 5 minutes or less. Let's see what happens...He will have my truck running like a champ in no time Im sure. Oh well..we can't know everything. /forums/images/graemlins/confused.gif
     
  15. Highlander

    Highlander 1/2 ton status

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    The only thing I'll add well two things First is a word about safety WD-40 is a Flammable Liquid, If you need to check for a missfireing Cylinder you would be better off using a spray bottle of water or a Crayon of your favorite color.
    Now have you put a Vauume Gauge or a Compression tester on the motor yet?


    Eric
     
  16. 89K1500Chevy

    89K1500Chevy 1/2 ton status

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    Well if the truck runs really lopey at Idle revs up then drops down really low almost shutting off and sometimes shutting off I would say its the MAP sensor it use's a vac. line from the TBI and will cause [censored] to read wrong. I know cuz it happend to me but lucky for me at my Tech school we got a SnapOn Scan tool com reader and i used it on my truck it came up with Bad egr, O2 sensor, TPS, and MAP. The map will cause everything else to read wrong if its not working right. I did a Road Test scan with it also and it said the same parts were reading wrong. I replaced the TPS and the MAP sensor b/c it has new O2 and egr already on it and the truck runs perfect now.(but no tranny right now but today on sat ill be going to TPU to get a TH350 to build to replace the 700R4) Now if you have access to a Scan tool to read your com id go use it. The paper clip trick while saving money is sometimes useful but most of the time when 1 part reads wrong it will cause a few others to read wrong with it and once you see what different parts are reading wrong you can trace it down. /forums/images/graemlins/thumb.gif /forums/images/graemlins/truck.gif /forums/images/graemlins/usaflag.gif www.zombieoffroading.8m.net
     
  17. ChevyTrucker

    ChevyTrucker Registered Member

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    I apologize for not responding to all of your comments and very helpful advice in a timely manner. I work for the DoD and I am also in the U.S. Army reserve. As you all know, we have been very busy with making sure our brothers ans sisters in arms can complete their missions and return home to their families to enjoy the freedom we take for granted in this country. I've been workin 12-16 hour shifts 7 days a week to ensure equipment readiness is at 100% and ready for deployment. I'm a Heavy Wheeled Vehicle mechanic/technician. It's kinda cool, becuase I have full access to the Shop and all of our shop equipment, On occasion I get to pluck parts off of vehicles that have been taken out of service and are headed to a Gov't scrap yard or to Local emergency response agencies. If you saw what I have to make paper work to be trashed you would want to cry /forums/images/graemlins/confused.gif Many of the 1985-91 K5's get scrapped with less than 60k miles on them. Most of them is excellent body condition and drivetrain. A shame I tell ya. I love K5's like I love dogs. every stray I run into I want to take home and nurse em back to health. If any of you out there are lookin for great trail rigs or military K5's. By all means..research if there are any gov't sales of these vehicels in your area. You will not be disappointed with what you bring home. These trucks are perfect candidates for some serious trail machines ! worth every penny. I know for fact that a good lookin and runnin Mil Spec K5 sells for no more than $1,000! Good luck hunting for your dream machine. /forums/images/graemlins/thumb.gif

    Back to my problem...here is an overview of what I replaced.
    EGR Valve, PCV Valve, O2 Sensor, Spark plugs, Cap &amp; Rotor, Ignition coil, Fuel filter, IAC Valve, and I thoroughly cleaned the Injectors and throttle body assy. NO SALE ! /forums/images/graemlins/angryfire.gif She is still shaking at idle ! But not as bad as it was when this problem surfaced. I just read your posts and I too have thought that i should replace the MAP Sensor and TPS Sensor. I will price them this afternoon on my lunch break and try to rectify this problem once and for all. I can't sleep well at night knowing that my G-Machine is feeling a lil under the weather. I take care of my truck better than I take care of myself most of the time. Shouldn't we all ? /forums/images/graemlins/smirk.gif I'll be back today with the verdict. Keep on truckin ! and make sure your ridin in an AMERICAN MADE TRUCK /forums/images/graemlins/usaflag.gif! I wouldnt have it any other way ! /forums/images/graemlins/k5.gif
     
  18. shane74

    shane74 1/2 ton status

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    I went through all of that with a K5 I owned awhile ago. I see you have replaced everything BUT the spark plug wires. I was experiencing the EXACT same thing. I had a bad wire to the #3 cylinder. That was causing the computer to overcompensate and was giving me all kinds of codes. What mechanics fail to tell you is that the code RARLEY means that the part or the sensor is bad. It just gives you an area to start troubleshooting. If it is a bad wire, you're gonna be pissed at youself for not checking that sooner. If you have and I missed it somewhere in the post, then...nevermind...
     
  19. ChevyTrucker

    ChevyTrucker Registered Member

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    /forums/images/graemlins/crazy.gifDohh! That was my next thing to do troop. Before I go out and buy a new TPS and MAP sensor. I have a very, very good feeling that you are %100 correct ! /forums/images/graemlins/thumb.gif
    I will post again as soon as I replace the wires. To every sad story something positive comes from it.. in my case that would be the fact that I shouln't have to replace all of these bought for a very, very long time. Oh well..until next time amigos..Keepin on truckin on /forums/images/graemlins/usaflag.gif /forums/images/graemlins/k5.gif /forums/images/graemlins/burb.gif /forums/images/graemlins/pimp1.gif
     

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