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84 305 ESC? help please

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by sled_dog, Feb 8, 2003.

  1. sled_dog

    sled_dog 1 ton status

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    Ok my K5 came with a 305, and well after beating the living crap out of it its gone on to the junkyard in the sky. I pulled it out and replaced it with a 350 that has had problem after problem and well now it sits in my driveway waiting for me to install the next 350 I am getting for it. I have a problem I realized when someone here asked me about ESC(I believe those are the letters). I read in the service book(haynes) that 305s of this year anyway may have ESC and I am trying to figure out what this is? When I removed the 305 it had sensors on different parts of it and I removed them all. The 350 didn't have places for these to be reinstalled so I figured, well I don't have a computer in this truck so it won't be a problem, they were prolly just temp and oil pressure sensors. Well I have discovered I was wrong, i found the silver box under hte dash. I thought that all K5 computers were located behind the glovebox, turns out mine is up dead center in the dash. So what does this thing do and could it be the reason my truck has been running so poorly? By the way my problems have been that I just can't seem to get the timing right no matter how hard I tried. then after flooding it a couple times it got gas in the oil and long story short new engine time. Thank you in advance.
     
  2. bablazer73

    bablazer73 1/2 ton status

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    Re: 84 305 ETS? help please

    What you are talking about is E.S.C (Electronic Spark Control) It the computer for the distributer and such. I don't know if the computers are the same for a 350 and 305. All i know about them is junk it and put a regular distributer in it!!
     
  3. sled_dog

    sled_dog 1 ton status

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    Re: 84 305 ETS? help please

    Yeah ESC is what I meant sorry, reading through my book right now. How do I go about eliminating it?
     
  4. Can Can

    Can Can Pusher Man Staff Member Super Moderator

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    Re: 84 305 ETS? help please

    Basically, the ESC system automtically retards your timing if pinging occurs. When I eliminated all my emissions crap I disconnected the ESC and had to get a non-ESC distributor. That was about 6 years ago so I can't remember all the details, but I believe my original distributor was a 4-pin and I ended up getting a 2-pin. I'm probably wrong, though..... That was a long time ago.
     
  5. sled_dog

    sled_dog 1 ton status

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    Re: 84 305 ETS? help please

    I am reading through the haynes and all and I just don't get ti all. I dont' see the ESC causing my present problems. The manual shows an ESC module and it looks like it is in the engine compartment but I definetally don't have one of those. If I have ESC I have an ECM right? But on my fuseblock the ECM thing doesn't even have a connector and when I removed my glovebox I didn't see anything. Man now I am just confused.
     
  6. R72K5

    R72K5 Banned

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    thE controller boxz uNder DASh IS IN CORRECT PLACE iN THR TRUCK AlL OF THEm ARE UNDER THE DASH CEnTER>
    my keyboardhas issues
     
  7. sled_dog

    sled_dog 1 ton status

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    Ahh I figured out the ECM thing and where it is and all. Hmm I really hate computers in cars.
     
  8. bablazer73

    bablazer73 1/2 ton status

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    Re: 84 305 ETS? help please

    Unless you have one of those carbs with the electronics on it also, all you need to do is replace the distributer. What problems are you having with it?
     
  9. sled_dog

    sled_dog 1 ton status

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    Re: 84 305 ETS? help please

    My carb has one wire on it, I figured this was electric choke. Problems well I just haven't been able to get the timing down. I think I really needed to just set it to TDC again and redo the whole shooting match. I was about to do that literally starting work on it and my dad called me and said he got me a new engine and nevermind that. For a while I didn't ahve spark at all then I found this one wire I missed that apparently as I can tell goes to the ECM and when I plugged it into the coil power line(with the other power line going to the same spot, which had 12Vs going to it) I suddenlly had spark. Now the whole timing thing seems to have gone downhill though. Like it barely idles and when I put it to a spot(timing by ear) that it idles alright if I hit the gas it misfires a lot of cylinders. I through a timing light on it last time I was doing it and some reason it didn't work.
     
  10. R72K5

    R72K5 Banned

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    Re: 84 305 ETS? help please

    hei feed on esc vehicles is controlled usually by a sensor just above the oil filter, oil pressure sensor switch,if the est carb was still there it would have a blue and also a white wire harness plug on front part of carb, cant miss them
     
  11. sled_dog

    sled_dog 1 ton status

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    Re: 84 305 ETS? help please

    the 305 had that oil pressure switch thing youa re talking about. The 350 had a hole at the same spot which had a set screw plug in it that I just couldn't get out. The 305 also had a knock sensor that the 350 just didn't have a place for. The 350 was out of a late 70s chevy.
     
  12. txbartman

    txbartman 1/2 ton status

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    Okay, the ESC and the ECm are two different animals. Your 84 (as with my 85) did not have an ECM (electronic control module). But you do/did have an ESC (electronic spark control) computer. As stated, it is inside the rig under the dash somewhere around the glove box area.

    For the ESC to work, there are several wires that connect to it from the distributor itself. You should see a set of wires that plugs into it and goes through the firewall about midway up at about the 1/3rd point on the left (passenger's) side. There is also a wire that goes to a knock sensor on your block.

    Basically, the ESC takes the feedback from the knock sensor and electronically adjusts the retardation (very appropriate word) of your distributor.

    Word of advice, ditch it. Pinging was a big problem with the 305s. Especially as you got lots of miles on it. I don't suspect it will make any difference to you on your 350. How to ditch it? Simple, replace your stock distributor with an aftermarket HEI unit. That is all you haev to do. It is simple. You can pick a good one up from Summit for around $150. Since you are having timing problems and going with a new motor, I would HIGHLY recommend spending this additional money and going with a new distributor as well.

    If it saves you all the heartache, time, and difficulties you have had so far and makes this new engine work, it is a cheap investment!
     
  13. sled_dog

    sled_dog 1 ton status

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    Thanks a lot.
     
  14. schmuck

    schmuck 1/2 ton status

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    the control modul is all ou need to replace get one from say an 82 and just leave off the harness in the back of the dist
     
  15. sled_dog

    sled_dog 1 ton status

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    I have extra HEI distributors sitting around and my dad made the good point that the engine I am getting may have a distributor with it. The yard we are getting it from doesn't really deal in parts. If they see some rare part they know they can get money for they will pull that but a simple HEI Chevy distributor well thats just not rare /forums/images/graemlins/smile.gif.
     

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