Announcement

Collapse
No announcement yet.

84 GM 5.0 liter bucking/surging after totally warmed up

Collapse
X
Collapse
 
  • Page of 2
  • Filter
  • Time
  • Show
Clear All
new posts
Previous 1 2 template Next
    #1

    84 GM 5.0 liter bucking/surging after totally warmed up

    Hi,

    I have an 84 GM with the 5.0 liter V8. About 2-3 years ago the engine started to intermittently buck/surge after fully warming up. It would also intermittently die as you would decelerate. It progressively got worse so I took it to a mechanic and he told me there was a "hard code" for the coolant temperature sensor. He replaced the sensor and everything seemed to be fine. It has started doing the same thing again. Is it likely that this new sensor has failed already or could there be something else temperature related I should take a look at given these symptoms? I hate to spend another $200 + with the mechanic if it's the same sensor gone bad. You can buy these for around $30.00 and they're fairly easy to get to and replace. Any thoughts would be greatly appreciated!

    Monty
    Last edited by montyrobison; 11-28-2013, 04:52 PM. Reason: Grammar errors
    Tags: None
    #2
    could be the sensor. could be the air charge sensor (does CFI have that?). If you have a multimeter, you can test it.

    oldfuelinjection.com
    http://oldfuelinjection.com/?p=28


    the chart at the bottom shows what the values should be. If you get close to the stated value, it's good. if it's open or shorted, replace it.

    Only two things are infinite, the universe and human stupidity, and I'm not sure about the former. -- Albert Einstein
    rides: 93 Crown Vic LX (The Red Velvet Cake), 2000 Crown Vic base model (Sandy), 2003 Expedition (the vacation beast)

    Originally posted by gadget73
    ... and it should all work like magic and unicorns and stuff.

    Originally posted by dmccaig
    Overhead, some poor bastards are flying in airplanes.

    Comment

      #3
      Sly,

      Thanks for the reply, the suggestions and the link. Senors, sensors, sensors..... do they ever end? Makes me want to go back to my old cars and trucks from my early days. They were so much easier to work on and maintain. I'll do some testing on the CTS and the ACS and see if there's an obvious problem. Actually I hope there is as it makes the "fix" simpler. I may even buy a code reader as they're only about $30.00 nowadays and may save a lot of headaches troubleshooting. If you come up with any other thoughts or suggestions please let me know. I'll let you know how this turns out. Thanks again!

      Monty

      Comment

        #4
        read the codes, test the sensors. These things are actually pretty simple to work on. There aren't all that many sensors involved. Most of the rest of it is what you'd do with a carb vehicle, vacuum lines, tuneup stuff, etc.

        If you buy a code scanner, get one with a digital display. The ones that are just a blinky light are a $30 light bulb. The digitals are usually not much more expensive.
        86 Lincoln Town Car (Galactica).
        5.0 HO, CompCams XE258,Scorpion 1.72 roller rockers, 3.55 K code rear, tow package, BHPerformance ported E7 heads, Tmoss Explorer intake, 65mm throttle body, Hedman 1 5/8" headers, 2.5" dual exhaust, ASP underdrive pulley

        91 Lincoln Mark VII LSC grandpa spec white and cranberry

        1984 Lincoln Continental TurboDiesel - rolls coal

        Originally posted by phayzer5
        I drive a Lincoln. I can't be bothered to shift like the peasants and rabble rousers

        Everything looks like voodoo if you don't understand how it works

        Comment

          #5
          Gadget73,

          Thanks for the reply. The code scanner I was looking at is an Innova 3145 and it is a digital display. You can get one through Summit Racing for less than $30.00 including shipping. Pretty reasonable for the time it may save.

          Monty

          Comment

            #6
            Got my scanner at oreillys for 30$ if you do not want to wait. Great tool for the money,and I would say nearly essential for one of these aging cars.
            1989 crown Vic daily driver 165k and counting!
            1987 MGM 49xxx mi awaiting light resto

            Comment

              #7
              Djtb78,

              Thanks for the reply and suggestion. I'll check out the local O'reillys and see if they have one.

              Monty

              Comment

                #8
                Originally posted by montyrobison View Post
                Djtb78,

                Thanks for the reply and suggestion. I'll check out the local O'reillys and see if they have one.

                Monty
                On amazon: http://www.amazon.com/gp/aw/d/B000EW...110_SY165_QL70

                Comment

                  #9
                  Could also be a clogged EGR valve along with passages clogged up with carbon. Had the same symptoms on my '84 302 awhile back and cleaning resolved it.

                  Comment

                    #10
                    Mobydick,

                    Thanks for the link. I actually did buy the Innova 3145 along with the Innova 3149 extension cable on Amazon for a total of $49.98.

                    Monty

                    Comment

                      #11
                      Louis,

                      Thanks for your suggestion. I'll check the EGR valve and see if it's clogged. When you say passages clogged are you referring to the intake manifold? If so how did you clean the passages?

                      Monty

                      Comment

                        #12
                        If its the iron intake, you can remove the CFI unit and the EGR spacer under it. Chip out the carbon buildup in the spacer and in the passages inside the intake where you can get at them. Vacuum up the chunks and re-assemble. The aluminum intake you can't pull the spacer out of. There may or may not be a cooler in there between the egr valve and the intake. Pull that out and make sure its not packed solid too. They have a screen in there that tends to get packed up with crap.

                        Another thing that makes these hitch and buck is slop in the timing chain. Its a poor design on the 85- cars that will let it get very slack and let it jump by 100k or so. Might be worth replacing that as a preventative measure. These are an interference engine, so if the chain jumps it will bend valves.
                        86 Lincoln Town Car (Galactica).
                        5.0 HO, CompCams XE258,Scorpion 1.72 roller rockers, 3.55 K code rear, tow package, BHPerformance ported E7 heads, Tmoss Explorer intake, 65mm throttle body, Hedman 1 5/8" headers, 2.5" dual exhaust, ASP underdrive pulley

                        91 Lincoln Mark VII LSC grandpa spec white and cranberry

                        1984 Lincoln Continental TurboDiesel - rolls coal

                        Originally posted by phayzer5
                        I drive a Lincoln. I can't be bothered to shift like the peasants and rabble rousers

                        Everything looks like voodoo if you don't understand how it works

                        Comment

                          #13
                          Gadget73,

                          Thanks for the info. I may have to wait until things warm up a little to tackle this. The engine only has 83K original on it so I would hope the timing chain isn't the culprit. Thanks again!

                          Monty

                          Comment

                            #14
                            You'd be surprised. 83k but its nearly 30 years old. The cam gear had plastic teeth, and they wore down fairly quickly. It probably does need a chain. I've seen a few of these under 100k with incredible amounts of slop in the chain.
                            86 Lincoln Town Car (Galactica).
                            5.0 HO, CompCams XE258,Scorpion 1.72 roller rockers, 3.55 K code rear, tow package, BHPerformance ported E7 heads, Tmoss Explorer intake, 65mm throttle body, Hedman 1 5/8" headers, 2.5" dual exhaust, ASP underdrive pulley

                            91 Lincoln Mark VII LSC grandpa spec white and cranberry

                            1984 Lincoln Continental TurboDiesel - rolls coal

                            Originally posted by phayzer5
                            I drive a Lincoln. I can't be bothered to shift like the peasants and rabble rousers

                            Everything looks like voodoo if you don't understand how it works

                            Comment

                              #15
                              gadget 73,

                              Wow! I didn't realize they used plastic for the gears. What a bad idea! I'll definitely consider replacing the chain. Haven't done one of these on a Ford before. Do you have to drop the oil pan to do the replacement or just a front cover?

                              Monty

                              Comment

                              Previous 1 2 template Next
                              Working...
                              X