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Chevy Tracker will not hot restart.

WilliinTalkeetnaWilliinTalkeetna Posts: 6
edited June 7 in Chevrolet
I have a 2000 Chevy Tracker 4x4 with a 1.6 Liter 4 cylinder. It has developed a problem, and there are no associated error codes from the computer. It runs perfectly, but if taken on a long highway run, especially when the weather in warm (Alaska), as in never in winter, if the engine is shut off it will not hot start until you wait about 20 minutes. Then it starts and runs fine. In warm weather it will occasionally stall when idling in traffic for too long, or going at slower speed up a steep hill after a highway run. I replaced spark plugs and wires (needed after 101,000 miles) and did other tune up chores. No difference. A GMC dealer was convinced that it was due to both catalytic converters being plugged—I was skeptical but had them replace them. No difference. I was able to catch the engine when it wouldn't start and pulled a plug and attached a spark tester and there was no spark. I replaced both coils (no distributor in this model) thinking it may be a coil pack failure. No change. The only other think I can think of is a malfunctioning control unit (computer). Anyone have any thoughts?

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Answers

  • PF_FlyerPF_Flyer Pennsylvania Furnace, PAPosts: 9,279
    Could be a coil. Could be a problem with the temperature sensor in the coolant system, thinking the engine is cold when it's actually hot, and you get too rich a mixture for it to start.

    ECT engine coolant temp sensor itself could be bad, or maybe just a wiring problem to the sensor.

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  • Thanks for taking time to reply. As I noted above, I replaced both coils already. Also, as noted above, when it doesn't start, there is no spark, so it is not a mixture problem.
  • Thanks "thecardoc3" that's some concrete steps to take before messing with the control unit!
  • imidazol97imidazol97 Crossroads of America I70 & I75 Posts: 23,693
    edited June 9
    If you know where the crankshaft position sensor is located, an empirical test on the 3800's which had some failures was to pour cold water on the CPS and the area around it to cool it. This was because the typical restart time was about 20-30 minutes waiting for the lower engine to cool and the sensor to be able to read the magnetic signals. If your leSabre started up after cooling that area quicker than normal, that was a good sign it was the CPS causing your problem.

    The other was a unit the Tracker doesn't have and that was a small computer unit that received the signals from the CPS and generated the spark in the 3 coils sitting on top of it. Those also could fail and yet test okay at the parts stores. Called ISC, ignition spark control, IIRC. I don't see that in a Rockauto.com parts list for ignition.

    So I'm hoping you can isolate it to your CPS.

    There used to be some instructions on the net for isolating the ISC units by checking for the signals from the CPS when the engine was cranking to see if the CPS was sending electrical pulses. I believe there were two lines actually and if they were both carrying pulses, then the ISC was bad.

    Cardoc3's symptoms of cps versus camshaft position sensor match what usually happened on the 3800s in H-bodies with which I'm reasonably familiar. The occurrence in hot weather because cold weather has more air cooling on lower engine, the higher temp of engine block with climbing hill or sitting and idling..., all make me think the CPS needs checking FIRST.

    Removing the harmonic balancer to get to it is not a difficult task for a fast garage tech.

    2015 Cruze 2LT, 2014 Malibu 2LT, 2008 Cobalt 2LT

  • Thanks! My next to do. The Tracker 1.6-Liter engine has a CPS easy to get to, the 2-Liter engine which I do not have requires removal of the transmission (ducked the bullet on that one!).
  • Well, the crankshaft position sensor was not the culprit. Mine tested fine cold, but was just outside spec for resistance between the two terminals when hot, so I replaced it, despite being skeptical. No change. Next, I'll test the camshaft position sensor, but am skeptical of this too. I'm tending more toward the computer now. . .
  • imidazol97imidazol97 Crossroads of America I70 & I75 Posts: 23,693
    edited June 18
    I was hoping that replacing the CPS would fix your spark problem.

    The CPS testing is not necessarily static testing. It's dynamic. This video talks about the testing
    to see if the CPS is generating the AC currents that the module or computer needs to synthesize
    the timing for a spark to a plug.

    There are some empirical tests at the end using a soldering gun and it's magnetic field to see if
    a magnetic field generates an AC current from the CPS.

    https://www.youtube.com/watch?time_continue=5&v=Exz4f4RfBFY

    Usually testing the CPS for proper output when engine cranking, even when generating no spark from the modules, was a way of seeing if it was working.

    The CPS uses a magnetic field and the disturbance of that magnetic field as each tooth of the harmonic balancer moves past to generate the AC current signal. The aging and weakening of the magnetic field form heat causes that AC signal to fail. That was the usual weakening pattern. Cooling the engine makes the magnetic field more effective again to generate the signal from the Hall Effect.

    2015 Cruze 2LT, 2014 Malibu 2LT, 2008 Cobalt 2LT

  • The crankshaft sensor was not the problem, the new one did not fix the problem. I have proper voltages within spec to the camshaft position sensor. My manual does not go into procedure to actual testing of the camshaft position sensor, it just gives voltage input specs which are within spec both cold and hot when the engine won't start. This is not checking the sensor directly though, only the input voltages from the power train control module (main computer). I suppose that at least tells me that the powertrain control module is functioning properly? My understanding is that if the camshaft position sensor is bad, it will not stall or not start, it will run poorly and be hard starting, is this true? I'm not sure where I go next with this. Is the new crankshaft position sensor bad? Is it possible that the powertrain control module (main computer) is bad?
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