hello gentlemen.
i am seeking guidance to help steer me in the direction of what is causing my problem....
i have a 2000 4.3 4 dr blazer 270k miles. it has a problem of randomly sneezing, surging , hiccuping. . i have seen no pattern as to when it occurs.
it does it at no throttle mid throttle. it seems as if it is completely shut off, sometimes momentarily illuminating a random dash light. bat,abs, etc. only once has a check engine light occurred. it was p0339 open or short in cam position sensor.....
watching the 02 sensor front it indicates excess fuel just after the sneeze.....
if the sneeze was loss of ignition wouldn't i see a miss count increase?
how is the cam sensor powered? through ignition module?
take a look at screen shot of when the ONLY code was set.
mph 44 ... maybe correct. throttle position 0.0?? i know rpm is wrong. this blazer has never seen 7500 as long as i have owned.
please throw an opinion out.
if you have no clue just tell me ls swap it
The misfire detection function senses a brief rotation speed change near that cylinders firing point, regardless of cause and not specific to ignition. If all cylinders lose ignition simultaneously or if the the ECM loses power during the glitch, there may not be a detected “misfire”.
The misfire detection function senses a brief rotation speed change near that cylinders firing point, regardless of cause and not specific to ignition. If all cylinders lose ignition simultaneously or if the the ECM loses power during the glitch, there may not be a detected “misfire”.
George
so do you think i am loosing all ignition? and how? is there a pid i can monitor that could help me identify.. not excited about paying $80/hr for someone to look at it and not find it because it is intermittent.
The camshaft position sensor gets its power on the pink wire via the Eng 1 fuse. The crankshaft position sensor gets its power on the pink wire via the ECM 1 fuse.
Since you get dashboard disturbances during an event my guess at this point is that a simple intermittent failure of one of these 2 sensors is not your problem although if it is, I am thinking crank sensor. Do you have CMP retard on live data as this would help you decide if the cam sensor is your problem during an event?
Back to my no sensor theory, why don't you get a voltage monitor in your cigarette lighter socket and see what happens to system voltage during a hiccup.
i will monitor cmp retard this week. ?voltage monitor?.... do you mean there is a voltmeter that plugs into cig lighter? makes sense never seen one i will google search.
if
Its a simple way to do a first order check. Some radar detectors also serve this function.
Intermittent problems can be tough. Monitor system voltage, monitor live scanner data. look at freeze frame data if codes appear, look at pending codes, tape a fuel pressure gauge to the windshield while running. Another level of diagnosis is a complete ODBII scan including all mnfg codes, not just generic codes. That's more expensive if you don't know anyone.
I monitored cam retard, TC lock up misfire counters today as the wife drove. Cam retard is a bit o -2.9 -3. Is never wavered.. miss count never changed. The TC lock however was moving from 1 to 8100... I have no idea what those numbers mean.
on my way to work this morning I added a "guage" engine run time... this seems to be a counter counting up in seconds. this number resets almost every time the truck stumbles. I am then assuming the stumble is coming from an interruption of either the I gnition source or the power to the computer. again guessing this would explain the gauges (rpm, mph) dropping out. would also explain the intermittent flash of a dash light. at highway speed converter locked up split second interruption car restarts....
.. does any one know where the ground is for the computer? if I ran a wire from that ground and the fed side of ecm1 fuse I could monitor voltage to see if it is dropping out. it could be ground or positive voltage. or a component on ecm...
06-30-2018, 10:14 AM
surge,buck,sneeze no code help
