dohc v6 Posted July 8, 2005 Report Share Posted July 8, 2005 i was driving my car this morning and all the sudden i step on the gas and it bogs. so i put in in 1 and it is bogging at fuel throttle. so i pull over and start it up and it works fine. it has never done this to me. wha could it have been. Quote Link to comment Share on other sites More sharing options...
slick Posted July 8, 2005 Report Share Posted July 8, 2005 Faulty iac or tps maybe? It bogged, didn't miss, correct? Quote Link to comment Share on other sites More sharing options...
Turbocharged400sbc Posted July 8, 2005 Report Share Posted July 8, 2005 any # of things...clogged fuel filter/low fuel pressure, bad/intermittent TPS (the carbon track likes to crack on well worn sensors) was the SES/CEL tripped on when this occured? Quote Link to comment Share on other sites More sharing options...
Robby1870 Posted July 8, 2005 Report Share Posted July 8, 2005 goblins? Quote Link to comment Share on other sites More sharing options...
dohc v6 Posted July 8, 2005 Author Report Share Posted July 8, 2005 i dont have a tps hooked up. but hit has been fine for a month now with out it Quote Link to comment Share on other sites More sharing options...
Robby1870 Posted July 8, 2005 Report Share Posted July 8, 2005 bogging is a sign of a bad, or your case non-existant TPS. Maybe for a second the ECM got confused Quote Link to comment Share on other sites More sharing options...
Canada Posted July 8, 2005 Report Share Posted July 8, 2005 If the TPS is bad.....then there will be a DTC set for it, which will turn the SES on. Why do people like replacing this sensor so much??? In the two years expereience I have working on cars professionally, I have NEVER replaced a TPS. Quote Link to comment Share on other sites More sharing options...
Robby1870 Posted July 8, 2005 Report Share Posted July 8, 2005 Funny...Ive had a TPS go out and it didnt throw a code. Quote Link to comment Share on other sites More sharing options...
Canada Posted July 8, 2005 Report Share Posted July 8, 2005 How did it go out? What was the failure that happened? Did it have a dead spot in it? If so, then you must of used a voltmeter on the output and watched for it as you turned it. Even then, TPS really isn't THAT important of an input to the PCM....it already knows the throttle is being opened because of the MAP sensor and vacuum. Quote Link to comment Share on other sites More sharing options...
Turbocharged400sbc Posted July 8, 2005 Report Share Posted July 8, 2005 When the carbon track inside the TPS goes bad (from old age/heat cycling/wear and tear-the glitch will usually be in the first 1/4-1/2 of Throttle blade travel) 9 out of ten times it will not trip a code, and most of the time you cannot get a multimeter to catch it, that is why i have a digital storage occiliscope where I can capture that Glitch (mometary dropout where the signal drops/spikes) these Glitches are what confuse the computer (suddenly for some reason it thinks you closed/WOT the TB when you havent, and if the glitch is smaller than 20-50ms the computer cant catch it but a DSO will.... this can cause off the line slow speed acceleration boggs (if in the first 1/4 travel usually) or high speed cruising boggs/stumbles/hesittation (much like a clogged fuel filter/bad pump) if the glitch is in the 1/2 travel range.... the TPS get used allot! in the 1/4 range and less so as you go WOT (dep on the driver...if it's a digital driver (with them driving, no pedal or through the firewall pedal) it's anyone's guess lol I have also had people come in and tell me the other shop said they need a TPS and I found, a bad/noisy crank sensor signal (below trigger threshold) to an EGR partially stuck open etc. Proper diagnosis is key, you can replace all the parts you want and if you dont fix the problem...the customer isnt going to like you... I had a 90 Caddy Deville random engine missfire, one shop (F&F tire) charged him 300$ for a full tuneup didnt fix his problem, "well it may be a bad injector" so he had to pay them anyway for not fixing the car... the tech just assumed it needed a tuneup (car has 47K orig miles)... he took it to another shop and they told him it didnt have injectors ( ) that it needed a tuneup... well needless to say he brought it to us, I performed a compression test, cylinder leakage test, and checked all the tuneup parts (no engine will runn smooth if it has a dead hole or a sticking/burned valve) I covered all the bases...then I went into the onboard Diagnostics (built into the HVAC on Caddy's) and noticed when it would misfire the computer would blackout...hmmm I know what this is (one of the reasons handson exp comes in handy...you know the pattern failure's) pull down the ECM engine running perfectly...tap on it lightly, still running perfectly...knock on it with my knuckles, engine starts misfiring...rap it again it goes away... so i do my usual test i apply med pressure and twist the ECM, engine dies! as long as i had the ECM twisted (counterclockwise with my right hand-connectors pointed up) the engine ran fine all day long...flex it the other way the engine would run rough, rougher then die... 250$ ECM 165$ labor (gave discount boss's buddy) and for 415$ his problem was fixed yeah it took us a few days but now he never bothers with the master parts changers at F&F.... Just a lesson in life about getting someone with the knowhow to fix it properly the first time...instead of spending twice as much...just replacing parts that MAY be the problem... thats why i get paid 25$ bk hr...i love this job for the chalenges James Quote Link to comment Share on other sites More sharing options...
Robby1870 Posted July 8, 2005 Report Share Posted July 8, 2005 nice post. Thats how most TPS's Ive messed with go out. Quote Link to comment Share on other sites More sharing options...
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