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P0300 need some ideas
My 2000 2wd blazer is throwing the good ole p0300. Need some ideas on getting rid of it. Here's a story leading up to this. Parked it on a Sunday. It sat on Monday. Tuesday I get up to go to work and in similar fashion to a carburated vehicle I let off the key before it fired. Usually it fires up with no issues right away.[just let off too early]. I couldn't get it to start after that. It was acting like it was flooded. So I grabbed keys for another vehicle and off to work i went. Got home that night with a can of ether. Gave it a shot and it poofed back. Repeated the same situation 2 more times. Let it sit overnight and on Wednesday morning it fired up, ran rough and smoked a little till it cleared the cylinders. Threw the p0300 code. Put a new cap,rotor,plugs and wires on today the 19th. Still missing and running rough. I sprayed the ether around the plenum and vacuum hoses with no noticeable change in idle or harmonics, vacuum hoses were soft and pliable and secure.Im kinda stumped as to where to go next.Any help would be appreciated. TIA
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"Gave it a shot and it poofed back". Can you explain this further please?
First step is look for 1" of strong blue spark at a plug end when it wont start. Next step is the 10 min fuel pressure leak down test. George |
Thanks for replying, when I sprayed the starting fluid it backfired I guess you could say out the throttle body as it it was cranking. I do have some freeze frame data as well. Hopefully it shows up here. Short term fuel trims are definitely outta whack. I am hoping to get a fuel pressure tester this weekend and verify pressure and leak down. Will report back on that.
https://cimg5.ibsrv.net/gimg/blazerf...e26623562a.jpg https://cimg7.ibsrv.net/gimg/blazerf...ea40afbb8a.jpg https://cimg9.ibsrv.net/gimg/blazerf...9a1b6b86ed.jpg |
I was able to check fuel pressure today and got a new code as well. Key on while pump primes 62psi. When pump stops priming holds about 60 psi.Turn key back off, 58psi holds for over 10 minutes no noticeable change after 10 minutes. 56 psi while running. I drove it down the road and the check engine light started flashing. It was like driving down a bumpy road felt it in the whole vehicle lol. I got back home and read the code again and got p0155 bank 2 sensor 1 Could an oxygen sensor be causing all this mess? Fuel pressure doesn't seem to be the "issue". The freeze frame shows the misfire problem starting while the fuel system is in closed loop. No freeze frame data for the o2 sensor code.
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Fuel pressure is not the problem, but at least we ruled it out because its a common issue.
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Originally Posted by GeorgeLG
(Post 757962)
Fuel pressure is not the problem, but at least we ruled it out because its a common issue.
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When the truck starts cold the truck is in open loop which means that the O2 sensors are cold and not yet controlling fuel delivery. Fuel delivery control is in speed density mode using sensors like ECT, TPS, MAP and MAF along with factory look up tables. As soon as the engine is warm enough the fuel is controlled entirely by the O2 sensors in closed loop except at full throttle.
Yes a better scanner will show you which cylinders are misfiring Yes a defective spider can be involved in this and has no codes per se, we figure that out through other tests. If your O2 sensors are behaving properly then we move on to other tests. In the mean time you can deal with that sensor heater problem. Its either the heater coil in the sensor or the 12v wiring driving the sensor. I can help you with that when your ready.. George |
11111
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Originally Posted by GeorgeLG
(Post 757962)
Fuel pressure is not the problem, but at least we ruled it out because its a common issue.
George |
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