Help please tired of spending money
#1
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Help please tired of spending money
For about a year now i have been struggling to figure out what my problem is...
Here is what is going on, When my car uses the o2 sensors for amount of fuel it uses way too much and runs like **** until it stalls out. When i pull the plugs they are black as can be.
The reason i say when the o2 sensors are not being used is because i have unhooked them and the car runs moderately good. I talked to PCM4less who tuned the computer they told me the wires from the PCM to o2 sensors are not supplying the proper ohms due to them being cut to accomodate the extra length for long tube headers.
They suggested a new harness and o2 extensions which i bought both as well as new o2 sensors.
I have had datamaster on the car and i have used up all the free logs trying to diagnose this problem. I have been through numerous spark plugs.
This vehicle is a 94 firebird formula 383 stroker 10.5-1 compressiob with edelbrock heads ported and flow tested at 270 cfm the valves were cut. Crower cam as big as i could get. BBK 58mm throttle body, 1.6 rollers hooker long tube headers, mufflex 3" ypipe into 4" cat back with flowmaster exhaust. And of course a tune from PCM4Less.
I have no idea where to look with this other than sending my PCM back assuming there is a bad tune...
Here is what is going on, When my car uses the o2 sensors for amount of fuel it uses way too much and runs like **** until it stalls out. When i pull the plugs they are black as can be.
The reason i say when the o2 sensors are not being used is because i have unhooked them and the car runs moderately good. I talked to PCM4less who tuned the computer they told me the wires from the PCM to o2 sensors are not supplying the proper ohms due to them being cut to accomodate the extra length for long tube headers.
They suggested a new harness and o2 extensions which i bought both as well as new o2 sensors.
I have had datamaster on the car and i have used up all the free logs trying to diagnose this problem. I have been through numerous spark plugs.
This vehicle is a 94 firebird formula 383 stroker 10.5-1 compressiob with edelbrock heads ported and flow tested at 270 cfm the valves were cut. Crower cam as big as i could get. BBK 58mm throttle body, 1.6 rollers hooker long tube headers, mufflex 3" ypipe into 4" cat back with flowmaster exhaust. And of course a tune from PCM4Less.
I have no idea where to look with this other than sending my PCM back assuming there is a bad tune...
#6
MAF sensor*.
MAP is Manifold Absolute Pressure. It tells what the vacuum is.
MAF is Mass Airflow Sensor. It tells how much air is coming in.
Not going into how it works, but if this fixes your probably you can try cleaning the MAF with a Qtip dipped in rubbing alcohol. (You clean the wire filaments inside the MAF) if cleaning it doesn't work, try using a known working one.
MAP is Manifold Absolute Pressure. It tells what the vacuum is.
MAF is Mass Airflow Sensor. It tells how much air is coming in.
Not going into how it works, but if this fixes your probably you can try cleaning the MAF with a Qtip dipped in rubbing alcohol. (You clean the wire filaments inside the MAF) if cleaning it doesn't work, try using a known working one.
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#9
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I have had ntk o2 brand new as well as now bosch brand new. I have used datamaster coolant temp sensor was a problem. I changed it and it is reading properly now. It runs fine until going into closed loop. It then goes all over the place the short and long term blms dont seem to correct it.
#10
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That could be your problem....most here will tell you only use AC Delco O2's...me being one of them I would spend a little bit more on the proper GM sensors and see how it runs; then start looking at getting a ALDL cable to hook up to a laptop so you can pinpoint the issue.
#11
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That could be your problem....most here will tell you only use AC Delco O2's...me being one of them I would spend a little bit more on the proper GM sensors and see how it runs; then start looking at getting a ALDL cable to hook up to a laptop so you can pinpoint the issue.
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The car sat over the winter a year and a half ago. I change the fuel pump, after that winter was when all the problems started. I had a problem with the coolant temp sensor reading -40 changed it and it fixed that problem but now im stuck with this one and ive been trying to figure it out ever since.
I changed out the stock fuel pump because it could not keep up at WOT. Put in a walbro 255 lph pump is there any chance this could have anything to do with it. My mechanical gauge on the rail does say approx 40 psi.
I changed out the stock fuel pump because it could not keep up at WOT. Put in a walbro 255 lph pump is there any chance this could have anything to do with it. My mechanical gauge on the rail does say approx 40 psi.
#15
Nope the fuel pump won't be otherwise it'd do it in open loop. It's something in closed loop. Said the MAF hasn't changed anything so you know it's not that.
If you have 40 psi at idle that's in spec. ~44psi key on, then idle should drop 3 - 7 psi.
You are running two different o2 sensors? I'd replace both with brand new ac Delcos. Never good mismatching things. Just like plugs change them all at once blah blah.
Things that control fuel in closed loop are, MAF, IAT, o2 sensors, coolant temp sensors.
If you have 40 psi at idle that's in spec. ~44psi key on, then idle should drop 3 - 7 psi.
You are running two different o2 sensors? I'd replace both with brand new ac Delcos. Never good mismatching things. Just like plugs change them all at once blah blah.
Things that control fuel in closed loop are, MAF, IAT, o2 sensors, coolant temp sensors.