Engine Pops and wont Rev at all

93luv · Mar 15, 2010

just got my first stang '93 5.0'and now have my first bugs... pulled codes and got (koeo)
81 map has not changed normally
82 super charger bypass circuit failure
91 no oxygen sensor switching detected
96 fuel pump secondary circuit failure

i have to give it gas for the car to start and when it does idle is very irratic, it used to smooth out with a couple hits of the throttle. sometimes i would have to keep it at 2k if not it would sputter and struggle to stay alive... now when i give it gas it doesnt rev at all, i can push it all the way down itll just make a semi loud poppin sound from the front end . > if i just BARELY touch the gas pedal rpm would drop a few 100 and car would die if i dont let off.
i got a new tps, reset idle 750-800(.99v tps), this cleared 33 63 codes.

Question is -would the codes i pulled be causing this?
-what would be first steps to finding the problem?

bmo37 · Mar 15, 2010

I would do simple basics first, check your firing order, pull the plugs and inspect them, see if you're getting spark, when you turn the key does your fuel pump prime (do you hear the motor), unplug your maf sensor and try starting the car (if it starts and idle's better your maf may be dirty and need to be cleaned on the sensor or connector) or your maf maybe bad in general. If you can get the car to idle check your base timing, it's possible the distributor moved and isn't anywhere near where it needs to be.

Did you do anything to the car recently which might have caused one of these issues?

stykthyn · Mar 16, 2010

the MAP code most certainly would.

Go through Jrichkers surging idle checklist. It will help you eliminate all the idle surging issues.

liljoe07 · Mar 16, 2010

None of those are a MAP/BP sensor code. 81 and 82 are smog related codes.

91 as stated is a lean code. Unplug the 02 sensors, and swap them around in the H-pipe. Re-run the codes. If code 41 now shows. Then the 02 that was originally on the driver side(now on the passenger side) is bad. If code 91 still shows, then its a wiring issue or an exhaust leak, or an actual lean condition on that bank.

96 normally wouldn't concern me, but the fact that you are having to pedal the gas worries me. Maybe its an actual fuel pump issue. What's the fuel pressure like when you have to pedal it?

93luv · Mar 16, 2010

i have HO firing order and made sure its right, plugs are good, sparks there..come to think bout it my cousin tryd to rotate the dzzy..if thats even possible. Before it started dyin and just idling bad i did disconnect the tube just before the TB and it revvd up stayed at 1000 and very rich.. but it did seem to work >>>>>>but wouldnt it throw code if it was bad?<<<<<<
>>>-would TB cleaner kill MAF<<<, cuz that wat i used days b4 this issue..
i can hear pump prime , and just changed filter(looked like brown water)
fuel pressure is 0 it acts like nothing is entering combustion chamber just air...
Full throttle=No rpm rise and "pop, pop."
but i will go through the checklist and thanks for the Tip on switching 02 sensors, will do .

liljoe07 · Mar 16, 2010

93luv said:
i have HO firing order and made sure its right, plugs are good, sparks there..come to think bout it my cousin tryd to rotate the dzzy..if thats even possible. Before it started dyin and just idling bad i did disconnect the tube just before the TB and it revvd up stayed at 1000 and very rich.. but it did seem to work >>>>>>but wouldnt it throw code if it was bad?<<<<<<
>>>-would TB cleaner kill MAF<<<, cuz that wat i used days b4 this issue..
i can hear pump prime , and just changed filter(looked like brown water)
fuel pressure is 0 it acts like nothing is entering combustion chamber just air...
Full throttle=No rpm rise and "pop, pop."
but i will go through the checklist and thanks for the Tip on switching 02 sensors, will do .

So you have 0 fuel pressure? Or was that a typo?

93luv · Mar 16, 2010

lol .my bad. 0 was an exaggeration, i really dont know how much fuel pressure i have..do i need to rent something from autozone? how-to?

liljoe07 · Mar 16, 2010

Rent one and check.

Engine Pops and wont Rev at all

93luv

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stykthyn

I want to measure mine. It doesn't look that tall.

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93luv

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Engine Pops and wont Rev at all

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I want to measure mine. It doesn't look that tall.

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