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exhaust pops, runs like ass, no codes

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DigitalDC89

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Discussion starter · #1 · (Edited)
'88 GT Hatchback, with a relatively stock 5.0. just the usual mods, CAI, headers, O/R X-pipe, MSD coil and wires, timing at 14*. i just recently pull the engine to install new gaskets, such as rear main seal and head gaskets. after i got the engine back in the car, it fired right up.

idle was a tad rough, and it smoked a little. i then noticed i left the vacuum of off the BAR sensor, attached it and it ran real smooth and the smoke went away. i then proceeded to reset the base idle to assure that everything was fine.

disconnected the negative battery cable for awhile, and continued to finish up the reset. started the car up and the idle surged up and down and kept stalling. after some messing around, i somehow got it to idle decent, but it still lacks power and pops out the exhaust.

i checked the TPS and it was at .98v. checked all the plug wires which are new and cleaned all the terminals up. checked the cap and rotor. plugs are brand new and set to .045".

why was it running so well before the base idle reset, and now it runs like ass? also, car is not showing any codes. any thoughts?
 
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Discussion starter · #3 ·
dizzy was never removed so that should be fine. ill check vacuum lines and see whats up.
 
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Discussion starter · #5 ·
i did remove the intake manifold, just not the dizzy. or is it possible the dizzy got moved anyway? i re-checked timing once everything was back together and started running like poop, and it was still at 14*, i even bumped it back to the factory 10* but no change.
 
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Discussion starter · #6 · (Edited)
replaced a bunch of lines that were all dry rotted and no improvement, actually got worse. if i disconnect the electrical plug to the BAR sensor, it idles fine, just a little high. the moment i plug it back in, it idle lopes and eventually dies.
 
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Discussion starter · #7 · (Edited)
also, if i unplug the vacuum line it runs better but idles higher from the vacuum leak, but doesnt miss at all. is it time for a new BAR sensor?

EDIT: i took it for a spin with the vacuum line disconnected, and the electrical plug connected to the BAR sensor. it run alright with a high idle, but lacked power.
 
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Discussion starter · #10 ·
my car is NOT mass air, being an '88 it is speed density. and timing is set right around 10* as well. im thinking i messed the BAR sensor up when i removed the engine, maybe pinched it between the engine and the firewall. i dont see any cracks or anything, but maybe something internal got messed up.
 
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Discussion starter · #12 ·
sadly no. i wish i did, that would make troubleshooting so much easier. anybody near allentown PA that could meet up and test? lol
 
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Discussion starter · #13 ·
looking into buying a new BAR sensor, but im getting confused. do i want to buy a BAR sensor or a MAP sensor? RockAuto.com list both for my year and model, but only the MAP sensor they have listed matches the serial number on my sensor (E7EF9F479A2A). ive read that the BAR and MAP sensor are essentially the same thing, so why so many different options to buy, all for different prices?
 
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#15 ·
I'm bout to get into the fox world, and i'm a young padawan. I'm going to trust ya'll to show me your ways with these cars lol...
 
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Discussion starter · #16 ·
if they are the same, i dont understand why these sites list both MAP and BAR sensors, with different part numbers, and different prices... :(
 
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#17 ·
and sorry to thread jack lol, the car i've been looking at pops but thats because someone overtightened the valve spring and it doesnt open all the way. Good luck with the car!
 
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#18 ·
DigitalDC89 said:
if they are the same, i dont understand why these sites list both MAP and BAR sensors, with different part numbers, and different prices... :(
Click to expand...
Don't know honestly... i'd go to some place autozone and purchase one. Swap it in and see if it makes a difference. If it doesn't then take it back and tell them it turns out you don't need it so you never used it and get your $ back
 
#19 ·
DigitalDC89 said:
if they are the same, i dont understand why these sites list both MAP and BAR sensors, with different part numbers, and different prices... :(
Click to expand...
They are called MAP sensors on speed density cars because they measure manifold vacuum. On Mass Air cars they are called Barometric pressure sensors because they measure atmosphere pressure. The sensors are the same. The only difference is on a speed density car they have a vacuum line hooked up and on a Mass Air car they port is left open, with no vacuum line.
 
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DigitalDC89
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