need help on fuel miss

[iluvdrt]

i am haveing a serious fuel miss on my 87 ea82t. i have cleaned the injectors, new fuel filter, and cleaned intake with sea foam. while driving down the road it shutters al little, and will hesitate in the lower rpm range. while at full boost(6 psi) the fuel cut off will come on at about 4k and then kick back on emitting a large cloud of black smoke. it has new ngk plugs, 8mm accel wires, new cap, rotor, and msd blaster coil. the cel will come on every now and again, but it will go off as soon as i quit accelerating, so i am not getting any codes.

 

what i think is, is the o2 sensor is going bad and making the car run lean. the last time i checked the plugs they did have a little more carbon build up on them than usual. it is making the car run rich, and during boost applications, the o2 sensor fools the computer into the fuel cutoff because it is already rich.

 

does this sound right? any other ideas? thanks for the help, i really need it soon because i am going on a trip. thanks

 

-iluvdrt

[BlueTrain]

how were the injectors cleaned? those bottles of cleaner you throw in the gas tank don't work too well if they are really gummed up. injectors could also be leaky as well..

[iluvdrt]

they were pulled out and professionally cleaned. new o-rings and gaskets were then installed. this has been a problem since i put the engine in. it is a jdm replacement, that had 40k on it. also the seafoam was put directly into the intake manifold by the use of vacume lines.

[BlueTrain]

well, do you have a spare o2 sensor you can swap in to see if thats the prob? sounds like your injectors should be fine, as they were professionally serviced. hmmmm...

[archemitis]

dont think its your o2 sensor. they dont do that much, especially make you hit fuel cut.

[Subi81]

Had a similar problem with my 86 turbo wagon. It would idle fine and everything but when I put the pedal down it would cut out and so on so forth. Ended up being the main coil wire was not makeing a solid connection with the disty cap. and basicaly fried out the connector. worth takeing a look at it.

[iluvdrt]

Had a similar problem with my 86 turbo wagon. It would idle fine and everything but when I put the pedal down it would cut out and so on so forth. Ended up being the main coil wire was not makeing a solid connection with the disty cap. and basicaly fried out the connector. worth takeing a look at it.

i put in a new o2 sensor, cleaned the plugs, and fixed a small leak in my intake. the car hasnt hit fuel cut yet, but it will stutter real hard in the lower rpm band intermittenly. i will check the coil wires, and see if that helps. feel free to add anymore ideas, as i am completely out. thanks.

[rallyruss]

what you described is not a fuel miss. its a spark misfire.

 

actually sounds like what my POS accel coil did when it died on me.

 

if it were lean you would not have carbon on the plugs. thats from a rich mixture or unburnt. it would be white. also the puff of smoke is fuel that was not burnt geting dumped into the hot cat. if it were lack of fuel it would be a softer feeling missfire with out smoke or poping.

A Ignition miss will hapen under load especially off the line or high speed.

 

O2 is not going to be you problem. If you want I can help you check the o2 (and fuel system).

but I am rather certian you will find the problem in the ignition system. do you still have the stock wires and coil? if so swap em back on. personally I dont like the accel wires but nobody likes to hear that. good luck.

[iluvdrt]

what you described is not a fuel miss. its a spark misfire.

 

actually sounds like what my POS accel coil did when it died on me.

 

if it were lean you would not have carbon on the plugs. thats from a rich mixture or unburnt. it would be white. also the puff of smoke is fuel that was not burnt geting dumped into the hot cat. if it were lack of fuel it would be a softer feeling missfire with out smoke or poping.

A Ignition miss will hapen under load especially off the line or high speed.

 

O2 is not going to be you problem. If you want I can help you check the o2 (and fuel system).

but I am rather certian you will find the problem in the ignition system. do you still have the stock wires and coil? if so swap em back on. personally I dont like the accel wires but nobody likes to hear that. good luck.

 

thanks guys, i did mean to put rick instead of lean.:duh:

any way, i think i got it figured out, heres what i did:

first i replaced the o2 sensor with a nice bosh unit from advanced auto.

 

i noticed when i had my injectors cleaned, the mechanics replaced my ngk plugs with a junky autolite. those were quickly swapped out for some more ngk's. they were gapped at .040.

 

i cleaned and tightened the contacts on the coil, making sure the black wire went to the positive terminal, and yellow went to negative.

 

i noticed my custom intake had separated a little BEHIND the maf sensor, so it was getting unmetered air into it. i put some more sealer (electrical tape) on it, and clamped her back together.

 

new fuel filter, and new cone air filter.

 

the results- WOW, she feels like a new car. the cel, no longer comes on, and the new power being felt feels incredible. it screams all the wat up to redline. i can even bark the tires in 3rd gear. now i just have to do comparative testing on the accel ign. componets to see if they are hindering any performance.

 

thanks for all the help and suggestions.-iluvdrt