so for some odd reason this just started happening... *the story* after months of sitting in the garage, it was ready to drive. so it was on E and i drove it to the gas station. put about 9 bucks in for 87 octane and started to drive off but just after exeting the gas station it would try to die, catch itself, try to die, catch itself... then it cut off, started it up and it did the same thing so this time i had to feather the gas with my foot on the brake and the clutch in all at the same time to keep it running, if i held the gas a little with my foot it would run fine, and it drove fine down the raod through all the gears (other than the 3800 problem) and then whenever at idle it would do it again.. so i took it home, idled it up with the idle screw a little and it ran great at idel and didnt cut off. drove it around and when at idle ran great at about 6h rpm. next morning i get up and start it up, runs great at idle, let it warm up to operating temp. and then back out of the driveway, no problem other than chatter from the clutch, put it in 1st gear and start to go and its bucking really really bad, but not in reverse, only in foreward gear, sounds like its hitting some kind of fuel cut, but its got brand new injectors and fuel pump and spark plugs. but this time it idled just fine, only when you reved it up this time it would go vroooom --- vrooom --- vroooom ---- vroooooom ----- (rev up and down by itself when i held the gas steady) and when i held it above 2 grand it ran like a machine gun (not backfiring) the motor kind went brombrombrombrombrom... what the effing heck is this????!!!! i need to fix it asap. my life depends on it. motor is all stock except 3'' exhuast, no cat, no air pump. tho i just removed the air pump... not that big mess thats associated with it on the side of the block. i just put screws and crimped tubing in the holes that used to go to the air pump. and the car has no air filter. just havnt got arond to getting one but dont thing any of those would cuase it. HELP QUICK PLEASE THANKS ALL

have you checked the computer codes? maybe its in limp mode.. does it smell rich?

how do you check codes? theres no diagnostic port?? and it smokes alot, but its always smoked, doesnt smell too sweet like cooland and its not black rich smoke. its got a different computer in it. was in it when i got the car. its from an 87 n/a but should be same as the 86 n/a... hell ive got an 89 n/a parts car with computer... will it match up with my 86... ill try swapping computers and see what i come up with but soudns to me like its soemthing else...

the s5 ecu wont work, check your afm if youve done any kind of motor swap or something you said it had been sitting till ready what was it sitting for?

sitting cause i was converting it to 5-lug with drilled/slotted rotors and 4 pistons, took a while to get the parts. anyway all i can think of is some kind of valve or sensor isnt working right... where is the afm?

wer eyou dirivng it around with n o air filter or airbox at all? if so you could have possible sucked up a foreign object, and bang goes the motor.



kevin.

i only ran it about 100 feet and back like that tho. i think its got something to do with the bacv or the afm.

I think I replied to another one of your posts concerning this car as well... but it's possible it could be the fuel filter. If you replaced the fuel pump, etc recently did you replace the filter? It could be clogged and starving it of fuel. Along those lines, recheck all your connections you made for the fuel pump as well. What type of pump did you put in? A highflow fuel pump (and even normal ones) can be killed when you run low gas...if you run your tank low on fuel, sedement builds up in the tank and then gets sucked up through the pump/filter. This is just my thoughts.



...also, make sure all your lines are capped where appropriate and see if you have a vacuum leak..that would cause sparatic driveability, so would a bad TPS...

feul system is completely new. all of it pretty much. new secondaries, new pump (oem) and filter. take was clean with no rust or dirt when replaced. see the thing is... 2 dyas ago it ran great at high rpm, but at idle would stumble and cut off. so my buddy turned the idle screw up what looked like a hell of alot. then it ran great at idle. next morning it ran great at idle still but when i put it in gear and drove it bucked and surged really crazy and bad. i was like FUUUUUUUUGGE...

Are you using the stock FPR? They are plastic and prone to breaking...causing sparatic fuel pressure and bad idle/driveability..

you can use a multimeter to check the TPS. someone post the specs =D

yeah its all stock. where is the fuel pressure regulator on these things? ill check it when find out where it is. i just did the s5 afm swap a few minutes ago... maybe that will help. oh and im in the process right now of doing the TPS trick with a much nicer, cleaner throttle body.. that might help also...(being cleaner)

Start w/ the basics: Fuel, air, spark. I am going to say it has something to do w/ the intake. You have adjusted the throtal butterflies and have changed how much air is entering the chamber. Also never run it w/o a air filter, even if it is only for 5 ft. I would check that nothing is blocking air flow. Always start at the basics. Sometimes it is smaller than you think.

well i figured since its screwing up and i have these parts on hand i do this: alright so heres what i have done so far... as of a few hours ago... had an s5 throttle body. took 1 piece of linkage for omp off of s4 tb and put it on s5 and spliced the wires correctly so the tps would hook up. did the throttle body mod. (took out thermowax valve and 2 front butterflies for better high end airflow) the throttle body was waaaay cleaner than my s4 anyway so i figured i use it. i used a bolt and jb weld to fill in the hole that is left from the actuator that controls the 2 butterfly valves i took out. being as this is a cleaner tb and the idle is already set from factory and all that it might help a bit. also as of a few hours ago i found the s5 air flow meter and box with a brand new k&n air filter laying in my parts car. couldnt believe it at first i was like WHOOHOO. so i did the s4 to s5 air flow meter conversion so i can use the s5 one. as soon as i get everyting put back together and my air control vavle block off plate comes in ill start her up and see if it is still doing whats its doing and keep you guys posted

S4 to S5 AFM conversion..... ok, this may seem harsh, but man..you should really figure out some easier answers before trying "conversions" and modifications....all of these little things your doing may result in the car NOT starting at all and cause you to have to back-track to find the original problem....catch what I'm saying? It's never good to throw more variables into an algorithm unless your testing the solution,lol... it's like a large corporation throwing money at a problem ..then they go bankrupt!

BTW, the FPR is a little plastic yellow thing (may look orange w/ age,lol)on the end of your fuel rail....you'll see it as soon as the UIM is off...

I had the same problem a bit ago, my friend was attaching my battery and connected it down too close to the belt....long story short my positive cable was cut half way thru by the belt. I could reverse, but anytime i gassed it in first it bucked really bad.

Now thats an interesting, yet simple fix, lol..thats why its always good to check the obvious... did you kill your friend? lol..

haha yes the friend was discontinued...

yeah i know im geting things a bit complicated by doing the conversion, but i figured out why it was bucking and all that. simple fix. a budy of mine (without me knowing) messed with the idle screw and something else which in turn messed up the TPS signal. so i figured what the hell. ill go ahead and take the upper intake off and TB and plenem and just see if anything is bad and ad another ground wire to the factory ground under the intake anyway. so i had an s5 afm laying around with a brand new K&N intake and an s5 throttle body wich was in much nicer shape so i found out about these so call "mods" you can do, becuase im not interested in fuel miliage, im more interested in simplicity of my engine bay so i figured ide do these mods for the hell of it. on a good not after i took off my upper intake i scraped off all the oil buildup and dirt and grime from off of my block and found out that it (at some piont) was rebuilt and adds (maybe) some truth that it actually does have a street port as said from previous owner who wasnt quite sure, becuase the irons and housings and front cover or whatever was painted red, silver, red, silver, red... and i know thats not factory. anyway... if it blows it blows