idle and running problems on 90 240

[bk240sx]

my car idles extreamly rough. i have replaced the fuel filter,mas air sensor,plugs, wires, cap and rotor.

the car also stumbles and bogs down durring mid throttle (highway) driving. seems to only bog down once in awhile but with each new part the problem got worse.i think it might be a fuel problem.

i thought i could hear one of my injectors rapping but not sure. anyway to check them or any sugestions on what my problem could be would be great. otherwise the shop will probably rake me over the coals with a bunch of BS.

[Exar-Kun]

check your TPS(throttle positioning sensor), and run a fuel system cleaner through possibly to lcean out any clogged injectors yo might have.

-chet

[bk240sx]

already ran stuff through it.

how do i check the TPS on my car?

thanks for any help

[Exar-Kun]

you'd need an OHM meter, descibed in the FAQ. but a visual check, its on the side of the throttlebody, should be a little black box, check the conections, if they are corroded/missing that could be your problem(theres a harness going to it.)

also check your MAF sensor, that might be causing a problem

-chet

[Stock-S13]

hey now that were talking about that fuse box. Iam missing somthing that says Anti slip somthing, is it necessary i replace it i've driven in rain and i didnt get any slip so any suggestions?-edgar

[bk240sx]

i just replaced the MAF not the problem. i have to keep on the gas other wise the car will drop to 100 rpms and raise to about 1200 and then sometime stall.

[bk240sx]

no ideas beside the tps???

[GodDrivesA240sx]

There a process described somewhere around here. You check the resistance of the wires. It sounds like that's going to be your problem.

For stock-s13. That's your abs system fuse, I believe. If you're car doesn't have ABS don't worry about it, it's not suppose to be there

[Stock-S13]

cool i was kinda scared there i was gonna have to spend some more cash i dont have.. i really need a job.. god but one more question how do i know if i have abs? manual? i have two so which one?

[Bay Dog]

Chances are you don't have ABS. To check for sure, pull out the fuse next to the empty slot. If your empty ABS slot doesnt have those metal clips in it to hold the fuse, then you don't have ABS. Make sense??

[leper421]

but one more question how do i know if i have abs? manual? i have two so which one?

An ABS warning light in the instrument cluster is a good indication

[bk240sx]

ok went to the shop today they cleaned the throttle plates said there was a lot of build up. now the car idles fine in park and nt in gear or it idles right in gear and not in park its always one or the other now but it did seem to help. but still having problem.

how much for a new TPS anyone know???

[bk240sx]

just checked autozone web site and its 35$ so if this might fix it ill try it but im getting sick of trying parts. so anymore info or experiences would be great.

[bk240sx]

oh yeah the shop must have dropped my intake on the floor or something cause its got a big chip out of the polished metal. looks nasty but try telling them it wasnt there. anyone know a way to polish these thing yourself?

[bk240sx]

ok i talked directly to the mechanic today and he said its the idle air control valve. anyone know where i can get one and how much will it be around?

[JDT]

Your problem sounds very similar to the one I just fixed on my '91.

Check the line from the BPT to the EGR valve. It' very short about 2 inches. Mine was very soft and completely worn out.

Cost me 3 bucks for the line (including a couple feet of vacume line I had to cut to get it off. The valves are located at the back of the engine by the firewall.

Hope this helps.

[bk240sx]

ill check but my car only has 60k miles on it so everything seems to be in good condition as far as hoses go but ill check it out. thanks

[HaveBlue]

i have similar problems with my 1990 auto. rough idle, horrible milage (16-18mpg), etc. Did cap, rotor, plugs, wires, checked maf, checked engine grounds (in the back of the block to firewall, maf ground to front near driverside headlight etc). Cleaned AIV, IAC/IAA, checked compression, temp sensor, new injectors about 30k ago. Almost everything. Only thing i have left to check is the grounding wire for the injectors and engine harness and i suspect this may be what is causing my poor milage and idle problem. btw plugs are bone white but there is a huge black stain on the rear bumper, weird. how can it be rich enough to spew like that but not leave residue on the plugs?

HB

[bk240sx]

my plugs are fine but i do have a lot of black smoke coming out of my exhaust. when i leave it run for a minute near snow the snow is black. let me know if you find your problem. maybe its the same as mine.

[HaveBlue]

replace the o2 sensor.

[bk240sx]

oh yeah i replaced that too

[bk240sx]

where is the idle air control valve located on my car (90 auto soch) i want to check it out and i think ill probably replace it myself if its not too hard.

[HaveBlue]

the iac is behind the throttle body. It is shown in the second link. note the pics are for a dohc 91+ but it is in the same place on the sohc 89-90. the pics are also taken from an engine that is outside of the car and would be impossible to take from the engine compartment (you are looking at the engine from the rear).

http://240sx.org/faq/articles/...t.htmh ... or....html

[bk240sx]

thanks i tried the adjustment thing didnt help. buying a new one if i can figure out which one to get.

[HaveBlue]

test it to make sure it works. if it doesnt, remove it, clean it and test it again. then replace it as a last resort. Then again if you find one cheap replace it and see

[shawns1234]

have you change the first O2 sensor? I had this problem and this fixed it.