msladypaula

I am now plagued with my car sputtering, stalling, hesitating, acting like a fool. it went from intermittent to barely driveable. Lets start off with the bad girl in question.Basically stock KAonly things upgraded is more of my suspension (not important to this thread), hks exhaust, walbro 255 fuel pump, so like i said, she stock. its a 1995 240sx Automatic with only 61444 miles. No that is not a misprint. And yes it is an obdII. i know some have the obdi. not the case. So lets rewind the issue. 9 months ago: hesitation in my car when accelerating over 50mph on highway. very sporadic. Never stalled. but when the hesitation turned more into a bucking motion, took it to a shop. IACC. Balls it sucked getting a new one. But then she ran like her old champ self. about 8 weeks ago....did my car just hiccup? very very light hesitation in highway driving. was kind of early to do this, but i figure no big deal, changed the spark plugs (look slightly lean ALWAYS the ngk plat) and changed the spark plug wires from NGK to the denso ones (i've seen it where on others, ngk wires actually contribute to the car running kinda crappy or bog like, so i figure id give it a change and see) and changed the fuel filter. thats seemed to make her happy. Moving along....Last weekHighway driving....its morning...pretty cool out maybe somewhere in 50s or low 60s.... alittle misty....traffic is moderate so i'm going on and off between 40 to only 50....PUTTPUTTPUTT... oh the hesitation came back i see; well let me just get to work ....now its hesitating like mad for abut a mile. feels like loss of power. giving gas not helping. shit. roll to side of road and ...STALL. Now she really has my attention because this is the first time she has ever stalled on me from a moving point. start her right up and take her slow to work (was at this point only a few blocks away)....some older gears heads at work and i talk cars...no one had a clue. Drove her home.... i was waiting for impending doom of another stall. ...NOPE. RAN like a champ. You kidding me right? My bf takes a look at it and says we'll take a look at it.... we go to the garage.... car was on the driveway for about 15 maybde 20s mins just idling... no problems.... then dies. we didnt even get a chance to touch. ALL hands on deck now. so now we have been going back and forth with this car chasing the tail of the neverending hesitation gremlin. BTW no CEL so we changed the maf and the pigtail (thought maybe a terminal on plug was bad cause sometimes you shake the plug, she stumbles...) still happens. Trying changing the ecu thinking its a malfunction in the unit. Nope. Change fuel pump thinking it doesnt have enough pressure or volume (even though testing i did have 37psi at idle...okay shut up i just wanted to change it anyway)no diceChange the ECT and the senor for the guage next to it. AH...... for 30 mins her idle was good. not jumpy. not shakey. next day i wanted to take her to stretch her legs and i wanted to do it from a cold start. NOPE7 mins in i heard the faint bog coming back.At 10 mins, STALL. (barely enough time to get her over and beyond the C)okay...front oxygen sensor... that looked shitty. and the reading were all over the placeREplace.... around the block.... nah still there but not so bad. scan shows a healthy pattern reading. TPScar ran much better and the hestiation seemed to be very very mild. ...Nope scratch that. next day drove, 10 mins in, bogging.... and just as we turn into the drive...stall. as many times as i could, we hooked up a scanner and tried videoing the results to see if there was a pattern. it seems like the gremlin shows up most often (but not always) during light to moderate throttle closed loop.while my car isnt showing a CEL on the dash, the scanner did have a malfunction indicator on (unfortantely i did not notice it right away, so i am not sure at what point in the process it came on)and it says rear oyxgen sensor. i can replace the rearo2 and hollow the cat if thats fried or test pipe it but im not really convinced that this is my issue.it seems too intermittent for it to be a vacleak. running out of options and ideas. trying to go through some of the FSM, but i reach alot of deadendstcc? injectors? the dizzy and the cps on the trans bell housing were changed about 2 years ago..used but working. (p1320 still haunts my dreams). i know this issue has haunted many of us...and ive hunted and tried may of the top common solutions to fix the 240sx hiccup.anyone have other suggestions ...things ive overlooked.....i feel like i am missing something. what the hell am i missing?

msladypaula

went back to tps.... wires were pushed out the back end from the new tps. didnt have a black backing like the oem one did. cut the plug from old tps and connected to the new tps.
CAR was able to idle for about 40 mins on driveway, about an hour driving on street and highway.
Came home. quickly rinsed her off because she has been sitting in a filth of pollen.... go to start it up later at night( about 5 hours later) just to hear her pur for alittle while.
Guess who stalled on the driveway?.......
Took several mins after forcing the car to stay on by feathering the gas pedal...she magically leveled out.

msladypaula

saga continues.... so still stumbling/.falling on face in driveway.
did find that the ground was out of spec on the maf. it was reading way over 2.2 when at idle with no load.... created a redundant ground and hooked that up to chassis. she actually behaved well on the driveway with some minor misfire...changed plugs and for about 40 mins she was well behaved on driveway under no load. idle 688 to713 for about 40 mins. It was hot and humid here yesterday in ny but the engine maintain a temp of around 178. no major flux. timing was on money at 20. let her cool down for a few hours and tried to take her out at night. she sputtered again. only differences was it was now under some load (with lights on) and the temperature was much cooler...... going to recheck that wire. maybe it became loose or the solder needs to be done again. if not, i may have to redo the wire straight from the maf to the ecu??? maybe there is another break in the harness? maybe maf taking a dump? (kinda feel like maf dump is alittle of a stretch since i have two oem mafs and both have same problem...but its not out of realm of possibilities). my bf was atleast about to get her to drive about half a mile to get gas as it seriously ate through fuel like a monster doing all this checking and diagnostics ......

NickS14

How is your fuel pump wired? Do you have an external relay wired for the pump? Hows your fuel pressure regulator? You mentioned in the OP that you changed the fuel pump - was it from stock to the walbro? I'm thinking it may have something to do with too much fuel pressure... Im guessing its the stock MAF ?

Lilredsx

Your saga sounds similar to what I went through with my 95 automatic as well. $600 and a new to me $50 MAF later she is running strong. He checked every sensor over two weeks of troubleshooting. The MAF was the last thing we checked and it turned out to be the issue. You could try cleaning the sensor inside it.

msladypaula

fuel pump stock to walbro 255. stock maf. and stock fpr if that was the next question.

during this whole sage i have two stock s14 mafs.
and the issue has happened with both.
Leaning toward something in the wires.
But its not impossible to have two bad mafs. (one was a recent purchased from a place in long island)
so i do have a 3rd on the way....

and i have 2 ecus as well. and have tested both with same results. thus i leaning away from the idea of a rare but bad ecu.

msladypaula

if it is the maf, then why does she sometimes run fine during this whole thing, and other times like a$$? I thought once they malfunction, thats it.
it seems odd to me that sometimes i can turn her on right now, and she purrs like a kitten, and other times its like she wants to roll over and die.