EDIT: UPDATE: Engine doesn't die now after replacing the TPS but the other problems are still there - normal RPMs at Neutral idle, but they drop to 500 in Drive, engine still bouncy. Other stuff explained in my last post.
I've been having a problem with low RPM's when in gear, and with a "bouncy" engine which sounds like a muscle car like it's running lean or rich (?). When in PARK and NEUTRAL it idles fine, but the engine would shake a lot unless I gave it some gas then it would act normal. It had been doing this off and on for a while, like suddenly for no reason it would switch to "muscle car" mode and bounce around and sound all mean, but recently it started doing it 100% of the time. (And it was slow, with top speed at about 45mph, WOT) And in REVERSE, DRIVE, 2nd & LOW, it idles around 500 and feels like it's going to die. It did die while driving before if I wasn't giving it gas (which is hard to do while breaking!), but after I replaced the spark plugs, oil+seafoam, fuel filter and O2 sensor it idles a little bit better; not about to die, but still real low. I adjusted the idle with the distributor and with the wires that open the intake valve, but that made it idle super high in park/neutral and didn't seem like a solution to the real problem.
I have a .pdf of the FSM (from 240edge.com), so you can tell me what page or section something is at if you need to give detailed advice. Or please link to detail information since I'm no car pro here, and need very explicit directions! Thanks.
Modified by ViolatoR at 6:45 AM 2/8/2009
Engine dies after 8seconds after testing TPS. '93 coupe ka24de A/T
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mikestrizak
- Posts: 12
- Joined: Fri Dec 05, 2008 5:55 pm
- Car: 1965 mustang, 1990 240sx se
Re: Engine dies after 8seconds after testing TPS. ' ... (ViolatoR)
hey i had some similar issues. you cant not run a tps and if its not making the idle irractic or you have no throttle response i would move on to something else. my 240 died like that and it was a combo of things. id pull the iacv and clean it, as well as clean the maf, and make sure your vac lines are good. could also be a fuel filter but not likely. luckily you can change some lines and clean those sensor for under ten bucks, and a new fuel filter is another ten or less. good luck to ya. -mike-
Re: Engine dies after 8seconds after testing TPS. ' ... (ViolatoR)
Can you give the results of your tps testing? That may help...
car off w/ the bigger plug unplugged from the tps (from what I remember): - does it read about 1 kOhm @ closed position?- does it read from about 1-9 kOhm smoothly w/ throttle opening up?
car w/ ign on & harness plugged in but not started:- is the voltage between .4-.5 volts?
Please verify/confirm those before anything else.
car off w/ the bigger plug unplugged from the tps (from what I remember): - does it read about 1 kOhm @ closed position?- does it read from about 1-9 kOhm smoothly w/ throttle opening up?
car w/ ign on & harness plugged in but not started:- is the voltage between .4-.5 volts?
Please verify/confirm those before anything else.
Re: Engine dies after 8seconds after testing TPS. ' ... (onosqv)
The TPS most likely isn't the problem. First, if its a powered (3 or more prong plug) TPS, it'll almost always trigger a code if it's gone bad, even in OBDI
If its 2 prongs, it works basically like a rheostat. Just take it off the car and Ohm it out with your DVOM, assuming you have one. It'll have a 90 degree cycle, with probably 75 degrees of that a steady decrease in Ohms, and anything past that will be either near or equal to zero ohms. The input circuit should be a steady, normally 5 or 6 volts in this case.
It sounds more like a MAF or AFM problem...I'm not familiar with the KA24's setup, but very few manufacturers messed with speed-density systems because of their lack of adaptability. The MAF and AFM do the same thing, but work differently. I'll not get into the specifics for that just yet, but if you can score a junkyard air flow sensor, or know someone with a Nissan Hardbody pickup with a 4-cyl or another KA24 240, see if they'll let you swap the airflow sensor, see if that fixes the problem. It's safer than just randomly swapping plugs
On that note, you sound like you can read instructions quite well, but you aren't actually familiar with what you're doing...I'd recommend taking it to a tech. Take no offense, but people that read well get confident, and generally won't know they messed something up right away. Plugging in random plugs is more likely to ruin your computer than ruin the part its hooked up to...take care.
If its 2 prongs, it works basically like a rheostat. Just take it off the car and Ohm it out with your DVOM, assuming you have one. It'll have a 90 degree cycle, with probably 75 degrees of that a steady decrease in Ohms, and anything past that will be either near or equal to zero ohms. The input circuit should be a steady, normally 5 or 6 volts in this case.
It sounds more like a MAF or AFM problem...I'm not familiar with the KA24's setup, but very few manufacturers messed with speed-density systems because of their lack of adaptability. The MAF and AFM do the same thing, but work differently. I'll not get into the specifics for that just yet, but if you can score a junkyard air flow sensor, or know someone with a Nissan Hardbody pickup with a 4-cyl or another KA24 240, see if they'll let you swap the airflow sensor, see if that fixes the problem. It's safer than just randomly swapping plugs
On that note, you sound like you can read instructions quite well, but you aren't actually familiar with what you're doing...I'd recommend taking it to a tech. Take no offense, but people that read well get confident, and generally won't know they messed something up right away. Plugging in random plugs is more likely to ruin your computer than ruin the part its hooked up to...take care.
Re: Engine dies after 8seconds after testing TPS. ' ... (del82)
Thanks for the replys, guys. Well the TPS took longer to get because they forgot to order it! So I replaced it, but haven't adjusted it or even turned the car on yet. Saving it for after I clean a few things:
I cleaned the MAF.
The BPT was super f'ing clogged and the hose coming out the bottom was torn. I'm debating on getting a new one because it looks like some of the rubber from the crumbly hose got into it. And the filter is a total loss.
For the EGR, should I just spray it as it sits, or take it out and give it a good going-over with carb cleaner?
But anyways, do you think my real problem was the BPT being so clogged with a torn hose? What would make it run ok in park/neutral but terrible in drive?
I cleaned the MAF.
The BPT was super f'ing clogged and the hose coming out the bottom was torn. I'm debating on getting a new one because it looks like some of the rubber from the crumbly hose got into it. And the filter is a total loss.
For the EGR, should I just spray it as it sits, or take it out and give it a good going-over with carb cleaner?
But anyways, do you think my real problem was the BPT being so clogged with a torn hose? What would make it run ok in park/neutral but terrible in drive?
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lil_ben_20200
- Posts: 6
- Joined: Wed Jan 07, 2009 2:35 pm
- Car: 240sx
Re: Engine dies after 8seconds after testing TPS. ' ... (ViolatoR)
chwck ur distributer cap and rotor
Re: Engine dies after 8seconds after testing TPS. ' ... (ViolatoR)
Thanks for the suggestions. Ok, put in new TPS and the engine is running again! I think all the cleaning I did helped a bit, but I'm still having problems with the RPM's dropping to around 500 when in Reverse, Drive, 2nd and 1st. The idle is fine (in Park & Neutral), I adjusted it with the TPS and idle adjust screw; engine sounds normal, no odd smells, sounds or smoke, though the engine is still bouncy when at idle. The engine sounds normal when revving up and the RPM's looked normal up and down, except they always went back down to 500 when in Drive.
What happens in the engine when going from Park/Neutral to Drive? What becomes engaged or turned on? Because if this part is messed up, like something with a belt or vacuume hose which is not on or needed when in Neutral, then it would explain why when putting it into gear the RPM's drop out.
Also my spark plug #2 looks brand new. All the plugs are new actually, but the others are blackened already while #2 is still clean. I swapped plug wires to see if the wire was bad, but after running it with a different wire it was still clean, so maybe the injector isn't squirting.(?) I've seen many threads with people complaining about #2, might there be something with the computer in these cars..?
My coolant levels look fine, there may have been a bit of light white smoke in the exhaust when first starting it, and when I turned to AC on, but it's raining here so it's hard to tell if the temperature is making it look more visible than normal. (I added seafoam to gas & oil by the way, incase this explains the whiteness). The AC made the RPMs go up, and when I turned it off they dropped down and stayed at 500 until I turned the car off and on again. The second time I turned to AC on the RPMs didn't seem to go up. The engine temp gauge needle didn't go past the center mark when fully warmed up. Oh yeah, when letting it run in Park with the AC on, the RPM's would drop to 500 every 2 minutes and stay there for about 10 seconds, and then go back up to normal. If the AC unit is crapped out, would it explain why (when the AC is off) my idle RPM's are normal in Park/Neutral and not in Drive? How can I test this, can I just unplug it or take the belt off and and run the engine?
Things I've fixed or checked since the start of this thread:I cleaned out the MAF, IACV and replaced the BPT and its torn hose, and cleaned the EGR as best as I could without taking it all the way off. New plugs, new fuel filter, fresh oil. Checked the timing and everything was TDC at compression and the distributor was lined up to plug #1. Cleaned distributor contact. Replaced TPS. Cleaned some engine grounds which were dirty and checked most of the hoses and grounds, but I'm gonna lift the car up tomarrow so I can get a better view of whats going on at the bottom. I don't have access to spare 240 parts to swap and check, and I can't afford a mechanic, but I do have an autozone gift card. So, I have to do the work myself, but I just need to know what to do!
What happens in the engine when going from Park/Neutral to Drive? What becomes engaged or turned on? Because if this part is messed up, like something with a belt or vacuume hose which is not on or needed when in Neutral, then it would explain why when putting it into gear the RPM's drop out.
Also my spark plug #2 looks brand new. All the plugs are new actually, but the others are blackened already while #2 is still clean. I swapped plug wires to see if the wire was bad, but after running it with a different wire it was still clean, so maybe the injector isn't squirting.(?) I've seen many threads with people complaining about #2, might there be something with the computer in these cars..?
My coolant levels look fine, there may have been a bit of light white smoke in the exhaust when first starting it, and when I turned to AC on, but it's raining here so it's hard to tell if the temperature is making it look more visible than normal. (I added seafoam to gas & oil by the way, incase this explains the whiteness). The AC made the RPMs go up, and when I turned it off they dropped down and stayed at 500 until I turned the car off and on again. The second time I turned to AC on the RPMs didn't seem to go up. The engine temp gauge needle didn't go past the center mark when fully warmed up. Oh yeah, when letting it run in Park with the AC on, the RPM's would drop to 500 every 2 minutes and stay there for about 10 seconds, and then go back up to normal. If the AC unit is crapped out, would it explain why (when the AC is off) my idle RPM's are normal in Park/Neutral and not in Drive? How can I test this, can I just unplug it or take the belt off and and run the engine?
Things I've fixed or checked since the start of this thread:I cleaned out the MAF, IACV and replaced the BPT and its torn hose, and cleaned the EGR as best as I could without taking it all the way off. New plugs, new fuel filter, fresh oil. Checked the timing and everything was TDC at compression and the distributor was lined up to plug #1. Cleaned distributor contact. Replaced TPS. Cleaned some engine grounds which were dirty and checked most of the hoses and grounds, but I'm gonna lift the car up tomarrow so I can get a better view of whats going on at the bottom. I don't have access to spare 240 parts to swap and check, and I can't afford a mechanic, but I do have an autozone gift card. So, I have to do the work myself, but I just need to know what to do!