89 240 with a few problems...

[Pa240drifter]

I just bought my 90 240sx hatchback and I have a few problems that im trying to get rid of. The first problem is that the car seems to hit a rev limiter at 5000 rpms, and it dogs up to that point. My last car was a 91 infiniti g20 and it seemed much quicker, despite the lower dispacement and worse gearing. My one dash light seems to be out, it makes half the tach dark and the temp gauge(which seems to flutter intermittently but never read) dark. The previous owner was a total moron and ran the pads till they went into the rotors, now the rotors are paper thin and I need to replace them, but they're rusted/welded on... any ideas? thats pretty much all I've noticed so far, if you could give me what you think, and any fixes you have, that would be helpful. Thanks.

Modified by Pa240drifter at 9:19 AM 9/28/2004
Modified by Pa240drifter at 3:56 PM 9/28/2004

[s13sr20chris]

I just bought my 89 240sx hatchback and I have a few problems that im trying to get rid of. The first problem is that the car seems to hit a rev limiter at 5000 rpms, and it dogs up to that point.

dogs good or dogs bad? if bad then check the swirl control valve function. if good, then i need a little more info. is it ign cut or fuel? is it hard or soft?

My last car was a 91 infiniti g20 and it seemed much quicker, despite the lower dispacement and worse gearing. My one dash light seems to be out, it makes half the tach dark and the temp gauge(which seems to flutter intermittently but never read) dark. [?QUOTE]pull out the cluster and take apart. there are a bunch of bulbs in the back. easy fix. will prob have to lower the steering column a hair to get cluster out. still easy.

The previous owner was a total moron and ran the pads till they went into the rotors, now the rotors are paper thin and I need to replace them, but they're rusted/welded on... any ideas? thats pretty much all I've noticed so far, if you could give me what you think, and any fixes you have, that would be helpful. Thanks.

hammer and penetrating oil. if you intend to replace them anyway just whack them all over with a $10 mini sledge from sears.

[Pa240drifter]

dogs bad. where is this swirl control valve? the rev limiter feels like its soft. it gradually gets to 5000-5250 or so and then backs off, not really hard or anything, just enough to piss me off. im having even more problems that i didnt know about now. it was acting weird and all the electronics went out when i shut it off. but it still cranked. the battery tested bad so i got a new one, put it in and the electronics still didnt come on. when they finally did it was ok for a little while, but now its back to doing that. if i rev over 2300rpms they'll come on again, but as soon as its off they shut back off. i took a multimeter to it and im reading like the alt is bad(12.5V when idling, 12.6ish when off). im gonna get that changed, but i dont have much money to throw into it anymore. it almost seems like an ignition switch problem though, cause normally if you turn the key the dash and all turn on, as it is nothing does until you rev it.

PS. no idea about why half my instrument cluster isnt working?

[180fan]

Is the rev-limiter-esque problem occuring in all the gears or just one or two gears? Take the alternator to get tested. If your motors running without any load it should be reading around 14 volts, my electrical system reads 14.4v when warming up and decreases to 14.0v when idling warm and gets to about 12.5v when I'm at a stop with my headlights on and my brake lights on. Not sure why it'd turn on at certain rpm or not. I'd take a guess at it being your electrical system's not giving enough juice but I could be wrong on that so don't take my word on that lol.

Half your instrument cluster works and the other half doesn't? Is the white plug that goes to the instrument plugged in all the way? The plug is next to the blower motor on the passengers side, up from the ecu plug.

[Pa240drifter]

rev problem happens in all gears. the white plug seems to be all the way in, but maybe something is a little loose. the temp gauge seems to "flutter" a little and as the revs go up, it stops working. come to think of it, when it hits that rev limiter type thing occasionally i can smell a gas like smell, so it would seem to be an ignition cut, and not a fuel cut. also when i rev it above the 2250 or so needed to get everything to come on, my wipers come on, then off. and the light behind the clock comes on with the ignition like its supposed to, before everything else does. i have no clue whats goin on, plz help.

[s13sr20chris]

half of your instrument cluster is dark? thats prob just a bulb. they are easy to fix. if you pull the cluster you will see them in the back. it really sounds like you need to get an alt and go from there.

[Pa240drifter]

its not just dark... the temp gauge flutters, never reads right. it will move up to reading right, then flutter and go low... then itll shut off altogether, then itll flutter real low again. its drops most when i hit the gas a little. but thats really the least of my probs... im almost completely sure my alt is shot. hooked it to a battery charger today reads 7.5 amp draw. quite high. hoping thatll solve most of the problem... think my stereo system has anything to do with it? it didnt really effect my g20, but the alt did blow on that too. i checked the grounds and it was reading a high resistance so i re-grounded the chassis. didnt seem to help. the battery reads 12.6V when the car is off and 12.5V when its running. sounds like an alt to me. im still tryin to figure out this rev-limiter-esque thing. any help on that would be good.

[s13sr20chris]

i have seen big bad stereo systems done up right and wussy little ones that were installed improperly both suck an alt dead.

[Prelude Guy]

Hmm, I would try checking the ground wire. Based on the issues you are having with the car, I believe it's the alternator.

As for the bogging at 5000rpms, I read on another forum that the fuel pump was the issue. I am having a similar issue (kind of but not really) so I pulled out the fuel pump. I bought a new Walbro 255 fuel pump. I will try to install it tomorrow or Wed. I'll post back if it solves the problem.

[Pa240drifter]

well, i re-grounded it(ground read 42 ohms... bad!) and it didnt help, so i decided that id pull the alt fuse... it rattled. i popped the cover off and it was melted to hell on one side. some moron put a 45 amp fuse in the spot for a 75 amp fuse. apparently my stereo drew enough current to blow it out. now i have another problem though. i went to test it for the hell of it and it reads 15.6 volts at idle, climbing after that. no good. sounds like a bad voltage reg... could the fuse being blown and the car still running, and a bad ground have caused this? it really doesnt seem like a fuel pump to me for the hesitation/limit though, it seems more like an ignition problem. eh, tell me how it goes.

[Pa240drifter]

not to postwhore or anything, but id like to think i hooked the stereo up correctly... the infiniti was a 91 and it was the original alt... it was time to die. plus it didnt go until about 6 months after the install. i spose ive finally realized that the amperage draw is more than i thought (1/4 volume with headlights and blower on 2 with car running drawing over 45 amps... eeeerrrr) but i still think this problem was before i had the system in(i seem to remember seeing the batt light flickering when i test drove it) now it seems more like a regulator problem. not to say that im perfect, but id hope that my stereo isnt whack since ive done many others for friends/co-workers, and other people who pay me.

*edit* my bad, but i think i worded that a little wrong... dont mean to sound like a jerk, but i get defensive about my stereo . btw, 15.6volts at idle cant be healthy, but would it make the battery light come on? cause mine is flickering at idle... and it shuts off as it goes higher, but it starts at 15.6 volts and just a bit of reving puts it over 16. */edit*

[s13sr20chris]

ok, your alt is def screwed all up. even with your batt totally dead your alt should never pump all the way up to 15.6 v. you def need an alternator bro. high voltage should not cause the batt light to flicker but whos to say when you go over a bump it doesnt drop and spike? try to find a oem alt in a junkyard. that is better than getting a non nissan reman.

[Pa240drifter]

picked up a nissan reman for a decent price(i work at a ford dealer, i get parts thru the nissan branch). i was just wondering... is there any maf sensor we can use with a ka24e as a replacement(like how sr20's can use cobra MAFs) i know going bigger only helps if you have more airflow, but chances are i could get an equivalent for cheaper if its available(our nissan division prices are crazy, even for us).

[s13sr20chris]

probably so if you dont mind swapping wires around. however, i do not know of any.

[Pa240drifter]

Update time: Changed alternator, works good but still have some problems. My idle seems to be weird. When cold its roughly 500-750 rpms, but when hot it is roughly 1000 rpms. I have what seems like a flat spot or hesitation at 2500ish rpms, and it still hits a limiter at 5250 rpms. The car runs like a champ when cold, sucks when hot. I pulled the air filter and it has quite a bit of black area on it, looked at the airbox and it looks like the EGR is pumpin quite a bit of black smoke in. I checked voltages on the MAF, and at idle I get 14.5 , 0 ,and 1.6(seems a little high, but i dont recall what it was on my old car). I saw one day some smoke comin out the tailpipes when I pulled out at work... seems like I'ts gonna be a long road to recovery. Do you think my MAF is shot, if not, what else could it be? I'm leaning towards the MAF, the o2 sensor is brand new, and I don't know what else will make it run pig rich like this.

[JNM240]

Ok, now it sounds like you have an overly rich running condition when the car is warm. COOLANT TEMP SENSOR CONNECTOR!!! This tiny little contraption is the bane of all 240SX owners. Pull the electrical connector off of the sensor (directly behind the powersteering pump, the 2 wire conenctor on the intake manifold next to the burp valve) and you will most likely notice it is corroded green. Scrub it with a wire brush, grease it up with dialetic grease, get a new sensor, get a new pigtail connector, do whatever it takes to fix this. The ECU reads coolant temp off this sensor and regulates fuel accordingly. If the ECU cant read it, it reads it as the car hasnt warmed up yet, dumping loads of fuel in, waiting for it to warm up. Coincendentally, the single wire plug next to the coolant temp sensor is the TEMP GAUGE wire. The fluttering of your gauge is directly related to how well this wire is getting signal. Play around with it, clean it, cut it off and solder a new connector, whatever you have to do, this is why your gauge flutters. Hope this helps.

[s13sr20chris]

if you air injection sys is backfeeding exhaust into the airbox that is a major prob. it will make the car run horrible and mess up your maf quick. fix or disable your pair valve or aiv.

[Prelude Guy]

Ok, now it sounds like you have an overly rich running condition when the car is warm. COOLANT TEMP SENSOR CONNECTOR!!! This tiny little contraption is the bane of all 240SX owners. Pull the electrical connector off of the sensor (directly behind the powersteering pump, the 2 wire conenctor on the intake manifold next to the burp valve) and you will most likely notice it is corroded green. Scrub it with a wire brush, grease it up with dialetic grease, get a new sensor, get a new pigtail connector, do whatever it takes to fix this. The ECU reads coolant temp off this sensor and regulates fuel accordingly. If the ECU cant read it, it reads it as the car hasnt warmed up yet, dumping loads of fuel in, waiting for it to warm up. Coincendentally, the single wire plug next to the coolant temp sensor is the TEMP GAUGE wire. The fluttering of your gauge is directly related to how well this wire is getting signal. Play around with it, clean it, cut it off and solder a new connector, whatever you have to do, this is why your gauge flutters. Hope this helps.

I am going to try this when I go home today. My car bogs BAD no matter if the car is warm or cold.
Modified by Prelude Guy at 9:42 PM 9/27/2004

[Pa240drifter]

Ok, I bought a coolant temp sensor(2 pin) and put it in. I cleaned the contacts thoroughly and pressed the contacts out to make a better connection. I also did this to the other sensor, and my gauge reads again. I didn't really notice any performance difference, it seems a little better, but I still have that "rev limiter" problem, and it still feels quite weak(doesn't pull thoroughly through 2nd uphill, can't even break 5krpms). I plugged the AIV hose and the part coming out of the airbox. Still feels sluggish. Does anybody know what the normal voltage for a MAF signal reading on a ka24e at idle? Mine reads 1.6 still, I'm still wondering if its too high. The exhaust smells rich yet as well. Any help is appreciated(still).

*edit* I looked around and it appears that at 750rpms 1.45V is normal, so at my idle(around 1000) 1.6 doesnt seem far off(I think). So if it isn't the MAF, what else could it be... Hmmm */edit*
Modified by Pa240drifter at 6:22 PM 9/27/2004

[Prelude Guy]

How far away do you live from Maryland?? maybe we can meet up one day to check our cars over.

[Pa240drifter]

I'm about an hr north of Philly, so a good bit away from Maryland.

*edit* Ok, I lowered my idle using the adjustment screw(about 700-750rpms) to check the MAF again, it reads 1.45 volts. Now I'm begining to wonder about this rich condition having something to do with the "rev limiter". Could it be possible for the injectors to max out when it is running at 5500rpm and extremely rich? It seems to me that if the injectors were to run at full duty cycle, the ecu would limit them from overloading. This in turn would stop the injectors from adding more fuel, and stop your engine from revving. I'll have to unplug the 4th and 5th sensors, and see if it makes a difference. My biggest concern at the moment is how rich the mixture is. I dont want to do any damage to my cat and o2 from this condition, plus it's hell on my wallet, since my gas mileage is horrible. Any input still appreciated. */edit*
Modified by Pa240drifter at 3:53 PM 9/28/2004

[s13sr20chris]

that maf reading is not too bad. how is it during the rev limit prob?

[Pa240drifter]

At the "rev limiter" it reads 4.8 volts signal. The input voltage also goes up as the revs cause of the alt. but it seems to jump from 3.9 to 4.8 nearly instantly.

[s13sr20chris]

wow! that is bad. i cant say for sure that its the maf itself, but 4.8 should not happen on a stock or even anywhere near stock motor. i use a sohc maf on my sr20 at 13 psi and i dont see 4.8(that i know of).

[Pa240drifter]

Without getting a new MAF, is there any way to tell if its bad? I don't have anyone around with a 240, but I do have the person I sold my G20 to, so I have access to a SR20DE MAF, but its different pins, he also has another MAF, from a sentra, I believe its more pins though. any other tests or anything?

[s13sr20chris]

not really. if the maf has the proper power and ground the only other thing is the signal. maf meters are such dynamic items. so many faults they could have that could cause them to mess up at different times. like a tps that just has one little dead spot. a sure sign of a prob is the big jump in voltage. .1 volts is no big deal around 1v. it increases exponentially so at 3.5 it is a very big deal.

[Pa240drifter]

Well, I'd rather not be cutting wires for my MAF so i can use another one, but I'd also rather not spend the money on a MAF just to find out theres another problem. I don't know what would be the better route, and I suppose im gonna end up cutting and splicing most likely.

[s13sr20chris]

man, too bad you are not in va i would let you use my spare. actually i dont know if it even works. anyone in your area you can work with?

[Pa240drifter]

I have no idea if anybody lives around me. Is there some kind of directory or something?

[s13sr20chris]

not that i know of. try posting in the 240 tech forum. maybe someone will want to meet up and borrow something from your car to see if it fixes theirs.