Help, serious BOG from 3k to 5k on cold KA24DE?

[MELLO*SOS]

** SOLVED - Read through to find the solution (replacing KS with resistor) **

Hi all,

I have noticed this problem with my car (92 KA24DE) since the day I bought it... When the engine is cold, it will usually bog very heavily on WOT after shifting into second. It's noticeable enough that it throw you forward in the seat. I've dealt with it, but now it's just out of control...

For the last few days it's been overcast and cool (60s) in the mornings here. When I leave to drive to work, the engine DOES NOT want to rev on WOT between 3000 and 5000 RPM while driving! Sitting in nuetral the engine takes forever to rev and noticeably slows down between 3k and 5k. Everything on the car is stock, and since this only seems to happen when the engine is cold I think it might be a sensor loose or malfunctioning... It seems to go away after driving the car for 15-20 minutes; my commute to work is all city streets and only takes about 10-15 minutes.

The bog-after-shift-into-second will happen when I leave from work each day, but only seems to happen once.

If anyone has experienced this or has any suggestions, please let me know. I have replaced the plugs and fuel filter very recently (as soon as I got the car actually), so it's not either of those......

edit: it doesn't matter the temperature, hot or cold it still does this
edit: the problem is solved. Scroll down for the solution

[Var]

Blindly guessing i'd say try changing the TPS first.

[MELLO*SOS]

My first guesses (well after fuel filter and plugs) were TPS and fuel pump and/or regulator. I wanted to post on here first hoping someone else has experienced this before I start replacing everything one sensor at a time .

Thanks for your input

[sr240mike]

You could try measuring the voltage of the tps before replacing it. Grab a voltmeter and shove the prongs through the back of the sensor connector to make contact.

[MELLO*SOS]

Aw I forgot to ask in my last post about TPS testing techniques. I have a DMM, which wires should I measure and what should the voltage be at 0% and 100%?

Any other sensors or devices that could possibly be causing this? Moisture/condensation in the TPS could very well be the culprit; although it seems unlikely since it has this same problem whenever the engine is cold... Like when leaving from work (car baking outside in 95+ temps all day long). It only lasts for a brief moment, then it's gone for the rest of the drive....

[Var]

With 0% throttle the voltage should be .5 and at WOT(wide open throttle) it should be 4.5


The problem you're having shouldnt show up at these areas and you need a DSO to check it. A multimeter is only good for showing high and low, but not mid-range and it wont find electrical noise like a DSO will. I would just go ahead and test it with a multimeter like mike said, but if it check out ok, it still may be damaged. Swap it out with a junkyard one to save money

[MELLO*SOS]

Thanks for the info.

I don't think the DMM will show anything either; due to the fact that this problem "goes away", and if there really were a dead spot on the TPS, it should show up/be there 100% of the time...

Forgive me for asking, but what is DSO? Edit: doh, a digital storage oscilloscope. I would sure love one, but don't have the funds at the moment

I had a great obd2 setup for my 99 cougar for my laptop that let me see EVERYTHING going on in real time, plot graphs, etc... I really miss having a nice diagnostic tool like that for my 240. Is there a tool that will allow me to do something similar on the s13s?

I'm almost certain it's a bad sensor somewhere. If I could watch their outputs and compare that to "normal" ranges I would probably be able to figure it out instantly. Maybe something has a bad ground... It could be a million things at this point, and I don't have the time or money to get into a "replace one sensor at a time until it's fixed" state...

[idlafie]

Have you tried putting your ECU into Diagnostic Mode & see if the engine is throwing any DTC's, (diagnostic trouble codes)...????

Check the wire leading to your Engine Coolant Temperature Sensor, along with your Oxygen sensor. Also check to see if the EGR valve is working properly. Maybe sticking due to carbon buildup.
Cheap & easy fixes you might want to try are 1). Replace the air filter along with the distributor cap & rotor, (if you already haven't). 2) Check the spark plug wires with an ohm meter to make sure they are still in good shape...no shorts in the wires. Make sure they are firmly attached to the distributor cap & plugs. 3). Pour a bottle of fuel injector cleaner into the gas tank at your next fill up 4). Clean out the throttle body, EGR & IIAV AIV valve with a bottle of carburator cleaner. And 5), Check your ground wire that runs from your engine block right above the 02 sensor to your firewall. Make sure it's still connected.
See if any of the above help to improve or fix your bogging problem.
Hope this helps....
Good Luck!!
ID
'95 SE

[MELLO*SOS]

Hi

Thanks for the suggestions!

All the plugs and filters were replaced less than 3000 miles ago, but the cap & rotor and plug wires were not replaced. I am buying a new cap & rotor tonight, possibly a set of plug wires too.

When I was having this problem originally I thought it was either a fuel delivery problem (clogged lines, filter or injectors) or a timing problem (retarded due to bad sensor). I replaced the fuel filter and ran 2 bottles of injector cleaner through, with no positive results. I am wondering if I could have a faulty fuel pump, but I don't have a fuel pressure gauge yet. Regarding sensors, I contemplated TPS, ECT and MAFS (of course). None of these have been replaced yet though... I'll do the more simple/cheap stuff first (wires, cap, etc) and hope that solves it.

Can you please link me to a tek to get my ECU into diagnostic mode so I can read any stored DTCs? My check engine LED seems to be burnt out, as I've never seen it turn on (even during startup or a stall). I hope it doesn't require that LED (# flashes = DTC, etc)

[idlafie]

http://www.240sx.org/faq/index.html

Off the 240SX.Org website. Click on the FAQ button...the above link should already put you there though.

Once the page loads, look to the links on the left. Scroll down till you get to ECM...Reading Trouble Codes...DOHC

It should tell you how to put your ECU into Diagnostic Mode. If you still have any questions, then download a S13 FSM from here....
http://www.ffdet.com/members/rich/Nissan/nissan.htm
It will be the links on your right side...S13 KA24DE Manual....click & download.

All this info should get you going in the right direction. Hopefully it will help you solve your Bogging problem...

Anyhow...hope all this helps....Good luck!!!
ID
'95 SE

[MELLO*SOS]

Wow thanks for that link; somehow (?!) that got past me... I'll definitely put that to use tomorrow and find out what the ECU has to say. I have a feeling the check engine led is burnt out, so it's great that the ECU has it's own led...

Are there any serial or USB devices for our ECU?

Bump.. Anyone?

[MELLO*SOS]

Alright..

I still haven't pulled the codes, and the problem has got much more consistent. Every single morning it will have this feeling like it's only putting out 75% power on WOT only. I am starting to think the problem might be with condensation inside something, because it does this every morning until something heats up and/or dries out. Anyways, it will also do this sometimes when the engine is cool (sitting for a whIle).

I replaced the distributor cap and rotor this morning before work. I was (almost) certain that it would solve the problem, because I examined the cap when I installed the efans and both the cap and rotor were showing signs of wear. I cleaned them up as good as I could but knew they should be replaced... Anyway I replaced em both today, but sadly the problem is STILL there. I guess the good news is that now when the problem "goes away" the car pulls harder on the top end due to the new cap&rotor.

I am going to pull the codes and/or replace the plug wires next. Then most likely TPS, unless the codes tell me something useful (which I have a feeling they wont).

[Flybert]

WOT on a cold engine? Anyone else see a problem with this?

[MELLO*SOS]

Once my '88 ranger (2.9L V6) had a very similar bug... But it wasn't just on cold engine, it was WOT in general. I popped the hood and revved the motor, heard a clicking/arcing and saw that one of the plug wire boots was arcing to the exhaust manifold. Only at WOT did it have enough spark power to jump the gap, otherwise the engine ran fine.

My plugwires LOOK okay but who knows... I haven't replaced them since I bought the car, so who knows when they were last replaced. Those are next on the list

TIA

[MELLO*SOS]

Originally Posted by Flybert

WOT on a cold engine? Anyone else see a problem with this?

Let me clarify...

By "cold" I mean 5-10 minutes after the engine has been started and warmed up to normal operating temps. Go get in your car in the morning, fire it up and drive around your block a few times until your temp gauge is reading normal. Now go WOT in whatever gear you want -- you have power right? Well my car doesn't, it feels like it's only firing on 3 cylinders OR there is something retarding timing (or something else is fucked). It's scary when you're trying to merge into traffic and the car is falling on it's face instead of pulling with normal power. I shouldn't have to drive a car for 15-20 minutes before it operates correctly; the car didn't USE to work like that and my KA24DE powered Altima has no problems whatsoever like this.

If you don't have anything constructive to add, please don't post. I don't need that kind of shit in my thread, it doesn't help me solve my problems any quicker.

[MELLO*SOS]

Well I just got the car back from my mechanic, he too doesn't know what's going on. His best guess is a clogged cat. Go figure....

I'll buy a high flow from ebay and try that out. I hope it solves the problem. What fun is a car with coilovers, sways and powerbrace when it has no power

[idlafie]

From the folllowing website:
http://mysite.verizon.net/res0pda6/id40.html
Sometimes you can tell that a converter is clogged because you don't go any faster when you push the gas pedal. Also, there usually is a noticeable drop in gas mileage associated with a clogged catalytic converter. A partially clogged converter often acts like an engine governor, limiting the actual RPMs to a fast idle. A totally clogged converter causes the engine to quit after a few minutes because of all the increased exhaust back pressure.

Often, the only way to tell if a catalytic converter is malfunctioning (plugged) is to remove it and check the change in engine performance. When a clogged converter is suspected, some mechanics temporarily remove the O2 sensor from the exhaust pipe ahead of the catalytic converter and look for a change in performance.

Try that out & see if it works...

Another way to test to see if your cat is clogged, install a vacuum gauge at a port that has full vacuum, (at the carbon cannister or the throttle body..you'll have to check the FSM for the right spot). Fully warm up the motor; the reading at idle should be 18 - 20 InHg. Run the Rs up to 4,000; it should be at least 21 InHg. If the reading plummets way under 18 InHg, then there is a major exhaust restriction. I'm surprised your mechanic didn't do this...???

Anyhow, hope this helps....
ID

[idlafie]

Originally Posted by mello88

Let me clarify...

I shouldn't have to drive a car for 15-20 minutes before it operates correctly; the car didn't USE to work like that and my KA24DE powered Altima has no problems whatsoever like this.

D'OH!!!!.....forget my last post about the cat....if your car runs fine after 15-20 minutes of warming up, then it's NOT gonna be your cat that's causing a problem. If it WAS your cat that was bad, then your car would be running like crap ALL the time..and not when it's just cold.

It sounds like one of your soleniod valves is stuck open when it shouldn't be, allowing too much air back into the intake manifold past the MAF causing your car to bog. Only thing I can suggest is for you to crack open the FSM you downloaded, (I hope you did..see previous post), and check out the PCV valve, IACV system, & the EGR system. You're gonna have to follow the diagnostic procedures written in the FSM to track down your problem.

Just out of stupid curiosity, did you check your ECU for any Diagnostic Trouble Codes?? Did it kick any? If so, what were they??....If you haven't, then I suggest you do...you WON"T be able to figure out what your problem is till you do....

ID

[Dream240]

Okay, couple things, this is manual right? Then how about the clutch being bad? Or maybe there's a problem with the throttle body getting stuck? I know the problem goes away, but maybe that's just cause of the warm up. I know in my bro's integra he had a bog problem and when he replaced the engine and installed a new clutch and flywheel the old clutch came out in pieces (totally fubared). Just a suggestion.

Also if that's not it then what about the engine codes? That's a for sure check...I know it was already mentioned but I'm just emphasizing (spell it right?)

[MELLO*SOS]

Okay, thank you guys for the replies I am determined to keep working on this and posting until it's solved. Even if it means ripping this ka out dropping something else in :P

BTW the problem has got worse, now it doesn't even matter what temperature it is or how long you've been driving. Sometimes there is power, sometimes not... It really sucks, I mean our cars should be able to do a wicked burnout when it's wet outside, and when this problem is present the GD thing doesn't even have enough power to break the back loose on a wet corner

So, following my mechanics advice I picked up a high flow cat from PDM... It should be here next week sometime so next weekend you guys should see a post from me again. I'm not certain that it will solve the problem, actually I'm betting it's probably not but this is a good excuse to install upgrades on the car

I don't think it's clutch or throttle body. Clutch should mean that the engine revs clean but the power never makes it to the wheels... Throttle body, what could go wrong there, except bad TPS or something? I think it *COULD* be TPS..... But as said above, if cat doesn't fix it then I'm going to examine IAV.

I have yet to pull the codes :P I know I'm lazy... That will probably give more insight if the cat doesn't solve the problem. I really don't want to put much time or money into this engine, as I'm hoping to get it swapped out in the next 3-4 months. Right now I'm upgrading suspension, then brakes/wheels and trying to save for an engine swap, so I'm hesitant to spend much money on parts that won't transfer over after the swap.

[Dream240]

Originally Posted by mello88

I don't think it's clutch or throttle body. Clutch should mean that the engine revs clean but the power never makes it to the wheels... Throttle body, what could go wrong there, except bad TPS or something? I think it *COULD* be TPS..... But as said above, if cat doesn't fix it then I'm going to examine IAV.

Well, the throttle body could be sticking....just alot of carbon build up in there causing it to stick when trying WOT thus producing that lagging feeling. I've had this problem before with my old Accord. Just grab some throttle body cleaner and spray it down pretty good. Car should be off. make sure to open the throttle manually with your hand and spray some in there good. check to see if it's all black inside (probably is). Also spray the outside of the throttle body, get the whole area nice and wet, Let it settle for about a min. then start up the car (put the intake back on first). let it run the cleaner through for about 30 seconds, then shut it off, and repeat. Maybe 3 or four times. Then take the car out and see if it helped. Worth a try considering a can of cleaner costs 2.50 at autozone. Try it and see if that helps.

[nissandr1ft]

My car acted like that sort of, not just when cold. It was my MAFS, just cleaned the wires with carb spray.

[MELLO*SOS]

A buddy suggested MAF too, looks like a can of carb cleaner will do both the TB and the MAFS. Thank you guys for all these suggestions! I'm sure it's ONE of the things above, now it's just figuring out which :/

[MELLO*SOS]

Alright, this past weekend I installed a brand spankin new cat from PDM racing, only to find out -- guess what -- it's not the problem. I sort of knew that it wouldn't fix the problem, because the "OEM" cat looked clean inside & I was able to look through the honeycomb...

So now I'm trying to buy a MAF off a fellow zilvian, with hopes that it solves the problem. I'm still lazy & haven't pulled the codes.

[Dream240]

okay WTF...? Now I've got a bog. But it's only when I go to take off from a dead stop and only when I give it a little gas. I can't feel it when I push on the throttle normally or hard. i already cleaned out the throttle body with cleaner and added a can of Lucas fuel cleaner to my last fill up. No luck. before all this I installed my new high flow cat, which BTW didn't solve the problem either. I've got to fix a small leak in the cat-header bolt up but I'm sure that's not it. Next is the spark plugs and fuel filter, which aren't really that old. Maybe 60k miles...? hmm....

so now i'm jacking your thread

[idlafie]

Originally Posted by Dream240

okay WTF...? Now I've got a bog. But it's only when I go to take off from a dead stop and only when I give it a little gas.
.....Next is the spark plugs and fuel filter, which aren't really that old. Maybe 60k miles...? hmm....

so now i'm jacking your thread

Hey!!!...no jacking threads...start your own!!!

Hahaha...all kidding aside....check your throttle cables....they might have stretched & be slightly out of adjustment. If that doesn't do it, then check your ECU for codes. If none pop up, try cleaning out your PCV & EGR valves. Changing plugs & fuel filter should definitely help though....just make sure to run NGK plugs....I've heard too many people complain about other types of plugs.
Anyhow, hope this helps....
ID

[Dream240]

Yeah NGK iridiums are what I run. Throttle cable hmmm? didn't think of that. I'll check it this weekend. And the EGR and PCV maybe get to that too....got alot of stuff to do this weekend. Swap doors swap out brake hard lines and MC resevior, change out front pillow mounts, find suqeaking in rear shock assembly, whew....!!!!

Thanks for the tips.

[stinky_180]

how would you go about cleaning the EGR valve?

[ledzeppelin240]

Fully warm up the motor; the reading at idle should be 18 - 20 InHg. Run the Rs up to 4,000; it should be at least 21 InHg.

The vacuume should decrease the more the throttle plate is opened. This is due to less restriction. This is why diesels engines have a vacuum pump, due to there is no restrictions to create vacuum.

[eliterit]

i had horrible bogging when i swapped to a dohc motor.

what i did was i checked the ecu for codes

and it was throwing a code for a bad knock sensor

took my knock sensor out and it was badly cracked

that fixed it


try checking for codes