Causes of Bogging after Operating Temp

[Matt_240]

My car bogs. bad. around after 15-20mins of driving and car reaches operating temperature. buckles, chokes, fuel cuts, you name it, it does it.

i know there is closed loop/open loop. what are the components that change after closed loop?

i know the o2 sensor is one. anything else?

Any help is appreciated.

[Matt_240]

any advise would help. thanks

[Al_S14]

waht year is your car? does power suddenly drop off when you haul ass then return moment later and jsut pick back up as if nothing happend?

it seems i got same problem but nobody seems to know the fix

[IvanAtSPRacing]

Your car will run on an open loop program untill it reaches normal operating tempature. It switches to closed loop at this point. It relies on feedback from the O2 sensor at this time. If the O2 sensor is not reading right, then your car wont run right. Does your car run ok at WOT once up to temp? At WOT the ECU switches back to open loop and doesnt use the O2 for adjustments.

[sciamop]

It takes 20 minutes to reach operating temp in Hawaii? IIRC, you can just unplug the 02 sensor and the car will be in open loop mode = bad gas mileage but better than junk signal.

My car acts this way sometimes too. I'll be troubleshooting it in the spring... I'll post my findings.

Todd
93 Coupe
91 SE-R

[Matt_240]

i know the o2 sensor isnt' the only thing. the coolant temp, and other things are relied upon in closed loop as well.

when it starts bogging like that, i will disconnect my 02 sensor and see if that works. in the meantime im gonna change my ecu and coolant temp sensoor.

any other suggestions as to what it could be? thanks for the help guys. im sure lots of people have this same problem.

[KOUKI KA-T]

Guess I'll ask the obvious..... throwing any codes?
I had a similar problem once, got hot enough in the engine bay to melt the 02 sensor plug and cause a short. Threw the entire ECU program out of wack and the car would shutdown randomly, sometimes not idle etc. Had to go through the all the fuses and replace the ones that went and it was that simple. Had me stumped for a while as I didn't notice the plug had been melted on the side...

[Matt_240]

Originally Posted by KOUKI KA-T

Guess I'll ask the obvious..... throwing any codes?
I had a similar problem once, got hot enough in the engine bay to melt the 02 sensor plug and cause a short. Threw the entire ECU program out of wack and the car would shutdown randomly, sometimes not idle etc. Had to go through the all the fuses and replace the ones that went and it was that simple. Had me stumped for a while as I didn't notice the plug had been melted on the side...

so you just replaced the fuses and o2 sensor??

[KOUKI KA-T]

Originally Posted by Matt_240

so you just replaced the fuses and o2 sensor??

02 was fine, just had to cut off the melted plugs and solder the wires, then replace a couple fuses that blew from it all.
So are you throwing any codes???

[Matt_240]

code 55. crap.

i guess i gotta check all the wiring and sensors. =P

[KOUKI KA-T]

Originally Posted by Matt_240

code 55. crap.

i guess i gotta check all the wiring and sensors. =P

Ha, no malfunction.
Definitley not the same problem as me then, mine threw more than 12 different codes (I just stopped counting after it flashed the 12th one and checked all the fuses and found my problem.)

[Al_S14]

o this is driving me insane! i've replaced every part of ignition system except for the distributor coil...anyone have this part fail? and since i am not getting any codes i am like a blind man trying to shop.

i dont see how this could be a misfire since CEL never comes on and this happens to me on every dive cyle(since my driving style is umm well suicidal).

can knock sensor be faulty and fuck with my timing thinking engine is about to blow. same as matt this happens only when car is hot (or when it's cold and it happens its not nearly as severe as when hot)

[KOUKI KA-T]

Originally Posted by Al_S14

o this is driving me insane! i've replaced every part of ignition system except for the distributor coil...anyone have this part fail? and since i am not getting any codes i am like a blind man trying to shop.

i dont see how this could be a misfire since CEL never comes on and this happens to me on every dive cyle(since my driving style is umm well suicidal).

can knock sensor be faulty and fuck with my timing thinking engine is about to blow. same as matt this happens only when car is hot (or when it's cold and it happens its not nearly as severe as when hot)

How is the idle? Does it seem like the car runs on 3 cylinders?

[Matt_240]

idle is perfect on my car. just when hot, extreme bogging. sucks

i have a feeling it has something to do with our wiring harness or sensors. either ground is faulty somewhere, sensor is going bad, or just old harness crapping out.

keep the suggestions coming. we need all the help we can get cause no one seems to know whats wrong. thanks!

[Yuri]

Wow, my car has the exact same problem, but it is totally random, like sometimes it will happen right after startup, and then it will come and go. I spoke with someone at Bulletproof, and they said it's probably the airflow meter. The Nissan dealer agreed with this. I'll wait to see if the O2 sensor fixes your problem, so keep us up to date..

[Al_S14]

car idles likr shit.....well its smooth but whole car vibrates(um thats almost an oxymoron but you know what i mean) like it misses.
doubt its maf... usually it either works or doesnt. if maf dont work car will not run at all. plus you got to remember dealer will tell you anything to get you in the shop and paying the diag fee only then they will focus on finding the real problem. its always "its proalby your XXX but i got to look at it first" .
cant be teh 02 either(if were all talking about same problem) it just dont have this much effect on performance at WOT...if any at all
i've come to a conclusion it's the coil that cant put out at high load which make sence. as car heats up resistance increases making things even worse preventing faulty coil to produce enough spark...and it misses. shoping for a used distributor now ill let you know how it goes

[Matt_240]

distributor? i dont think thats it.

Im borrowing parts tomorrow... coolant temp sensor, o2 sensor, and throttle position sensor. i'll let you guys know how that goes. if these are not it, im almost sure that its the harness.. maybe bad ground somewhere. we'll see..

[idlafie]

Originally Posted by Matt_240

My car bogs. bad. around after 15-20mins of driving and car reaches operating temperature. buckles, chokes, fuel cuts, you name it, it does it.

i know there is closed loop/open loop. what are the components that change after closed loop?

i know the o2 sensor is one. anything else?

Any help is appreciated.

When your bogging problem occurs, does it occur during acceleration and braking? Do your dash lights come on & the engine dies on you or seems like it's gonna die on you??

If you are getting weird symptoms like the above, check the ground connections on the rear driverside portion of the engine block right above the O2 sensor. Nissan in their ultimate wisedom grounds several components at that point - fuel pump/distributor coil/etc. If one of those ground wires goes bad, (and it can, remember it's right above the exhaust manifold where it gets really hot - heat & wires are not a good combination - wire connections get brittle & break), then you could have an intermittent short in one of your ground wires. Easiest way to fix it is find a new grounding grommet & cut the existing one off & solder all the ground wires to your new grommet. That should fix your bogging problems.
Anyhow, hope this helps...
ID

[Matt_240]

Originally Posted by idlafie

When your bogging problem occurs, does it occur during acceleration and braking? Do your dash lights come on & the engine dies on you or seems like it's gonna die on you??

If you are getting weird symptoms like the above, check the ground connections on the rear driverside portion of the engine block right above the O2 sensor. Nissan in their ultimate wisedom grounds several components at that point - fuel pump/distributor coil/etc. If one of those ground wires goes bad, (and it can, remember it's right above the exhaust manifold where it gets really hot - heat & wires are not a good combination - wire connections get brittle & break), then you could have an intermittent short in one of your ground wires. Easiest way to fix it is find a new grounding grommet & cut the existing one off & solder all the ground wires to your new grommet. That should fix your bogging problems.
Anyhow, hope this helps...
ID

it only occurs during accelration. and it seems like its gonna die cause it jerks so much but if i accelrate through it, its ok sometimes. yeah, the ground connections by the manifold are definitely a possibility. where should i cut the ground wires from though?

thanks for the help

[KOUKI KA-T]

Originally Posted by Al_S14

car idles likr shit.....well its smooth but whole car vibrates(um thats almost an oxymoron but you know what i mean) like it misses.
doubt its maf... usually it either works or doesnt. if maf dont work car will not run at all. plus you got to remember dealer will tell you anything to get you in the shop and paying the diag fee only then they will focus on finding the real problem. its always "its proalby your XXX but i got to look at it first" .
cant be teh 02 either(if were all talking about same problem) it just dont have this much effect on performance at WOT...if any at all
i've come to a conclusion it's the coil that cant put out at high load which make sence. as car heats up resistance increases making things even worse preventing faulty coil to produce enough spark...and it misses. shoping for a used distributor now ill let you know how it goes

another thing that causes the shitty idle and bogging like it's running on 3 cylinders is a torn lower o-ring on the injectors. If there's a slight tear or nick in the o-ring fuel just dumps on through and can be so bad it drowns the spark causing it to bog like all hell.
start your car and let it idle. unplug one injector at a time and see if there's one you unplug that has no effect on idle. I think yours is a fuel/spark problem.

[Al_S14]

Originally Posted by Matt_240

distributor? i dont think thats it.

Im borrowing parts tomorrow... coolant temp sensor, o2 sensor, and throttle position sensor. i'll let you guys know how that goes. if these are not it, im almost sure that its the harness.. maybe bad ground somewhere. we'll see..

coil which is built in to the distributor not the distributor itself

[Matt_240]

Originally Posted by Al_S14

coil which is built in to the distributor not the distributor itself

ok. let me know if that works.

i put in a new cts and o2 sensor. but im in denial of driving it. haha. cause i doubt it fixed the problem. i'll let you guys know tomorrow. but if it is the distributor then that would be an easy fix.

[Prelude Guy]

I have the same problem with my 89 240

Changed:
O2 sensor
fuel filter
Plugs
Wires
dist. cap
rotor
CTS
new ground wire
new catalytic converter
new fuel pump
new TPS
checked the MAF (fine)
checked the ignition coil (fine)
new oil
injector cleaner
new alternator (with my old one, the batt. light would light up a little)

STILL bogging.

Let me know what you find out.

I am going to try swapping out my ECU with my friend's and clean the EGR valve. Other than that, I will have to to take it to a shop. I've been fighting this for 5 months now.

[Matt_240]

well, if changing the cts and o2 sensor doesnt work out for me, im gonna straight change the whole wire harness.

[Al_S14]

Prelude Guy, how did you check your coil? just check for resistance ... was it when hot or cold ? if its an intermittent problem with a coil it will test fine everytime except for that instance when car bogs(but that cant be check while driving ...)

[monkeyspeed]

check the timing

[Matt_240]

change the cts and o2. no change.

gonna replace part of the harness next. also, switch out distributors. will update.

[Yuri]

What kind of engines does everyone have? Mine is an SR that I'm experiancing the problem with. I had the wiring harness thoroughly checked and repaired, replaced a bad coil, and replaced a clogged cat. It still bogs...

[Matt_240]

ok, sent the car to an electrical shop to redo part of the harness.

will update.

[idlafie]

Originally Posted by Matt_240

it only occurs during accelration. and it seems like its gonna die cause it jerks so much but if i accelrate through it, its ok sometimes. yeah, the ground connections by the manifold are definitely a possibility. where should i cut the ground wires from though?

thanks for the help

Your problem occurs ONLY during acceleration?? Could it be possible that your car is NOT getting enough fuel or air mixture??. Could be a screwed up fuel pressure regulator OR vacuum line running to it or a lagging fuel pump. Maybe even PCV valve..who knows...
What RPM band does your problem seem most apparent? Does it clear up when you go to Wide Open Throttle? Your bogging could be due to a stuck EGR valve or carbon buildup in your EGR valve or a clogged line that runs behind the EGR to the exhaust manifold.
Troubleshooting this problem is gonna be a royal BEOYTCH!!...Find yourself someone extremely knowledgeable in tuning 240's...you're gonna need their expertise!!
Anyhow, hope this helps..
ID