sr runs bad after warming up

[blacksilvia84]

I recently got my car back on the road after an accident. I have had this swap now for 3 years and all has been good. Now once my car heats up it begins to bog back fire and miss. Before that the car runs strong and above like 4000 rpms bogs and continues to then get worse. Also if the car is shut off for say 10 min then started back up the problem is 10 times worse. At idle the car is great but when given gas in neutral or when driving the problem occurs.

Changed
coolant temp sensor

Checked
tps
grounds
plugs white at tip with black charcoal at base
timing without light
o2 sensor wires

everything is how it was before the crash and now it runs like shit any sugestions of what else to check

[Sileighty_85]

Vaccume leak or MAF, check your alt, my buddy had an electric fan on his when he turned it on Volts dropped to 12 and it ran like shit until he turned the fan off

Was your car hit in the front? Did it have any engine (parts) damage?

[GRIPPY]

Is it possible some of your intercooler piping got knocked around causing a boost leak?

[blacksilvia84]

I have checked for boost leaks there are none no engine parts were damaged it didnt touch the motor I will check the alternator. I have an electric fan but it turns on at engine start. Either my mass air or alt. thanks for your help i will repost if any thing changes or doesnt.

[blacksilvia84]

Okay i have checked the mass air and alternator both are good. I have also taken my wiring harness back out and went over all the wiring and re wrapped it. The problem still exists. After it warms up the motor from start will run good then as the vaccum pressure builds up before boost it starts to bog out. I have done a leak down test and fixed the vaccume leaks i had. my problems seems to me to be a major computer issue. If anyone has had similar issues or knows of something else to try let me know. i have gone through and checked my coil packs as stated above but i wonder if under load one may be bad causing the boging and then back firing. not sure some more help would be appreciated before i just give up and sell this thing. I am tired of screwing around i need a car.

[blacksilvia84]

i also should add that the car idles great but as soon as any gas is given it starts the problem.

[Slippin'eight-nine]

My car did the same exact thing and it was the TPS. Swap it out with a good one and go from there..shoots

[fliprayzin240sx]

Which water temp sensor did you swap out? The 2 prong one on the left side not the single prong on the right side. If that wasnt it, my bet is on the o2. Running fine when cold, then bogging when warm is typically the ECU water temp sensor but can be caused too by a bad o2.

[xxxjovaxxx]

Did you look INSIDE the MAF? Make sure the tiny hairline filament is in tact. I had that problem once with my car and I had someone look at it and they didn't notice anything, but once you take a closer look you might see differently.

[Edgar]

sounds like you should buy a new maf

[blacksilvia84]

I swaped out the two prong temp sensor the one the ecu reads from. My O2 sensor is new it might have about 10 hrs on it and i have checked it out with a ohm meter and it was in range. my mass air was in range to but was dirty. i am just going to swap the mass air and go from there. I will try to find a ka24e one in a junk yard in the next day. Ill repost with any new info. Thanks guys.

[blacksilvia84]

ok today i recieved a mass air in the mail and it turned out to be the wrong fing one but i did find out that where my turbo inlet pipe bolts to the mass air wasnt tight so i put a new clamp on it. anyways my car ran alot better but i took notice to something new that could be my whole problem. my car is boosting up around 20 lbs. I watched my gauge closely and as i get up to speed it boost low then spikes to 20. I put the stock turbo back on and this still happened. anyone have any ideas why it would jump like that.

[mextaliano]

By buddy had the same problem, << fuel filter>>

[Mikester]

How's it goin? I'm new here, but know fliprayin 240SX from another forum. I had the exact same problem, changed everything known to man. As luck would have it, the last thnig I changed fixed the problem- exact same as your, ran fine cold but was exactly as you described when she warmed up. Your ECU is F$%^ed. If you got a buddy with an SR swap, swap with him/her and you'll most likely see the problem migrate to the othre car,. Perfect excuse to get yourself a power FC, that's what I did. Good luck- and sorry to jump right in... Is there a spot on this forum for introductions?

[Mikester]

Originally Posted by Edgar

sounds like you should buy a new maf

If his MAF was bad, it would run like crap cold or warm.

[blacksilvia84]

Cool i know someone i can swap an ecu with to check it out. Thanks alot and hopefully this works out. Ill repost again with updates.

[Mikester]

Also you may want to swap coil paks with yoiur bud as well. They can get flaky when they heat up once they reach the end of their life. Lastly, change out your plugs- unless you know when your last tune up was.

[fliprayzin240sx]

Umm, if its boosting pass 14 psi on the stock actuator, either its stuck or you forgot to hook up a vacuum line to it.

[Mikester]

Originally Posted by fliprayzin240sx

Umm, if its boosting pass 14 psi on the stock actuator, either its stuck or you forgot to hook up a vacuum line to it.

I agree Ray, either his vaccuum line to the actuator or the actuator itself is FUBAR. But I still don't think that's the main problem, but somethnig separate that obviously requires immediate attentionl.

[blacksilvia84]

Its been a while since my last post but i finally got a new ecu. Plugged it in and the same problems. The car ran great for about 20 min then started cutting out at any throttle position. The same old back firing and cutting out. I noticed my boost doesnt peak at 10psi more like around 20psi for some reason. Pulling my hair out trying to solve this anybody with other sugestions or similar problems

[fliprayzin240sx]

K water temp sensor, which one did you replace of the 2 sensors? Just gotta make sure you changed the correct one. 2 prong sensor (should be the one on the left if your looking at the 2). If you did change that one, did you use a brand new sensor? Look up the FSM on how to check it them and make sure theyre in spec.

Boost problem, did you replace the damn actuator yet? Double check the vacuum line to it, change the actuator. With the actuator off, make sure the flapper opens and not rust welded shut.

PS: Stop flogging the car with 20 psi boost spikes. Thatll be the fastest way for you to fix all your problems because you will be buying another set of engine when you blow this one...

[blacksilvia84]

I changed the 2 prong sensor with a new one. My actuator is good this problem is consistant between two turbos. I am wondering if the sensor where the vacuum line from the actuator goes to is bad. can i bypass this sensor?

[unicoladron]

run a vac line straight from your wastegate to your IC piping. if you are having this many problems for this long, bypass any other aftermarket stuff you have to take them out of the equation. have you checked your ecu to see if it is even throwing any codes?

[sblack13]

my friend had a problem, where his car would run perfect upon startup. Then when his car settled to normal operating temp. His car ran like shit, don't know why this was the problem. But it was his injector that was sticking.

He replaced coilpacks, headgasket, maf, etc etc.

[blacksilvia84]

okay the boosting problems are fixed vacuum line had a hole in it. The car ran great for a while and continued to just bog down. It is definately a power loss like bad grounds or maybe a coil pack. It has the power sometimes and boosts then cuts in and out. Other times as soon as the gas is pushed the car seems like its holding back. Plugs and fuel filter were just changed. Gonna check my timing again and mass air wiring maybe i missed bad wires or the timing is off just a little.