2G Stumbling from first 2 Stop Signs... Here We Go Again...

[pointblank9957]

well, everyday i drive my car (cold engine) the 1st 2 stop signs i come to and take off from, i ALWAYS get stumbling/misfires, sometimes to the point where the engine is not running for 1-2 seconds.

2 things i have done that could affect it:
EGR Delete, ever since i did this, torque/response perked up
Oil Catch Can: the clear line has collapsed (b/t PCV and OCC)

think it could be either of these? i have replaced a couple other parts like the air filter and a turbo timer but none could've caused this...

 

[Afizzle]

Sounds like a big boost leak.

Boost Leak Testing - YouTube

 

[pointblank9957]

Sounds like a big boost leak.

Boost Leak Testing - YouTube

it's not a boost leak

 

[mitsubishikid]

The engine is most likely missing one of these fuel,spark, or air.

Did you install new spark plugs, and inspect the wires, could be an ignition system issue.

it also could be clogged or worn injectors, fuel lines,filter fuel pump, fpr.
also if the issue goes away in certain conditions it may mean a part is almost about to go bad ( if it's not already bad)
o2 sensor.
c.a.s
transistor
coil
I shouldn't need to state the obvious, but double check all the vacuum lines and recent work you did.

I hope you get the issues sorted out, I had something like this happen to my dd, I eventually sorted it all out and I'm still in that ''should I trust it again'' mentality
let us know what you find.

 

[pointblank9957]

The engine is most likely missing one of these fuel,spark, or air.

Did you install new spark plugs, and inspect the wires, could be an ignition system issue.

it also could be clogged or worn injectors, fuel lines,filter fuel pump, fpr.
also if the issue goes away in certain conditions it may mean a part is almost about to go bad ( if it's not already bad)
o2 sensor.
c.a.s
transistor
coil
I shouldn't need to state the obvious, but double check all the vacuum lines and recent work you did.

I hope you get the issues sorted out, I had something like this happen to my dd, I eventually sorted it all out and I'm still in that ''should I trust it again'' mentality
let us know what you find.

if it was an injector, it would be missing all the time, i just had that problem on my 4Runner. i have a new set of SFI 660's yet so they'll be going in, FP is a couple months old Walbro 190. maybe the o2 sensor but thats pretty new too.. all the plug wires read b/t 5k-8kohm which is right, i'll throw in some new sparkplugs and see if thats it, NGK 4644's

 

[USAF 98 GSX]

How about your tune? The fact you car won't be in closed loop for the first few mins might affect it. Too much air, too much fuel? Idle tune and cruise tune off a little. If you have already checked all of the previously stated possibilities the your tune would be my next guess.

 

[dot45]

Have you looked at a log of what is going on when it dies?

 

[pointblank9957]

How about your tune? The fact you car won't be in closed loop for the first few mins might affect it. Too much air, too much fuel? Idle tune and cruise tune off a little. If you have already checked all of the previously stated possibilities the your tune would be my next guess.

the AF ratio on my Turbo timer goes max low 10:1 when it happens, too much fuel

 

[USAF 98 GSX]

You said the AFR on your turbo timer hits max low, what about a stand alone W/B? IIRC Turbo timers that have the AFR feature use a narrowband sensor. I'm not saying that its not extremely rich, but an exact AFR would be nice to know. Also are you sure your idle tune is correct. Remember idle tune is accurate AFTER it's in closed loop. I think it's after 180* coolant temp.

 

[pointblank9957]

You said the AFR on your turbo timer hits max low, what about a stand alone W/B? IIRC Turbo timers that have the AFR feature use a narrowband sensor. I'm not saying that its not extremely rich, but an exact AFR would be nice to know. Also are you sure your idle tune is correct. Remember idle tune is accurate AFTER it's in closed loop. I think it's after 180* coolant temp.

narrows are just slower arent they? like A LOT slower

 

[USAF 98 GSX]

Narrowband are less accurate. 0-1 volt spectrum whereas Widebands are more accurate with 0-5 volts. Basically narrowband sensors estimate AFR. Ive seen narrowband sensors 1-2 full AFR points off sometimes.

What's your airflow per rev value in closed loop? Combined Fuel Trim value in closed loop?

 

[pointblank9957]

Have you looked at a log of what is going on when it dies?

i'll take a log tomorrow with my OP2

 

[PotatoFlakeSTi]

You've verified that it's not a boost leak by doing a boost leak test right?

I get that you wrote that it's not a boost leak, but it's probably a boost leak.

 

[USAF 98 GSX]

You've verified that it's not a boost leak by doing a boost leak test right?

I get that you wrote that it's not a boost leak, but it's probably a boost leak.

I'd believe it might be a boost leak if it wasn't only for the first few mins of driving. He'd have problems driving all the time otherwise

 

[pointblank9957]

I'd believe it might be a boost leak if it wasn't only for the first few mins of driving. He'd have problems driving all the time otherwise

exactly. its for the first about 45 seconds from a stop, then it behaves

 

[Afizzle]

Okay, before you boost leak test no one is going to care. I will tell you like someone told me, a boost leak will make these cars not make sense.

Sure a boost leak may never leave any trace that youre losing air but you could have a bad biss o-ring or a missing or cracked lower-injector seal. Boost leaks in certain places will make it look like something else.

Bottom line is your intake system has to be tight before you can start looking somewhere else. Its the cheapest and easiest process of all and it will have to be done eventually if you ever want to make real power.

20$ for a boost leak tester that you can make in 30 minutes at home, a compressor, and a bottle of soapy water. It takes an hour max if youre taking your time and will save you time and money down the road.

Your problem sounds like a dsm running dsmlink with shitty combinedft's (shitty tune) which means youre either running rich or lean which may very well be caused by a boost leak.

 

[pointblank9957]

Okay, before you boost leak test no one is going to care. I will tell you like someone told me, a boost leak will make these cars not make sense.

Sure a boost leak may never leave any trace that youre losing air but you could have a bad biss o-ring or a missing or cracked lower-injector seal. Boost leaks in certain places will make it look like something else.

Bottom line is your intake system has to be tight before you can start looking somewhere else. Its the cheapest and easiest process of all and it will have to be done eventually if you ever want to make real power.

20$ for a boost leak tester that you can make in 30 minutes at home, a compressor, and a bottle of soapy water. It takes an hour max if youre taking your time and will save you time and money down the road.

Your problem sounds like a dsm running dsmlink with shitty combinedft's (shitty tune) which means youre either running rich or lean which may very well be caused by a boost leak.

its a stock GST tune w/ rescaled injectors and ECUFlash. i am willing to bet my next paycheck its not a boost leak.