sr20det-car bogs/jerks randomly

[speeddreamz]

Alright, well recently i've been noticing sometimes my car "stutters". (stuttering being sorta of like when you learned how to drive stick, it jerks violently when u don't clutch correctly). Sometimes I'll be going in reverse or just going straight slowly below 15 mph and it'll jerk/stutter. Also, when I boost sometimes it'll jerk and stutter. It will happen very randomly, there is no consistancy to the problem. Before it was happening on occasion, once-3 times a week but not real violent just felt like the fuel cut off or the air something similar to when there is a bad maf sensor. Also during the time when it seemed to be something minor, the idle was off, when i came to a stop it would almost die, goes 500rpm or lower sometimes it does sometimes it doesnt. So overal view of symptoms:

1. Idles horrible when out of gear, like when coming to a stop or when i put it in neutral, goes to 500rpms or less and then almost dies or dies sometimes.

2. Car jerks violently and sometimes less violently at random points, when going less than 15 mph sometimess more like 25 mph or 35. Doesn't matter whether i'm boosting, starting to boost, or not boosting at all. when it jerks, and i press on the gas, seems as if theres no gas/air being put into the car the throttle doesn't seem to do anything, similar to when theres a vacume leak. (but its inconsistant so i don't know why it would be a vacume leak)

3. My car seems to be running rich, I have fooled around with the s-afc but there doesn't seem to be any compromise. Car still jerks the same.

4. Problem seems to be totally intermitent...but occuring offten.

5. Car was running fine then i startd to notice the problem smaller and it seems as if it got worse

6. It seems like when i realy gun it I can still achieve good boost and power. (damn sti only beat me by half a car length)


I've changed my plugs very recently like less than a week ago
list of specs:
-sr20det redtop
-greddy fmic
-hks megaflow z32 with z32 maf of course
-s-afc to compensate and yes the settings are correct they've been working fine
-3 inch dp=>straightpipe=>n1 dual
-greddy profec-b but not turned on while the problem is occuring, i'm leaving it on stock boost
-greddy type s bov...I don't think its the bov opening.


I'm thinking..maybe
MAF-but its been working, and i had a bad one before and problems were consistant
BOV- has been working as well...but any thoughts?
Injectors- possibly clogged?
fuel filter- bad maybe?
fuel pressure regular is bent, but its been that way and its been fine...?

[silviasichigo]

Maybe..... hmmmm Check all of your intercooler piping all the points that are banded together and the hoses that band them together. I have another S-14 that the intercooler pipe popped off enough to make it have all the symptoms you have claimed. So that is a starting point.

[autobahNESSA]

Sounds like u got intercooler leak.

Drop down here in Milpitas sometime, try and figure out what it is.

[kazuo]

The richness is being caused by the BOV dude. The AFC should have a setting to compensate for it, I forget what its called. :P

Anywho, my guess is its some sort of vacuum/IC leak like Chris said... I say do the old "spray some soapy water" around all the lines and whatnot and see if you can find any leaks.

Where'd you take on a STi? The usual place?

laters

[speeddreamz]

yea thats a good idea chris how about this saturday, i need to visit a friend thats in the hospital in fremont, and i need to return your fsm.

[autobahNESSA]

Ya just give me a call. I will be insatlling my lsd in the morning, so just drop on down in the afternoon.

[lok]

So was it ever running fine?

Mine was having this problem too. One the cold side the ic was loose due to a drifting accident, and got worse slowly so I didnt notice it at first. I replaced the hose clamp and everything was fine.

My friend is running almost the same setup as you, and turns out his timing was way off. We set it close to mine and his ran great after that.

We tried swapping mafs(he is running z32 w/ safc), coilpacks. His timing light from walmart made my timing look like it was very retarded, but my car runs great. His so far advanced his was fowling his plugs every week.

Hope that helps,

[wylin]

I had a similar problem last weekend.

it turned out to be 2 specific culprits

1. a leak in the intercooler/ piping system my couplings had gotten loose over time. Tightened them and it got alot better but still ran funny.

2. dirt/grease on my air flow meters plug/ pins/ and near the hot wire of the maf, which i blew out using automotice electrical contact cleaner (autozone)...then waited couple hours to let it dry 100%

Now my car runs perfectly fine.

[180sxjdm]

:boink: Hey Im having the same problem right now with my SR. I was thinking it was the timing but the timing is just fine. Then I checked spark plugs and they are ok. hopefully its just a boost leak.