Problem with s13 blacktop sr20det...help fast so i don't blow my motor!!!

[Deadrodent]

hey everyone...my sr20det has been acting messed up lately...let me outline the problem for you....
At first startup the engine idles normally - tho a bit high - ~1500rpm or so....

^normally it eventually kicks down to about 800-900 - and is relatively steady...sometimes it waivers but not by more than 200 rpm....

Here's where it starts getting interesting....after startup - maybe 3-4 minutes after the engine progressively idles higher until it reaches about 1800-2000 rpm....at which it will be steady...until.....


the idle starts fluctuating in a clean repetetive pattern...it revs from about 1400-1900rpm cleanly and repetetively every 2-3 seconds...it's as if i'm pressing the gas then letting off...etc...

i hooked up a vac gauge and the gauge reads 20-22 at startup...20-22 at high idle...and then the gauge needle follows the engine's rev pattern when the idle starts fluctuating...it actually jumps up from 22-25 and follows the exact same pattern at the exact same time....

i'm not too familiar with reading vac gauges but i know it's either an ignition problem, timing, or a bad valve/s....

i also can smell a sweet burning smell and there is a significant power loss - BUT i'm still boosting around 7-8 psi...

i also unplugged the maf and the car ran like crap so the maf is good...
i then unplugged the tps and the car searched for an idle....and didn't really have the problem....

at shutdown i can hear one single tap with an accompaning squeek....

i'm thinking i might have a stuck valve - worst case scenario?

sorry for the long post but i'm trying to be as thorough as possible...this car is my daily and i have spent extensive time and money on my baby....this pretty much covers everything i could think of at the moment...i'm all stressed out so i might have forgotten something....hope this can provide u guys with an accurate description of my problem....

[RedSuns]

have you checked for any boost/vaccum leaks?

[McRussellPants]

sweet burning smell says headgasket.
I'd give the Idle Air Control Valve a good cleaning, it could be that.
or it could be a shitty ground somewhere.

[Deadrodent]

there's no smoke coming out of the exhaust indicating a blown headgasket but ofcourse i haven't checked compression yet...

haven't checked for vac leaks but my vac gauge isn't indicating a leak...it's around 20-22 everytime....

what are common places for vac leaks? and would a vacuum leak cause such an idle anyway? isn't it usually a drop in vacuum?

how would i go about checking for a bad ground/grounds?

[Deadrodent]

when i pop my radiator cap should i visually see coolant? all i see are the cooling fins....maybe my car's overheating and my temp gauge isn't reading it?

my temp gauge has been all fucked up since i swapped in the motor...it won't register anything after long trips and then sometimes it will...it's hit or miss....

[koukidough]

you should see coolant in the radiator. You said you seen only the cooling fins under the cap...I'm pretty sure you are leaking coolant somewhere. Sweet smell indicates burning coolant. I'd check to make sure all coolant hoses are properly secure and also visually check them to see any signs of leaks. Check headgasket afterwards.

[Deadrodent]

is there an easy way to check the headgasket without removing the whole fucking head? i def want to check it cuz i don't want to just dump coolant in and drive off thinking my problem is solved....

[street_white180sx]

aight 1st tings if i remember from a past experience when an sr overheats the idle does shoot up to almost 2000 rpms. also i wud also consider cleanin out your iacv. and like everyone said usually that sweet smell indicates a leak. if u have access to a coolant system leak tester use it ,if not let the car cool down real nice and start then go ahead and start it up and begin searching searching. But i definately believe u have a coolant leak. Also i wud check on y your gauge isnt reading you overheating if that is the case.

[Deadrodent]

how much does a coolant leak tester run? do i need compressed air like a cylinder leakdown test? anyone else have experience with overheating their sr?

[aznpoopy]

easy to check

leakdown test, 4 tests, 1 per cylinder

open the radiator cap and fill it. leave it open.
close the valves for the cylinder you're testing
compressed air into the cylinder
bubbles/coolant spray out the rad = you have a bad headgasket

here's a link
http://www.dsmgrrrl.com/FAQs/leakdown.htm

[Deadrodent]

ahhh a cyl leakdown test....i don't have access to compressed air and i don't have the leakdown gauge....if i had a bad headgasket it would have a definite effect on compression, correct?

[s13_gearhead]

ahhh a cyl leakdown test....i don't have access to compressed air and i don't have the leakdown gauge....if i had a bad headgasket it would have a definite effect on compression, correct?

That depends. More naturally the prior is a symptom of the latter, not vice versa. What I mean is that crappy compression is more often a symptom of a blown head gasket (especially if two cylinders adjacent to each other are low) than a blown head gasket will mean bad compression. That might not make sense, but I'm having trouble wording it. Head gaskets can blow in a lot of different places. You can get oil/coolant passages mixing, coolant leaking into your combustion chambers, oil leaking there, etc... or a mix of all. But very typically a good rule of thumb is that YES, if compression is shit on two cylinders right next to each other, your gasket is fucked.