Problem with sr20det...need 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....

[navysnail]

im going to put this in the SR engine forum for you.

[highmilehatch]

Download the factory service manual and go through the procedures for checking/adjusting idle speed and ignition timing. It's in the EC section. You can find the download here: http://www.zeroyon.com

[Blown240sx]

Sweet smell and loss of power sounds bad like coolant burning. Are you getting smoke (white smoke) out of the exhuast? because a sweet smell and bad power loss is usually a sign of compression loss due to head gasket and burning coolant.

[Deadrodent]

would a blown headgasket aka loss of compression cause an increase in vacuum tho?

what i think really is the problem is my engine overheating because of lack of coolant via some coolant leak- that's most likely the cause of the sweet burning smell. i checked the radiator and there's absolutely no coolant in there...all i see are the cooling fins....

this could also mean that a small section - probably on only one cylinder of - headgasket blew indicated by the vacuum gauge

hopefully it's not that...

btw i put this topic in this forum because no one's really giving me any help or advice...the thread is pretty much dead...