Sr won't idle

[NoStickers]

When I try to start my engine, it revs to 1500rpm for 5-8sec then drops to 500rpm and bounces there for a few seconds then stalls out. I can't keep the engine running by opening the throttle when the rpm falls to try and idle. The throttle does work when it shoots to 1500rpm on start up but regardless of the rpm it still falls to 500 after 5-8 sec and stalls out.

The engine did run in its stock form perfectly for about a year and a half. I upgraded the turbo/exhaust, new valve springs, valve guides, valve job, 264 w/ 11.5mm lift hks cams, new mafs, enthalpy ecu tune and 850cc injectors.

Please help me I'm stumped.

[karmakaze]

When I try to start my engine, it revs to 1500rpm for 5-8sec then drops to 500rpm and bounces there for a few seconds then stalls out. I can't keep the engine running by opening the throttle when the rpm falls to try and idle. The throttle does work when it shoots to 1500rpm on start up but regardless of the rpm it still falls to 500 after 5-8 sec and stalls out.

The engine did run in its stock form perfectly for about a year and a half. I upgraded the turbo/exhaust, new valve springs, valve guides, valve job, 264 w/ 11.5mm lift hks cams, new mafs, enthalpy ecu tune and 850cc injectors.

Please help me I'm stumped.

you may need to turn up you IACV.

[NoStickers]

did that and it does the same thing

[karmakaze]

fuel pressure? and are you sure your timing is right? i had a similar problem and it turned out i had my CAS aligned to the wrong mark.

[NoStickers]

i hear the fuel pump come on but once i start it i can't tell anymore b/c of the exhaust. im getting a fuel pressure gauge soon.

i dont think its the timing b/c for the first 6-8 seconds after it starts up you can play with the throttle and it sounds really nice. ok lets say it is wrong how can i check it?

[180fan]

first check vac, then iacv, then mafs wiring.

[Hijacker]

it sounds like a timing issue to me.

Since you aren't sure how to set the timing, I'm going to assume that someone else did it for you? Also, do the new gears have adjustability, or did you stick with stock cam gears?

From the sounds of it, you're off on timing somewhere. I'm not sure if 264s with that kind of lift can get off a tooth and not cause damage to the valves/pistons, but I know stock can get off a tooth and be fine, it just plays havic on idle.

zerothread?id=28535thanks to speed for an excellent explanation on this one. Funny how 5-10 minutes of searching can turn up results

[NoStickers]

Actually, I did everything but the valve job myself.

They are the stock cam sprockets.

SR20DET S13/S14 Timing:Camshafts/sprockets should not be set at 0 degrees.The intake will be set at 10'o clock, the exhaust will be set at 12'o clock, when the crank sprocket is at TDC. TDC is the second mark from the left out of the little notches. However look in the piston to make sure its really at the top of the stroke and not the bottom. Also do not remover the sprockets from the chain before turning the pistons or you will most likely cause damage to the pistons and or valves.

CAS setting: You will notice that there are three dots on the CAS gear. The outer ones are mating marks, the yellow middle one is the pilot mark. Match the mating mark on the outside (away from the engine) with the yellow mark so that they are aligned. Now (while at TDC) slide the CAS back in, you will see the gear turn. When the CAS has been slid all the way in, the two outer mating marks will be aligned and the yellow paint mark will have turned in, towards the engine. Finally bolt the CAS back on the engine with the two 13mm(14mm?) bolts, do not torque tightly. Put the rest of the engine together. Start the car, it may run bad, but rotate the CAS back and forth until you find the proper ignition timing. Then proceed to torque the bolts to 9-12 ftlbs.

Picture of the proper camshaft setting at TDC http://sr20.hybrids.jp/install...3.jpgS14 SR20DET FSM http://www.zilvia.net/faqs/faqs.asp Go to pages 55-68 for the Nissan instructions.This website has good instructions, follow their suggestions on camshaft sprocket retention too, http://sr20.hybrids.jp/install....html

I did all this but move around the cas which I didn't think could be that far off as to not allow me to keep the engine running by using the throttle.

Maybe I didn't explain the problem where the thottle doesn't work after 5-8 seconds of running nicely and functioning. I can drop the gas pedal to the floor after those 5-8sec and it does nothing. But during those 5-8sec it works fine and the engine revs up nicely.

[NoStickers]

first check vac, then iacv, then mafs wiring.

I really doubt its vac or mafs b/c I can rev passed 2500 for the first 5-8 sec it starts up and it would rev nicely too. I also disconnected the mafs and it would give the typical symptoms of a bad mafs or vac leak. And even with a bad mafs or vac leak I'd be able to keep the engine running but I can't.

I messed with the iacv which did nothing. So I tried messing with the set screw on the throttle body and that would make the engine go to a higher rpm on the first 5-8sec when it started up but then would still drop to 500 rpm then stall.

[drifter_for_life06]

hearing the fuel pump come on, doesnt mean you're getting the right fuel pressure

[NoStickers]

Yes, you are correct. I plan to get a fuel pressure gauge next week.

[NoStickers]

It was the mafs. I got another to try it out and it worked. Thanks for all the help everyone. Those are just some wierd symptoms for a bad mafs though.