motor will not idle

[rocket455]

so i just built this motor and dropped it in. it starts up but will not stay at idle. the motor will not stay alive unless i give it gas. and it does not sound like a clean smooth running motor unless it take it up to around 4k rpm. and when you would think "ok that hiccup is gone, i can let the R's back down and it should stay alive"......nope. dies. now i have the shonut fuel pressure regulator on here. if thats not set right would that be the culprit? any input is welcome and i thank you ahead of time for it.

 

[shomethe$$$]

whats the fuel pressure?

 

[LOUDSHO92]

Check and make sure that the spark plugs are hooked up correctly. Some of the manuals are not correct. Grounding strap hooked up?

 

[rocket455]

i had used this diagram http://z.about.com/d/autorepair/1/0/s/c/92714663.gif

im pretty sure i had hooked up every grounding strap, but just to make sure, where is it located?

and how do you check the fuel pressure? i had read the tech notes on shonut, but it didnt make too much sense to me

 

[SuperHO]

The strap goes from the rear head by the diagnostic port to the firewall by the hood strut. Can't miss it if it's there.

You can check fuel pressure via the Schrader valve popping up in the middle of the intake runners. Should be running around 50psi at idle.


And correct me if I'm wrong, but is plug #5 and #4 bass-ackwards on the coil pack in the diagram? Shouldn't 5 be on the bottom left instead of 4?

 

[rocket455]

ok i found the ground strap. it was not connected. but it doesnt make too much sense to me. it goes from the firewall to the intake on my friends car.....why would you be grounding the ALUMINUM intake?

 

[SuperHO]

You mean aluminum doesn't conduct electricity? Tell that to a ladder company...

 

[rocket455]

so grounding to the intake will make a sufficient ground?

 

[LOUDSHO92]

Yes this will help out a lot.

 

[rocket455]

ok, and is the diagram right or is superho right about the coil pack?

 

[LOUDSHO92]

The diagram is correct.

 

[rocket455]

ok, i got it running at a constant rpm. 1500. vacuum leaks? any ideas?

 

[LOUDSHO92]

Was the idle screw screwed with? Do you have an LPM?

You might want to reset the idle too and that might help. Since the computer has been drained probably you can reset it and might bring it back to normal.

 

[rocket455]

well, now i had just installed the stock fuel regulator. ill put in the shonut unit when i get closer to my setup. now it starts up and idles at 1500 and i give it a little rev and it settles down to about 800-900. and yes i have an lpm. since its been so long would i have to reprogram it for my cams and other mods?

 

[LOUDSHO92]

I would first reset the idle. I believe SHOtimes has a how too. Your computer needs to relearn the idle. I would probably do it without the LPM. Once you put the LPM in it should take care of the mods.

 

[rocket455]

ok everything is going smooooth. then suddenly, the motor starts to studder and drop r's down to about 500 and shake, then you can hear the air intake cut out then the motor dies suddenly after.....what gives?

 

[SHOZ123]

Sounds like the IAC can't keep up.

Try whacking it with a screwdriver handle when it's stumbling and see if the idle improves.

 

[LOUDSHO92]

Might need to clean out the IAC. I do have a spare one.

 

[Storm-Chaser]

Have you pulled the codes yet . . . ?

 

[Aleffewmo]

Sounds like the IAC can't keep up.

Try whacking it with a screwdriver handle when it's stumbling and see if the idle improves.

x2

Same thing was happening to me, and JoesSHO wacked my IAC with a screwdriver handle a couple of times and it started and ran fine.