NEW 347 WON'T IDLE

Zeffer

Member
May 27, 2020
41
13
18
Mission B.C.
Hey guys, I have recently built a 347 for my 89 Hatch. I will give you some specs. It's a Scat rotating assembly, PW aluminum heads, 175cc intake, 2.02/1.60 valves, 61cc chamber, Comp cam XE274HR, Edelbrock performer rpm intake, BBK 70mm TB and egr spacer (deleted egr valve), 24 lb Ford motorsport injectors, Pro M mass air sensor matched for injectors and BBK fenderwell cold air intake, MSD pro billet distributor with matching tfi module. All engine sensors are new, coolant, iat, tps etc. I managed to get it running and it surged aggressively, played with idle speed and managed to get it to idle long enough to set timing at 12 deg. I have gone through the checklist and I have even built a smoke tester to check for vacuum leaks, the only thing that showed up was a minor leak at my tb through the tps sensor and throttle shaft below. Now it won't idle at all, I can manipulate the throttle pedal to get it to come to near a reasonable idle but won't stay. I've ordered a new tb as the one that's leaking, I bought used.
Any help would be much appreciated!! I'm frustrated to the point of selling the whole top end and installing a Holley Sniper system
 

Zeffer

Member
May 27, 2020
41
13
18
Mission B.C.
Stock computer
I know with my cam it will need to idle higher than normal, but it flat out won't.
One thing I noticed was when it was running and i unplugged the IAC it instantly died.
How do I pull codes without a scan tool and where do i find what the blink codes mean?
I'm stuck for a few days until my new TB arrives.
I really appreciate your guys help!!
 

General karthief

wonder how much it would cost to ship you a pair
Mod Dude
Aug 25, 2016
23,396
8,615
203
polk county florida
I think there is a download for the codes in the resource section, upper left, next to the stangnet.com icon are three horizontal bars, hit that, resources in the drop down box
 

j753303

Active Member
Aug 25, 2020
73
30
28
45
MASS
you should set your idle with the throttle stop. then your iac will only control start up and warm up. Thats how mine is set up. I have the xe282hr cam in my 347 and it idles at 875 no problem
 
  • Like
Reactions: 3 users

Zeffer

Member
May 27, 2020
41
13
18
Mission B.C.
I have a 20 second video of it running when I first fired it up and it sounded great and idled. (I can't upload the video as it says file too large)
Shut it down to check levels etc and that is when it won't start without some throttle pedal help, and won't idle at all.
I bought one of those Innova code readers today so I'm going to check for codes tonight.
 

Noobz347

Stangnet Facilities Maint Tech... Er... Janitor
Admin Dude
Jan 4, 1985
33,236
15,064
234
Box behind Walmart
www.stangnet.com
The video I posted was when I first started the car, set timing etc and didn't seem to be any issues. After shutting it off and checking for leaks etc, it won't idle at all
Try clearing the CAM and starting over.

I'll preface that by saying that it won't fix all of your issues and that there is more going on but still... It [did] run once... sorta.

Disconnect the battery and step on the brake pedal half a dozen times. Go have a beer and a smoke. Come back and hook the battery back up and try it again. Don't shut it down this time until it's had time to get to temp.

Be prepared to pull [engine on] codes when you do it. Take yourself down to Walmart or get on amazon and get one of these to make your life easier:

Amazon product
View: https://smile.amazon.com/INNOVA-3145-Ford-Digital-Reader/dp/B000EW0KHW/ref=sr_1_2?crid=2VKGQB707R8E5&keywords=obd1+scanner&qid=1638456325&sprefix=obd1%2Caps%2C253&sr=8-2
 
  • Useful
  • Like
Reactions: 1 users

90sickfox

Wasn't a pretty sight...and I've got big hands
SN Certified Technician
Mar 2, 2015
6,395
5,479
203
44
you should set your idle with the throttle stop. then your iac will only control start up and warm up. Thats how mine is set up. I have the xe282hr cam in my 347 and it idles at 875 no problem

Hey man. Thats the same cam in my 331 with TF TW heads. Just curious, how much vacuum do you pull at 875 ?
 

Gs1987GT

Active Member
Sep 25, 2019
461
174
53
MidAtlantic
Try clearing the CAM and starting over.

I'll preface that by saying that it won't fix all of your issues and that there is more going on but still... It [did] run once... sorta.

Disconnect the battery and step on the brake pedal half a dozen times. Go have a beer and a smoke. Come back and hook the battery back up and try it again. Don't shut it down this time until it's had time to get to temp.

Be prepared to pull [engine on] codes when you do it. Take yourself down to Walmart or get on amazon and get one of these to make your life easier:

Amazon product
View: https://smile.amazon.com/INNOVA-3145-Ford-Digital-Reader/dp/B000EW0KHW/ref=sr_1_2?crid=2VKGQB707R8E5&keywords=obd1+scanner&qid=1638456325&sprefix=obd1%2Caps%2C253&sr=8-2



Just a quick thank you for the link Noobz, I just ordered that scanner and the extension cable so I have it if I need it someday. All of my other scanners are for obdII. Thanks agsin.
 
  • Like
Reactions: 1 user

Zeffer

Member
May 27, 2020
41
13
18
Mission B.C.
OK.....
Installed my new TB today, managed to get the car to start and idle after adjusting the idle screw, not perfect, but idling at about 800 rpm. Removed IAC connector and it would stay running this time. Checked timing again and it's bang on 12 degrees, fuel pressure is 40psi. I swear I can hear a vacuum leak, smoke tested again and there seems to be a lot of smoke from the oil fill cap, removed cap and lots of smoke coming from filler neck. I'm assuming the intake manifold is coming off....
 

Noobz347

Stangnet Facilities Maint Tech... Er... Janitor
Admin Dude
Jan 4, 1985
33,236
15,064
234
Box behind Walmart
www.stangnet.com
OK.....
Installed my new TB today, managed to get the car to start and idle after adjusting the idle screw, not perfect, but idling at about 800 rpm. Removed IAC connector and it would stay running this time. Checked timing again and it's bang on 12 degrees, fuel pressure is 40psi. I swear I can hear a vacuum leak, smoke tested again and there seems to be a lot of smoke from the oil fill cap, removed cap and lots of smoke coming from filler neck. I'm assuming the intake manifold is coming off....
Maybe not. Pull the PCV and the screen that's down in the intake beneath it.

Make sure the PCV valve "rattles" and that you can only blow through it in one direction. Ensure that the PCV screen is not clogged.
 
  • Useful
Reactions: 1 user