idling problems

RacingBryan · 07-16-2001, 12:23 AM

hey everyone i just put a brand new engine in my 88 gt but it has a problem it seems to only want to idle with a vaccuum leak? anyone ever heard of this? heres what my package includes: Trickflow intake, 24lb injectors, 75mm pro mass air, crane cam 2031 cam, 1.7 roller rockers, stock ported heads, nitrous sporstman fogger kit, any suggestions on thinks to check i would appreciate!

jimberg · 07-16-2001, 12:40 AM

To set your idle screw, back it off until you can fit a .010" feeler gauge between it and the stop. Tighten the screw until you can remove the feeler with a little friction. Then turn the screw in for another 1 1/2 turns. Disconnect the battery for 15 minutes and reconnect it. Start the engine and let it idle with all accessories off until the idle smooths out. When it does, let it idle for an additional 2 minutes. Turn the car off and then start it again with all accessories on. Do the same as you did with them all off. Turn off the accessories you don't need and take it for a spin.

If the idle doesn't smooth out after 10 minutes, it probably is the IAB valve. Try cleaning it.

Let us know what happens.

------------------
351W 89 Mustang GT Convertible

RacingBryan · 07-16-2001, 03:23 PM

but what would make it only want to run will a vaccum hose off of the tee? i mean i have to unplug one to get it to even idle!?
thanks

07-16-2001, 04:24 PM

Jimberg, I have to say that I didn't believe you when I read your post last week on resetting the computer. My car was idling rough, and would stall out after 2 minutes of sitting idle. I tried it out this weekend and I SWEAR that the car idles like it's stock (not really, but close enough). *******' amazing

! Thanks.

------------------
'90 LX 5.0; 12K original miles (no sh*&); 3.55 gears; pulleys;Edelbrock Performer Heads; BBK shorties; MSD 6AL box w/ blaster 2 coil; Motorsport E303 cam; Pro-M 75mm MAF; BBK 70mm TB; Eibach spring kit; Southside welded subs; K&N cone filter charger; Hurst shifter; fiberglass turbo hood; A/C-less; rear seat-less; cat-less; 2 chamber Flos; Corbeau racing seats (fronts);
30# injectors; JMS Chip; 190 lb fp; TFS track heat Intake (12.299 @ 113)

RacingBryan · 07-16-2001, 04:44 PM

i just tried exactly what you said, and it idled nicely and then i turned it off and back on and now it wont idle at all? i also noticed that when i let it idle after the battery was hooked back up that gas what coming out of the tail pipe? any ideas why it would run so rich? i got stock regulator and pump in it. i got a adjustable regulator and a bigger pump but i dont think i should put them in till i figure out this problem.
thanks Bryan

exgmguy · 07-16-2001, 06:07 PM

I just copied this from another post I replied to: Try this. First a tip for resetting the TPS, computer etc... Disconnect the battery for 20 minutes to clear all computer memory. Reconnect the battery. Now disconnect the IAC motor and start the car. You may have to hold your foot on the gas to keep it running. turn the idle screw until the car idles by itself @ 700-750 RPM. Now adjust the TPS sensor to read about .95 volts. Shut the car off. Plug the IAC motor back in and let the car idle for 2 minutes with all accessories operating on high. Shut the car off for 2 minutes. Start the car again and let it idle for 2 minutes with no accessories on. This is the proper way to do it.
If you still have a hunting idle remove the smallest vacuum cap from the vacuum log at the firewall. My car will not idle without giving it the very slight vacuum leak.
remember to let us know if it works.

------------------
1988 Mustang GT
11.8 @ 123 (7/14/01)
1992 BadAzz Wrangler
1993 Explorer

jimberg · 07-16-2001, 06:51 PM

RacingBryan, bad O2 sensors can cause it to run rich. When's the last time that you replaced them? Do you have any codes from the computer that may cause a rich condition? Check your fuel pressure and make sure it's between 37 and 40 psi. Do a leakdown test of the fuel system. Verify your firing order and that all plugs are firing.

Clearly your idle problem isn't TB or IAB related. You're having fuel management problems. I would leave your idle adjustment setting alone until you get that resolved.

------------------
351W 89 Mustang GT Convertible

RacingBryan · 07-16-2001, 07:04 PM

i have 2 new o2 sensors in it with about 500 miles on them and the pressure is about 32 psi at idle! thanks

jimberg · 07-18-2001, 01:59 PM

Bryan,

Did you get a chance to scan your codes and do the cylinder balance test, yet? Just following up.

bada$$lx, I'm glad the procedure worked for you. It's pretty much a sure thing as long as something else isn't messed up.

------------------
351W 89 Mustang GT Convertible

07-18-2001, 03:25 PM

How long have you been running the Trick Flow intake? (prior to the new engine?)

The reason I ask, is that I had a Trick Flow intake that caused my car to idle like crap. I changed intakes and the problem went away.

Strange but true.

RacingBryan · 08-02-2001, 08:58 PM

well guys i finally had time to run the codes on my car and i used a xray scanner from work and it says my ecm isnt responding? what does that mean? we tryed the scanner on my buddys 93 gt and it worked so i know the scanner is good? anyone out there use a aftermarket computer setup that you can adjust your ecm with a labtop? if so which ones have you used?
THanks Bryan

07-16-2001, 12:23 AM	#1
RacingBryan Registered Member Join Date: May 2001 Location: Racine wi 53405 Posts: 11	idling problems hey everyone i just put a brand new engine in my 88 gt but it has a problem it seems to only want to idle with a vaccuum leak? anyone ever heard of this? heres what my package includes: Trickflow intake, 24lb injectors, 75mm pro mass air, crane cam 2031 cam, 1.7 roller rockers, stock ported heads, nitrous sporstman fogger kit, any suggestions on thinks to check i would appreciate!

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07-16-2001, 12:40 AM	#2
jimberg Registered Member Join Date: Oct 1998 Location: Rogers, MN Posts: 2,089	To set your idle screw, back it off until you can fit a .010" feeler gauge between it and the stop. Tighten the screw until you can remove the feeler with a little friction. Then turn the screw in for another 1 1/2 turns. Disconnect the battery for 15 minutes and reconnect it. Start the engine and let it idle with all accessories off until the idle smooths out. When it does, let it idle for an additional 2 minutes. Turn the car off and then start it again with all accessories on. Do the same as you did with them all off. Turn off the accessories you don't need and take it for a spin. If the idle doesn't smooth out after 10 minutes, it probably is the IAB valve. Try cleaning it. Let us know what happens. ------------------ 351W 89 Mustang GT Convertible

07-16-2001, 03:23 PM	#3
RacingBryan Registered Member Join Date: May 2001 Location: Racine wi 53405 Posts: 11	but what would make it only want to run will a vaccum hose off of the tee? i mean i have to unplug one to get it to even idle!? thanks

07-16-2001, 04:24 PM	#4
bada$$lx Guest Posts: n/a	Jimberg, I have to say that I didn't believe you when I read your post last week on resetting the computer. My car was idling rough, and would stall out after 2 minutes of sitting idle. I tried it out this weekend and I SWEAR that the car idles like it's stock (not really, but close enough). ******' amazing ! Thanks. ------------------ '90 LX 5.0; 12K original miles (no sh&); 3.55 gears; pulleys;Edelbrock Performer Heads; BBK shorties; MSD 6AL box w/ blaster 2 coil; Motorsport E303 cam; Pro-M 75mm MAF; BBK 70mm TB; Eibach spring kit; Southside welded subs; K&N cone filter charger; Hurst shifter; fiberglass turbo hood; A/C-less; rear seat-less; cat-less; 2 chamber Flos; Corbeau racing seats (fronts); 30# injectors; JMS Chip; 190 lb fp; TFS track heat Intake (12.299 @ 113)

07-16-2001, 04:44 PM	#5
RacingBryan Registered Member Join Date: May 2001 Location: Racine wi 53405 Posts: 11	i just tried exactly what you said, and it idled nicely and then i turned it off and back on and now it wont idle at all? i also noticed that when i let it idle after the battery was hooked back up that gas what coming out of the tail pipe? any ideas why it would run so rich? i got stock regulator and pump in it. i got a adjustable regulator and a bigger pump but i dont think i should put them in till i figure out this problem. thanks Bryan

07-16-2001, 06:07 PM	#6
exgmguy Registered Member Join Date: Feb 1999 Location: Utica, Michigan Posts: 2,631	I just copied this from another post I replied to: Try this. First a tip for resetting the TPS, computer etc... Disconnect the battery for 20 minutes to clear all computer memory. Reconnect the battery. Now disconnect the IAC motor and start the car. You may have to hold your foot on the gas to keep it running. turn the idle screw until the car idles by itself @ 700-750 RPM. Now adjust the TPS sensor to read about .95 volts. Shut the car off. Plug the IAC motor back in and let the car idle for 2 minutes with all accessories operating on high. Shut the car off for 2 minutes. Start the car again and let it idle for 2 minutes with no accessories on. This is the proper way to do it. If you still have a hunting idle remove the smallest vacuum cap from the vacuum log at the firewall. My car will not idle without giving it the very slight vacuum leak. remember to let us know if it works. ------------------ 1988 Mustang GT 11.8 @ 123 (7/14/01) 1992 BadAzz Wrangler 1993 Explorer

07-16-2001, 06:51 PM	#7
jimberg Registered Member Join Date: Oct 1998 Location: Rogers, MN Posts: 2,089	RacingBryan, bad O2 sensors can cause it to run rich. When's the last time that you replaced them? Do you have any codes from the computer that may cause a rich condition? Check your fuel pressure and make sure it's between 37 and 40 psi. Do a leakdown test of the fuel system. Verify your firing order and that all plugs are firing. Clearly your idle problem isn't TB or IAB related. You're having fuel management problems. I would leave your idle adjustment setting alone until you get that resolved. ------------------ 351W 89 Mustang GT Convertible

07-16-2001, 07:04 PM	#8
RacingBryan Registered Member Join Date: May 2001 Location: Racine wi 53405 Posts: 11	i have 2 new o2 sensors in it with about 500 miles on them and the pressure is about 32 psi at idle! thanks

07-18-2001, 01:59 PM	#9
jimberg Registered Member Join Date: Oct 1998 Location: Rogers, MN Posts: 2,089	Bryan, Did you get a chance to scan your codes and do the cylinder balance test, yet? Just following up. bada$$lx, I'm glad the procedure worked for you. It's pretty much a sure thing as long as something else isn't messed up. ------------------ 351W 89 Mustang GT Convertible

07-18-2001, 03:25 PM	#10
stanglx347 Guest Posts: n/a	How long have you been running the Trick Flow intake? (prior to the new engine?) The reason I ask, is that I had a Trick Flow intake that caused my car to idle like crap. I changed intakes and the problem went away. Strange but true.

08-02-2001, 08:58 PM	#11
RacingBryan Registered Member Join Date: May 2001 Location: Racine wi 53405 Posts: 11	well guys i finally had time to run the codes on my car and i used a xray scanner from work and it says my ecm isnt responding? what does that mean? we tryed the scanner on my buddys 93 gt and it worked so i know the scanner is good? anyone out there use a aftermarket computer setup that you can adjust your ecm with a labtop? if so which ones have you used? THanks Bryan