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04-13-05, 04:55 PM
|  | Founding Member | | Join Date: November 2001 Location: Horsham, Pennsylvania
Posts: 357
| | would replacing the vacuum lines with rubber hose that is rated at 15 psi +/- cause a surge if my vacuum pulls at -17.5 psi at idle? |
04-13-05, 08:24 PM
|  | StangNet's favorite TOOL | | Join Date: March 2000 Location: Dublin GA
Posts: 15,742
| | Quote: |
Originally Posted by Funanin would replacing the vacuum lines with rubber hose that is rated at 15 psi +/- cause a surge if my vacuum pulls at -17.5 psi at idle? | Vacuum is measured in inches of mercury, 30 inces of vacuum = roughly 15 psi. Hose designed for pressure will generally carry vacuum with no problem. Vaccum would try to colapse a hose with no reinforcement by sucking it flat, like a soda straw stuck in the ice cream in the bottom of a milk shake.
With this in mind, the cause of your surge is not the rubber hose. |
04-13-05, 11:29 PM
|  | The Voice of Reason | | Join Date: January 1999 Location: Hagerstown MD
Posts: 5,305
| | D, I just dremel out a little at a time till it idles around 1k. In my experience the stock puter doesn't like to idle a cammed car down low.
Jamie |
04-13-05, 11:54 PM
| | Official Member | | Join Date: September 2004
Posts: 218
| | Quote: |
Originally Posted by Ranchero5.0 D, I just dremel out a little at a time till it idles around 1k. In my experience the stock puter doesn't like to idle a cammed car down low.
Jamie | So basically the 950 or so idle I have is about the lowest Im gonna be able to get it right? |
04-14-05, 08:07 AM
|  | Official Member | | Join Date: February 2004 Location: Ontario, Canada
Posts: 327
| | Quote: |
Originally Posted by jrichker Vacuum is measured in inches of mercury, 30 inces of vacuum = roughly 15 psi. Hose designed for pressure will generally carry vacuum with no problem. Vaccum would try to colapse a hose with no reinforcement by sucking it flat, like a soda straw stuck in the ice cream in the bottom of a milk shake.
With this in mind, the cause of your surge is not the rubber hose. |
Just wondering how much vac. does a stang pull? by the way this a great idea, I have had this prob. for a long time, and this is giving me a lot of potential solutions. |
04-14-05, 01:30 PM
| | Member | | Join Date: October 2004 Location: Portsmouth, VA
Posts: 27
| | Once you have all the checklists done up, have them as a sticky on page one.  Make it a one stop shop before a "this-has-been-answered-already" question gets posted.  |
04-14-05, 02:49 PM
| | StangNet's favorite TOOL | | Join Date: March 2000 Location: Dublin GA
Posts: 15,742
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Originally Posted by dvs bullet Just wondering how much vac. does a stang pull? by the way this a great idea, I have had this prob. for a long time, and this is giving me a lot of potential solutions. | A healthy engine with a stock cam will pull anywhere from 16"-19" at 675-750 RPM. Changes in spark advance, camshaft timing, and overall engine health will make this figure vary greatly from one engine to another. |
04-14-05, 02:55 PM
| | Official Member | | Join Date: February 2004 Location: Ontario, Canada
Posts: 327
| | Quote: |
Originally Posted by jrichker A healthy engine with a stock cam will pull anywhere from 16"-19" at 675-750 RPM. Changes in spark advance, camshaft timing, and overall engine health will make this figure vary greatly from one engine to another. | Thanks man!  It will give me more ammo when I go after my car with this list |
04-15-05, 07:12 AM
|  | Founding Member | | Join Date: June 2000 Location: British Columbia
Posts: 1,456
| | If you have R12 in your A/C you might want to check the charge on your A/C.
Low Charge = hunting idle
unplug your commpressor and see if it makes a difference.
did with my 88 GT and it went to a steady 650 rpms.
Decided to take the A/C out,got rid of everything except the compressor(I use the compressor as a pulley only,that way I didn't have to change the belt)
I've had a steady idle ever since I took everything out.
I also run with a vacuum guage and that is also running steady at idle.
Gained on horsepower and fuel mileage.
Last edited by Snake1; 04-15-05 at 07:15 AM.
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04-15-05, 03:36 PM
| | Member | | Join Date: October 2004 Location: Ventura, CA
Posts: 22
| | Quote: |
Originally Posted by Snake1 Low Charge = hunting idle | Only possible if the hunting idle only happens when the A/C is on. |
04-15-05, 07:36 PM
| | Founding Member | | Join Date: June 2000 Location: British Columbia
Posts: 1,456
| | Quote: |
Originally Posted by 88GTsocal Only possible if the hunting idle only happens when the A/C is on. | as you probably know Ford heaters are on all the time except when in the off position,doesn't matter is the A/C is on, or heater side is on because your Compressor kicks in on heat side also.
Put your lever on mix on the heat side and go watch your compressor kick in, Trust me i've been thru all of this with my 88GT and R 12. if it doesn't kick in,not enough oil in your system to activate it. |
04-15-05, 07:53 PM
| | Member | | Join Date: October 2004 Location: Ventura, CA
Posts: 22
| | Quote: |
Originally Posted by Snake1 as you probably know Ford heaters are on all the time except when in the off position,doesn't matter is the A/C is on, or heater side is on because your Compressor kicks in on heat side also.
Put your lever on mix on the heat side and go watch your compressor kick in, Trust me i've been thru all of this with my 88GT and R 12. if it doesn't kick in,not enough oil in your system to activate it. | I could be wrong, but I'm almost positive that the compressor turns on in the A/C positions and defrost. Not in any of the other positions. |
04-15-05, 08:05 PM
| | Founding Member | | Join Date: June 2000 Location: British Columbia
Posts: 1,456
| | On the heat side, the compressor kicks on for a bit then kicks off,on the ac side it stays on until you switch over to the heat side,then it starts its on/off cycle again
Last edited by Snake1; 04-15-05 at 08:09 PM.
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04-15-05, 08:11 PM
|  | Official Member | | Join Date: September 2004 Location: Binghamton NY
Posts: 141
| | If you have the original IAC motor on a higher mileage car the idle hunting seems to be a common problem. I have found that simply pulling off the IAC motor and hosing it out with cleaner helps it out a lot. My '90 vert that I just got this year had this problem so bad that it would actually stall. I cleaned out the IAC motor and now it idles perfect. I'm sure this isnt a permanent fix and that it needs to be replaced but it works for now. |
04-15-05, 09:01 PM
|  | I have nothing productive to add! | | Join Date: July 2001 Location: Mill Creek, WA
Posts: 10,344
| | Quote: |
Originally Posted by Snake1 On the heat side, the compressor kicks on for a bit then kicks off,on the ac side it stays on until you switch over to the heat side,then it starts its on/off cycle again | I've never seen this before, not on any of my Fords ... and the A/C has worked fine.
As mentioned above, the A/C only cycles on with A/C and Defrost. It does cycle when it's on however, that is normal.
It sounds like maybe you had a stuck clutch in your compressor or something else going on. 
Last edited by 89MustangGX; 04-15-05 at 09:02 PM.
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04-16-05, 12:53 AM
| | Founding Member | | Join Date: June 2000 Location: British Columbia
Posts: 1,456
| | hey 89 Gx maybe i'm not saying this right,what I mean is the compressor cycles on and off on the heat side,I don't mean it's is running the A/C,
and you'll notice below 9 deg Celsius that your compressor won't cycle in and out and your compressor is basically a pulley then.
That's what tweaked me to the rough idle,went away when it was below 9 deg.
Hope you can understand all that.
getting tired of typing,have a good one. |
04-17-05, 02:53 PM
|  | Member | | Join Date: December 2004 Location: indian trail,nc
Posts: 49
| | My car idles around 800 but I have a rpm spike between shifts. any thoughts also what is IAC |
04-17-05, 08:23 PM
| | Official Member | | Join Date: September 2004 Location: Binghamton NY
Posts: 141
| | Quote: |
Originally Posted by mkkrs1 My car idles around 800 but I have a rpm spike between shifts. any thoughts also what is IAC |
IAC= Idle air control. It is the thing that bolts to the front of your throttle body that has wires plug into it. |
04-18-05, 10:41 PM
| | Member | | Join Date: December 2004
Posts: 38
| | my car had a pretty bad surge problem. used the checklist and l ceaned my IAC and my throtle body. idols real nice now. thanks |
04-19-05, 08:56 PM
|  | Silver Stanger | | Join Date: April 2002
Posts: 1,552
| | How do you guys clean your throttle body? Doesnt it say not to clean it? Also were is the salt/pepper connector located?
I bought that IAC adjuster from 50resto.com and it sucks!..used the new gasket that it came with and threw the rest!  |
04-21-05, 01:57 PM
| | StangNet's favorite TOOL | | Join Date: March 2000 Location: Dublin GA
Posts: 15,742
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Originally Posted by MUSTANGJOE How do you guys clean your throttle body? Doesnt it say not to clean it? Also were is the salt/pepper connector located?
I bought that IAC adjuster from 50resto.com and it sucks!..used the new gasket that it came with and threw the rest! | Some TB's are coated and are marked "Do not clean". If they have no markings, spray them down & use a toothbrush to do the tough places that refuse to come clean. Spray some more and wipe up the mess with a paper towel. The rest will go through the engine with no problems.
The salt & pepper shakers are the 10 pin connectors on the rear of the upper manifold.
Photo courtsey of Tmoss & Stang&2birds.   |
04-22-05, 08:20 PM
| | Member | | Join Date: December 2004 Location: indian trail,nc
Posts: 49
| | What kind of spray are you using to clean with |
04-22-05, 08:24 PM
|  | Official Member | | Join Date: April 2005 Location: Granite City, IL
Posts: 153
| | Quote: |
Originally Posted by jrichker Some TB's are coated and are marked "Do not clean". If they have no markings, spray them down & use a toothbrush to do the tough places that refuse to come clean. Spray some more and wipe up the mess with a paper towel. The rest will go through the engine with no problems.
The salt & pepper shakers are the 10 pin connectors on the rear of the upper manifold.
Photo courtsey of Tmoss & Stang&2birds. | Will you take a pic and draw on it where the pcv valve is? i dont know where it is. i have a 1990 5.0 |
04-23-05, 11:33 AM
|  | Official Member | | Join Date: December 2002 Location: Vancouver, Canada
Posts: 92
| | | Still have this bad cold idle
I have a cold start idle problem that lasts for about 5 mins of driving then is fine or if I shut it off and start it up again couple of times it seems to go away as well. It doesn't do the standard high idle at start anymore, rather it now surges up to 1500 RPM and the down to 100-400 RPM. If you don't give some throttle, it just dies.
I have replaced the Idle Air Bypass
Cleaned the ACT, Mass Air filiments
tested the temp sensor at 180* it reads the right ohms (as per a Chilton manual)
I should probably check it cold and clean Pin 10 as suggested in this thread.
What else should I be looking at? |
04-23-05, 12:39 PM
| | StangNet's favorite TOOL | | Join Date: March 2000 Location: Dublin GA
Posts: 15,742
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Originally Posted by Slo 5.0 Will you take a pic and draw on it where the pcv valve is? i dont know where it is. i have a 1990 5.0 | The PCV is almost imposible to see unless you have the engine out of the car, have the intake manifold off, or you are a snail & have an eyeball on a stalk. 
The PCV fits in a rubber grommet that plugs in the block at the rear of the lower intake manifold. The rubber grommet is notorious for not fitting tight or sealing like it should. It connects to the upper manifold by a 3/8" vacuum hose coming from the rear of the upper intake manifold. The easiest way to find it is to follow the hose with your hand and pull it out of the rubber grommet. Check the screen below the PCV while you have it & the grommet out if you can get to it.
Last edited by jrichker; 04-23-05 at 12:54 PM.
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