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Please help with idle...I just want to drive my car!

  • Thread starter Thread starter funkytrunk92
  • Start date Start date Nov 5, 2006
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funkytrunk92

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  • Nov 5, 2006
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Ok so I have just completed building the engine.
306 cobra motor with e cam. Also has aod with shift kit and stall converter. I am having an awful time getting this thing to idle. Here is what I have done so far.
1. checked for vacuum. reading around 15
2. cleaned MAF, IAC, TB, set tps to .98,99 whatever.
3. set base idle, which is a feat with the surging crap

I was toying around with it today and seemed to get it to run smooth and idle around 900 rpm-no surge. it ran like that for about five minutes. Then on to the next step of putting it in gear and of course it died. After I tried to start it up, more of the same surging and dying. when I unplug the MAF it changes the way it idles, so that leads me to believe that is not the prob. IAC also changes when unhooked-could be this, but I have not had a chance to get to auto parts store to get one. Fuel pressure is 39-40 vac off. TPS seems to be working fine. I have no idea what it could be and am about to set the car on fire. Does anyone have any ideas that might help me out. I know the car will idle right, but it takes about 10 minutes of tuning and then if I turn it off I am back to square one. It wasn't surging before I rebuilt it, but it did die a lot when shifted from park into rev or drive. I purchased the car as is and have not made any changes other than the rebuild due to blown pistons. All emissions stuff is gone. I can't think of anything else to help with diagnosis, but feel free to ask more questions because I just want to get the stupid thing running

ps. I will be happy to post pics of certain lines, components etc if it will help diagnose the problem.
 
8

86bluecobra

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have you tried running the codes to see what the puter says the problem is?
 

funkytrunk92

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86bluecobra said:
have you tried running the codes to see what the puter says the problem is?
Click to expand...

No. I will try to do that and post my results.
 

jrichker

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See "Help me create the Surging Idle Checklist" at http://forums.stangnet.com/showthread.php?t=534062
for help with your idle problems. The first post contains all the updates to the fixes. I continue to update it as more people post fixes or ask questions.
 

txstang84

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just a thought...

I didn't notice, but you mentioned it has an AOD...did you swap computers? If you're still running the X3Z ecm then you may've fried something in the computer if you connected the transmission to the original tranny harness connector...I recall reading somewhere here in these forums that if you try to use a 5 spd computer with an auto, then the 12v signal going to the ecu will fry the keep alive memory, as the A9L, or X3Z only takes a 5 volt signal from a T-5.

...of course I could be WAY off.
 

txstang84

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jrichker said:
See "Help me create the Surging Idle Checklist" at http://forums.stangnet.com/showthread.php?t=534062
for help with your idle problems. The first post contains all the updates to the fixes. I continue to update it as more people post fixes or ask questions.
Click to expand...


...duh-I forgot there was a sticky for surging idle...thanks j
 

funkytrunk92

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  • Nov 6, 2006
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txstang84 said:
just a thought...

I didn't notice, but you mentioned it has an AOD...did you swap computers? If you're still running the X3Z ecm then you may've fried something in the computer if you connected the transmission to the original tranny harness connector...I recall reading somewhere here in these forums that if you try to use a 5 spd computer with an auto, then the 12v signal going to the ecu will fry the keep alive memory, as the A9L, or X3Z only takes a 5 volt signal from a T-5.

...of course I could be WAY off.
Click to expand...

What would I need to do to diagnose that. Would pulling codes tell me that. I never like to hear fried and computer in the same sentence. Maybe a custom tune would help some of my probs.
 

jrichker

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Check out the link to the sticky I posted. There is a long and thoughly documented tech note on fixing idle problems. All the fixes are documented in the first post.
 
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bentley429

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When you unplugged the MAF did it smooth out? If so put it in gear and just take a for a quick ride do the street to see if it runs alright. If it does check out your MAF meter it could need to be cleaned or is no good. This happend to my truck afew weeks ago, did the same thing your car is doing turns out somehow a sprider made a nest right where the air flows threw so the computer can read it. Yes that is a true story .
 

funkytrunk92

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bentley429 said:
When you unplugged the MAF did it smooth out? If so put it in gear and just take a for a quick ride do the street to see if it runs alright. If it does check out your MAF meter it could need to be cleaned or is no good. This happend to my truck afew weeks ago, did the same thing your car is doing turns out somehow a sprider made a nest right where the air flows threw so the computer can read it. Yes that is a true story .
Click to expand...

when i unplug it the engine bogs. it does not die, but it just bogs and starts running rough. I disassembled the MAF and cleaned it thouroughly.
-

I have relied on the surging idle check list heavily(other than the codes which will happen tonight when I get off of work) and I am posting becuase I have tried many of those fixes. I was hoping someone may have some experience to help me out. Believe me I have poured over the surge check list, but I will reference it again.
 
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bentley429

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funkytrunk92 said:
when i unplug it the engine bogs. it does not die, but it just bogs and starts running rough. I disassembled the MAF and cleaned it thouroughly.
-

I have relied on the surging idle check list heavily(other than the codes which will happen tonight when I get off of work) and I am posting becuase I have tried many of those fixes. I was hoping someone may have some experience to help me out. Believe me I have poured over the surge check list, but I will reference it again.
Click to expand...

Hmmm, sorry I couldnt help you out. Good luck.
 

bryce93lx

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it could be that egr valve is plugged stuck or other wise screwed up, unplug and cap the vaccum lines that go to it, this was the casue of surging idle and dying with my vert, hope that help
p.s runs fins with out it just leave the connector plugged in and the cel will stay off
 

jrichker

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Are you experiencing surging with the IAC disconnected? If so, you have mechanical problems that need to be fixed.
 

funkytrunk92

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I ran the codes tonight. I am guessing the 67 has to do with the AOD in the 5spd computer. the others are 85,66,87,96....possibly fuel pump issues? That is KOEO by the way.


jrichker said:
Are you experiencing surging with the IAC disconnected? If so, you have mechanical problems that need to be fixed.
Click to expand...


What type of mechanical problems would you suspect with this issue.
 

jrichker

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Quote:
Originally Posted by jrichker
Are you experiencing surging with the IAC disconnected? If so, you have mechanical problems that need to be fixed.

funkytrunk92 said:
What type of mechanical problems would you suspect with this issue.
Click to expand...


Once again, from the "Help me create the Surging Idle Checklist"
Vacuum leaks are the #1 suspect in this case. An extreme cam can make the 600 RPM set point difficult to set. Contact your cam supplier or manufacturer to get information on idle speed and quality. Improperly adjusted valves are another possibility. A vacuum gauge will help pinpoint both vacuum leaks and improperly adjusted valves. A sticking valve or one adjusted too tight will cause low vacuum and a 5"-8" sweep every time the bad cylinder comes up on compression stroke.

Vacuum readings can run from 14.5"-18" at 650-725 RPM, at 1000 RPM, look for 18"-21" of vacuum.

Your code 66 may be from disconnecting the MAF while the key was in the run position. I would recommend that you clear the codes by disconnecting the test dump jumper when the codes start to dump. Then run the engine or drive the car and see if the code 66 comes back.

Code 66 MAF below minimum test voltage.
Insufficient or no voltage from MAF. Dirty MAF element, bad MAF, bad MAF wiring, missing power to MAF. Check for missing +12 volts on this circuit. Check the two links for a wiring diagram to help you find the red wire for computer power relay switched +12 volts. Check for 12 volts between the red and black wires on the MAF heater (usually pins A & B). while the connector is plugged into the MAF. This may require the use of a couple of safety pins to probe the MAF connector from the back side of it.

There are three parts in a MAF: the heater, the sensor element and the amplifier. The heater heats the MAF sensor element causing the resistance to increase. The amplifier buffers the MAF output signal and has a resistor that is laser trimmed to provide an output range compatible with the computer's load tables.

The MAF element is secured by 2 screws & has 1 wiring connector. To clean the element, remove it from the MAF housing and spray it down with electronic parts cleaner or non-inflammable brake parts cleaner (same stuff in a bigger can and cheaper too).

The MAF output varies with RPM which causes the airflow to increase or decease. The increase of air across the MAF sensor element causes it to cool, allowing more voltage to pass and telling the computer to increase the fuel flow. A decrease in airflow causes the MAF sensor element to get warmer, decreasing the voltage and reducing the fuel flow. Measure the MAF output at pins C & D on the MAF connector (dark blue/orange and tan/light blue) or at pins 50 & 9 on the computer.

At idle = approximately .6 volt
20 MPH = approximately 1.10 volt
40 MPH = approximately 1.70 volt
60 MPH = approximately 2.10 volt

Check the resistance of the MAF signal wiring. Pin D on the MAF and pin 50 on the computer (dark blue/orange wire) should be less than 2 ohms. Pin C on the MAF and pin 9 on the computer (tan/light blue wire) should be less than 2 ohms.

There should be a minimum of 10K ohms between either pin C or D on the MAF and ground.

See the following website for some help from Tmoss (diagram designer) & Stang&2Birds (website host)

http://www.veryuseful.com/mustang/tech/engine/images/fuel-alt-links-ign-ac.gif

http://www.veryuseful.com/mustang/tech/engine/images/88-91eecPinout.gif


Code 67 - clutch not depressed (5 speed) or car not in neutral or park (auto) or A/C in On position when codes where dumped. Possible neutral safety switch or wiring problem. This code may prevent you from running the Key On Engine On tests. You can generally ignore this code, since it has no effect on engine performance.

Code 85 - CANP solenoid - The Carbon Canister solenoid is inoperative. Check vacuum lines for leaks and cracks. Check electrical wiring for loose connections, damaged wiring and insulation. Check solenoid valve operation by grounding the gray/yellow wire to the solenoid and blowing through it.
The computer provides the ground for the solenoid. The red wire to the solenoid is always energized any time the ignition switch is in the run position.

Charcoal canister plumbing - one 3/8" tube from the bottom of the upper manifold to the rubber hose. Rubber hose connects to one side of the canister solenoid valve. Other side of the solenoid valve connects to one side of the canister. The other side of the canister connects to a rubber hose that connects to a line that goes all the way back to the gas tank. There is an electrical connector coming from the passenger side injector harness near #1 injector that plugs into the canister solenoid valve. It's purpose is to vent the gas tank. The solenoid valve opens at cruse to provide some extra fuel.

It does not weigh but a pound or so and helps richen up the cruse mixture. It draws no HP & keeps the car from smelling like gasoline in a closed garage. So with all these good things and no bad ones, why not hook it up & use it?

Code 87 – fuel pump primary circuit failure. The fuel pump lost power while the engine was running. Check fuel pump relay, check inertia switch, wiring to/from inertia switch, red wire going to inertia switch for +12volts. Check the other side of inertia switch for +12 volts.

To help troubleshoot the 87 code, follow this link for a wiring diagram for 89-93 cars http://www.autozone.com/servlet/UiB..._us/0900823d/80/19/59/5a/0900823d8019595a.jsp

For 79-88 cars use, http://www.autozone.com/servlet/UiB..._us/0900823d/80/16/71/3c/0900823d8016713c.jsp


Code 96 – KOEO- Fuel pump monitor circuit shows no power - Fuel pump relay or battery power feed was open - Power / Fuel Pump Circuits. The fuel pump circuit lost power at one time or another.

Look for a failing fuel pump relay, bad connections or broken wiring. The fuel pump relay is located under the Mass Air Meter on Fox bodied stangs built after 91. On earlier model cars is under the passenger seat. On Mass Air Conversions, the signal lead that tells the computer that the fuel pump has power may not have been wired correctly. See http://www.stangnet.com/tech/maf/massairconversion.html

To help troubleshoot the 96 code for 91-93 models see http://www.autozone.com/images/cds/gif/large/0900823d80195960.gif

Look for power at the fuel pump - the fuel pump has a connector at the rear of the car with a pink/black wire and a black wire that goes to the fuel pump. The pink/black wire should be hot when the test connector is jumpered to the test position. . To trick the fuel pump into running, find the ECC test connector and jump the connector in the lower RH corner to ground.

for a description of the test connector.. No voltage when jumpered, check the fuel pump relay and fuse links.

Power feed: Look for 12 volts at the pink/black wire (power source for fuel pump relay). No voltage or low voltage, bad fuse link, bad wiring, or connections. Remember that on 92 or later models the fuel pump relay is located under the Mass Air meter. Watch out for the WOT A/C control relay on these cars, as it is located in the same place and can easily be mistaken for the fuel pump relay.

Relay: Turn on the key and jumper the ECC test connector as previously described. Look for 12 volts at the dark green\yellow wire (relay controlled power for the fuel pump). No voltage there means that the relay has failed, or there is a broken wire in the relay control circuit.
 

funkytrunk92

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looks like I got some work ahead of me! Thanks for the help jrichker. That give me somewhere to start.
===
when you are talking about valves being adjusted wrong or too tight, would you be refering to adjusting the rockers because 2 of my rockers were borderline tight in my opinion and may need shims. would this have a possible effect. Also, what should the intake vacuum be(may not be the correct name, but the vacuum when i hood to pcv port on the intake).

thanks for all of the replys
 

funkytrunk92

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#17
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funkytrunk92 said:
===
when you are talking about valves being adjusted wrong or too tight, would you be refering to adjusting the rockers because 2 of my rockers were borderline tight in my opinion and may need shims. would this have a possible effect. Also, what should the intake vacuum be(may not be the correct name, but the vacuum when i hook to pcv port on the intake).
Click to expand...

bump
 

jrichker

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Use a vacuum gauge connected to the vacuum tree on the firewall to find out if you have vacuum related problems such as valves or vacuum leaks.

From my previous post:
Vacuum readings can run from 14.5"-18" at 650-725 RPM, at 1000 RPM, look for 18"-21" of vacuum.
 

funkytrunk92

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jrichker said:
Use a vacuum gauge connected to the vacuum tree on the firewall to find out if you have vacuum related problems such as valves or vacuum leaks.

From my previous post:
Vacuum readings can run from 14.5"-18" at 650-725 RPM, at 1000 RPM, look for 18"-21" of vacuum.
Click to expand...

I understand that, but when you talk about valves being out of adjustment are you referenceing rocker adjustment or something to do with the springs. Please bear with me because I am still learning when it comes to some of the more in depth aspects of engine work.
 

funkytrunk92

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bump
 
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