still problems surging idle on cold start

notch351

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Jul 30, 2010

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Apr 5, 2011

#1

• Apr 5, 2011

• #1

ok i have been trying to figure out why my car is surging on cold start up barely does it if it is warm outside. only surges for a minute then i believe the computer is going to limp mode. the other thing i noticed is if i try to pull out and drive it right when i cold start it. it has a stumble or sputtering to it just for like the first 30sec of driving. after that or if i let it sit and idle just for a minute the car drives fine minus probably running a little rich i would assume from what ever the heck is going on.

 

toyman

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Apr 5, 2011

#2

• Apr 5, 2011

• #2

What mods if any have you done? Kind of important info to know before making suggestions.

 

HISSIN50

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Apr 5, 2011

#3

• Apr 5, 2011

• #3

And what codes did you retrieve?

Has the ECT been checked?

 

notch351

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Jul 30, 2010

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Apr 5, 2011

#4

• Apr 5, 2011

• #4

I have the basic bolt ons. cai edlebrock performer intake, 70mm t.b. fox swap. full exhaust with shorty headers underdrive pulleys. egr is completly deleted. when i checked codes it was throwing one for the thermactor which i believe is just the pollution pump being removed. it also threw a code for the egr but i think that should be fixed because i installed that little plug in bypass solenoid to trick the computer and reset code but i haven't resacnned to make sure that specific code is not coming up. then the last code was a 10. said something about low ballance in number one cylinder but that was a stored code it said not present. there are also no chips on car or tunes i am aware of

 

HISSIN50

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Apr 5, 2011

#5

• Apr 5, 2011

• #5

I would recheck codes to be sure of what is present. I would retrieve KOEO, memory and KOER codes.

It sounds like the ten you saw was a separator code. You need to blip the throttle to enter cylinder-balance testing.

 

notch351

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Apr 6, 2011

#6

• Apr 6, 2011

• #6

from the looks of it the codes that read on scanner were old stored codes so whats next. should i be checking fuel pressure to make sure regulator is working

 

HISSIN50

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Apr 7, 2011

#7

• Apr 7, 2011

• #7

Again, I would retrieve all codes again.

Have you checked the ECT calibration?

 

notch351

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Apr 7, 2011

#8

• Apr 7, 2011

• #8

how do you ck the ect never had to do that before. I will let you know what codes #s are being thrown

 

notch351

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Apr 7, 2011

#9

• Apr 7, 2011

• #9

the codes are all readings stored codes none new found but here they are 314, 332, 311, and 10
and please let me know hoe to check my ect. thanks

 

HISSIN50

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Apr 8, 2011

#10

• Apr 8, 2011

• #10

To check the ECT, have the engine at 50*F. Turn the key on and note the voltage (one wire will show 5V and the other will have less voltage than that. You want the latter wire). The one with less voltage is variable and will change inversely with respect to increases in engine temperature. Note the meter reading.

You can also try doing this before getting the engine up to 50*F and we can interpolate the results. It's just that a reading below 50* is not very accurate.

 

notch351

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Apr 8, 2011

#11

• Apr 8, 2011

• #11

I know it doesn't hurt to check it but would it not throw a code if there was a problem? just wondering

 

HISSIN50

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Apr 8, 2011

#12

• Apr 8, 2011

• #12

The sensor can be out of calibration - it can be within absolute spec but not read correctly for the conditions. It's not likely to be the issue but since it takes 30 seconds to check, it can be worth doing.

 

toyman

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Apr 9, 2011

#13

• Apr 9, 2011

• #13

For a table of volts vs temp go here http://www.fordfuelinjection.com/index.php?p=28

 

notch351

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Apr 10, 2011

#14

• Apr 10, 2011

• #14

hey the sensor checks out ok.??????????????? now what. I have noticed that when i start car if i throttle it right away couple times it seems to settle the idle in after that

 

toyman

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Apr 10, 2011

#15

• Apr 10, 2011

• #15

From personal experience excessive cold start enrichment will cause the idle to surge (oscillate) when first starting. Since the enrichment is commanded by the PCM from a look-up table and you can't change it without a chip that would lead me to think that a sensor is giving the PCM some bad data. We've eliminated the ECT sensor so that doesn't leave to many others. The first one that comes to mind is the O2 but I'm not certain that they are switched on until the engine warms. Perhaps someone can confirm that. The other thing that I don't understand is the 2 digit code 10. All OBD1 systems are 3 digits starting at 111 - 998. I think you should retest and confirm there are no codes. You can buy a reader for about $30.

Save on Equus 3145 at ToolTopia.com

 

HISSIN50

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Apr 11, 2011

#16

• Apr 11, 2011

• #16

The O2's are not utilized till they light off (about 600*F), which can take 30-120 seconds.

I would need to look it up but code 10 might still be used on the three digit cars (since it's not a code but a prompt to do a WOT goose for the CBT).

 

notch351

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Apr 11, 2011

#17

• Apr 11, 2011

• #17

my buddy has the scanner so i will rerun the test. at this point i think I might back track through everything to make sure something it not being over looked. this one is a real hair puller one of the harder problems i have had to deal with. had idle issues before but always been able to figure it out. thanks for the help. i will keep you posted but feel free to post if another ideas comes up

 

notch351

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Jul 30, 2010

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Apr 11, 2011

#18

• Apr 11, 2011

• #18

alright i am convinced i have a vacuum leak. when i am coming to a stop the car idles down to about 1000rpm with clutch pushed in. then when i stop it idles down to normal about 800rpm and does a quick little jump to about 1,100 and goes right back to normal. does this about every time i come to a stop. and I also hear a little whistle sound when i am under the hood

 

HISSIN50

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Apr 11, 2011

#19

• Apr 11, 2011

• #19

Some TB's whistle.

The rolling idle cannot be considered - it's supposed to be at 1200 RPM or so till the car stops (this is to keep the car from stalling).

 

notch351

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Apr 11, 2011

#20

• Apr 11, 2011

• #20

yeah i know that is normal but then when i come to a stop it goes to idle than jumps for a split second to about 1,100 then right back to normal and this is once i have just come to a complete stop