Idle dips.....

Markus2

Markus2

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.... when you begin to feather the accelerator with the least amount of pressure...
...instead of the rpms rising..
...it dips, but only at the first touch of gas.

Is this symptons of vac. leak?
I know this is prbly more of a car question-and less of a mk7 question.


thanks my people.

-g-
 
soo...

if the dipping issue goes away after the car is warmed-than it cant be a vaccum leak-or it would be there all the time right?
 
Sounds like a few possible things to me.

The first thing that I would check though is the EGR valve and next the throttle position sensor.
 
update

Did the EGR as suggested and sensor.
Did the TPS.
Ran DIAG and got code for-if i remember correctly-something along the lines of- NO CONTROL OF HIGHER RPMS-something like that.
So i replaced the IAC-no more check engine light flashing now-

And after the above were done-it still has a rough idle- I posted in the thread i started last night about my 24 lb injectors possibly being the issue.

Idle is still choppy-all the time-goes up and down 100-200 rpms SOMETIMES. And when it is steady will hickup like a miss every few seconds or so...like 50-100 rpms-slight but enough to notice.
Bout to yank my BOSCH plat plus 2's-i dont think lsc is liking the spark
 
... and the next step is ...

Markus2 said:
...Bout to yank my BOSCH plat plus 2's-i dont think lsc is liking the spark
Click to expand...
Our Marks will operate with the PLUS plugs. The plugs won't cause surging.

What was the code's number?

Disconnect and temporarily plug the vacuum line for the exhaust gas recirculating system and ensure that the valve is seated. If the engine hunting continues then reconnect it and move to the next item.

The next things that will cause surging are the oxygen sensors especially on a Mark with over 100,000 miles. If they're original, they'll need to be replaced.

Come back in six months or so and let us know what you've found :)
 
Can Less Be More?

Frogman said:
Could be the ginormous 24lb injectors someone put on there.
Click to expand...

Wow. I missed that.

I only have experience with bolt on/out-of-the-box modifications and not the re-engineering stuff. I ~do~ know that if I change injector size then I also have to change/adjust/replace/remove/fabricate just about everything else in the fuel/air/spark systems to be compatible.
 
Whatchamacallit

I'm not exactly sure what it's called but our stock Mark VIIs have NO electronics metering the air intake, such as a Mustang or Mark VIII's mass air sensor.

There ~is~ a throttle position sensor though.
 
tried adjusting the old one when my idle was surging more...
did not help....
so i replaced with new one.
 
Frogman said:
Could be the ginormous 24lb injectors someone put on there.
Click to expand...


dontcha love how the important details are left out of "this" problem.

the large injectors are WRONG, WRONG, WRONG.
The minimum pulsewidth is WRONG.
The entire Injector part of the PCM is WRONG.

hence the idle "dropping" when you barely get into the gas.

OH yea.. the "accelerator pump" area in the PCM calibration is also WRONG, due to the WRONG injectors.

Bigger is better if you like FUBAR engine management, and driveability issues.
 
Last edited:
So my brand new injectors gotta come out and i should toss the old ones back in. is that what you are saying?
 
:shifty:
Markus2 said:
So my brand new injectors gotta come out and i should toss the old ones back in. is that what you are saying?
Click to expand...

yes, believe it or not you have to treat fuel injectors very badly before they really need to be replaced.

i put 400K on my last set..
 
Yeah man put the old ones back in before you damage anything more. Running real rich can wash the oil off parts you really don't want to be dry.
 
I Gotta Say This

Now now everybody ... cut Markus2Dude a break.

Everyone was once new to Mark VIIs and he's gonna make some mistakes.

He now has experience with a couple of systems and will eventually learn to tackle one problem at a time and do preventive maintenance with the correct parts and tools and stuff.

Read my sig.
 
OldSchool1 said:
Now now everybody ... cut Markus2Dude a break.
Click to expand...

yea screw this little prick.
I gave him on a platter a wealth of information to pour over.
Gave him a great resource to gain the knowledge he so desperately needs.
The little nutsack wants to make comments questioning my SEXUAL orientation and some BS political comments that have no bearing on ANYTHING.

Good luck spoonfeeding this "noob".. I'm done with him...

To think I thought about burning my spare SCT chip with the correct value files for his injectors...(shakes head)

steps off the burning bridge..
 
thanks MK7 people

you guys know everything i need to know.
thats why im here.
thanks for the attempt to carry me through this issue.
Injectors are coming out in next week or so.

**At least I have some preventative (minimal cost) maintenance done now.

Code spit out EGR-forget the number- so instead of cleaning it-i changed the 17 year old part and sensor.

Only other code it spit out was "something about not controling high rpms..." and it was explained to me that that code meant IAC -idle air control valve.
Now there is no codes other than the one refering to the removed air pump.

******THE ONLY PART I PUT IN THAT I DID NOT NEED TO...and it tops my bank at 45 bucks for the TPS SENSOR.

I swapped out the platinum plus 2's and put in motorcraft plugs-also not nes. but I wanted to see if there was a difference.


SO after all is said and done-i fixed two problems with codes and put in a new set of plugs and a new TPS.


I dont think i did anything that stupid-except put in injectors that the computer is not programmed for.

all in all...
thanks guys.

i WILL SWAP OUT THE INJECTORS.
 
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