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Topic: Idle Problems continue, Checked IAC, and TPS...Now WHAT!? (Read 2591 times) previous topic - next topic

Idle Problems continue, Checked IAC, and TPS...Now WHAT!?

I got my codes checked today to see if I could solve the problem of my car wanting to die out and running really rough at idle, and the only code that was pulled was "33". I briefly glanced at the code book in the Autozone and it was something EGR related.

Anyone have the more detailed description of this "Code 33"?
<---One must always remember to Remain cool, calm and collected when dealing with your fellow man, especially on the Internet....
-DMC24guy
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Idle Problems continue, Checked IAC, and TPS...Now WHAT!?

Reply #2 –
I was about to go out and buy a new Valve Positioning Sensor, should I continue? How can I check to see if the EGR is bad?
<---One must always remember to Remain cool, calm and collected when dealing with your fellow man, especially on the Internet....
-DMC24guy
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Idle Problems continue, Checked IAC, and TPS...Now WHAT!?

Reply #3 –
I would check a few things first.

First, check to see that the EGR itself holds vacuum. If it doesn't it means the bladder is busted. New EGR needed.
Next, check to see that, while applying increasing vacuum, the EGR valve moves smoothly to full compression (should occur ~4 in Hg).
Next, backprobe the EGR VPS and find out what the voltage/resistance is at 0 vacuum - and at 10" Hg. While increasing the vacuum, make sure the resistance change doesn't have any discontinuities in it.

If you don't have the tools to do said procedures...I'd just throw parts at it.

At some point in the troubleshooting, you should find your problem.
I had issues with bucking at light throttle. I did all the tests and everything passed with flying colors. I put in a new Motorcraft EGR and EGR VPS...the problem went away.
:confused: :)

Idle Problems continue, Checked IAC, and TPS...Now WHAT!?

Reply #4 –
to go with what jeremyb said,,,

here is something else in the general section
http://www.foxtbirdcougarforums.com/showthread.php?t=2984

which i pulled out for you,,,,

=============================
EGR/emissions solenoids (codes)
Dual Thermactor Air control Solenoid Valve- both should read 51-108 ohms
EGR Solenoid Vacuum Valve Assembly - both should read 32 to 64 ohms
EGR Valve Position Sensor EVP (OR/W to brn/ltgrn resistance is 5.5k with no vac and 100ohms with vac)(4-6vdc on VREF or/wht)
Electronic Vacuum Regulator EVR  30 to 70 ohms (koeo voltage is about 10.5vdc)

============================\
EGR test and EVP sensor test
apply vac pres to egr vac line fitting.
if it holds the diaphram for a long time,, the diaphram is good
remove carbon buildup on egr base as well as egr base plate assy for 3.8l engines

EVP test (egr sensor)
wire id...
EEC PIN 26   "VREF" orange/white (parallels off to map)
EEC PIN 27   "EVP SIGNAL" brown/light green   
EEC PIN 46   "SIG Return" black/white (parallels off to self test conn)

disconnect vac line
disconnect elec conn
hook ohm meter up to the VREF adn EVP Sig contacts
hook up vac guage or apply vac to egr
ohm meter should start out at about 5.5k ohms.
as vac is increased to max, resistance should bottom out to no less than 100ohms.

key on, engine off
cap off vac fitting on evp sensor
measure for 4 to 6 volts dc between VREF and SIGNAL RETURN (ground)

Idle Problems continue, Checked IAC, and TPS...Now WHAT!?

Reply #5 –
Ok guys, I changed the EGR valve positioning sensor and it made a huge difference in the way the engine performed. It woke up something in the engine and it runs much better now.

HOWEVER, I'm still having this one problem which is driving me insane. When I'm driving around and come to a stop light or any stop, my RPM's get really low. They hover around 600. And fluctuate. There is a feeling of a slight rumble when stopped, and every once in a while the rpm's drop so low the engine just dies. When I'm in park, the RPM's fluctuate up and down from 600-800rpm.

Everything else is fine. Like I said, changing that sensor seems to have awaken the engine quite a bit, but still when I come to stops, the rpms get really low, the car stutters just slightly, and occasionally the engine will die.

I changed the plugs very recently, oil changed not too long ago, Fuel Pressure Regulator changed about 2 weeks ago, car has brand new cap and rotor.....what more can I change? I mean, I suppose I could follow every single vacuum line to see if anyone is broken, but that would take some time. And the only engine code that came up when I tested it was "33".

So in closing, the car runs great now, seems to have more power, yet, when I come to stops and sit for a little while, the RPM's only hover at 600 and sometimes drop, and occasionally the engine will die out all together.
<---One must always remember to Remain cool, calm and collected when dealing with your fellow man, especially on the Internet....
-DMC24guy
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Idle Problems continue, Checked IAC, and TPS...Now WHAT!?

Reply #6 –
see what your voltage is on the green wire of the tps with just the key on

if you had a vac line broke,, it should be hissing somewhere.  The lines are not that hard to test ,, it should'nt take more than one beer and a little patience.

My wifes bronco with the duel throttle body has and idle adjustment screw ,, not sure on the 5.0's but "factory set" does not always mean "tamper proof"

do the idle control assembly's become pr0ne to carbon build up ,,,,anyone?  ,,since they are half stuck up inside the tb anyway?

in all reality,, id pull out the air charge temp sensor and clean it off next since it is responsible for some of the math involed in pulsing the injectors or adding in the width of pulse that is.  Its gonna be located on an intake runner somewhere.

Idle Problems continue, Checked IAC, and TPS...Now WHAT!?

Reply #7 –
just for grinns,, superglue a piece of thin plastic on the side of the throttle stop tab.  this will act as a temporary shim perse'.  take it for a drive and see if it stalls. 

if it does not, it tells you your idle is too low for unknown reasons at this time.

if it improves after you clean the act,, then leave it alone.

Idle Problems continue, Checked IAC, and TPS...Now WHAT!?

Reply #8 –
Where is the "tps" located? And where is this "Air charge temp sensor" you want me to clean?
<---One must always remember to Remain cool, calm and collected when dealing with your fellow man, especially on the Internet....
-DMC24guy
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Idle Problems continue, Checked IAC, and TPS...Now WHAT!?

Reply #9 –
the ACT should be the second sensor back on the driver side of the intake manifold.,,black white and light green/pink wires. (two wires)

the tps is on the throttle body,, red/green/black wires. (three wires)

Idle Problems continue, Checked IAC, and TPS...Now WHAT!?

Reply #10 –
I`m with Scott with this, check the voltage of your TPS. Actually i did the same thing in a ford explorer (is the same procedure for many ford fuel injection cars) and the idle is very good now. Get a cheap digital multimeter and check between the 3 TPS wires the voltage. It must be under 1 volt (.960 is the best setting according to many users). I can point a webpage to do so in the 5.0 engine.....
1985 Mercury Cougar V6
1989 F-200 V8
1996 Explorer V6
2001 F-150

Idle Problems continue, Checked IAC, and TPS...Now WHAT!?

Reply #11 –
Ok, I describe in detail what the engine is doing. When I'm at idle, just sitting (not in park, but in drive), the engine revs up and down between 600 and 800 rpm. I can see it on the digital tach, and can hear it revving up and down. When it drops from 800 to 600 I can also feel the engine almost wanting to sputter out.

I sat in a parking lot yesterday for about 5 minutes holding the breaks, while in drive, and for the entire time I was sitting, the engine just kept doing that. Revving up and down between 6 and 800 rpm. I could feel it, see it, and hear it.

What could cause this?
<---One must always remember to Remain cool, calm and collected when dealing with your fellow man, especially on the Internet....
-DMC24guy
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Idle Problems continue, Checked IAC, and TPS...Now WHAT!?

Reply #12 –
Quote from: DMC24guy;120636
Ok guys, I changed the EGR valve positioning sensor and it made a huge difference in the way the engine performed.


thats only half the egr system.  did you do what jeremy said?  you gotta see if the egr is holding vac.

if you dont have a vac guage / pump thing a ma jig then place a longer vac hose on the egr.  suck on the hose and the vac will hold your tongue to it.  just stay put for a little while and see if you loose suction.,, if so, its hosed up.

Idle Problems continue, Checked IAC, and TPS...Now WHAT!?

Reply #13 –
For TPS adjustment:

http://www.allfordmustangs.com/Detailed/581.shtml
-- 05 Mustang GT-Whipplecharged !!
--87 5.0 Trick Flow Heads & Intake - Custom Cam - Many other goodies...3100Lbs...Low12's!

Idle Problems continue, Checked IAC, and TPS...Now WHAT!?

Reply #14 –
Ok, more info to report.

First I checked the voltage at the Green wire on the "TPS". I was running right at where It should have been, between .98 and .99 volts.

Second, I did take off the electrical connector connected to the "IAC" and there was a drop in the RPM's, so I don't think that it's bad.

Finally I should mention this, as it may be important. The engine idles just fine for about 3 minutes. It's only after sitting for 3 minutes that the RPM's begin to fluctuate anywhere between 1k and sometimes as low as 400rpm. It's also during this time when I've noticed a strong smell of gasoline. I don't know if that has anything to do with it, but I thought I would point it out.

Any ideas? Suggestions?

(I don't what I'm supposed to be doing with that "Spout" seen in the picture above. It's there, but not connected to anything, so....?)
<---One must always remember to Remain cool, calm and collected when dealing with your fellow man, especially on the Internet....
-DMC24guy
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