• đź’ˇ Fun fact. Whenever you start a thread, TCG Mechanic 5000 (our AI bot) will reply to you to start helping. It doesn't know everything and it will struggle with more complex questions but it can get the thread going and provide valuable information. You can choose to disable it prior to submitting a thread.

CEL, running rough, stalling...

clinton

Member
Mar 24, 2012
17
0
Hello-
I have been having some issues with the MM. My car has the following mods:

Zack tune
4.10
JLT intake
SW headers & exhaust
Factory COP with GMS connectors

For starters the car has been throwing P0171 and P0174 on and off for a while. I am under the impression it is a vacuum leak somewhere as the car was running fine. Recently the car started stumbling, running rough, and rich exhaust smell at an idle. It would also occasionally stall right after being started. It has gotten worse where the car will now stall if it's let to sit and idle for about 3-4 minutes. It still drives good with no detectable issues until I come to a stop. When it stalls it does not make any funny noises its as if the key was shut off. I scanned the codes and the following showed up:

P0171 lean bank 1
P0173 lean bank 2
P1131 OP2 sensor 1 bank 1
P1151 Heated O2
P1235 Fuel pump out of range

I cleaned the iac real good and reset the codes. Cleaning the iac did not help the stalling at idle. The car seems to run fine in traffic. I have driven it about 70 miles after clearing the codes and the light is still out.

Anyone have any ideas?
 

musclemerc

Addict
Jan 6, 2010
554
0
Well let's see.... You cleaned the IAC.... You probably already checked the MAF.... Cleaned the TB.... Right? LOL!!!

It sounds like you've got a vacuum leak to throw a lean code on both banks. Look over the fitting that goes from the pcv tube to the upper intake (these are prone to cracking). If you need a replacement shoot me a PM.

If the intake fitting is OK your EGR valve is stuck in the open position. Replace it.

Carry on......
 

clinton

Member
Mar 24, 2012
17
0
Well let's see.... You cleaned the IAC.... You probably already checked the MAF.... Cleaned the TB.... Right? LOL!!!

It sounds like you've got a vacuum leak to throw a lean code on both banks. Look over the fitting that goes from the pcv tube to the upper intake (these are prone to cracking). If you need a replacement shoot me a PM.

If the intake fitting is OK your EGR valve is stuck in the open position.

Carry on......

:jg: is there a way to check the EGR or just replace it? I have one of your catch cans on the car so that hose is a non issue. I only assumed the IAC because the car would stall when started. I didn't do anything with the MAF or TB.
 

MMBLUE

Regular
Apr 27, 2011
171
0
That was just an inside joke with a few of us here. I've got a document saved on one of my PC's on how to test if it's working correct let me look.

Didn't we gave this same problem with my EGR? If I remember correctly, it has something to do with when it idles and doesn't close/open and gets stuck. When you stuck my car on the Computer thingy (can't remember the name) it had parameters to operate between (20ish) and took forever to level out to normal when idling.
 

clinton

Member
Mar 24, 2012
17
0
Didn't we gave this same problem with my EGR? If I remember correctly, it has something to do with when it idles and doesn't close/open and gets stuck. When you stuck my car on the Computer thingy (can't remember the name) it had parameters to operate between (20ish) and took forever to level out to normal when idling.

Did you just replace the EGR or did you do something else?

I have an egr delete for my eaton swap can I just do that now or would it somehow damage something? :hsughno:
 

musclemerc

Addict
Jan 6, 2010
554
0
Didn't we gave this same problem with my EGR? If I remember correctly, it has something to do with when it idles and doesn't close/open and gets stuck. When you stuck my car on the Computer thingy (can't remember the name) it had parameters to operate between (20ish) and took forever to level out to normal when idling.

Yep

Did you just replace the EGR or did you do something else?

I have an egr delete for my eaton swap can I just do that now or would it somehow damage something? :hsughno:

Install the block off plate and see if the car will idle. You will throw a code for the EGR but atleast you will know if it's the EGR or not
 

clinton

Member
Mar 24, 2012
17
0
Yes. And we replaced the whole motor.


The EGR was just part of the problem. It ended up having the dreaded 4.6 heated cylinder effed up burnt valve loss of compression disease.


Well, I got a new set of plugs in the mail yesterday I will throw those in and the block off plate to see if it runs better. Lets hope I don't have the same problem as yours....:pedobear:
 

MMBLUE

Regular
Apr 27, 2011
171
0
Mine ran like shit for a long time before I got sick of it and Musclemerc did the engine swap out( Much thanks again) After that...Problem cured.

We replaced cops, plugs,egr, fuel filter yadda yada you name it. Compression test was the straw that broke the camels back. If you run into a brick wall, try a compression test.
 

clinton

Member
Mar 24, 2012
17
0
I have one from Harbor Freight.
I seem to recall I had to modify it to work, but not sure.

Good luck! Check for obvious things, like vacuum leaks.

I will head over there today and see what they have available.

I checked again for vacuum leaks both visually and with carb cleaner. I sprayed the shit out of this thing. No results.

:dunno: I did check fuel pressure and here is a quick video below.

Also one of these days I will get my grill over to you Zack.

https://www.youtube.com/watch?v=K92SxmTrKmA&feature=youtube_gdata_player

or Photobucket

 

clinton

Member
Mar 24, 2012
17
0
Good point you made here Zack. I'm getting my fuel pressure reading from an Aeroforce gauge that pulls the info directly from the PCM. If you have 30psi at idle then fuel isn't your problem.

Time to do a compression and a leak down test

Good to know fuel isn't the issue. Didn't have time to go to Harbor Freight to get the compression tester. I ordered a set of OEM coils as suggested by Zack. He stated that he experienced the same codes with a motor he installed and it was fixed when he swapped the coils. They are going to be here on Friday. If is still doing the same thing I will be doing the compression test.
 

clinton

Member
Mar 24, 2012
17
0
I have about had it with this thing. I have replaced the coils with brand new ford units, new NGK plugs, checked fuel pressure and determined that is not an issue, and swapped EGR with a verified good used unit. I cleared the codes and fired it up. After idling for about 5-7 minutes....the damn thing died again. Its as if the key was shut off. No sputtering etc. I fired it back up after that then took it out for several WOT blasts and drove for a couple miles after that. No codes, again the cycle is not complete yet. Once I returned from the drive I let it idle, it died again after several minutes.
 
Old Thread: Hello . There have been no replies in this thread for 90 days.
Content in this thread may no longer be relevant. Consider starting a new thread to get fresh replies.

Thread Info