Running Rich Rough Idle pls HELP

[glenn_a]

Hi fellow Explorers, I need your help...

First couple of months ago I have this issues on and off problem that I can smell the car running rich and when ever I start the Explorer I cant just take off and drive because it kinda runs rough and it feels like its about to stall and when you accelerate it feels like its surging but eventually it will clear out and its good to go. this only happens on first time start if its sitting for a half a day...

2days ago I took the Engine off just to work on the Oil Sump, after all the job done the Explorer started fine like it should be but soon I drove it for half hour and starting to rough idle and puffing on the exhaust with a black smoke (kinda running rough and it surging soon you accelerate but on high revs it feels like it clears out but when it back to normal idle then it surge again)

Now Ive been reading forum to forums, people says it could be Air Flow Meter, PCM, Oxygen Sensor, EGR, Vacuum Leaks, Foul Plugs, Fuel pressure...

I have done the scanning and found my Air Flow Meter was faulty P1100 (MAF Sensor Intermittent) and noticed the P1000 (OBD11 System checks Incomplete) was there too.

Then first I replaced the Air Flow Meter and It cleared from the scanning but the P1000 still there and the Explorer still running same problem...

Second I replaced the PCM and it cleared the from scanning but then the problem still there...

I was thinking maybe the Injectors are playing up so I removed it and check for pattern spray which is still looking good, while I'm at it I checked for any vacuum hoses it maybe cracked or came off and if there's any gasket been damaged but no sign either...

Now I'm definitely stuck and don't know where to go now... I replaced the spark plugs again but still the same, leads and coil pack still good too...

................Please If there's anyone out there could help me out and maybe had same experiences please share what you done to solve this issue..............


[note] I have a SOHC V6 engine Ford Explorer XLT 1997....
Thank you!

 

[glenn_a]

 

[glenn_a]

 

[glenn_a]

 

[glenn_a]

 

[rocketcouch]

On my ohv it was the egr valve. I put a piece of gasket material between the valve and the tube and ran the car and it was smooth. You may get a code if you run it too long like that though

 

[2000StreetRod]

FPR ruptured diaphragm?

I confirmed from your other thread that you have the SOHC V6.

One possible source of a rich mixture is a defective engine coolant temperature sensor (reads cold when the engine is actually warmed up). But apparently according to your 3rd post that has been tested and it is good.

Another possibility is a ruptured diaphragm in the fuel pressure regulator (FPR). Fuel flows thru the rupture and is pulled into the intake manifold by vacuum. You can test the FPR diaphragm with a hand vacuum pump. If it won't hold a vacuum then the diaphragm is shot. If you don't have a vacuum pump just disconnect the vacuum line to the FPR and see if fuel is present.

 

[glenn_a]

On my ohv it was the egr valve. I put a piece of gasket material between the valve and the tube and ran the car and it was smooth. You may get a code if you run it too long like that though

thanks mate, what would happen if i disconnect the egr completely? is it bad?

 

[glenn_a]

I confirmed from your other thread that you have the SOHC V6.

One possible source of a rich mixture is a defective engine coolant temperature sensor (reads cold when the engine is actually warmed up). But apparently according to your 3rd post that has been tested and it is good.

Another possibility is a ruptured diaphragm in the fuel pressure regulator (FPR). Fuel flows thru the rupture and is pulled into the intake manifold by vacuum. You can test the FPR diaphragm with a hand vacuum pump. If it won't hold a vacuum then the diaphragm is shot. If you don't have a vacuum pump just disconnect the vacuum line to the FPR and see if fuel is present.

thank's...

I did checked that fuel pressure regulator and its all good. . . theres a good vacuum in the hose and no fuel coming out of the regulator plus it does still hold the vacuum no problem....

 

[glenn_a]

if the egr valve faulty would it do this problem? I just noticed that when I pulled out the vacuum hose to the egr it seems no vacuum in there but when i rev the engine i can just barely feel the vaccum... is that normal?

what else should i check for...?

 

[2000StreetRod]

No EGR at idle

The PCM should disable the EGR at idle and moderate to full throttle: EGR System O&T

With black smoke out the tailpipe I'm surprised there are no DTCs such as:
P0172 System too Rich (Bank 1)
P0175 System too Rich (Bank 2)

Do you have any way to read the long term fuel trims?
Do you have any way to determine if the PCM transitions from open to closed loop after engine start?
Have you checked for obstructions in the intake (mouse nest in air filter box)?
Is mud caked on the precat O2 sensors?
Have you tested the MAF sensor: MAF Sensor Test Procedure

 

[glenn_a]

The PCM should disable the EGR at idle and moderate to full throttle: EGR System O&T

With black smoke out the tailpipe I'm surprised there are no DTCs such as:
P0172 System too Rich (Bank 1)
P0175 System too Rich (Bank 2)

Do you have any way to read the long term fuel trims?
Do you have any way to determine if the PCM transitions from open to closed loop after engine start?
Have you checked for obstructions in the intake (mouse nest in air filter box)?
Is mud caked on the precat O2 sensors?
Have you tested the MAF sensor: MAF Sensor Test Procedure

I really appreciate for your time 2000StreetRod....

yes no codes for system running rich....
About the injectors it been service not long ago...
Air intake been checked and exhaust system was new too 6mths ago...

this morning I start the Explorer and notice that it runs okay when its cold but 30secs-1mimute later starting to splatter and runs rough...
I double checked the spark plugs which I just put them on while the engine was off last week and found (right bank are all slightly black and the left bank front and rear cyl. plug looks clean but I pulled out the middle plugs and same as the right bank all slightly black...

(it seems the front and rear left bank not firing or not working that is why its running rich...)

I checked the coil and high tension leads and it has strong spark...

try too cool it down now and do a compression check but I doubt the cylinder problem and Im thinking it could be a faulty spark plugs...

 

[glenn_a]

 

[glenn_a]

 

[2000StreetRod]

plug type & gap?

What type of plugs are those and what is the gap? I use discontinued Champion Truck Plugs with copper electrodes gapped at .054 in.

Your waste spark ignition system simultaneously fires two plugs - one on compression and one on exhaust stroke.

The plugs on one bank fire from center electrode to outer and on the other bank from outer electrode to center. For that reason, if you purchase platinum or iridium plugs they need to be dual platinum or iridium

 

[glenn_a]

if the firing order is

I guess my no. 4 & 6 cyl. seems to be not working but when ever I pulled the high tension leads off it has a pretty strong spark... so im guessing its the spark plugs but still waiting for the parts to arrive...

 

[glenn_a]

What type of plugs are those and what is the gap? I use discontinued Champion Truck Plugs with copper electrodes gapped at .054 in.

I'm using a Champion spark plugs before all these problem I used Champion RS12PYP (standard) but then 2weeks ago I followed what the book says Champion Iridium 9204.... not been gapped just straight from the box

what would you recommend..?

 

[2000StreetRod]

can't trust out of the box gaps

The reason I asked about the gap is because it looked excessive to me in the photo. You can't assume plugs that are used in many different vehicles will be gapped correctly for your application. Even if they were, sometimes they get thrown around in the box which can reduce the gap. I think most people on the forum seem to like Motorcraft or Autolite dual platinum for extended mileage. I bought the Truck Plugs because they have heavy duty electrodes and are designed for rugged use. I only drive about 3,000 miles per year and I don't drive off road but I thought they might hold up better for forced induction. When they were discontinued I purchased 3 sets for about $12 a set.

Edit: According to the literature:
They have a copper cored center electrode that has a spark area 20% greater than a conventional plug for longer life and heavy duty performance.
The insulator upper is black glazed zirconium encased ceramic that offers 40% more strength providing durability under rough driving conditions.
They have a semi-conductor suppressor to eliminate RF interference.
The shell is triple coated with special anti-seizing coating.
The copper cored ground electrode dissipates heat at a rate ten times greater than a conventional plug to prevent pre-ignition under high load conditions.

 

[glenn_a]

The reason I asked about the gap is because it looked excessive to me in the photo. You can't assume plugs that are used in many different vehicles will be gapped correctly for your application. Even if they were, sometimes they get thrown around in the box which can reduce the gap. I think most people on the forum seem to like Motorcraft or Autolite dual platinum for extended mileage. I bought the Truck Plugs because they have heavy duty electrodes and are designed for rugged use. I only drive about 3,000 miles per year and I don't drive off road but I thought they might hold up better for forced induction. When they were discontinued I purchased 3 sets for about $12 a set.

I see, would you know the part numbers for the Champion plugs...?

I just rang City Ford too and says MOTOCRAFT SP500 SPARK PLUG (AGSF22FM) I should use...

what would you recommend and can you give me the part numbers too please...

thank you!

 

[2000StreetRod]

Champion 4401 Truck Plugs

I purchased Champion 4401 Truck Plugs. I just did a Google search and ordered two more plugs @ $1.95 each with free shipping: CHAMPION 4401 TRUCK SPARK PLUG . I don't know how many they have left. Champion discontinued them a couple of years ago.

Rock Auto shows the Motorcraft SP500 AGSF22FM as suitable for a 1997 SOHC V6. I suspect they are finewire single platinum with a nickel plated shell. The Motorcraft AGSF22PP are double platinum and should last longer in one of the banks. I'd have to think about which bank fires from the outer electrode to the inner electrode and transfers metal in that direction. The Ford factory used to install different plugs in bank 1 than bank 2 because of the different direction of current flow. Coil over plug implementation on the later generation Explorers eliminated the waste spark system which I've never been impressed with.

Edit: I just did an eBay search and found a set of six for $6 plus $6 (for a set) shipping to US. Let me know if you don't want them so I can buy them.