Replaced upper intake manifold gaskets MORE PROBLEMS

[Daisywheels]

Hi all--

Now the truck (1999 Explorer 4.0 SOHC 4X4) is running like crap. Rough idle, loss of power, generally runs like crap. I took off some vacuum hoses while in rough idle, and they seem to make it worse. Ok, good news. At least the hoses I checked s/b working.

Since the idle is rough, I disconnected the IAC connector while running and no change whatsoever. Do not know if that is significant.

Scan codes: Well first I noticed a flashing CEL when I took it for a short test drive to store codes. Sure enough, misfires in 3 cylinders. WHAT WOULD CAUSE THIS? This never happened before.

I just changed the plugs a month ago, and checked for loose plug wire connectors and found nothing.

I am literally at my wits end.

Also, I took off the throttle body, and wasn't real sure which way to put back on that “spacer” gasket.” The “fanned out part” is on top, like the auto stores show, but it could be facing the wrong direction? I’m worse off than when I started. Still need to get to my exhaust problems. Thank you for any help! I could use any right now! Thanks again!

DW

 

[lobo411]

Make sure you wired the plugs correctly. It's really easy to get confused.

 

[Daisywheels]

Make sure you wired the plugs correctly. It's really easy to get confused.

Yeah, the plugs were wired correctly. Much improved performance before I started this new disaster of a project. DW

 

[lobo411]

Yeah, the plugs were wired correctly. Much improved performance before I started this new disaster of a project. DW

Also, I'd work the connections a little. I've miswired it a couple of times and it usually idled fine, but would start shuddering when you put it in gear. Once I had it wired correctly but it gave me a misfire code, so I disconnected the wire for the affected cylinder at the coil and reconnected it. That solved the issue.

I really doubt anything else you might have done (vacuum, gaskets) can cause 3 cylinders to misfire. It might not idle right with a big vacuum leak, but not misfire.

Did you do anything with the injector wires?

 

[Daisywheels]

No, didn't touch the injectors. The only thing close to that was the throttle body and the cover I took off. I've never had ANY misfire codes until I replaced the upper manifold. I just read somewhere that vacuum leaks and those coming from the upper manifold CAN cause misfire codes. Makes no sense to me either. Gonna do some research on the IAC since unplugging it had no effect on the motor. DW

 

[Daisywheels]

Did you do anything with the injector wires?

Well I might have if I knew where they are. Gotta take a look at the book. Would taking the upper intake manifold off inadvertently move the injector wires? I'll try to check that. I don't even know where the injectors are! Thanks - DW

 

[lobo411]

Well I might have if I knew where they are. Gotta take a look at the book. Would taking the upper intake manifold off inadvertently move the injector wires? I'll try to check that. I don't even know where the injectors are! Thanks - DW

Probably not. They're between the lower intake manifold and the upper intake manifold, roughly above the same general area where the spark plugs are for each cylinder.

Check the electrical connection to the coil pack too. Unplug it and plug it back in a few times to make sure you have a good connection.

 

[Daisywheels]

Probably not. They're between the lower intake manifold and the upper intake manifold, roughly above the same general area where the spark plugs are for each cylinder.

Check the electrical connection to the coil pack too. Unplug it and plug it back in a few times to make sure you have a good connection.

I'll disconnect and reconnect all wires - plugs and coil, but the only reason I would do that is because I might have knocked something loose. Hey, it's a free check, and why not I'm not overly confident though.....DW

 

[Daisywheels]

Yup. Everything snug, clean, and in order. Still have to replce passenger side wheel well. Thanks Ford. DW

 

[rb142]

Which three cylinders have misfires? (Are they on the same bank, etc.)

It probably an air leak (vacuum line that didn't get re-connected or something). Air leaks absolutely can create misfire. Are there any lean or rich codes?

 

[Daisywheels]

Which three cylinders have misfires? (Are they on the same bank, etc.)

It probably an air leak (vacuum line that didn't get re-connected or something). Air leaks absolutely can create misfire. Are there any lean or rich codes?

Yes, there is a lean code. I'll list the codes below:

P0303 - Ford
Type Powertrain - Ignition System or Misfire - ISO/SAE Controlled
Description
Cylinder Number 3 Misfire Conditions
Cause
Engine running in a positive torque condition, then the PCM detected a misfire condition in engine cylinder number 3 (lack of spark or fuel metering, base engine)

P1504 - Ford
Type Powertrain - Manufacturer Controlled DTC - Manufacturer Controlled
Description Idle Air Control Circuit Conditions
Cause Engine running for 1 minute, then the PCM detected an electrical load failure on the IAC motor circuit.

P0305 - Ford
Type Powertrain - Ignition System or Misfire - ISO/SAE Controlled
Description Cylinder Number 5 Misfire Conditions
Cause Engine running in a positive torque condition, then the PCM detected a misfire condition in engine cylinder number 5 (lack of spark or fuel metering, base engine)

P0306 - Ford
Type Powertrain - Ignition System or Misfire - ISO/SAE Controlled
Description Cylinder Number 6 Misfire Conditions
Cause Engine running in a positive torque condition, then the PCM detected a misfire condition in engine cylinder number 6 (lack of spark or fuel metering, base engine)

P0174 - Generic
Type Powertrain - Fuel and Air Metering - ISO/SAE Controlled
Description System Too Lean Location Bank 2

I'm at a trotal loss right now -

DW

 

[rb142]

That really sounds like a leak in the intake manifold gaskets somewhere. Spray around the area with something like carb cleaner or even just a spray bottle of water. That will get sucked in by the vacuum leak and change the way the engine is running (either better or worse depending on what you are spraying). That is one way to try to locate the leak. Based on the missing cylinders, I would concentrate around the back on the driver's side. Check out the PCV valve and hoses back there carefully too. Something might have gotten knocked off or cracked.

 

[Daisywheels]

That really sounds like a leak in the intake manifold gaskets somewhere. Spray around the area with something like carb cleaner or even just a spray bottle of water. That will get sucked in by the vacuum leak and change the way the engine is running (either better or worse depending on what you are spraying). That is one way to try to locate the leak. Based on the missing cylinders, I would concentrate around the back on the driver's side. Check out the PCV valve and hoses back there carefully too. Something might have gotten knocked off or cracked.

I tend to agree. I never had these misfire codes until I took off the upper manifold, checked gaskets - (they seemed find to me, but what do I know)

I'll purchase some new gaskets, and re-install the upper manifold. Hopefully I find some loose connections too.

One thing I know is bad the air filter box. The air filter was cracked, so I replaced it, but it seems the whole intake air tube, especially around the boxed area where the filter goes. The new filter cracked again on the orange outside area, and it just doesn't seem air tight to me. Could that alone be the cause of all the problems? The air filter box just seemed warped in some way, and the air filter never seated properly. However, it was always that way when I just had a P0701 lean code (bank 1). Truck still ran well back then. Thanks - DW

 

[Daisywheels]

Also, I tightened down the upper manifold in the correct order, but I just used in lbs by feel. Would that alone cause truck to run like crap? I could untighten, and tighten in order again, but don't really know what to expect except possibly more lost bolts! Thanks - DW

 

[rb142]

The air filter is upstream of the MAF sensor, so leaks there won't be a problem. If you have leaks in the intake tube after the MAF sensor, that could be the source of your problems.

The reason it is running like crap is because it has so much unmetered air in there that four of six cylinders are misfiring. Find the air leak and it should clear right up. It sounds like a pretty large leak, so it may be more likely to be something like a broken pcv elbow instead of the manifold gaskets.

Doing the manifold bolts by feel is probably just fine, as long as they are somewhat close to each other in torque. I don't think that is the problem.

 

[Daisywheels]

Ooops Sorry. One more thing. I took off the throttle body to inspect, when re-instaliing I wasn't sure of the orientation of that spacer/gasket. It can only go in two ways. Right now the "fanned out" part is sitting on the bottom. It can either go on top or bottom. Better yet, here is a pic - which way should it be aligned? Hmmm just paid the 20 bucks and still cannot insert an image. Any ways:

https://www.dropbox.com/s/37g4mrf5dm7at2n/tb.jpg?dl=0

 

[Daisywheels]

The air filter is upstream of the MAF sensor, so leaks there won't be a problem. If you have leaks in the intake tube after the MAF sensor, that could be the source of your problems.

The reason it is running like crap is because it has so much unmetered air in there that four of six cylinders are misfiring. Find the air leak and it should clear right up. It sounds like a pretty large leak, so it may be more likely to be something like a broken pcv elbow instead of the manifold gaskets.

Doing the manifold bolts by feel is probably just fine, as long as they are somewhat close to each other in torque. I don't think that is the problem.

Good info. Thanks! I'm going out spraying with carb cleaner now. The PCV valve and connected houses were removed and replaced. All is intact. Even the PCV is new and rattles. I seems my quest for a leak will be a long one - maybe beyond the scope my abilities. We shall see! IS there a list some where of all where to look for a vaccum leak, IE, hoses, connectors, Etc? I think, probably wrong though, that an electrical connection may also be the cuprit. But, I have no idea. -DW

 

[Daisywheels]

Update: Neighbor came over and pulled the MAF sensor, and the motor ran better. Funny, a month ago, I unplugged the MAF sensor and the motor ran worse, as it should.

He also found a hose that may be bad. It's the passenger side hose that clips to the upper manifold with those little white clips (one on each side of upper intake manfold).

So, I'm going to replace the MAF sensor and the hose mentioned above. Anybody know what that hose is called? Anybody think I'm headed in the right direction, wrong? LOL

Thanks again! DW

 

[Daisywheels]

Here are the codes now after unplugging the MAF sensor:

P0113 PowerTrain Stored Intake Air Temperature Sensor 1 Circuit High

P0102 PowerTrain Stored Mass or Volume Air Flow Circuit Low Input

P0301 PowerTrain Stored Cylinder 1 Misfire Detected

P0302 PowerTrain Stored Cylinder 2 Misfire Detected

P0303 PowerTrain Stored Cylinder 3 Misfire Detected

Back to only one bank!

DW