# 5 Cylinder

[rmrakt]

Hello,

New to this great site and am looking for help.

On my 1992 Explorer 4.0 with 180,000 miles, I had a misfire problem that I traced to the number 5 cylinder. Pulled the plugs and all looked great except # 5 which appeared wet with oil and crud. I do have spark to the cylinder (new wires and plugs). The plug did not smell like gas. Do I have a head gasket or cracked head problem? Is this common? Is it possible to have a dead injector? Can I test this injector easily? Is it worth the cost of replacing the head gasket (if the case) on this hi mile engine? Tranny was rebuilt 40k ago, truck in great shape otherwise....

Thanks in advance for the help!

 

[rmrakt]

Ok.....did some searching in this forum and found some possibilities. First and cheapest, I'll try to retorque the lower intake manifold bolts. Haven't tore into this engine before. Can anyone tell me what I need to remove to get at these bolts?

Thanks!

 

[Cameron]

It looks like you stumped us!

When I get home this evening, I'll look it up in my Helm diagnostics book to see if they have anything to say about it. I'll let you know.

 

[rmrakt]

I think I scared everyone away with too many questions in one post!?! I'll stick with the technical question next time. Thanks Cameron! Anyone else help here too?

 

[Cameron]

I don't think you scared them away, there are some very literate people on this site. It's just that I think there could be many possible factors causing your problem. Like me, they were waiting to see if some SAE certified mechanic would come to your rescue. Seeing how none have, its now up to us moderately mechanically inclined people to step in and help our fellow Explorer owner!

 

[SteveVB]

You will have to remove the upper intake( and all that attaches to it) to get to the bolts- all of the accessories can stay- the a/c line needs to be unbolted from the manifold and moved aside, shouldnt take but maybe a half hour. You dont have to remove the fuel rail, but with the pper off you can examine the injectors and check the o-rings if you want - just remember to depressurize the fuel system if you work on it.

The upper intake will probably be dirty- I would clean it, the IAC valve, and the TB while your at it. Get a few cans of cleaner and go to it.

While your looking at the manifold check for oil at the rear, also at the head to block junction- may need a new gasket. If not just retorque the bolts and put everything back together.

As you probably found this is a pretty common problem on the hihger milage OHVs

Good luck and have fun!

 

[rmrakt]

SteveVB,

Looks like it won't be too horrible of a task? ( fun? ....rather be ice fishing here in Minnesnowta!). Thanks for the details / suggestions and especially for taking the time to respond.

Have a great day.

-Rick

 

[Cameron]

Without knowing a great deal about this topic, I'll ask this question in the hopes I don't sound like an idiot:

Aren't the intake manifold bolts "torque to spec"? That is, once you torque them, you can't (or shouldn't) re-torque them? You should remove and replace them with new bolts?

But since you'll be under there anyway, wouldn't it be a good time to replace the intake manifold gasket?

I need to look in my manual to see what's all involved with doing that though.

Anyways, just thinking out loud

 

[SteveVB]

Cameron

The head bolts are torque to spec. and shouldnt be reused, but the intakes are reusable. You should loosen them up and then fiollowing the tightening sequence torque them down.

It doesnt take that long to get to the bolts to tighten the intake down. I would try that first. Replacing the intake gasket requires the removal of the valve covers which adds to the time greatly. If you do have to replace the intake gasket get a new one along with valve cover gaskets. Ford has some really nice replacements that look and work much better than the composite/paper found in most rebuild kits.

Rick,

No problem, I always strive to have some fun, If it wasnt fun, for me it would be at the dealer!!

Good luck and have Fun!!

 

[rmrakt]

Tore into it last night. The lower intake manifold bolts were incredibly loose! It was a relatively easy job to do. Cleaned up everything with cleaner (also very dirty) as you recommended. Only tough part was wrestling around the AC hose when lifting the manifold out.

After putting it back together I took the #5 plug out and cleaned it up. Started the truck and the I'm still getting the miss....Pulled the plug wire off to see if there was any variation in the engine...nothing. Pulled/cleaned the plug again (no gas smell) and drove around for a while thinking I needed to clean out any residual oil and coolant from the cylinder. No change. Tried new plug no change. Holding the plug wire a distance from the plug I seem to get a strong spark.

Shouldn't I be smelling gas on this plug? Or could the leak still be bad enough to dilute the gas.....Could I have a dead injector not supplying gas to this cylinder? Is there a simple check I could with a meter across the connectors? Didn't have enough time to pull the fuel rail off last night.

Any final suggestions would be greatly appreciated.

 

[jimbo74]

im not an ase master tech by any means but im pretty truck literate im wondering if your problem was caused by a loose spark plug ie it backed itself out a little bit? this happened to me on my old car and it ran horribly until i checked it out. that could be why you had contaminants on the plug. im thinking not a missfire problem but a lack of compression on an opened up cylinder anyone agree?

 

[rmrakt]

Nope....plug was snug when I replaced with a set of platinums. Based on what I have been reading in previous posts, I'm pretty sure the loose intake bolts caused the oil and coolant leak. I'm just wondering if the plug didn't clear itself due to it not igniting with the absence of fuel. The intake manifold leak might just be an additional performance issue I have been having?

Thanks for the input and have a great day!

 

[SteveVB]

Sounds like it could be an injector. Have you done a quick test see what codes come up- if any?

An easy test would be to listen to the injectors. If you have one of those stethascope(sp?) type things just stick it on the injector and listen for the clicking. You can use a long screw driver also.

Check the wiring harness and the plug to the injector. Across the injector you can check resistance should be around 15 ohms. You could also pull the injector connector for each injector while running look for rpm drop, no drop then that injector has a problem.

One other thing, if the upper intake was really dirty, there could be enough junk around the injector to keep it from getting the fuel into the cylinder. You may be able to tell if you pull the injector. Otherwise removal of the lower intake to clean it would be a course of action

Hope that helps some.

 

[rmrakt]

Originally posted by SteveVB
Sounds like it could be an injector. Have you done a quick test see what codes come up- if any?

An easy test would be to listen to the injectors. If you have one of those stethascope(sp?) type things just stick it on the injector and listen for the clicking. You can use a long screw driver also.

Check the wiring harness and the plug to the injector. Across the injector you can check resistance should be around 15 ohms. You could also pull the injector connector for each injector while running look for rpm drop, no drop then that injector has a problem.

One other thing, if the upper intake was really dirty, there could be enough junk around the injector to keep it from getting the fuel into the cylinder. You may be able to tell if you pull the injector. Otherwise removal of the lower intake to clean it would be a course of action

Hope that helps some.

Did pull the codes but nothing related to fuel or injectors. Possible open injector... I'll get the Ohm meter out. I think I can get at that injector withor removing the intake manifold again. Will dig deeper if need be as well. I'll throw a final update here and let you know how it turns out if anyone is interested.

Thanks again for the help fellers!!!

 

[Cameron]

I don't get it. Why would loose intake manifold bolts cause oil to get into the cylinder? I didn't think oil ran in the intake manifold. Am I wrong? If not, your problem might be a crack in the cylinder or a bad oil ring????? And the oil clogged the fuel injector??? Hence no fuel???

Just thinking out loud again!

 

[SteveVB]

Cameron,

Oil doesnt run in the manifold per say, but the oil splash and fog inside the crankcase/ top of the engine can be drawn into the intake ports if there is a leak between the intake manifold and the head.

 

[Cameron]

See? I learn something new every day!

Thanks.

 

[rmrakt]

SteveVB

One last question-

After pulling the intake off again, can I pull the #5 (center driver side)injector out without having to take the whole fuel rail off? Wanted to give it a quick visual if the resistance looks normal. I can grab and spin the injector and it seems like it could just pop it out....assuming the o-rings are the only thing holding it in place.

Thanks again.

 

[SteveVB]

Sorry, the fuel rail needs to be removed to get the injectors out. The fuel rail also clamps the injectors into the manifold, so you cant get them out without removing it.

If you do remove it you may want to get some new O rings- you could replace them all while your in there, but I would have a couple on hand just in case- better to have them and not need them, than need them at 12am when you cant get them!! There are two on each injector- one at the base into the manifold, and one at the top into the fuel rail.

Taking the fuel rail off shouldnt be too big of a deal, depressurize the system, and remove the studs, same ones you removed the nuts on to get the upper manifold off.

If you can get the injector out you may be able to get into the injector mounting hole and knock the sludge away from the injector port- it will fall into the engine if you dont use a vacuum though. The better way to do it if you see the build up is to just pull the manifold and replace the gasket. Chances are that if one is plugged it wont be too long before another is, and cleaning the lower intake certainly wont hurt anything. Just a thought.

Good luck and have fun!

 

[rmrakt]

After driving to work for a few days I checked the #5 cylinder and the plug was completely dry. The re-torquing of the lower intake manifold did the trick.
# 5 still dead tho.
Got it all apart again, measured the resistance of each injector, all were close to 17 ohms. Took fuel rail off and found that the injector looked clogged and the plastic cap on the injector was cracked for some reason. Cleaned all the injectors (boiled in vinegar-seemed to help?), used shop vac to clean around and in ports, put in new o-rings, gaskets and put it back together. She runs like a champ again...

I'll post the history of my ordeal for those of you searching for info with similar problems:

-Shuddering while in overdrive at 45-55 mph.
-Miss at idle
-Pulled plugs and #5 plug was wet with what looked like oil, coolant and some crud.
-Had spark to plug but no fire
-Retorqued Lower Intake Manifold bolts (VERY loose)
-Cleaned intake manifold, IAC, throttle body
-Cleaned dead injector (also the other five) and replaced o-rings and gaskets (Plenum and upper intake)
-Reassembled.

Two mechanics quoted me 700-900 dollars to replace the head gasket and told me to expect more as they got into it. Also looked into replacing the engine. Saved me a BUNCH.

Thanks for all the help here SteveVB.
Have a great weekend!

Now I know what you meant by "have fun"......

-Rick