Explorer turns over, but won't start!

[2000StreetRod]

Bosch plugs

Some forum members have reported misfires after installing new Bosch plugs. I'm using Champion Truck Plugs myself but they are no longer available for purchase: Improving fuel economy (post #10 & 11)

Having used anti-seize on spark plugs in the past a few times I now agree with your mechanic. Almost all of the spark plugs now available are designed not to seize in the head (nickel coated threads). Anti-seize hardens with age from the heat making the plug difficult to unscrew after breaking it loose. I'm not familiar with its dielectric qualities but I've never experienced misfires attributed to the anti-seize compound. I think some anti-seize compounds are copper based and therefore conductive. NGK's position is not to use anti-seize for fear of over torquing and because it's not needed since their plug threads are nickel coated. Bosch takes the same position.

 

[Exproblems]

Some forum members have reported misfires after installing new Bosch plugs.

Having used anti-seize on spark plugs in the past a few times I now agree with your mechanic. Almost all of the spark plugs now available are designed not to seize in the head (nickel coated threads). Anti-seize hardens with age from the heat making the plug difficult to unscrew after breaking it loose. I'm not familiar with its dielectric qualities but I've never experienced misfires attributed to the anti-seize compound. I think some anti-seize compounds are copper based and therefore conductive. NGK's position is not to use anti-seize for fear of over torquing and because it's not needed since their plug threads are nickel coated. Bosch takes the same position.

Yeah, I saw some of the past comments in here on people having problems with Bosch plugs, but I was using them in my Explorer for the first few months after I bought it and didn't have any problems with them. While my vehicle was into a shop for some diagnostic work, another mechanic that I was using for the first time (recommended by a carpet installer working at my house) stated the Bosch plugs were the wrong type of plug to use and he installed Autolite's at the time. I didn't see any great benefit by using the Autolite's and thought that the engine ran better on the Bosch, but left the Autolite's in. Bosch is a German/European company as far as I know and they make parts that go into some really high end cars like Mercedes, BMW and Porsche's etc, so they must know what they are doing in my opinion. German's are known for their engineering and building quality merchandise.

My mechanic said the same as you, the anti-seize made the plugs harder to remove due to the heat involved and they harden into place over time. He said he's seen the cylinder threads get damaged from the stuck plugs. I told him the Haynes Manual recommends using anti-seize on the plug threads and I double checked on that yesterday and it is definitely written in the Haynes manual I have, which is for the 2002-2010 Ford Explorers and Mercury Mountaineers. It's on page 1-24, Illustration #29.11A at the bottom left hand side of the page. Picture shows a hand holding a spark plug and a small brush applying anti-seize compound to the threads. The instructions say to: "Apply a thin coat of anti-seize compound to the spark plug threads". My mechanic was pretty adamant against using anti seize on the plug threads so I won't be doing that anymore. Thanks again for the info and it's good to hear you say the same things as my mechanic. I know I can trust him, hasn't steered me wrong before, but it's just good to get the reinforcement.

 

[2000StreetRod]

waste spark ignition

The Explorers prior to the coil over plug ignition system utilize a waste spark ignition. The V6 coil pack has three coils (transformers) and the cylinder plugs are paired (wired in series). When one plug fires on the compression stroke its pair fires on the exhaust stroke. Current flows from tip electrode to center electrode on one bank and center electrode to tip electrode on the other bank.

The factory used to install different plug types on the left bank vs the right bank. Now that double platinum or double iridium plugs are available the same type plug can be installed in either bank. The gap is more important since two plugs are involved. I wonder if those who had problems with Bosch plugs installed single platinum or single iridium plugs with the preset gap.

I agree that German automotive engineering is usually high quality and that Bosch fuel injection systems were superior for many years to others available. However, in the case of the Cologne manufactured SOHC V6 the Germans made a serious mistake in placing the right camshaft timing components in the rear.

 

[Exproblems]

The factory used to install different plug types on the left bank vs the right bank.

I agree that German automotive engineering is usually high quality and that Bosch fuel injection systems were superior for many years to others available. However, in the case of the Cologne manufactured SOHC V6 the Germans made a serious mistake in placing the right camshaft timing components in the rear.

I remember reading in here a while back about there being a different plug type for each bank and I also saw it mentioned in the Haynes Manual under "Tune up and Routine Maintenance" where it lists the Motorcraft plug part numbers for each year vehicle. Different part numbers for the left and right sides.

I agree and I guess we'll just have to call the improper placement of the rear timing components a German "Mulligan", at the cost of probably me and many others before me. BTW, thanks for the schematic info!

 

[Jesla]

….

I agree and I guess we'll just have to call the improper placement of the rear timing components a German "Mulligan", at the cost of probably me and many others before me. BTW, thanks for the schematic info!

Wonder if they just didn't foresee the Americans take it and mount it longitudinal………*dunno*…….

 

[ScottieJ59]

Did you ever get the result from ford? And if I can ask, What was the cost to fix through them? Cause Im having the same problem and my Mechanic told me there was no compression..

 

[Yellohmmr]

Same symptoms

Hello,
I plan to complete my profile soon. I am hoping this thread will continue. I am having the same problem with a 1999 4.0L OHV engine with 147,000 miles. The hard starting came on fast and the problem grew progressively worse until it refused to start. Last try, the engine made a “poof” sound, similar to a weak backfire, after turning over several times. I’m in the early stages of diagnoses and hope to hear from anyone familiar with the 4.0 OHV engine. Thanks.

-Timing chain tensioner was changed at 102,000 miles.
-Currently ordering a Motorcraft IAC valve, will be testing fuel pressure soon and looking for vacuum leaks.

 

[john gillenwater]

Yeah I'm curious my 2002 xlt sohc is doing the same thing

 

[john gillenwater]

Mine wil

Yeah I'm curious my 2002 xlt sohc is doing the same thing

Mine will run with starting fluid

 

[Fish Use]

I'm looking for any ideas as to why my 2005 4.0L V-6 Explorer engine won't start up this morning. I went to start the vehicle and during the startup process with the key in the run/start position, I thought I heard a brief sound like a small "poof" or backfire and the engine wouldn't start. I backed off on the key and tried to start the vehicle again and it would just turn over, but not fire up. The starter is working okay, turning the motor over, and I can smell gas fumes in the air after trying to start it a few times. No strange noises coming from the engine as it turns over. I then checked a few fuses under the hood and they were okay. I also pressed the fuel pump reset button for $hits and giggles, but I do not believe that this is a fuel pump issue since I can smell gas fumes coming from the engine compartment, meaning gas is being delivered to the engine via the fuel pump. I checked the battery connections, spark wires etc, all okay. The vehicle had been starting and running fine since I bought it 2 + years ago. No unusual dash lights blinking on and off during the start up process. I will try to start it up again in a few hours since the engine probably got flooded by fuel trying to get it to fire up. So far all I could find in the forum as to the problem is possibly a "Crank Shaft Position Sensor" or a problem in the PATS system and I don't think the latter problem applies here. I'm going to have it towed up to my mechanic in the morning if it doesn't start later this morning.
Thanks to anyone that can give me some insight as to what this problem may be.

A few hours have passed by and I tried to re-start my Explorer and had put the battery on a charger for a few hours as well. Engine turned over, but would not start. After the 3rd try or so to start it, I noticed the engine spun slower like a huge drain of power, and after I switched off the ignition, I noticed the gauge needles for the RPM's and MPH's dropped below zero and rattled back and forth quickly for a few seconds before settling down at zero. I also saw a single word message on my message screen when the gauge needles were rattling and it said "Test". Don't know what the Test was for? Does anyone know what this is or means? I also pulled more fuses for the ignition, fuel pump and starter and all were good. I also had a neighbor turn on the ignition for me and I listened for the fuel pump to kick on and I heard a "clicking" sound by the gas tank. Tow truck is on it's way to my house as of right now. Dropping truck off at my mechanics shop. Thanks again for all who can help with this matter.

Hi, was there a happy ending?

 

[Fordowner7]

Mine wil
Mine will run with starting fluid

I have the same problem with 2002 Ford explorer XLT 4.0 sohc ... Would like to hear what the Ford mechanics said the exact problem was and how much it cost for the repair

 

[Fordowner7]

slipped timing chain

When you stated in the first post there was a small poof or backfire I began to suspect that the timing chain may have slipped. I agree with your mechanic that the next step is to check compression on both banks. Low compression for all cylinders on one bank equals slipped chain on that bank. No compression on one bank equals damaged valves. Low compression on both banks equals slipped primary (crankshaft to jackshaft) chain which is uncommon. If the right chain has slipped it may be cheaper to replace the engine with one from a salvage yard. How many miles are there on the odometer? If more than 200K then a slipped timing chain is more probable.

What if it was a rebuild engine not even a year ago ? Do you think a slipped timing chain is still probable ?

 

[Christi 444]

Not cool to leave us hanging. Thanks.