4.0 won't start or run

[unoleisu]

I've got a 97 expl XLT 2wd. When I bought it (winter, 08), it ran fine for a few weeks, then just quit starting. I replaced the MAF with a new one, and Temp. Sensor with new, also new plugs. It ran rough, and then died again. When I got it to start again after days of trying, I took it to Autozone and checked the codes.
Got P1151- lack of 02 switches, bank 2 sensor 1. ECM could not adjust because of lean or rich condition.
Probable causes: 1. fuel pressure high or low 2. MAF sensor dirty or defective 3. Vacuum leak on engine 4. leaking fuel injector or fuel pressure regulator
It ran fine thru the next summer then started acting up again. Took it back to autozone and scan test said 2,3, and 5 plugs misfiring. Replaced plugs and plugwires. Ran fine for a little while, then Started the same thing again. (only at first, I noted that it would not start only when the outside temp was under 50 deg. but ran fine in the 70's) It finely got to where it would not start and run at all.

Jan. 2010 I replaced TPS, IAC and Intake air sensor, as well as the O2 sensor at Bank2sensor 1
I tested the coils and harness and all passed according to the book. Found that the clips on the coil harness connector was broken and it was wire tied on, I made sure it was tight. After recharging the battery, It started and ran fine. Next day wouldn't start again. Checked the coil harness again, seemed fine and tight. Still no start.
I gave up and let it sit until june, 2010 trying occasionally to start it,Then finely towed it to a Mechanic, who kept it for 3 mths....
He said he fixed it. Replaced Battery, fuel filter, air filter, IAC, altrenator, Tested the fuel pressure, replaced the plugs, and finely disconnected the Stereo system (saying this was the REAL problem, it was shorting out).
The truck started up rough at the shop, but then leveled out, and ran fine on the way home. I went the next day to move it from my driveway to another spot, and it ran really rough, dying as i got it to the new spot. Can't get it to run again since then.
Today I tried to test the Crank position sensor, (since it seemed to me if this was an old car running like this, it might be timing) It seemed ok. The fuel pressure test port on the rail didn't seem to have much pressure when I depressed the "valve stem" only a little gas dribbled out. ( I thought it might have SOME pressure beyond that).

I'm obviuosly shooting into the dark here, and not getting any help from the mechanic.

Can anybody help a guy with no clues left?

 

[feellnfroggy]

Yeah disconnect the fuel lines from the rail, get you a catch can and turn the switch on(have a friend do it) an check for pressure directly from the pump. This will check for a clog in the fuel lines or a bad pressure regulator. Also have your fuel injectors removed and cleaned. check the fuel tank if you can for a bad pump or clogged pickup.

 

[unoleisu]

update:
I jumpered around the inertia switch to see if that might be the issue. NoGo.
Shot some starter fluid into the intake. NOGO
Pulled the coilpac and tested according to the haynes book.
Target range is 6.5-11.5 ohms, I got:
1-5= 12.9
2-6= 13.25
3-4= 13.52
primary resistance was .6 on all (target is .3-1.0)

I pulled a coil pac from my 92 EXP and tested and got:
1-5= 13.0
2-6= 13.19
3-4= 13.32
primary resistance was .6 on all
Put it in the 97 exp. NoGo

I pulled a coilpac from my old 97 Taurus wagon.
not exactly the same (connector was pointed upward)
tested it and got
1-5= 12.36
2-6= 12.65
3-4= 12.59
Primary resistance was .6 on all.
got it to plug in and tried to start. NoGo

I tested for power on the positive wire at coilpac, with ignition on, It was fine.

I'll try what feellnfroggy said about fuel lines, ect.

Any one else care to contribute? I seem to be learning alot about what is NOT wrong with this fine piece of Engineering. I think I'm getting that frustrated feeling again.....

 

[unoleisu]

Ok, I pulled the fuel line before and after the filter, and tested. It seems to have a fair amount of pressure. My book talks about the fuel pressure regulator, but doesn't show it, or it's location. I'm not sure which is the return line.

It would make since if I have fuel pressure to the fuel rail (assuming I have fire) that I should At least be trying to start, unless all the pressure is running strait back to the tank because of a bad pressure regulator. However, even with starter fluid, it didn't try to start up.

What am I missing here?

 

[Rudie Del Rude]

The regulator will be mounted on the fuel rail, it will have a vacuum line on it and a fuel hose. It's a round donut looking thing.

 

[Rudie Del Rude]

If your fuel pump works, yet you aren't getting much pressure at the rail then its a clog or your regulators bad. find that return and see if its spitting fuel back out.
if its not spitting fuel out then ide say have a clog.
if you're pressure at the rail is fine check the injectors and make sure they're ticking. I'm not sure if that will tell you how much fuel is spraying let alone any (clog) but it rules some things out.

have you tested the precise pressure? if not, its a good idea to. If its within specs at the rail then you can rule out the pump/regulator/lines. Make sure you test it as you crank the engine over and make sure it holds kind of steady.
I also noticed that when you tested the resistance between the coils they were off of what the book said they're supposed to be at. That's kind of a red flag. Unless you're 100% sure the one from you're other explorer is the exact same as in the problem explorer. ( wouldn't that mean that the resistannce is too high in that one too?) I'm kind of confused.

 

[cowboykilroy]

You said you bench tested you coil pack, did you check it on the engine by pulling a plug wire and grounding a sparkplug , or a screwdriver in the end or the wire and cranking the engine and looking for spark? I ask because we seem to be chasing a fuel problem but you say it won't hit on starting fluid, making fuel a non issue at this point in time.Next if you have a good spark and fuel then it is time to do a compression test, looking for indications of timing chain having jumped a tooth or two. Old school was simple set engine top dead center compression line up timing marks ,pop the distributor cap and see if the rotor was pointing to number one terminal . hope this all makes sense if not ask. Dennis

 

[unoleisu]

I do not have a working test light to use to check for voltage pulse from the Crank position sensor at the coil, or a fuel pressure gauge to check for correct pressure at the fuel Rail. I guess I'm running into town this morning to get these and do those checks.
I did try to get spark from a plug wire to engine, and from coil to plugwire, But at that time the sun was in my eyes and the battery died. So I decided it was time to recharge battery, and look elsewhere while that was happening.
I reallize the coils all tested above spec, But also know the 92 explorer, and the 97 Taurus were running fine, so they should have given me something.
According to my LMC catalogue, the coil is the same for the two years (from 91 to 2000, I think it said)I know they look exactly the same.

Thanks for the help guys. Please keep it coming!

 

[unoleisu]

OK, Got a fuel Pressure test gauge, a circuit tester (I think the wrong kind, book said it should be an LED, this one isn't) and a Spark tester.
* Fuel pressure pumps up to 45 psi, and holds that pressure, after 5 min. is staying at 35psi. These are in specs.
* there is spark at the #5 plug wire (using the spark tester). It is blue with a little yellow in it. I ran the battery down at this point, and am charging it back up.

I had the intake tube off, just in front of the throttle,TPS, and heard it litely backfire out this way. I opened the throttle all the way while cranking, and it occasionally backfired out the intake. ONCE, it almost started, but could not get it to repeat.

Is this timing? How hard is it to change a timing chain on a 4.0 SOHC? I've done it before on older carbed ingines, but the book I have said I have to pull the engine and do it from an engine stand...is it really that difficult?

I'm out of time to continue today, but plan to try to check timing at #1 cylinder tomorrow.

Is there something else I should concider first? Thanks for the input, guys!

 

[Rudie Del Rude]

Im sure you can get away with leaving the engine in to change the timing. You might have to pull the radiator to give you a little room to work.

How's you're exhaust lookin? I think a clogged cat can cause backfiring.

 

[unoleisu]

No exhaust whatsoever. Can't get it to start. Seriously, I think it was alittle smoky the last time it ran... thought it was condensation in the pipe.

OK, back to my reality. Found the culprit. All cylinders are approxamitly 100 Deg out of time. Apparently the 97 - 2000 4.0 SOHC's were notorius for the timing chain guides failing. There was a major recall to fix the issue. Ford seemed to wisen up after 2000 and fix the problem BEFORE they sold them. The recall is void now, so we're on our own. Both heads have timing chains in addition to the Primary timing chain, so it's important to check all the cylinders for timing position. Since they are all out of time the same amount, I think it's fairly safe to assume only the Primary chain is the issue.

I seriously would have thought that somebody on here would be aware of this recalled timing issue. Hmm. Oh well, I'm passing it on to whoever might want to know.

My internet research showed me that the 4.0 SOHC in general is concidered almost as powerful as the 5.0, and definately more than the pushrod 4.0, although it doesn't seem to produce as much low end torc that off roaders like. Mustang racers seem to really like it.
I personally don't know that I like it so much since it has 3 timing chains that could shut you down at a bad time, and require an engine pull to work on 2 of them.

WORD TO THE WISE:
If you have a 4.0 SOHC, and notice rattly sounds when starting cold, and especially going up into 2nd, and if it gets to where it is doing it warm as well, your chain guides are likely shot, and you are likely to jump time.

Now I need to find an affordable Primary Timing Chain rebuild kit.

 

[unoleisu]

BTW:
I think there is an excellent oppertunity to add a SOHC section to the 4.0 tech page.... It is a different beast, and apparently has a lot of modifications possible in the after-market.