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99 Sport 4.0 2WD issue


Curmudgeon

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I did an internet search, found a thread, think I posted in wrong year, so doing it here:

99 sport 2wd, 4.0 pushrod. 190K. Intermittent sometimes violent shaking. Sometimes it's great, sometimes you think the engine is going to part company with the mounts. Best description is a death rattle, like a loose front end on my 1950 F-1. Fuel filter early this year, 6600 Mac's injector cleaner (every time), Autolites, Belden wires, single 6 port coil pack, air filter, cleaned MAF, had a mouse eaten wire to #4 injector, unable any more to do that myself, had it done, no change, shop changed the injector (their scope showed an occasional #4 misfire), no change. I did EGR test, normal. NO CODES except the P0401 for the road test with EGR unplugged to see if it was dumping too fast...no change. Did NOT light CEL. Transmission shop drove it with me, said not trans as tach did not even flutter when this happened....he said trains issue would have caused tach to flutter or move radically. DeOxIt5 cleaned engine gang plug, PCM gang plug, performed wiggle test on all wire bundles and plugs while running, no change. Fuel pressure at 60PSI, loaded st 2200 RPM, still 60PSI. Serviced trans....no change. Can start at 25, usually goes away at 40, but shop said still there at freeway speeds. Plugs on LH bank look normal. No oil, no burning, no pearly white. Thought PCM, but all the folks I know who do this or did say 99, no. Never the PCM. Plug voltage about 10K at each end, cylinder balance normal. Haven't done compression test yet (have to wait for pain levels to go down). Shop threw their hands up (they said exactly that), 35 years of wrenching and I am at a loss. Has to be simple.
I'm running out of strength and energy, and ideas.
Thanks.
 


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Curmudgeon

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Two days now of perfect running. The intermittent part of this drives me nuts.
I put a vacuum gauge on it today, drove it all over, of course no failures, but vacuum was normal.
 




RickOTR

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Sounds like it could be a clyinder imbalance due to new fuel injector. Computers probably going crazy trying to keep fuel trims even due to new injector. Always a good Idea to install all new injectors not just one. Lots of info on it on this forum.
 




Curmudgeon

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Could be. In fact, if the issue began with a rebuilt or new injector, yeah. But this has been going on for months, injector was what, 10 days ago. Everything we do fixes it for a day, then back to original problem. I am noticing the issue seems to be "refining", not as broad, more narrow in grade and speed, load, but maybe it's my imagination.
My other two Fords here, I get cluster misfires like that, I look at the ammeter....6V positively grounded, generator not charging, primary voltage low, does this. One of the first things I did was check voltage.
Did plugs first, then wires, then coil, as it just acts like ignition. Doesn't seen to be any way on a 99 OBD to view crank or cam sensors. Thought about that a lot. However, crank sensors usually just fail.
 




RickOTR

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If the wire was cut and not firing the injector, then the injector probably had a lot of carbon built up on the nozzle. I went through this once and all new injectors solved the problem. In order to see real condition of the injectors or cylinder, you will need a scan tool that can deliver live data. As for the crankshaft sensor, it will not always suddenly fail or set a check engine light. Once again don't as me how I know.
 




Curmudgeon

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I was able to duplicate, drive, mash on the brakes, bring RPM's up to 2200-2400 and there it was. No driveline or wheel rotation.
Ran good for two days, today back with a vengeance, shakes all over under light load up a....guess...2% grade, 2 miles long.
Vacuum gauge showed normal, under load drops, slight variation due to road grade changing (and commensurate engine speed), but no wild waving of needle.
Did find the 3/8" vacuum line from charcoal canister to bottom of throttle body collapsed and split.
Replaced from canister to TB and road test....no change, same issue.

So tests indicate not trans, driveshaft, diff, axle and wheel bearings, wheels, or tires.

I have noticed RPM's are taking longer than I recall to come back down when you start it. Finally settles down 800-900 from high of 2K RPMs.

More data. The car now has a discernible misfire at idle when you start it. It also smells hot. Cat not glowing. STFT and LTFT oscillating around zero when this issue occurs, does not spike more than it does before the issue manifests itself.
I thought once while power loading that the....LTFT was giving low level jumps towards negative, but could not duplicate.
Since it smelled hot, I grabbed my IR temp gun and checked exhaust runners.
1,2,3,5 and6 are 215-250 F, depending on where I hit them.
4 (the problem cylinder) is 351F no matter where I hit it.
The idle being high and not wanting to come right down tends to make me think vacuum leak, yet vacuum gauge showed 20".

Unplugged EGR, tapped around the diaphram to make sure it seated. Drove it, no change.
Full flood crank, no "dead holes".
Opened #4 gap to .054", no change.
Squirt oiled around injector to make sure the o-ring wasn't leaking...no problem.
Another can of Carb Cleaner....no change in idle at all, anywhere.
Put the other coil pack on and closed the shop.
I did yank the PCM this morning, opened it up looking for any water damage, corrosion, burned bit....nothing.
I keep thinking if those chewed wires touched, you'd think it would fry the injector driver not make it intermittent. No idea where to go next.
 




Curmudgeon

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Yesterday wife has driven it all over, runs perfectly. Probably 50 miles, four fairly major local trips, up hills, flats, start and stop, and it's been fine. Not a hiccup.

Looking for something obscure like a rocker arm, intake gasket.....gasket's don't fix themselves like this. Rockers would clatter, and no clatter.

And the issue is back this morning under load...plus you can feel a misfire a bit at idle.

LTFT B1 -.8%
LTFT B2 +2.3%
This are stabilized just off idle.

Letting vehicle come back down to idle and stabilize:

LTFT B1 +1.6%
LTFT B2 +3.9%
So they both appear low, but from what I can read, Bank 1 (right side Ford) is too low. Yet the issue seems to be #4 cylinder, which is front of Bank 2.

Just re-checked, LTFT B1 is +4.7%, LTFT B2 is +5.5%.

Makes no sense.
How can Long Term change that fast?

The TPS is odd. I am used to early computer cars, EEC-IV stuff, TPS on carb or throttle body...definite readings like a volume control.
This one, it moves in directions you don't expect, then as you hold throttle it drifts to wherever it wants to be and not necessarily where it started.
Like an engine that "hunts" idle with a vacuum leak....yet we have 20" steady.
Also, today (different than yesterday) I cannot hold idle.
Bring it up to stabilize and read LTFT, pedal does not move, RPM drops back down to idle. Have to get it real high (1800-2000) to have it even think about holding enough to read values.

The idle is driving me nuts. I kept thinking I was doing something with my foot. So, I dragged the scan tool out under the bonnet, engine running, manually operated the throttle....and RPM's came up. And dropped back to idle with no change in position of throttle. Then it came up quite a bit, again with no change in throttle.
Since about halfway into this, the trans has been shifting...differently. Goes more rapidly through the gears. Road test this afternoon indicated 4th gear at 28 MPH.
Currently at idle 16.8% to 17% TPS.

Removed the TPS.
Bench tested with my ancient Triplett 630 VOM.
About 3.7K both increase side and decrease side, no jumps.
Started it, surged up to about 2K RPM, held for a bit, finally came down (not normal for this vehicle). Again held the RPM up and it dropped itself down to idle with pedal slightly depressed.
MAF about 1.5 GPM at 1500 RPM.
You would not believe the number of unresolved hits on the internet of 4.0L with #4 misfires.

Intake Air temp ambient.

When idle drops, gets rough.

I have ordered gaskets and I'll remove and clean Idle Air Control and Throttle Body next.

No definitive direction shown in test data it seems.
 




Curmudgeon

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in the middle of this...the battery died. At least 10 years old.
But I did clean throttle body and IAC. NAPA gave me FOUR throttle body gaskets. Initially didn't think any were right, as I was looking for black not blue...road test without new seal and it howled.
Blue thick o-ring with kickout for air bypass, fixed that.
NEW battery, road test monitoring TPS...moves where it's supposed to, 18% baseline, no glitches.
However, LTFT B2 is zero. I suppose battery disconnected for an hour while I obtained replacement is an issue there, wiped the LTFT numbers? But LTFT B1 is reading, so not sure.

Drove fine, transmission even shifted right, 40 MPG last shift instead of 28 MPH, OD kicks in and out normally now, like it used to, so tomorrow we drive it from cold.


IAC gasket from NAPA is a gasket. In the car is an almost figure 8. Did NOT put the gasket in...yet.
 




96eb96

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in the middle of this...the battery died. At least 10 years old.
But I did clean throttle body and IAC. NAPA gave me FOUR throttle body gaskets. Initially didn't think any were right, as I was looking for black not blue...road test without new seal and it howled.
Blue thick o-ring with kickout for air bypass, fixed that.
NEW battery, road test monitoring TPS...moves where it's supposed to, 18% baseline, no glitches.
However, LTFT B2 is zero. I suppose battery disconnected for an hour while I obtained replacement is an issue there, wiped the LTFT numbers? But LTFT B1 is reading, so not sure.

Drove fine, transmission even shifted right, 40 MPG last shift instead of 28 MPH, OD kicks in and out normally now, like it used to, so tomorrow we drive it from cold.


IAC gasket from NAPA is a gasket. In the car is an almost figure 8. Did NOT put the gasket in...yet.

I read all this and I'm going to suspect a cracked head if the injector is working. Not uncommon. Mine also did that on 4.
Blow compressed air into 4 at TDC and see if the coolant rises.

You can fix the head but there is a good mechanic in a bottle that works.

There is an app called Forscan (free) and a cheap obd adapter. It can view misfires counts on the cylinders.
 




410Fortune

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99 fuel pressure spec is 65 psi +/- 8 psi.... so you are in range but on the lower side
Check for cracked head/head gasket issue it sure sounds like it.....one or more cylinder fouling out due to water
Compression / head gasket test in order
with those miles and being a pushrod 4.0 I would suspect a head gasket issue
 




Curmudgeon

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No coolant loss. No fouled plugs. All plugs (old and new) same coloring. Vacuum stable.
Pushrods didn't crack like SOHC engines, did they?
 




Curmudgeon

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This morning after 5 miles of driving, symptoms all came back. I need to check and see what LTFT did as B2 was zero.
If it's changed, then I have a clue here as soon as I can decipher what that clue actually is.
Doesn't sound like any crack symptom I've ever seen, and Lord knows driving Flatheads since 1965 I have experience with cracks....albeit not computer controlled cracks!
 




Curmudgeon

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Data.
I tested the LTFT values, driving, shaking even, LTFT B1 0 at idle, moves up while driving.
LTFT B2 2.3 at idle, moves up and down a bit while driving.


Did some digging, looking at O2 sensors, and I have a problem.
O2 B1 S2 I thought was stuck at .775, but driving it does move, from about there up to .790.
O2 B2 S1 is .105 to .720 while driving.


This seems to be the one behind the cat...and not sure if that number I'm reading is correct.

Still no codes, trans seems to shift close to what it did last night...4th a couple miles and hour slower (like 38 vs 40)



Went out again, at idle, still warm, o2 b1 s2 now .090 to .100. Holding idle 1800-2000 starts climbing, quit my test at .410.
o2 b1 s1 .085-.765.
o2 b2 s1 .070-.745.
Two front o2 sensors look right.

stft b1 s1 -2.3 to +2.3.
sftf b2 s1 -2.3 to +2.3.
stft b1 s2 99.2%, and I read that is normal.

My readings look good. Other than post cat o2 which is odd. I think I changed that about 6 or 7 years ago. Remember it being a PITA on top.

I suppose comp test. Boy, that's gonna hurt.
 




Curmudgeon

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Road test with scanner (still jerking under load), LTFT B1 at cruise is zero. LTFT B2 is +4.7.
Come back, idle, B1 is 3.9, B2 is 6.9.

Replaced the IAC gasket first.

Sprayed upper end of engine with carb spray while monitoring STFT and LTFT and no change. So vacuum leaks are pretty much eliminated.
 




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