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Old 10-31-2011
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Icon5 Help with 1994 4.0L Ranger misfiring & hesitating under load?

As the title says, i have a 1994 Ranger, 2WD, 4.0L, 5-speed that has been gradually getting worse over the last few weeks.
The truck has 101k miles and it's pretty well maintained as far as tune-ups go.

Here is what i am dealing with: At idle, truck not moving - everything seems normal. RPM are stable, engine does not vibrate or shake more than usual. It feels the same as it did 3 years ago when i got it from previous owner.

The problem: When truck has not been driven for awhile, when accelerating or taking off from a stop, i can feel that the engine does not run smoothly and i can sense some roughness transmitted to the chassis. It feels like there is excessive engine vibration during slow or hard acceleration. What really bothers me is that as soon as i shift into second gear and i step on the gas (not floor it, but start to accelerate) i can feel that the truck is underpowered and that it starts to misfire, hesitate and even shake. It feels like it cuts on and off randomly.
If i happen to up-shift to 3rd gear a bit earlier and step on the gas, it misfires and SHAKES even worse and it feels extra sluggish! On 4th and 5th gear, this happens even more often and the shaking & misfiring are worse. Sometimes, i cannot even drive it on 5th when on the freeway because it shakes/misfires and it cannot accelerate to highway speeds and keep up. I am forced to keep it in 4th gear in order to do 65-70mph.

=> Another important symptom i noticed that is very disturbing is that sometimes, on 3rd gear or 4th, when i feel that truck is very underpowered and i floor it, it hesitates even more, shakes and i can hear & feel an audible"knock" or "detonation" somewhere seems like it's under my feet. Sometimes it does 2-3 or 4 detonations or audible "booms" in a row, until i back off from the gas. :(

=> The interesting thing is that once the truck warms up and has been driven for some time, the misfire, hesitations, shaking and overall sluggishness almost go away. It does not run perfectly but it is a lot better and smoother than it is when i drive it for the first few miles. It will still occasionally hesitate or misfire under hard acceleration. Unfortunately, over the last week, even when the truck warms up, it is still acting up.

So, what could be causing all this??

Here is what i have done so far to troubleshoot this with NO success:

1. Pulled OBD codes with OBD I Ford code scanner and only code i got is "214" which i've seen on and off for the last 3 years. I am 99% sure it is not related to this new misfire issue. Code 214 is Cylinder ID fault and i was never able to get rid of it. Again, i had this code 214 well before the misfire started. No other codes are stored in memory and the OBD I system seems very limited when it comes to diagnosis. :( It does not tell me which cylinder is misfiring.

2. I replaced all 6 spark plugs with properly gapped Autolite Platinum spark plugs. I installed new spark plug wires as well, few months ago. It made no difference.

3. I just replaced the coil pack with a brand new one (no brand name) that i got from Ebay. It made no difference compared the OEM one.

4. I got a spark tester and checked all 6 spark plugs for spark - all 6 tested good.

5. I cleaned the MAF sensor with MAF cleaner. It made no difference.

6. Air filter, PCV valve, and fuel filter are new. Made no difference.

7. Visually i do not see or hear any vacuum leaks, broken vacuum hoses, etc.

8. One of the oxygen sensors has been replaced in the past, since i see that it is branded Bosch and the other one is OEM Ford branded. I am not sure if a bad Oxygen sensor will cause such major misfire and/or detonations under load & acceleration.

9. This "problem" is gradually getting worse. The truck is driven very little since it is a third car and i use it only for weekend yard shopping trips. What started with minor hesitation and occasional misfire a year ago, is now happening 90-95% of the time. The truck is still drive-able and it starts every single time, does not die on me at stop lights and idles well. However, the loss of power is very obvious, the hesitation and misfires are common and the knocks/detonations are pretty loud under hard acceleration on 3rd/4th gear.

Given everything i listed above, what should i do next to diagnose and fix this?
Aside from the spark plugs and coil pack, what could be the next 2 or 3 most likely reasons for this problem? Injectors? Fuel pump? Catalytic converter? Bad MAF? Computer?
I cannot afford to buy brand new parts and try replacing everything on a truck that is worth $2k. This is why i want to start with the most likely areas first.


Thank you in advance for any input!

Last edited by danmm7; 10-31-2011 at 01:01 AM.
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Old 10-31-2011
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I've been down this road with two 4.0's. Common culprits are:
1. Dpfe and associated lines cracking/ melting
2. Vacuum leak in multiple spots on the intake, notably between the composite upper intake and fuel rail.
3. Burnt plug wire, check the driver side wires very closely as they have an awkwardly close positioning to the exhaust manifold.( although this would generally pull a cylinder x misfire code)

I would guess that since you admittedly do not drive the truck often you are not fully cycling through codes and it just hasn't thrown one yet. My truck would throw one after approximately 50 miles when I had dpfe issues.
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Old 11-03-2011
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214 is a CM DTC, the description is Cylinder Identification (CID) circuit failure. I don't have my diagnostic flow chart CD handy (but this is what you need to get your hands on to diagnose and fix it, short of the silly guessing game), but the description suggests cam position sensor/related circuit and/or crank position sensor or circuit. Get your hands on the Ford or Alldata (info is from Ford) diagnostic flow chart for resolving DTC #214 and follow it.

By the description of what the code means, Cylinder Identification (CID) circuit failure, it's suggesting that the ECM can't correctly find or is losing track of engine position. What happens in a distributorless ignition system (EDIS) is, when you go to start it the crank position sensor and circuity tell the ECM where top dead center (TDC) is for cyl #1, but there are two possibilities. It could find TDC for the exhaust/intake stroke, or it could find TDC for the compression/combustion stroke. The cam position sensor tells the ECM which of the two it is. Failure of these circuits (keyword = circuits, and that does not automatically mean a bad sensor) causes the ECM to make an assumption in an attempt to start the engine, and will put the system in limp mode and will trip the check engine light (CEL) . CM is a "hard fault" meaning it's always there, as opposed to a soft fault, like a KOER DTC, that may come and go for many reasons.

The problem should not be overly difficult to diagnose; if diagnostics prove that it is in fact the cam position sensor, access may prove to be humbling.
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Old 11-03-2011
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Here are some thoughts and questions i have about the CAMshaft position sensor.

I have been getting OBD I code #214 (Cylinder ID fault) for the last 2+ years but the truck seemed to run very well, despite the check engine light being always ON. I replaced the cranckshaft position sensor a year ago but it made no difference for the code. I still get 214. Sounds like the only other sensor left that can cause this 214 code is the CAMshaft position sensor. My truck is 1994, and many Ford/Mazda documents state that 1994 should not have a camshaft sensor and only 1995+ have it.

My 1994 truck (built 11/93) HAS such sensor. I saw it and even took a picture of it. It's by the firewall and very hard to get to. It's a California truck, so maybe they put a 1995 4.0L engine in it. Who knows?!?! Ideas? I am planning to buy a 1995 Camshaft position sensor and replace mine. I hope it fits since these things are not cheap. :(

As a side note, when i used my OBD I scanner and tried to run an "engine running" test to find more codes, during the testing the OBD scanner tells you how many cylinders it is testing and it always shows "4" on my truck. I have a V6! Isn't this strange? Why is the scanner seeing only 4 cylinders on a V6 engine. Maybe that 214 code is the reason for it.

Could a complete failure of the Camshaft position sensor be the reason for all my truck's misfiring, hesitation, engine vibration and loss of power??
My idle is still stable and the truck starts every time. It's only acting up under ANY acceleration and load. It's is getting worse by the day. :(

At this point i am leaning towards: a) bad Camshaft sensor, b) bad Catalytic converters, c) Bad Fuel pump or injector.
Am i missing anything else more obvious?


Thanks!
Dan
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Old 11-04-2011
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I've seem to have the same problem here as well, my 97 had been doing that for a long while. It did get to the point of killing itself at a medium load in any gear. Only big difference, after flooring it, and it puking in the intake, literally, for a quick minute, it would run like like a vengeful demon.

Cody's got it down to a science, the upper intake gaskets like to leek, the particular one he points was shot for me. After replacing that it ran good for a while, but the evap&egr systems screwed me worse.

I am definitely going to replace the position sensors if I can't prove they're good.
A fella had said to me about a screen at the fuel pump, and said you'd still have good pressure with that. Check your pressure before you needlessly replace the pump though.
My heads are cracked too.... yay
And I'm not entertaining the idea of reinstalling the egr system.
(perhaps the evap system too if I can?)
Lastly, can't you see if your cat is clogged, not sure though.

I feel your pain, Dan.
Godspeed.
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Old 11-06-2011
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Quote:
Originally Posted by danmm7 View Post
Here are some thoughts and questions i have about the CAMshaft position sensor.

I have been getting OBD I code #214 (Cylinder ID fault) for the last 2+ years but the truck seemed to run very well, despite the check engine light being always ON. I replaced the cranckshaft position sensor a year ago but it made no difference for the code. I still get 214. Sounds like the only other sensor left that can cause this 214 code is the CAMshaft position sensor. My truck is 1994, and many Ford/Mazda documents state that 1994 should not have a camshaft sensor and only 1995+ have it.

My 1994 truck (built 11/93) HAS such sensor. I saw it and even took a picture of it. It's by the firewall and very hard to get to. It's a California truck, so maybe they put a 1995 4.0L engine in it. Who knows?!?! Ideas? I am planning to buy a 1995 Camshaft position sensor and replace mine. I hope it fits since these things are not cheap. :(

As a side note, when i used my OBD I scanner and tried to run an "engine running" test to find more codes, during the testing the OBD scanner tells you how many cylinders it is testing and it always shows "4" on my truck. I have a V6! Isn't this strange? Why is the scanner seeing only 4 cylinders on a V6 engine. Maybe that 214 code is the reason for it.

Could a complete failure of the Camshaft position sensor be the reason for all my truck's misfiring, hesitation, engine vibration and loss of power??
My idle is still stable and the truck starts every time. It's only acting up under ANY acceleration and load. It's is getting worse by the day. :(

At this point i am leaning towards: a) bad Camshaft sensor, b) bad Catalytic converters, c) Bad Fuel pump or injector.
Am i missing anything else more obvious?


Thanks!
Dan
You are overlooking something very obvious and important. In particular, the acquisition, reading, invoking/application of the manufacturer service procedures for DTC #214, as laid out in their diagnostic flow charts.

If I understand you correctly, your code reader is being flakey. In light of this, I would bail on that reader and start the diagnosis from scratch. Begin by checking for obvious problmes under the hood, like disconnected wiring, disconnected vac hoses, vac hose nipples broke off of components, damaged components, and all that. Once that passes, use the CEL to check for codes, not your reader. You must understand that DTC's (codes) MUST be repaired following the sequence of KOEO, KOER, and CM, and withing each of those groups you MUST fix the lowest code # first, this is how it's (correctly) done. You need to realize that the elimination of one code can result of the elimination of other codes, this is why, if you want to do it right, you must follow the proper repair sequence.

*Leaking intake gaskets on the Ford OHV 4.0 caused by loose mounting bolts almost always first let the problem be known by causing engine knock under heavy load and on a warm engine. They can also cause small to medium quantities of coolant to be lost, with it being drawn into the intake ports. Retorquing the lower intake bolts cures leaky lower intake gaskets maybe 95% of the time. Not always will a leaky intake and the resulting lean mixture trip the CEL. To retorque correctly, follow the torque pattern when doing so, it's a freebie that will take you under 30 minutes.

*Clogged cats eventually make a sound when observed outside of the vehicle and with the drivers foot hard into it, that will sound like a Hoover. They are also known to glow red and in extreme circumstances make the interior carpet smoke and ignite undercoating on the vehicle, resulting in a fire. You can easily diagnose for clogged cats by using a vac gauge. Or for fun, you can always do like soe people do and make a guess, pay the $$$ to replace, and prey. Not too smart, IMO.

Dirty MAF's can also cause a lean condition that, under heavy load and on a warm engine, will cause knock. Not always will this trip the CEL. When you clean a MAF, don't spray it off and call it a day, to do it right you use a small artists paint brush (like the kind used to paint model cars) to clean the elements of the MAF sensor. They are delicate, this is why you use use a soft brush as I noted. Gently bow them off when done, and not with the compressor regulator set to 90psi. Gently means just that.

Assuming that you do in fact complete the visual as I noted, correct any obvious problems, pull codes and again find that the only code is CM DTC #214, then you need to fix that. It's an obvious problems staring you in the face.

When people take their car to the Ford dealer here, they pay $80/hr for repair plus full retail cost for parts. As such, customers expect the service tech to use his brain and all available knowledge to get to the point and solve the problem fast. This saves the customer money. I just don't understand why people like us that fix vehicle problems ourselves would not want to do the same, but some guys, for probably the reason being lack of knowledge/understanding or reading too much internet and concocting dreams, prefer to guess and prey, hoping for the better and usually wasting time and money.
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