Same 97 ranger, same mysterious problem, new thread

[lordkyleofearth]

I am going to start a new thread so that I can clarify the issues and hopefully find a solution (the old one is sort of a mixture of suggestions and things I've tried...)

The problem:
-It backfires, hesitates, idles rough and has very little power.
-Engine was rebuilt ~10k miles ago (rings, gaskets, bearings)
-The problem worsens the longer the truck runs.
-Check Engine Light is on, 2 codes thrown P0135 and P0141. Both were on long before the problem began.
-When it dies, the fuel pressure climbs to 40#s as the engine sputters and dies. (3:35 in the pressure test video) I don't know if this a symptom or effect.

Things I've checked:
-Fuel pressure checks out. (Between 25# and 35#s at idle/coasting, 40#s under WOT)
-No gas smell in pressure regulator's vacuum line (line is not plugged either).
-I have not been able to locate any vacuum leaks (aerosol spray test).
-I have installed a new fuel filter.
-Plug wires are routed correct.
-Plugs and wires are new, gapped correctly.
-MAF has been cleaned recently.
-IAC valve has been cleaned several times.


Things that have been suggested, but I haven't gotten to check:
-EGR could be clogged?



So that is the long and short of it. The problems seem to come and go, sometimes they are worse than others. I took the truck out the other day and drove it around for a bit and it was totally fine, not a single problem for 5-10 mins. Now it won't even idle.

I really doubt the EGR is the problem, if it were anyone with an EGR block-off plate should be having the same problem, right?

Could it possibly be a failing coil pack or injector?


*Video of driving fuel pressure test: http://www.youtube.com/watch?v=uzxkCnUuy_4

 

[tcranger]

just wondering have you checked your timing? i had a few of the same symptoms after i changed the timing belt. i checked again and i had the belt on 2 teeth off.

 

[lordkyleofearth]

I haven't checked it yet. The tensioner, belt, and all accessories are new, and it ran fine for 8 months before this started. Belt tension feels normal, and the problem comes and goes in severity. I will see if I can snag a timing light this weekend, but I suspect it will test normal.

 

[Ranger Kip]

I haven't checked it yet. The tensioner, belt, and all accessories are new, and it ran fine for 8 months before this started. Belt tension feels normal, and the problem comes and goes in severity. I will see if I can snag a timing light this weekend, but I suspect it will test normal.

I think its timing, or at the very most, a messup on your FI system's part

 

[JC 97]

I would test everything in the ignition system.Get a good manual and a good meter.Process of elimination.I would clear the codes first if it were my truck.Start with a clean slate.If you have access to a library the chilton manuals have alot of info.

 

[tcranger]

I haven't checked it yet. The tensioner, belt, and all accessories are new, and it ran fine for 8 months before this started. Belt tension feels normal, and the problem comes and goes in severity. I will see if I can snag a timing light this weekend, but I suspect it will test normal.

well not only test ignition timing, also check the valve timing. alingn your bottom pulley mark with 0* and make sure the #1 piston is at tdc, then look at you mark though the timing belt inspection cover hole to be sure the marks line up. thats what was wrong with mine.

 

[trommy]

Sound electrical.When electronic components start to die they become more sensitive to heat,thus it runs good until the affected component heats up.When it starts acting up try putting snow or cold water on one electronic component at a time (per pulling over and stopping) to cool it off.Do this until you get the right one.Hope it works out.G'night

 

[modelageek]

I am going to start a new thread so that I can clarify the issues and hopefully find a solution (the old one is sort of a mixture of suggestions and things I've tried...)

The problem:
-It backfires, hesitates, idles rough and has very little power.
-Engine was rebuilt ~10k miles ago (rings, gaskets, bearings)
-The problem worsens the longer the truck runs.
-Check Engine Light is on, 2 codes thrown P0135 and P0141. Both were on long before the problem began.
-When it dies, the fuel pressure climbs to 40#s as the engine sputters and dies. (3:35 in the pressure test video) I don't know if this a symptom or effect.

Things I've checked:
-Fuel pressure checks out. (Between 25# and 35#s at idle/coasting, 40#s under WOT)
-No gas smell in pressure regulator's vacuum line (line is not plugged either).
-I have not been able to locate any vacuum leaks (aerosol spray test).
-I have installed a new fuel filter.
-Plug wires are routed correct.
-Plugs and wires are new, gapped correctly.
-MAF has been cleaned recently.
-IAC valve has been cleaned several times.


Things that have been suggested, but I haven't gotten to check:
-EGR could be clogged?



So that is the long and short of it. The problems seem to come and go, sometimes they are worse than others. I took the truck out the other day and drove it around for a bit and it was totally fine, not a single problem for 5-10 mins. Now it won't even idle.

I really doubt the EGR is the problem, if it were anyone with an EGR block-off plate should be having the same problem, right?

Could it possibly be a failing coil pack or injector?


*Video of driving fuel pressure test: http://www.youtube.com/watch?v=uzxkCnUuy_4

I don't think it is the timing. the truck was running fine and for 8 months. plus timing would not be intermittent.

the idea of an elctroical component heating up is plausable.

some thoughts...... you said the fuel pressure climbs as the truck dies ->when your vacuum decreases the fuel pressure goes up. so either you are losing vacuum and that is raising the fuel pressure and killing the engine or something else is killing the engine and thus lowering the vacuum.


was the egr blocked off way before the issues started?

PLEASE CHECK/REPLACE FUSE #20 IN THE CABIN

I think the 2 codes that were on before are a clue p0135, and p0141. do you know if they came on at the same time or did one come on and then 6 months later the other.

if those 2 codes came on at the same time that could indicate a ground, pcm issue. please check. even though they were on long before the issue started they could have been an early sign of a bad ground etc.

do you have any other symptoms? is everything else working?

sorry if my ideas are all over the place,,,,,,,,,just doing a little brainstorming for you

 

[modelageek]

I am going to start a new thread so that I can clarify the issues and hopefully find a solution (the old one is sort of a mixture of suggestions and things I've tried...)

The problem:
-It backfires, hesitates, idles rough and has very little power.
-Engine was rebuilt ~10k miles ago (rings, gaskets, bearings)
-The problem worsens the longer the truck runs.
-Check Engine Light is on, 2 codes thrown P0135 and P0141. Both were on long before the problem began.
-When it dies, the fuel pressure climbs to 40#s as the engine sputters and dies. (3:35 in the pressure test video) I don't know if this a symptom or effect.

Things I've checked:
-Fuel pressure checks out. (Between 25# and 35#s at idle/coasting, 40#s under WOT)
-No gas smell in pressure regulator's vacuum line (line is not plugged either).
-I have not been able to locate any vacuum leaks (aerosol spray test).
-I have installed a new fuel filter.
-Plug wires are routed correct.
-Plugs and wires are new, gapped correctly.
-MAF has been cleaned recently.
-IAC valve has been cleaned several times.


Things that have been suggested, but I haven't gotten to check:
-EGR could be clogged?



So that is the long and short of it. The problems seem to come and go, sometimes they are worse than others. I took the truck out the other day and drove it around for a bit and it was totally fine, not a single problem for 5-10 mins. Now it won't even idle.

I really doubt the EGR is the problem, if it were anyone with an EGR block-off plate should be having the same problem, right?

Could it possibly be a failing coil pack or injector?


*Video of driving fuel pressure test: http://www.youtube.com/watch?v=uzxkCnUuy_4

afew more thoughts

Do you own a code reader? if so see if you can catch a pending code? I have solved a few issue this way. the code is pending and the CEL never goes on!!

next time it acts up, try the "pull a sensor one at a time DX technique" and see if anything happens. it could be a lot of things, the maf could still be bad. I however think that if codes p0135, p0141 came on at the same time that you have some short, ground, pcm issue and it took a while to manifest itself into a bad running truck? did you check the grounds on the engine etc?

 

[lordkyleofearth]

I don't think it is the timing. the truck was running fine and for 8 months. plus timing would not be intermittent.

the idea of an elctroical component heating up is plausable.

some thoughts...... you said the fuel pressure climbs as the truck dies ->when your vacuum decreases the fuel pressure goes up. so either you are losing vacuum and that is raising the fuel pressure and killing the engine or something else is killing the engine and thus lowering the vacuum.


was the egr blocked off way before the issues started?

PLEASE CHECK/REPLACE FUSE #20 IN THE CABIN

I think the 2 codes that were on before are a clue p0135, and p0141. do you know if they came on at the same time or did one come on and then 6 months later the other.

if those 2 codes came on at the same time that could indicate a ground, pcm issue. please check. even though they were on long before the issue started they could have been an early sign of a bad ground etc.

do you have any other symptoms? is everything else working?

sorry if my ideas are all over the place,,,,,,,,,just doing a little brainstorming for you

EGR isn't blocked off, it should be breathing fine. The codes were on when I bought the truck and remained on once I did my engine swap. I replaced both sensors, ran a new wire from pin-out to pin-out on the PCM and the codes are still on.

Everything else seems to work fine, but it's an XL with manual everything and and the radio was stolen before I obtained the truck; not much there other than the engine.

I have occasional access to a reader, and the only codes I've ever seen are p0141 and p0135. I got one for the MAF once, but I cleaned it and it cleared out.

I'll go check the fuses once it stops raining...

 

[JC 97]

From chilton manual your code PO135

■HO2S heater power circuit is open or heater ground circuit open

■HO2S signal tracking (due to oil or moisture in the connector)

■HO2S is damaged or has failed

■PCM has failed

PO141Engine running for 5 minutes, and the PCM detected an open or shorted condition, or excessive current draw in the heater circuit.

Possible Causes:

■HO2S heater power circuit is open or heater ground circuit open

■HO2S signal tracking (due to oil or moisture in the connector)

■HO2S is damaged or has failed

■PCM has failed

Just some more info.

 

[BLS2.3]

"HO2S" is that "Heated O2 Sensor"?

 

[JC 97]

Yes

 

[adsm08]

Dude, my first thoughts upon reading your symptom list was oxygen sensor. Then I saw your codes. Replace your oxygen sensor, clear your codes, and see what happens.

 

[lordkyleofearth]

Crappy weather outside today, so I wasn't able to test much. Started it up today and it would die and barely run. poked around the hood a little (didn't really do anything, just made sure nothing was unplugged-- nothing was) and then it idled like a champ.

Cabin fuse #20 checked out just fine.

Both O2 sensors are new. I suspected a short (the wiring harness was a bit ugly when I bought it) so I clipped the heater circuit wires and ran a new line from the PCM harness to the each sensor, and back to the PCM. Codes remain and return after reset.

I wonder if my PCM is failing... that could cause the bizarre running conditions, no?