'99 2.5 Rough Running, Terrible Idle, Detonation

[Bernard]

Hi All,

I'm getting desperate, where my Ranger is concerned.

Went out, for a routine drive, three weeks ago. On the way up a hill (not a severe grade) I heard some detonation. Slowed down, to relieve the problem. As the drive went on, it kept getting (gradually) worse, and started running rough. Still, it did not light up the check engine light.

Took it home, and connected my Actron code reader.
No codes.
Guessed that the problem had to be fuel starvation.
Replaced the fuel pump.
No joy.
Replaced the fuel filter.
No joy.
Replaced the injectors.
No joy.
Took it to a local shop, where the owner connected it to his diagnostic equipment. He came up with a laundry list, for me, which I have started on.
Replaced the front coil pack.
No joy.
Swapped the original front, for the rear coil pack.
No joy.
Replaced the four passenger side spark plugs.
No joy.
Replaced the idle control valve.
No joy.

At that point, I realized that I was pissing in the wind, and came up with a new strategy. I'm asking the hive mind for help.

Do any of you have any wisdom, that you'd be willing to share, on the topic?

Thank you, so much, in advance,
Bernard.


1999 Ranger 2-door, 2WD, 5-speed, short bed, regular cab, no cruise control, 125,000 miles.

 

[Mark_88]

Howdy Bernard,

I can suggest a few things that maybe you haven't tried and are easy enough...

did you try spraying starter fluid into the TB and cranking? If so, did it cough or just crank?

Are you able to test for spark either at the coil or the plug? you can just stick an extra plug in the #1 wire and hold it close to the valve cover...if you don't see spark it could be part of the problem.

do you hear the fuel pump kick in when you turn the key? It should pump for a few seconds and shut off every time you turn the key on to start...unless you hold the pedal to the floor...

You can also check the inertia switch to see if it is tripped...it should be up under the dash on the passenger side...small switch either near the center of the firewall near the hump or it could be under the side kick panel...my 96 is behind the kick panel (It is now) but it may have been centrally located before I swapped out the wires...

Anyway, it has a trip switch on it and they can do intermittent if they are fried...where it will allow the fuel pumps to come on but then shut down...sporadically.

It does sound like it went into limp mode going up the hill so it could be that your computer is not sending the proper firing information...meaning it could be the crank position sensor...but I do believe you would be getting a code on that...

 

[tomw]

If it is still 'rough running, poor idle and detonation' as the symptom list, have you checked coolant and temperature? You can get detonation and other symptoms if the engine is too hot.
If the EGR stuck open, you could get a VERY poor idle. If the MAP sensor went nutso, you would also have a poor idle, and maybe erratic fuel injected as the computer responded to the 'load' signal from the MAP.
You replaced the pump & filter, but did you check that the fuel pressure regulator is working properly? If it broke, it might not be supplying the fuel requested by the computer, leading to your symptoms.
tom

 

[Bernard]

Mark, Tom,

Thanks, for your replies. I appreciate your taking the time to write.

I should add, to the list of symptoms, that the engine smooths out, if I give it a little gas. That's with no load. With load, everything goes to hell. Also, the plugs I pulled, were showing lots of carbon fouling.

 

[tomw]

All that's left is the fuel pressure regulator. If it jammed or quit working consistently, you'd get more or less fuel than desired. Carbon fouled plugs mean too much fuel. If the pressure was too high, you'd get that. If the plugs weren't firing, you'd get that, but might get it 'washed' by enough excessive fuel.
What is it doing now?
tom

 

[Mark_88]

Mark, Tom,

Thanks, for your replies. I appreciate your taking the time to write.

I should add, to the list of symptoms, that the engine smooths out, if I give it a little gas. That's with no load. With load, everything goes to hell. Also, the plugs I pulled, were showing lots of carbon fouling.

OK, sorry, I was under the impression that it would not start. It does start but still runs like carp under load...

I'm with tomw on the FPR being a possible fault...there is a vacuum line on it that if you can get your nose close enough to it (or take it off) and sniff it...if you smell gas in the hose then the FPR is pooched. There is a diaphram inside that can break causing it to not work as intended...fairly easy fix too...

 

[Bernard]

I think we're on the same page. I'd wanted to replace the FPR initially, when I replaced the fuel pump, but the parts house(s) didn't have a listing for it, not even on their website(s). Finally had the good fortune of being helped by a counter man who chose to look under the 2000 model year, and . . . presto.

Part's on order.

Best regards,
Bernard.

 

[Mark_88]

That's good to know, actually.

I have a 98 2.5 running on the 96 2.3 fuel injection and spark system and was wondering if the 2.5 parts would swap in. They should...hypothetically...like fuel rails from the 96 bolted right in there so I don't see why they would be different...other than possible bigger injectors.

Anyway...hopefully that is the problem...did you try the sniff test on the vacuum hose? Should be a very distinct smell of gas in there if the diaphram ruptured...

 

[Bernard]

Mark,

No, I have not done the sniff test. In part, I'm lazy, in part, it's too cold (for me).

Will report after swapping FPR. Part has not arrived, as yet.

Best Regards,
Bernard.

 

[CajunPwnStar]

Same problem here. Very rough idle that will smooth out after a few minutes and drives fine. If I approach a stop sign/light and press the clutch in, it almost stalls from the RPM drop and goes back to a rough idle. I haven't thrown anything at it yet, but from what I can tell it may be the FPR.

 

[Bernard]

OK, I had ordered the FPR for a '00 MY, as my local Pep Boys did not have a listing, for a '99 MY FPR. Checked with AutoZone, and they did not have a listing, either.

'00 MY FPR arrived. I looked at it, and noticed that it was different. Returned it. While I was snooping, under the hood, I performed the sniff test. The vacuum line smelled like gasoline.

Called the Ford dealer, to find out, if I could get the correct FPR through them. I can. It is part #9F775 (actually F87Z-9F775-AA}. I asked if it comes with a hose attached. It does not.

Removed the FPR, and took it to the Dealer, to ensure we were talking about the same part (see pic). As part of that exercise, I made a hose connector separation tool, from aluminum sheet stock.

Parts man said that he can order the FPR, but that the attached hose carried a separate part number, that being #9F895. They also have a part number, for the assembly, FPR + hose = F87Z-9D980-AA. Sadly, that is obsolete. So is the hose.

Problem is, the hose does not seem to be of the type you'd want to try to re-use, as it looks like some kind of heat-swaging process was used. Have any of you attempted separating the hose from the old FPR, and re-using it, on a new FPR?

Best regards,
Bernard.

 

[Mark_88]

Can't say that I've done that myself since this is my first fuel injected 2.3/2.5. I've never actually had the thing apart to note any differences in the parts...just figured they must be really similar...but the intake side of things is new territory for me.

 

[tomw]

Try here:

http://www.fordpartsgiant.com/parts...-manifold-injectors-valves-related-parts.html

I muddled the part numbers & did a google for:

F87Z-9F895-AA

Oops. When I got to the parts page, I thought it had them stocked for ~$65. Not. Disco.

This site had 9 possible dealers...

https://www.easyparts.com/Parts/Fuel-and-Emissions/Fuel-Tank/Ford/F87Z9F895AA

I did not call any of them checking availability. Might be some aggregator that shows parts, but no one has them. I dunno.

Pretty sure FoMoCo bookends the base part number with year on one end and suffix for modded parts at the other ...
F8 == 98
Being old, my memory starts with C5AZ ... and I just keep adding to get to the year needed.
tom

added: For rough idle, look at two things: MAP and IAC. MAP can fiddle with the fuel mix based on manifold vacuum, and if broken, can/will buffalo the computer and lead to really BAD idle. IAC will just cause low idle or high idle, the former can be so low that the engine stumbles and stalls.

Sorry... MAF <> MAP, and I meant MAP in the last para.

 

[Bernard]

Could have sworn I posted, last night, so there must be a dictum I forgot, regarding reigning in the lingual flourishes.

Newest updates:
Replaced a few more plugs, and most of the ignition leads. The only ones I was too lazy to do, were #3 and 4, under the intake manifold.
No joy.
Replaced the downstrem O2 densor (couldn't do the upper, seized)
Nope.
Replaced the crankshaft position sensor.
Nada.
Pulled the computer, to look for an equivalent, on ebay. While they have a great many XL5F-12A650 units, they all have different suffixes. Mine carries the number XL5F-12A650-ARA

Have any of you replaced a computer, from this vintage, and are you aware if the suffix matters?

Thanks,
Bernard.

 

[Mark_88]

There was a recent post on the computer suffixes but I would suggest searching for it in this thread...I've been bouncing between two computers due to some problems and not sure if it is on my windows box or my Mac...but I'm pretty sure I stored a link to it somewhere...

Issue was about transmission but the I distinctly remember a discussion on the suffixes...let me check...

EDIT:

Not on my PC but I did find this post...scroll down to post number 12 by RonD...he describes the part number break down...

This wasn't the one I was thinking of so I need to search the Mac...

http://www.therangerstation.com/forums/showthread.php?t=164411&highlight=computer+part+numbers