Hey guys, I just bought a (new to me) work truck. Its a 99 b2500 with 170k.
Supposedly the guy that i bought it from put bad gas in it one day and two miles down the road it died. He says it threw off the timing-he got that fixed,new injectors,head gasket,fuel filter, he couldn't remember what else. Now the truck starts up fine , but whenever you, lets say shift to 5th going 45, it starts to sputter, Feels to me like fuel but I've read somewhere about spark plugs? He says he is sure that he did not replace the fuel pump, could this be the issue? that it pumps it fine at high rpms but not once you start to cruise? anybody have this before?? Thanks so much for the help.

 

the guy is blowing smoke about the timing and bad gas. get a fuel pressure gauge and check the fuel pressure at the shrader valve on the fuel rail. should be about 60 koeo, koer

 

Lets think about this some more.
Do you have a CEL lit, or blinking???? If so, run this puppy by your favorite autparts store for a no cost computer trouble code scan & post All of the code Numbers found, as they can provide good trouble shooting clues.

At some time the guy you bought the truck from might have gotten some bad gas, but as powersmoked has said, that won't throw the engines cam or spark timing off, but if the gas was sub par for octane, it can cause an engine to detonate/spark knock/ping & cause someone to think it's jumped timing.

Or maybe dirty gas has clogged the in tank fuel pump prefilter sock up, dropped the fuel pressure to the injectors & leaned air/fuel ratio out, so do the fuel pressure test powersmoked suggested.
Most autoparts stores have a fuel pressure gauge test kit in their "Loan-A-Tool" program, for a refundable deposit.

Your 4banger uses a timing belt to turn the overhead cam & this is supposed to be changed around 100K miles, so if the timing belt hadn't been changed in 170K, the timing belt may have worn & jumped a cog & threw the cam timing off, or more likely broke & thats what he had replaced.
The 4banger is a non interference engine, so the pistons won't hit the valves if that happened.

From your descripton of how it'll miss under load, I'd also put a spark problem on your suspect list.

If the plugs & wires haven't been changed in 170K miles, their Way past due.
Use the specified Motorcraft plugs & wires, as they have the correct heat range & are designed for the double work load our "waste spark ignition system puts on them.

If they've been replaced, suspect the plug gap is excessive, or maybe you have a cracked or chipped plug insulator, bad plug wire, or one of the coil packs has a problem, they are known to crack underneath & cause electrical leakage & weak spark, which is hidden such that we can't see it at night.
So if you come to suspect a coilpack, remove it & check for cracks.

A bunch more thoughts to ponder, let us know what you find.

 

Thanks a lot for the quick response. I didn't think the whole throwing timing thing off sounded right. There are no trouble codes on currently , only the ABS light.When I turn the ignition on before I start, I don't see a check engine light at all? is this normal? I'm gonna find a fuel pressure gauge somewhere and go for that first. If it is the fuel pump, do you have to buy the whole assembly or can you piece it together? Note: the fuel gauge isn't working either so I suppose changing the whole assembly will fix that. I read somewhere that " changing the spark plugs aren't easy on this motor, so I took it to a mechanic". Looks to me like they're just tucked in there. thanks again, this helps so much.

 

Your CEL should light up at KOEO, if it doesn't, it's likely burned out, or disconnected & if so you likely have some trouble codes stored in the computer, but you'll need a code reader, or scantool to pull them.

Yup the fuel sender & pump are one assy. If you find the pump is bad, it's easier to slide the bed back for access to change it, than dropping the gas tank.
BTW your fuel pressure should be 64 +/- 8psi.

On the gas gage not working, you can check the gauge movement, by grounding the senders wire & confirmng the gauge goes to Full, if so, the movement is ok.

If that checks out, you might consider that in the past few years some bad gas from Shell & private brands using Shell bulk fuel, that had too much sulphur in it, hit the market & messed up fuel pumps & corroded sending unit contacts, causing gas gauge problems.
However Chevron claims their Techron Concentate Plus, can clean the corroson off the sending units & wake em up, so maybe thats worth a try.

Run the present tank down below 1/4 remaining, add a 20 oz container of Techron at the pump Before filling up with Chevron, Texaco, or CalTex gas, which already have Techron in them & this will raise the treat rate 10X above the pump gas alone, so maybe it'll do it's thing on the sender if it's corroded.

At the least it'll tidy up the fuel injectors, intake valves & combustion chambers & thats always a good idea.

If your having someone else replace the plugs & wires, to avoid future problems, make sure they use the specified Motorcraft or Autolite wires & finewire double platinum plugs.

On the ABS light being on, you can pull the ABS codes, using the under dash jumper wire proceedure listed in the "Tech Info" thread, located atop this forums thread listing page & count the ABS light blinks to get the codes, lots of other good how too's there also.

If you only have RABS, then maybe put the rear speed sensor, located atop the rear differential housing, or it's connector, or wiring, on your ABS suspect list, as they are the most common problem parts.

More thoughts for consideration.

 

do what paw paw said. also on the 99's the sensor at the top of the differential is a vss/abs sensor. they are a common issue. that sensor also controls your speedometer. if your speedometer is acting funny along with the abs light that is probably your issue. check the differential fluid while you are there.

 

OK! This thing is gonna do me in. let me start off with saying; I plugged in a matco Determinator scantool and this is what it reads.

po122 (tps curcuit low)

Po302 (cyl 2 misfire

po460 ( something about fuel sending unit I believe)

p1125 (tps inconsistent with MAF)

p1125 ( tps intermittent)

p1401 ( don't remember if this didn't give a description or I forgot to write it down) But I believe it deals with the DPFE??? I took it off and its an aftermarked plastic one and the back panel fell off and all the jelly stuff in the back was covered in dust and grease. looks like it probably needs to be replaced but would that cause this???

Now this is what I have done so far...

I did not change the plugs but they looked good, should I test them somehow?

1 Changed spark plug wires to autolites

2 Chanaged one coil pack, the other looked new.

3 changed the TPS

4 changed the idle air control valve

5 checked fuel pressure its right at 65lbs

6 inspected mass air flow sensor it looked clean, I cleaned it with soapy water


Whatever you guys tell me to do, I'll do it. I guess my next guess would be this DPFE? because it looks terrible. but I don't really know. let me explain again exactly what its doing.


At idle its not perfect, a little bumps in idle, not really rough but not smooth.
You start going through the gears its smooth, even revving the rpm's up, as soon as you get to 40mph at the end of 3rd gear it starts to sputter constant. you shift to 4th and its better until it gets to that same speed/rpm ratio in 4th (about 47mph) Then you shift to 5th and it sputters and won't even go any faster to get out of that range. I have floored it past all of it in 5th and it eventually starts to clear up but its a slow process and i don't know if it ever completely gets perfect or just better. Please please , if anyone has any idea's please let me know . I'm here at home, having an off day hoping to fix this thing. Thank you so much everyone.

 

A few thoughts. In the code #'s. You use a zero not the letter o. You wnat to clean the MAF with maf cleaner. It comes in a spray can. Do you know what sparkplugs were in there. I also would disconnevt the neg battery for 10 minutes to reset the PCM after changing those sensores. Someone else will chime in about the DFPE sensor. I am not sure of the answer

I would finish the tuneup ie. pcv valve, air filter, clean thottle body,check for vacuum leaks

 

Also change the fuel filter and add a good fuel cleaner to the tank

 

Did you get these codes before you did all of the work, or afterward????

You've likely contaminated & uncalibrated your MAF sensors heated element with the soapy water residuals baking onto it's heated element when it gets hot.

SO, pull the MAF sensor & clean it with a properly formulated, non residual, platic safe spray cleaner, like CRC MAF spray cleaner.
Most autoparts & WallyWorld stores in my area carry it.

The codes about the TPS being intermittent needs to be resolved, if it's come about since you repaced the TPS.

The TPS & MAF sensor not matching, is likely being caused by the TPS being intermittently open & or the MAF sensor being contaminated, such that it's PID to the computer is now corupt such that it's not accurately measuring air flow into the engine, thus confusing the computers expected match between the TPS & MAF PID's.

If the DPFE sensor has come apart, replace it.

The computer is unhappy with cyl #2 for some reason, so when you get the TPS & MAF sensor problems resolved, look to the cyl 2 misfire problem.

It can be caused by a number of things, so maybe hook up an inductive timing light to cyl 2 ignition wire & see if you can catch it misfiring, in time with the rough idle.

Seeing as how fuel pressure checks ok, you can take the fuel pump off your suspect llst, but not the fuel filter, as you've not yet done a volume test, to see if the pump can push enough fuel through the filter, over time.
If it can't, because the fiter is clogged, or the pump is weak, or it's pressure regulator is acting out & limiting fuel flow under load, those things can limit engine output power.

So you need to know if the fuel pump can produce the volume the engine needs under load.

Then there is the possibilty you have a fuel injector problem on #2, so maybe listen to it with a stethoscope to try & detrmine if you can hear a difference between it's clicks & the others & if so, does the difference occur in time with the rough idle.

Or you might have a mechanical problem with #2 cyl. like a sticking or burned valve, or a compression problem.

So maybe consider hooking up a vacuum gauge to the intake manafold, for a quick analisis, or confirmation of the previous tests & go from there.

If you come to think you have a mechanical problem with #2 cyl, then do a compression test, or do a cyl balance test with your scantool, if it offers that option, as that test could quikly & easily help pinpoint or confirm your previous tests.

You can do an end to end plug wire resistane check, if you suspect a problem with it. You should have about 2K ohms/inch of length, 30K ohms max.

Anyway get the MAF, TPS, DPFE & #2 cyl miss problems resolved & let us know how it goes.

 

Sorry I forgot to say that I did change the fuel filter.
And also , when I had the fuel pressure gauge on, I gave it some throttle and it didn't change the reading. I don't know if that means anything. but the fuel pump seems to not have an issue.

And sorry about the soapy water mix. I just didn't have the cleaner and I was getting frustrated.

Oh, and I changed about half of that stuff before the scan, and half after. so should I clear the codes then start over?

 

I just called ford and they want 170 bucks for the dpfe!!!! is this right? thats crazy.

My question is , does the p1401 defiantly mean I MUST change the dpfe? or egr or which? Thanks for the help.

 

OK, good feedback, so with the fuel filter change & the engine rpm goose test & the fuel pressure being in range & not changing, I agree I believe the fuel pump is likely ok.

You posted that the DPFE sensors back had come off, so yes it should be replaced.

Call around to some autoparts stores & you'll likely be able to find it for less. If your strapped for cash, maybe consider a salvage yard DPFE sensor, from a low mileage donor, bet the price would be better.

Don't replace anything unless you've tested it, or know it's bad, so no, don't replace the EGR valve, as they're rarely bad, unless rusted out, or really carboned up from an engine in poor mechanical condition, thats burning lots of oil, or running rich for some time & even then we can often clean them up & they'll be ok.

SO, right now I'd carefully remove & re-clean the MAF sensor, make sure it's cool, before spray cleaning it.

Replace the DPFE sensor.

Erase the trouble codes & see how it goes with the #2 cyl miss & the driveability problems.

Keep us posted on how it goes.

 

rockauto.com has a motorcraft dfpe sensor for $50

 

Ok, thank you guys for your help. but I'm wondering now if I'll ever get her up and running.

I ran into parts store got a generic dpfe sensor. it was about 60 ish. Normally I would get motorcraft stuff but I don't got $110 more dollars just laying around so I got the cheap junk. Popped it in, didn't do a thing.

So I took the MAF back out spraying the heck out of it with maf cleaner, stuck it back in, test drove- Nothing.

I'm not a mechanic but I kinda bought this truck to learn Gas, as I'm a little more familiar with my 7.3 . This is a whole different animal.


I'm trying to do what you guys recommended , but I don't have a way to check the sound of injector #2

I now have changed all the mentioned sensors short of getting a new MAF sensor rather than just cleaning it.

How do I check to see if the (coil pack that I did not change because it looked new) is functioning? like a redneck way? AND how do I check the vacuum ? do I have to have a vacuum gauge?

Also, should I still throw the tank down to check if there is crap/water in there or the screen is clogged? I have no Idea, seems like if we have good pressure this is not my issue.

Thanks, hope I ever get this right.