Engine hesitates with accelerator push...

[Strike12]

Yours is the sohc 4.0l correct . if so its near the throttle body and is screwed into the manifold , I think just under the TB . It has a 2 wire connector going to it .It can be checked with a ohms meter . The resistance values will change according to temperature ,thus telling the comp. how warm/cold it is .Oh ECT= engine coolant temperature. 50 degrees=58k ohms , 68 degrees=37kohms . There a chart in the haynes manual for the temp=ohms values . If there not within specs , I would change it out , pretty easy to do.

 

[schaffdk]

Seems I'm having exactly the same problem as Jake's Dad and others, only here's the clincher... It's my GMC Jimmy... Poor acceleration under load, weird knocking/popping sound from beyond the firewall, the more I try to accelerate the less the truck seems to want to, and it's worst when the engine/outside temp is cold. Only mine seems to be worse than most- the (underpowered 2.8 L) engine actually stalls (manual tranny) suddenly and momentarilly, makes that awful popping noise, then catches again and bucks the truck like crazy. Every time it happens I think to myself, "Now that can't be good!"

Well earlier this evening the problem came back with a vengence... Even though the engine was warm, same old thing, only this time it was really bad and frequent. It popped and bucked more and more frequently, stalling momentarilly then catching again, until it finally just didn't catch. Kaput. Can't get 'er started now. I happen to have Bosch plugs and wires too, but the problem was evident even before switching to Bosch. What are the odds that this is really the problem? I am certain that the wires are not grounding (learned that the hard way). The truck is 15 years old and has seen better days, but I am confident I can fix the problem, if only I can find it first. Any suggestions from those with similar problems in Explorerland?

 

[vbtruk]

SCHAFFDK I CANT HELP AS I AM STOOPED BY THIS TOO!

ANYWAY I AM REALLY PEE'D OFF NOW, DONE THE WIRES AND PLUGS, FUEL FILTER, CLEANED MAF, TUNE UP AT FORD, OIL, COOLANT, TRANNY FLUID BUT THE HESITATION AND FLAT SPOT SEEM'S TO BE GETTING WORSE!!!!!!!
IT HAS STARTED HOPPING ALMOST WHEN ACCELERATING. USSUALLY WHEN ACCELERATING IT WAS THE SAME AS EVERYONE ELSE - ENGINE BOGG'S HIT'S A FLAT SPOT FROM TAKE OFF LIKE IN REAL SLOW MO AND THEN STARTS TO GO HARD THIS IS FROM A TAKE OFF! AND FROM CRUISING THE RIG WOULD FLAT SPOT AND DO THE SAME! NOW WHEN CRUISING THE ENGINE ALMOST SEEM'S TO BE HOPING AT TIMES LIKE IT CAN'T MAKE UP IT'S MIND WHETHER TO GO OR STOP?????
FORD DON'T KNOW WHAT'S WRONG (OF COURSE) AND IT DOESN'T ALWAYS DO IT SOME DAY'S MORE OFTEN THAN OTHER'S, I REALLY WANT TO FIX THIS ALREADY!!!!!
I HAVE READ THROUGH THE THREAD A FEW TIMES NOW AND WILL TRY CLEANING THE DPFE, AND REPLACING THE PCV AND TPS, BUT WOULD RATHER NOT IF I DON'T NEED TO.

 

[CHuntMD]

Damn your post was hard to read

Check my thread SOHC still hesitates as there is a test to check your coil pack. There is also instructions to replace the Fuel Presure Regulator.

Finally warmed up enough here in Wash DC so I can replace the plugs. Got a excellent deal on 6 Motorcraft AGSF22PP for under $40 delivered from www.fordpartsnetwork.com

Chris
Saving my pennies for the new Tonka SuperDuties.

 

[V8-X]

vbtruk - Sounds like me, just can't narrow done the problem. Been to two seperate Ford Service Depts four times, and neither can find the problem. Some days are better than others, but the problem is still there even on good days just not as bad. I've replaced the IAC, TPS, EGR, FPR, PCV (planning on changing the PCV assembly hoses), all 4 O2's, air filter, fuel filter, 8 plugs & 8 wires, had Ford clean the MAS/MAF & reflash the PCM. Nothing has corrected the problem. Ford states the truck acts normal, can't determine what's wrong with the truck without the CEL on, and that it's just getting old. B.S. In 6 months I've spent over $1K in parts and diagnosis fees, with no fix. I understand everyones frustration. Please post any remedies to the problem, as I'm willing to try just about anything to get the X running normal again.

 

[Strike12]

That really does sound like a bad TPS . Do you have a volt and ohm meter? You can verify if its bad . There should be 3 wires in the connector , green , orange , black . Disconnect the connector and from the sensor side , check the resistance between orange and green , while you have your leads still connected move the throttle very slowly and see if the ohms change very smoothly and no opens , would read oooo , infinity , if you had a open . Repeat this procedure with the green and black wires . Make sure the ohms rise or lower very smoothly as you move the throttle . Sometimes its easier with 2 people , one holds the leads to the sensor and the other moves the trottle. Good results would be a show of resistance and moves smoothly > Bad results would be no resistance , infinity(open) , or doesnt change smoothly . If you dont understand how to use one of these meters , I can explain , just ask . There one of the best tools a mechanic now a days must have , and they can be bought at a very reasonable price.

 

[vbtruk]

Nah STRIKE12 i dont have one of them but how much do they ussualy cost? do i need both volt and ohm meter or just one?
But V8-X changed his and it still didn't help???

 

[Strike12]

They can range from roughly $10 - $300 , but a $10 one will do just fine . They are called multi-meters and they will measure ac/dc volts , ohms , and usually up to 10 amps . Try to get a digital one , because there more accurate .Most parts stores carry them and eletronic/electrical supply joints. I get a tool magizine from Harbor Freight and they had one for $3.00 , wow cheap . The one I use is made by Greenlee , and is on the higher end , cause I do alot of electrical work , but you dont need to spend alot to do basic checks.
I wouldnt base your problem to others , because you could have the same symptoms as another , but could actually be different part . Basically if they cant pull a code on your rig , it doesnt mean it still doesnt have a faulty part . Could be out of calibration, enough to cause these problems . If one sensor is out of calibration , then the others have to compensate for the other , trying to make your rig to run smooth and with in parameters , set by the computer. If you can do some of your own checks , ohms(resistance) , and refrence voltage checks , then you can eliminate the possibility of a bad sensor out of calibration . If its not within specs then its bad . Electronics work , dont work , or malfunction(resistance , diode , bla,bla.bla ,gone bad)
Sometimes the computer cant give feedback of whats going on with a paticular sensor , its sending refrence voltage back , so it might be cool , no code. Now when you get a failed part , hard code , the computer says Im getting no refrence voltage back from this sensor and it sets a CEL , this thing aint responding. Some codes may not be set with things like , a dirty , or none seated IAC , plugged or restricted EGR , None calibrated emission parts , Faulty Ignition , plugged/bad injectors , and sever mechanical wear .The comp always tries to compensate for these problems , and its trying . There is , 1 or more bad parts in you truck to cause this and ford couldnt charge you enough to diagnos it , could be Alot of testing . Try to narrow it down with you new meter. Get that Haynes manuel yet?

 

[vbtruk]

Hey STRIKE12 that's great thank's for all the info!!!!! I know what a MULTI-METER is i just thought you were talking about something else so i'll get one ASAP also the HAYNE's Manual hasn't come yet it's been about 2 week's now already so i should get it soon!

Also one more think that you might be able to help me with as robert doesn't seem to be around is the Re-calibration of the PCM(powertrain control module) in another link "98 X hiccupped" Rob said that ford released a info letter regarding the re calibration of teh PCM to avoid the X's Hiccuping basically so can you tell me how long it would take FORD to recalibrate the PCM setting's just so i know how much i will be paying for? And if your familiar with those codes are they correct as FORD in AUSTRALIA haven't heard of it so i'll need to print it out and give it to them???
thank's heaps for your help STRIKE12!
link to thread is: Dead Link Removed

 

[Strike12]

Reflashing the pcm shouldnt take long at all , and from what I've read has fixed several x's .Reflashing the pcm is similar to reflashing your computers bios its , its an update .AS far as know I know , the codes are the same , but not 100% sure. Thats a long time to wait for that manuel , hope it comes in soon . Good luck .

 

[vbtruk]

Thank's Heaps STRIKE12

Hey thanks STRIKE it's just that FORD here have no idea about the codes so i'll just print them off and they want to charge me per hour (labour) that it takes to do, of course when i mentioned the fault within the warranty period they didn't know what i was on about and couldn't fix it so now it's out of warranty they won't take responsability for it and i have to fork out anyway i can't wait i will change the TPS like you said after i check it it only like $50AUSD like about $20 US so i'll let you know!
Ohh and i'll let you know how i go changing those intake mifold gasket's tomorrow!
Thank's for all your help guy's!

 

[CHuntMD]

Well changing the spark plugs in a 97 SOHC is a real PITA I followed the instructions found here

Dead Link Removed

Pics of the passenger side are at
http://www.peake.com/occ/My97Explorer/

Tried to test the coil pack as suggested by Strike12 but I'm missing something basic.

Chris

 

[schaffdk]

Bucking Problem Solved!!!

Well Fellas, I solved the popping and bucking problem- It was the COIL ! I tested my old coil per Hayne's instructions, and it checked out fine, but I figured what the hell, I'll try a new one anyway. And it solved the problem! Unfortunatly I must have screwed up something else (may be the timing, I messed with the distrib. cap while I was stranded on the roadside) and the engine is just lacking power now. Because of this, I'm not sure if the dead spot prob. is solved, but I'll definitely let y'all know once she's running normal again.

BTW- if anyone can help with my new problem, I'd appreciate it. When I open the throttle a noise comes form the intake manifold that sounds like an exaust pipe without a muffler- pretty bad... Also- and I may be imagining this- but it seemed that exhaust might have been coming out of the intake... Could this be timing? I didn't mess with valves or the cam chain or anything major, so hopefully it's nothing serious. Thanks

 

[Strike12]

ChuntMD , I sent you a e-mail.

 

[DarkFox1]

wow, howd I miss this? I've been having almost that exact problem.. right down to the clicking.. and its not a manifold (I checked)

I skipped a few threads (this would have taken me 4 hours to read lol) but plugs/wires were the problem with jakes dads truck.. my plugs/wires are all OEM and have 30k on them. I have an appointment monday with a new dealership to have this problem addressed, if they say its fine I may have the plugs/wires re-done with OEM stuff and see how it goes.

I'm not crazy after all hahah!

 

[Jake's Dad]

Dang - this is getting good!!!



JD

 

[schaffdk]

Solved the second problem... I never would have guessed it, but it was a clogged catalytic converter. I had a heck of a time getting the sucker out, so I just unbolted the y-pipe from the exhaust manifold, and she ran like new. So if anyone has similar symptoms, check the cat! Thanks for all your help!

-Dave

 

[DarkFox1]

I had my cats checked, the shop said they were fine, could go another 70k miles, no reason to look any futher. They followed it up with a pcm scan Here

I recently cleaned my MAS assembly, the truck has done alittle better but nothing ground breaking.. I just dont think this is in the engine...

when I pull out of any location, theres like.. a hump that the engine has to pull over before the truck will accelerate to any even half decent rate.

I plan on getting new plugs/wires soon, see if that helps a tiny bit too.

 

[MeatyCrab]

Another Aus. Exploder

Hey guys,

Been reading bits of this thread for a while now, but only when Vbtruk chimed in, I started looking closer. So I have the same truck, same year, same engine, SAME PROBLEM as Vbtruk...Only thing is, I have a Wedgewood Blue truck...not red.

That being said, here's my take on the whole issue.

As far as I know, there aren't any Yank Ex's with this problem (SOHC, that is)...unless I didn't read the thread too well...

My problem started a few years back, and when I noticed it, I took it to the dealer (under warranty) and talked their ear off about it (nice guys). Eventually the regional techie came down and had a chat with me, and it turns out, that for some (stupid effing) reason, Ford Australia decided to fiddle with the engine, so it makes less drive train noise and doesn't wear components down as quick. What they achieved is this hesitation that both my truck and vbtruk's has.

The other thing is, I have a KKM as well, and on a really hot day, the whole truck has a lot of trouble moving around, especially with the AC on. And this thing is usually really quick (for 2000kg anyway...). In really crispy cold weather, it takes off like a cat.

The other odd thing is, even on a warmish day, to get the best take off, I will usually only go just below half throttle...it takes off as if it's WOT. Then when it gets past 3000rpms, I'll floor it, and it will rev out to 6Krpm.

So I can absolutely rule out that it's the KKM and an over supply of warm air that is causing it, because the truck CAN accel. to its full potential.

Here's my solution. Vbtruk's and mine seem really similar and the way we take care of them is the same too (spoilt daddy's boys it looks like!), both truck's are in really good shape. So all I can think about is that there's a problem with the fuel mapping, particularly at WOT. In this case, I would suggest an aftermarket chip to take care of that.

Vbtruk, you're in Vic, so why don't you take a look at Powerchip. They have 4 levels of chips for the Ex. The GOLD98 raises power to about 180ish kW and more importantly 380Nm of torque. They will custom burn your chip according to your mods, so you can tell them where you want the power etc.

I don't think it's the transmission recall (although it does feel like it), as I can put it manually in first, and it will still do the same thing.

Anyway, tell me how you get on with this, hope it helps.
Vbtruk, shoot me an email...and mate, with a license plate like that, you should have got a green truck!


Cheers,
BK

 

[DarkFox1]

well I tried that.. a chip, thanks for the insight on the issue, but I do not beleive that the issue with my truck is something that has always been there, plus.. I'm not aussie lol

some peoples PCMS have service ports disabled (mine) and cannot accept a chip w/o modification.

are any of you finding that yer pcms are like that? I'm going to call around in a few to get some more info about how sure a backpressure test makes one about the condition of cats.