Jerking hesitation - Sort of urgent

[Hartman]

I just ran some Seafoam thru the engine a few months ago.

 

[Hartman]

I went and got a fuel pressure gauge and tested the pressure, which is right where it's supposed to be at 35 PSI on a warm engine. This tells me that my problem is not fuel related. I'm pretty sure it's either an oxygen sensor or plugs and wires. I'm leaning more and more towards plugs and wires, but I'm going to do a little more research on the symptoms of a bad O2 sensor before I order new plugs and wires.

 

[gordhunt]

I had a similar problem and it was the MAF sensor. I really don't think swapping parts out is going to fix the problem. I'd find a competent mechanic and just get him to check a few things out. I notice that on websites guys always think it's things like the fuel filter, plugs etc.. and I've yet to actually have any problem be those items.

 

[rydinhigh]

hartman I have one of those $25 code scanners with the book that lists the codes. It worked on my 95 and I had the same computer code as you (fig2). If you want it send me $7 to cover the shipping and you can have it.

 

[Hartman]

Nah I don't need a scanner because apparently you can't scan the code if the check engine light doesn't stay on. Mine comes on after a few minutes of driving.

 

[huskyfan23]

When the check engine light comes on, it saves the code. When I did my BBK TB I was getting a check engine light with the same symptoms your getting, now that I think about it. I bought a scanner and it gave me the codes. Turned out to be a bad DPFE.

 

[uwbradley]

When the check engine light comes on, it saves the code. When I did my BBK TB I was getting a check engine light with the same symptoms your getting, now that I think about it. I bought a scanner and it gave me the codes. Turned out to be a bad DPFE.

When that was the case, were you getting just horrible gas mileage? Cause I have basically the same symptoms in my 91 Mazda Navajo. I have replaced the plugs and wires, O2 and the MAF to no avail. A garage round here told me it was the fuel pump, but that didn't change anything in terms of symptoms or mileage. I should go back and get my money....cause it has been this way for months and I can't figure out what it is and neither can the local garage. I am tired of pouring cash into this freakin' CEL!

Brad

 

[daniel cauchon]

Hartman....ckeck your plugs ....a definite prob. ! mine does that too ....every 6 months or so....so I just clean them or change them....not everyone though....usualy the one on the driver side in the front..(right under the power steering) is my main prob.

 

[MrShorty]

Nah I don't need a scanner because apparently you can't scan the code if the check engine light doesn't stay on. Mine comes on after a few minutes of driving.

I don't know where the good folks at Autozone heard this, but it's batantly false. You can always run the tests and get some kind of code (even if it's only a 111 pass code). Hook up your code reading device (I prefer a jumper wire and an analog voltmeter), turn the key on, and read the KOEO and continuous memory codes. Turn the key off, wait ~10 seconds, then turn the key on, start the engine, and perform the KOER test. There are a few details I've left out obviously, but it's really that simple. And, again, you can perform this test on any EEC-IV vehicle at any time and you will get some kind of codes. If there are no faults to report, then you get pass codes.
I'm going to ask again. Are there some specific questions you have about pulling the codes yourself? What about the test protocol seems intimidating? I was intimidated the first time I tried to pull my own codes, but I hooked it up and tried it, and it wasn't at all difficult. Now I go pull the codes on my trucks when I'm bored, just for fun.
I hope I'm not coming across as some crazed lunatic. Just trying to help. Pulling the codes is the best, first place to start when the CEL comes on. If I can help you figure out how to get those codes, let me know.

 

[MrShorty]

UWBRADLEY: Your '91 can't have a problem with the DPFE, because it doesn't have an EGR system. Pull the codes and find out why the CEL is on.

 

[uwbradley]

UWBRADLEY: Your '91 can't have a problem with the DPFE, because it doesn't have an EGR system. Pull the codes and find out why the CEL is on.

Thanks, I didn't know that. I have had the codes pulled before, and it is a Code 41, lack of HEGO switches or something to that effect. Like I said, I have replaced the O2 twice in a 6 month period (ok, well I didn't say that but it is true) and I have changed the MAF.

Some guy at a garage told me that it was because the in tank fuel pump was going bad, and it was replaced. However, within a day or two, it was back to it's usual antics of hestitating at start, bad fuel economy, and the ever-so-popular CEL.

Mine was turning on in the same condidtions as posted earlier before, of turning on when I am coming to a stop, and sometimes it turns off during freeway driving.

Is there anything else besides an 02 replacement for the HEGO switches code? That is all I seem to get from mechanics around here and that doesn't do anything for my truck's condition. Thanks!

Brad

 

[Hartman]

Are there some specific questions you have about pulling the codes yourself? What about the test protocol seems intimidating?

Well I went to the site to find about 15 pages worth of crap and I know I don't need to know 90% of it. I just want to know how to pull the damn code. The check engine light goes off and stays off as soon as you turn off the ignition. Even if you turn the truck on but not start it, the light will stay off. It ONLY comes on after a few minutes of driving. Once you shut the truck off, the light will not come back on until you drive for a few minutes again.

Can you use a digital multimeter to perform the test?

 

[dunedago]

Had Same Problem... It's Fixed

Is it jerking when you're accelerating? Is it Putting? Is your head pounding from wondering wth is going on?

Change the spark plugs and wires. At least check their connections.
Reason for it not reading any codes is because youre not straining the parts by accelerating so its not going to cut out and show a code.

If it don't work, It needs MAJOR engine work.

Now the answer you seek why it does this if its your problem:
You're getting a bad fuel/air mixture, so too much fuel is going into the engine, why?? Mass Air Flow sensor is dirty, you're O2 sensor probably needs changed too. The Air Flow Sensor gets that wrong reading and you expend too much fuel which results in too much carbon buid up on the O2, so that reads wrong.
My Theory is because you're burning so much fuel, it burns the sparkplugs out faster, way faster, then the domino effect takes place on other parts, all because of a faulty MAF sensor.

Right now, everytime i go long trips,my Ex needs to take a break because it still reads the wrong reading, so now i have to buy an aftermarket MAS sensor along with a filter, because im tired of not getting to drive my vehicle on those trips.

Try that and please reply to me. Because i think that is the biggest complaint about everyone's Ex on this site.

 

[MrShorty]

Ok basic quick test procedure. You'll still need to refer to a manual or other reference to get the jumper wire hooked up right, but here's basically how it goes.
KOEO test
1) Open hood and locate self-test connectors. On Explorers they are on the passenger wheel well between the power distribution box and the heater fan.
2) Connect jumper wire/paper clip between the self-test input pin and the self-test return pin.
3) Get in the truck, put the key in the ignition and turn the key on (don't start the engine). Watch the check engine light.
4) Light will flash once representing the fast codes. Ignore.
5) KOEO hard fault codes are output as flashes of the CEL. Manuals try to describe in words how it looks. Best bet is to try it and see what you get. Note that, on a '95, you are expecting three digit codes (111 for example). After outputting all KOEO hard fault codes, the computer will repeat the codes (111 pause 111).
6) After KOEO codes are output, computer will give a longer pause, a single pulse (separator pulse) then output continuous memory codes.
7) KOEO test is complete. Turn off key.

KOER test
1) Set-up is the same as for KOEO test
2) Turn on key and start engine.
3) Engine i.d. is output (3 flashes for a 6 cylinder engine)
4) Press and release brake to actuate BOO switch.
5) Engine RPM will increase as KOER test is performed (can take several seconds to a minute or two).
6) As engine idles down at conclusion of test, CEL will flash. This is your cue for the "goose" test. Press and release the accelerator (Need to get about 3/4 to full throttle).
7) CEL flashes to indicate output of KOER fast codes. Ignore.
8) KOER codes are output.

Hope that helps.

 

[huskyfan23]

When that was the case, were you getting just horrible gas mileage? Cause I have basically the same symptoms in my 91 Mazda Navajo. I have replaced the plugs and wires, O2 and the MAF to no avail. A garage round here told me it was the fuel pump, but that didn't change anything in terms of symptoms or mileage. I should go back and get my money....cause it has been this way for months and I can't figure out what it is and neither can the local garage. I am tired of pouring cash into this freakin' CEL!

Brad

I don't think the mileage suffered, but it was fixed within a couple days of the CEL. I was thinking either EGR valve or DPFE, and I did the DPFE first. It was strange. After a few minutes of driving, everything under 1700 RPM I would get jerking, the CEL would come on, and stay on, and the X was a lot slower than usual.

 

[mhn3773]

i doubt its an 02 cartman..it could be but i doubt it my 02 is shot in my car and it doesnt hesitate at all..im getting it fixed i know i know

 

[Hartman]

mhn3773, that is just the info I need to start checking things off the list. Thanks.

Husky, did you experience any bogging or hesitation when your DPFE went bad? What about the EGR valve?

 

[huskyfan23]

I did notice some hesitation. I didn't change out the EGR valve since the DPFE fixed it. I heard the EGR could have the same symptoms though.

 

[Hartman]

I never really got an answer the first time, will bad plugs/wires cause a rough idle?

 

[gordhunt]

I never really got an answer the first time, will bad plugs/wires cause a rough idle?

Yes they can cause rough idle however about 20 other things can too.