After you purchase the items you described I would recommend you buy a good scan tool, go to class & brush up on your electrical dianostic skills and prepare yourself for a whole lot of head scracthing & headaches (don’t forget to also get some advil). Simply put todays cars are not as simple to work on as they used to be. Without a decent scan tool I wouldn’t work on them myself. A code reader cannot tell you if the part sensors are working or not. Stick with a decent mechanic whom thinks he shouldn’t charge more than 3 hrs for what he just spent 10 hrs to fix and you will come out way ahead. Just show some compassion when he apologizes for snap on not making a crystal ball so the fix would have been much quicker.
[One week later.} …AND?!
I’m awfully sorry everybody, I had to take a break from the car for a while. But I’m back.
Nothing unusual or miraculous has happened. I have the same codes as usual: P0135, P0155 (no mentions of lean or rich) and P0455 (“large leak”).
Freeze Frame:
DTCFRZF P0155
FUELSYS1 CL
FUELSYS2 N/A
LOAD_PCT(%) 39.2
ETC(?F) 189
SHRTFT1(%) -0.8
LONGFT1(%) -4.7
SHRTFT2(%) 2.3
LONGFT2(%) -4.7
RPM(/min) 1742
VSS(mph) 43
Now, for something old that’s new again: Waaaaaay back when I knew there was first a problem with the car, what prompted me to take it to a mechanic was that I would be driving along, at low speeds (or high speeds), and the car would start reving. Say I was doing 35, with my foot steady on the pedal. All of the sudden the car would lurch and the rpms would shoot up to say 3000. At that point if I put my foot on the gas, even a little, the RPMs will go even higher. Taking my foot off makes it drop a little (1K). Putting it into neutral has not effect. The car will be crazy like this for a few seconds and then downshift to a normal 2000 RMP. Then a couple seconds later rev up to 3000 again. The car does not overheat. If I pull over and turn if off, that sometimes solves it for the next drive. At 40mph the car’s RPMs is at 3.5k.
I bring this up now because it has not done this since I started monkeying around with it. Yesterday and today it did it again. Maybe since it has been a week since I disconnected the PCM, the car has now had enough drive cycles and that has to do with it doing this again. I don’t know, but I thought it might be a clue.
Today when it did this (it does it for the length of the drive…) I hooked up the scan tool and had it record. You can look at the graphs I made based on the results by clicking here: http://badsushi.net/images/livedata_graph_8sep08.gif. I have also attached the actual Excel spreadsheet to this post.
If it would help to have any of those graphs be clearer, or show just certain bits of info, I can easily change them.
Thanks again! (and again, and again…)
EDIT: Oh, and to answer your last question, hellokit, I’m pretty sure the battery was near 12V.
Let me try putting it another way.
It is as if instead of shifting from 3 to 4 as I accelerate, the car is shifting from 3 to 2, or not shifting at all. Again, this action is sporadic, but frequent.
I found a simple evap leak test on Chiltons:
Vacuum Leak Test
- Operate the engine at idle without touching the brake pedal for at least one minute.
2.Turn off the engine and wait one minute.
3.Test for the presence of assist vacuum by depressing the brake pedal and releasing it several times. If vacuum is present in the system, light application will produce less and less pedal travel. If there is no vacuum, air is leaking into the system.
So, I did this. The more I depressed the brake pedal, the harder it was to depress the pedal, until it didn’t really go down at all. Soooo, according to that test there is a vacuum…
By the way, this seems like a really good article on Fords EVAP system: http://www.asashop.org/autoinc/feb2002/techtips.htm
Did you read post 200? The referenced source outlines a method of checking the oxygen sensor heaters by watching your scan tool screen. (Alternatively, the test could be done by backprobing and the use of a multimeter.) To recap, the test is done this way:
- Start with a cool engine (the ignition switch MUST have been in the OFF position for 30 plus minuets). NOT in RUN, even once, during those 30 minuets.
- Set up your scan tool screen for testing one of the oxygen sensors. Disconnect the other oxygen sensors, to keep them cool; OR, wait 30 minuets between test for each oxygen sensor to cool.
- Get everything set up BEFORE you turn the ignition switch to RUN (not START).
- Select the test oxygen sensor on the scan tool screen.
- Turn the ignition switch to RUN (not START), and immediately
begin observation of the chosen oxygen sensor’s voltage.
Result: During the first few seconds of the test, as the oxygen sensor sensing element is heating to its operating temperature, the mV should be, fairly, stable at 450 mV.
The oxygen sensor voltage should go either high or low, as its sensing element reaches operating temperature of 600F degrees (over 600mV, or under 300 mV) within 10 seconds to 1 1/2 minuets. This test shows that the sensor heater element has heated the oxygen sensor sensing element to its operating temperature of about 600F degrees.
If the oxygen sensor voltage stays between 300 mV and 600 mV, that shows that the oxygen sensor sensing element hasn’t begun working because it didn’t get hot enough; or, it doesn’t work. Recheck the mV values after the engine is run long enough for the hot exhaust to heat the oxygen sensor sensing element.
Repeat procedure for testing the other oxygen sensors.
Fantastic, thanks hellokit, I will try that tonight!
I know the gas cap is the #1 answer to the P0455 code… I’ve looked at it a couple times and it looks great, so does the ring inside it. No spillage on the neck.
I also crawled under the car last night to investigate the charcoal canister. I tried like heck to unbolt the cage that holds it up, but the bolts are rusty, and when I did get them to turn, they would just turn, indefinitely, without actually coming out… So I inspected and shook, and felt the rubber hoses that were exposed and they looked good. I did not see any crack or hear anything rattling inside of them (little bits of charcoal). So… there’s that.
Alright, I’m not sure if I’ve done this correctly. Hellokit, when you say “RUN”, that is the same as on “ON” as in, “the position just before engine start”, correct? My manual uses “ON” and “START”, but not “RUN”.
I followed your instructions after the car had sat for 5 hours in the cool night air. B1S1 held steady at 0 volts, as did B2S1. B2S2 fluctuated rapidly between .010v and .005v. B2S2 was steady at .005v.
Maybe,the test procedure is too complex. From the various problems with the emissions system, I suspect that the PCM (engine computer) is at fault. If you can find a good diagnostic shop…because, I hate to just say, “Change the PCM and see what happens”.
Stating the key is in the RUN or ON position is saying the same thing. Most vehicles use one or the other terms for the ignition.
Like Hellokit, I do not like to just change parts to see what happens but in this case I feel we have pretty much eliminated any other possible cause of the problem except for the PCM. It is interesting though that the two bad heaters circuits showed zero volts while the two good ones had 5 to 10 millivolts at the connection point.
We didn’t exactly do the test proceedure I requested back in post 194 of this thread. You did take a voltage measurement but not a resistance measurement to see if you can see a difference between pins 93,94,95, and 96. At this point though I’m not sure it is worth pursuing. If you really wanted to prove it is the PCM then that may be the test to try.
Is the way that the car is acting now, i.e. seeming to shift into the wrong gear, or not at all most of the time, a possible outcome of the codes or bad PCM that I am experiencing now? In other words, is the shifting problem probably related to these other problems, or is it definitely something unrelated (god I hope not)? I could even take a little video of the dashboard instruments so you can see and hear what it’s doing as I’m driving…
I will perform your test from post 194, Cougar, tonight. With this test I’m going to do something slightly different from what I’ve done before, I’m going to test the pins coming out of the PCM, with the wiring harness detached and placed aside, correct?
Regardless, can I take the car to a shop (I assume not an autozone-type place…) and tell them to tell me if the PCM is bad? Do you think that would be an expensive test? If it’s bad, I’ll probably try a junkyard first, unless you all think that’s a bad idea.
You are correct about the test. You need to find a good ground point on the PCM to do this. I assume the case for the PCM is metal and you may be able to use that as your ground point. You can hopefully verify it by checking it to one of the other ground pins we looked at earlier and see if you have continuity between the two points.
Set your meter to measure ohms and on a fairly resistance high scale and then measure pins 93,94,95, and 96 and see how they compare to eachother. If you don’t see any difference you can also reverse the probes and do the same test to see if there is a change that way. If at any time you see a significant difference between the working and non working pins your testing is done. If that shows them about the same then another step is to set the meter to the diode function and do the test again and compare readings, along with reversing the probes also. One last step to try if you still don’t see any change is to place the reference probe on the power input pin (pin 15 IIRC)and do the testing again.
This testing procedure doesn’t always work but if there is a problem with the output stage to the pin it works pretty well.
As far as having a shop look at this problem you can do that and tell them what you have done so far and what you suspect is the trouble. They will probably do their own testing and you will be given the bill for the time and for whatever parts they need to fix it. If you want to do that, fine, it is your money and you will have a guarantee on the work hopefully. In my opinion, we have already done the testing that a shop would do, and beyond, to find the problem area. I think a shop would have swapped out the PCM long ago in an effort at least to minimize shop labor time to fix this. I think if you swap the PCM the heater problem will go away. The other issues can be addressed after that. They have NOTHING to do with the heater code errors.
crap, I guess I should start a new thread for the shifting problem then…
So, no matter which probes I used, pin 93 is 336Kohms… 94, 95, and 96 register 0ohms… It doesn’t look like my multimeter does diode tests.
Well you’re done testing the PCM Matthew. It’s bad. Replace it, then we can move on to the other things. Who knows, perhaps some of the other issues will clear up also with the replacement PCM.
(Doing a bit more research)
I’m looking in the PCM now to see if there is an obvious burned out transistor, or whatnot. Everything looks good.
The trouble is most likely within an IC that ties to those pins. Just a guess, since I haven’t worked on that particular PCM.
What about this? This doesn’t look so good:
http://badsushi.net/images/throttlebody.gif
Note that there is not a rubber throttle body gasket. According the autozone repair guide, there should be…
EDIT: I take it back, the top photo shoes the gasket. For some odd reason the gasket is shiny and looks like metal…
IC stands for what?
In the electronics world IC stands for integrated circuit.