The vacuum is created and regulated by the engine itself. It sounds to me like you have a bad CPS. The next time it doesn't want to crank, pull a plug and check for spark.Quote:
Originally Posted by riceburner
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The vacuum is created and regulated by the engine itself. It sounds to me like you have a bad CPS. The next time it doesn't want to crank, pull a plug and check for spark.Quote:
Originally Posted by riceburner
Yeah, I posed that possibility eariler, but his symptoms are not so symptomatic of a bad CPS so Ive held off from saying anything definitively, but I mentioned a dual issue in my last post and the CPS was the other issue I had in mind. I sure am curious about this one cause if it is a bad CPS, these symptoms are indeed atypical for a CPS going bad.
You can't avoid going down a possible path during troubleshooting just because it doesn't fit all the criteria. Not every problem will be "by the book" on its symptoms.
Oh I agree with you. But the CPS, over the years, has generated a very predictable set of symptoms and to date I have yet to see that component breech that list. But as you stated, its not guaranteed that it will always be that set of symptoms. Ive been troubleshooting for a very long time and it often comes down to playing the odds. In this case, with the symptoms the CPS typically produces when it fails, gave me pause to call out that part, though it was in the back of my head. So I chose rather to try and eliminate anything else I could.
As it has been said before, if you eliminate all the possibilities then what remains, no matter how absurd, must be the solution.
I'm not saying he should run out and replace it first. Just perform the test, since it isn't intrusive to the engine or difficult.
I prefer to eliminate everything I can that's even remotely related. Makes finding the actual problem that much easier. An old saying: All things being equal, if you eliminate all other possibilities whatever is left, however improbable, must be the truth.
Working on a 160ft long aircraft with wires running everywhere and more electronics than my car weighs (that I'm responsible for, not to mention other shops), you live by that saying.
Seems like we posted near identical things, LOL.
So it would seem. :)
ok ok...so how do i go about testing the cps? and also, when the regulator went out would fuel have gotten back to the MAP sensor on the other end of the vacuum line? shorting it out? and how would i go about testing that? and sabor, i am getting spark and was able to run the car for around 15 min before it died again...i went thru with a tester and checked all the wires with a tester and am getting spark to all 6. and the fuel pump is reading 40-45 psi
It is for that reason, the fact that you have spark, that Im hesitant to point a finger at the CPS. Unless that thing is dying and then immediately recovering, Im not so confident that that is the issue. However, in the interest of eliminating as much as we can, you test it much in the same way I believe the Cam sensor would be tested. The CPS is a hall effect sensor. The Vanes on the back of the harmonic balancer are technically called disruptors (some engineer watched too much Star Trek I guess). Since you'd have to remove the harmonic balancer in order to remove the CPS, the best way to test it would be to somehow get your fingers up in there where you can disconnect the electrical connector to the CPS.
Once you have that done, you'll need a multi-meter and probably some alligator test clips (you can get those at Radio Shack if you dont have any). I dont remember exactly how many pins are in there, but since its a two part sensor, Im going to assume for the moment there are at least 4, two should be for the ignition side and two should be for the tach signal side. I'll be able to confirm once I get home.
Take two of the alligator test clip and clip one to one pin and the other to the next ajacent pin on the CPS, then connect the other end of one to one lead on the multimeter and the other clip to the other lead on the multimeter. Set your multimeter to measure continuity/resistance/ohms. Then use a breaker bar with a 15/16" socket I believe it is and rotate the crank and watch for changes in continuity. If you get changes, that is to say it goes from being open (near infinate resistance) to closed (shorted or no resistance) then that side of the sensor is good. Do the same for the other pins and if both give you the same results then the CPS is good.
Here's the catch to this though. The CPS is known for being affected by heat. That is to say that it fails when it gets hot, then acts normally when its cooled off. So just because it tests good now, does not mean it remains so once the car is running.
I know that leaves a big wide open unknown, but its just a fact of how the CPS craps out sometimes.
When I get home, if it is where I can, I will hook up to my CPS and try to confirm I gave you good directions and correct anything I may have wrong. The one I have on my engine is just a few months old and is a known good one so I should be able to let you know how it responds. I dont know if I kept my bad one around. I had one go bad where it affected the tach side and I had one go bad that affected the spark side. The last one went bad taking out the spark side and would be perfect for this if I still have it around somewhere, but Im not terribly hopeful that I do.
now could that barametric pressure sensor be bad as well? is there a way to test that?
There is, but you need a tool that can put pressure/vacuum on the sensor and then a multimeter to read the changes, and Im not 100% certain, but you may need a DC voltage source as well.
Im not sure whether or not a bad MAP can keep the car from starting, hopefully someone else will be able to answer that.
Okay, bad news, sorta.
The Crankshaft Position Sensor (CPS) uses a 10VDC reference voltage to produce its signal, so is no way you can test it in car unless you have the tools to test for signals through the wiring insulation.
And its nearly the same for the MAP sensor as well except it uses a 5Vdc voltage reference.
The Camshaft Position Sensor also uses a 10Vdc voltage reference and interestingly enough, it shares that reference voltage with the CPS. Whats odd to me is that it is a 10vdc reference and Im not sure how they get it down to 10v, unless thats the minimum voltage need which in my experience is not typically the case, it usually states what it uses, not the minimums.
As a sidebar not related specifically to your issue, if that may not be the reason why those things fail so often. They use 10v as a reference but the electrical system when the engine is running is typically around 13.6v give or take a few tenths and if one were to use a voltage booster which would push that over 14vdc, meaning a 40% increase, that would push most electronics to the brink.
Okay, that said, both the crankshaft and camshaft position sensor go DIRECTLY to the Ignition Control Module. They are connected no where else. The ICM then uses those signal to output signals to the PCM such as the Camshaft position signal (obviously), timing signal, timing control and a couple others.
It looks to me that the 10vdc voltage reference comes from the underhood fuse block through a 15Amp fuse which appears to also provide the DC voltage to the primary side of the ignition coils.
So all that to say this. It leads me to wonder if you dont have a blown fuse anywhere, though I think you said you checked those (may warrant physically pulling and checking any fuse related to the ignition system, especially if its a 15amp fuse) or if there may be an issue with your ignition control module.
Now the good news in all this is that you can pull your ignition control module and take it some place like Autozone and they can test it for you. I think they can even test your ignition coils as well, which they can probably test it better anyway. You can check the resistance all day long on those things and it may be fine, but once they get warmed up they can open up, so that may be worth looking into.
ok i will take my ICM in to get tested and see what advance says...i am also probably gunna pick up a new MAP since its only 50 bills. and i guess we will se...and if those dont fix it i am going to cry...and push her into the road and collect insurance!!! :th_angry-teeth:
LOL. Dont do that, we'll get 'er figured out its just kinda hard to do so on a message board, but as we eliminate things we're also moving closer to what it could be too.
that is true. just a pain in the butt...haha
well i will let you know as soon as i get off work here...and im hopin for the best haha
so the ICM was good when tested today, and i picked up a new map sensor, and will plug that in when i get home. so far i have replaced, plugs/wires, FPR, MAP. what else could be wrong if this does not work...
Well, if the new MAP sensor doesnt work you're really down to just a few things. There are two key events here that have me a bit troubled.
1. The fact it started up and ran for a bit after you replaced the FPR after so long of it not starting at all.
2. The fact it just upped and died on its own after it ran fine for several minutes.
Do you have a cell phone with free long distance? Or are you going to be around after 5pm Central time?
If so, PM me and if its where I can, when I get home I will try and call you and maybe we can beat heads on this thing and see if we can get it worked out. Maybe with both of us can come up with something.
haha i dont have LD on my phone...but i do have a laptop at my house and work till 7 mnt time. so i can be around the comp pretty much the whole night. go wireless i do however have free texting if you can do that?