I Know You Guys can figure it out

mustang462002 · May 15, 2007

So I recieved the code of camshaft circuit malfunction. I replaced the sensor. Then I checked the alternator all fine. So I took it to my dealership. They still can't find the problem. What happens is if I start it, it will bog down and die. I need to start it with my foot on the gas. Later when its started everythings fine. The fuel pressure is fine. But only when its running they didn't say if they checked it while it was cranking. Could it be my fuel pump is dying? It only does it on start up. I also have this wheezing sound in the engine. Please help.

Nater · May 15, 2007

It won't start and run without the foot on the gas? How about the IAC? Where is the wheezing sound coming from? Does it happen all the time while the engine is running or is it dependent on RPM's?

mustang462002 · May 15, 2007

I already cleaned the IAC. It only happens if I start the car without my foot on the gas. The wheezing sound only happens when the car is in iddle. Well, It might be all around its just I can't hear it because of engine noise.

Matt's 03 GT · May 15, 2007

Vacume leak? Maybe a hose popped off???

Kilgore Trout · May 15, 2007

Now try replacing the IAC if you already cleaned it...

mustang462002 · May 15, 2007

Nope I already checked for hoses poping out. Replacing the IAC? Wouldn't it throw a code that wasn't the Cam shaft circuit malfunction?

What is the price for a fuel pump?

RandyStinchcomb · May 15, 2007

sounds like a bad FRPS = fuel rail pressure sensor. check and see if your's is stamped wth "F8CF" or "3R3E"

oh and checking "fuel pressure" is one thing but whats the volume? you can have tons of pressure but if the volume isn't there, it won't run right at all

steveb24 · May 15, 2007

RandyStinchcomb said:
sounds like a bad FRPS = fuel rail pressure sensor. check and see if your's is stamped wth "F8CF" or "3R3E"

oh and checking "fuel pressure" is one thing but whats the volume? you can have tons of pressure but if the volume isn't there, it won't run right at all

I had one go bad on me.. this is what I would suggest to.

chuck943 · May 15, 2007

The PCM uses CAM sensor to sychronize the firing of the injectors,basically it tells the PCM where number one cylinder is. PCM if it doesn't see this signal will fire all the injectors continuously. It will run but will have a hard start burn more fuel etc.
This sensor is very suspect to interference, usually from DPFE sensor. Do you have a way to retrieve codes? If so clear codes then unplug DPFE,ignore the code you will get for it(DPFE) just see if you can get the CAM sensor code to repeat then,if you can't then replace DPFE.

chuck943 · May 16, 2007

Worked on one today,same exact yr/model/p0340 code. Problem turned out to be alternator. The problem is a malfunctioning diode or open phase in alternator. Vehicle charged good and had no charging issues but did an alternator ripple test on osciliscope and it failed. If you have a way to clear and test codes try unplugging regulator on alternator and crank it several times and see if you can get this code to reset.

Brute03 · May 17, 2007

RandyStinchcomb said:
sounds like a bad FRPS = fuel rail pressure sensor. check and see if your's is stamped wth "F8CF" or "3R3E"

....and if it is, what would it mean? just curious

as far as the cps code is concerned, i'm betting it's the alternator that's causing the CEL to trigger. like someone said before, a bad diode causes interference with the signal from the cps ,however the alt. will still pass the standard voltage and load tests which is why the shop probably thought is was good

mustang462002 · May 17, 2007

Wow, this is astounding. Thanks for all the wonderful help. I took it to a local dealership. They told me that it was the fuel pressure regulator plus the fuel pump. Is this correct. I'm going to try all of the above. I'm going to buy a code reader and try this.

Why is it important if its stamped a certain way? RandyStinch

RandyStinchcomb · May 17, 2007

mustang462002 said:
Wow, this is astounding. Thanks for all the wonderful help. I took it to a local dealership. They told me that it was the fuel pressure regulator plus the fuel pump. Is this correct. I'm going to try all of the above. I'm going to buy a code reader and try this.

Why is it important if its stamped a certain way? RandyStinch

there is NO fuel pressure regulator on YOUR car and I doubt if the fuel pump is bad, sounds like a scam to me.
on the FRPS, there was a design change and an improved version, so thats why a stamp # would help to see if you have the old style that was a problem or the new and improved one.

Kilgore Trout · May 17, 2007

Most likely you are getting better info from Randy than the stealership.

Check FRPS.

mustang462002 · May 17, 2007

I was just about to go out and buy a fuel pump. I would have sounded really stupid if I was to look for a fuel pressure regulator. I'm at work right now. What is the old style FRPS the F8CF or 3R3E.

RandyStinchcomb · May 17, 2007

the new and improved one has the "3R3E" stampped on it and if you do need a fuel pump, its much cheaper to buy a SVT Focus pump for yours as there only about $100.00 vs you fuel pump asbly which is closer to $300.00

mustang462002 · May 17, 2007

I'm still thinking of trying out all the steps before I go for the fuel pump. But can I just plug in the Focus SVT Fuel pump. Like the 300 buck one. Is it identical?

chuck943 · May 17, 2007

I curious? How or what led them to fuel pump? I could understand the fuel rail pressure sensor( I am assuming that is what they are calling the regulator but this vehicle does not have a regulator) simply because it shares the same signal return back to PCM and is pretty close to the CMP sensor but I can't understand fuel pump setting a P0340 code its to far away and is not on that circuit.

Like I told you in earlier post the one I worked on yesterday had the exact same symptoms you described, even having to press accel to get it to run then it was ok after that. I could get code to set just by starting it let it idle for a sec then shut down and restart, it would set the code as a pending code after 2 to 3 start ups and by 8 or 9 start ups it would turn on CEL

RandyStinchcomb · May 18, 2007

mustang462002 said:
I'm still thinking of trying out all the steps before I go for the fuel pump. But can I just plug in the Focus SVT Fuel pump. Like the 300 buck one. Is it identical?

yeah, replace the FRPS as it's only @$60.00

now the fuel pump is not quite "plug n' play", you will have to re-move the electric pump motors out of each and swap them. so for the price, it's an easy mod and allows you room to grow, wth mods

mustang462002 · May 22, 2007

Thanks a lot for all your help. After checking and unpluging sensors I got to the alternator. It turns out it was putting 12 v but the signal was messed up and throwing off the pcm. I replaced it and good as new. I did think it was the alternator but since it was putting the correct voltage I thought that it was good. It never occured to me as chuck said to just unplug the harness. Thanks a lot for all your help. I just don't get it either why would they tell me to replace the fuel pump. Last time I'm taking it to that dealer. I wanted to talk to the mechanic but my service advisor said he was busy. What a load of crap. I'm glad my car is back to its self. Thanks a lot.

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