Camshaft sensor P38

boycie · Feb 13, 2021

Hi Folks I would very much like your opinion on an intermittent fault I have on my 1999 4.7 Thor engined p38 for the last few months it would very occasionally be quite difficult to start this would occur about once a month. I’d lift the bonnet have a look to see if anything obvious was wrong turn the key again and it would start ,on one occasion I managed to get a spark tester on it and there was no spark then a minute later it fired ,once started it would run fine for weeks then the same again no fault codes showing The Rev counter wasn’t moving so I suspected the crank sensor so I changed it and everything was fine for a couple of weeks .Well this morning the car stalled momentarily then picked up then minutes later it cut out ,we rolled into a lay-by and tried to start it it just turned over so we took the dog for a walk down the footpath off of the lay-by for 15 minutes came back the car started straight away and run fine on the way home .I plugged the Nanocom in and the first code to come up was P1000 = camshaft sensor fault / valve timing error drive cycle A occurred 2 times,I’m going to replace the cam sensor but is this normally how a failing cam sensor acts or could there be another fault.Sorry to be so long winded with my question but I really would appreciate your opinions.

brianp38dse · Feb 13, 2021

Normaly they start playing up when they get hot can be tested with a quick spray of plumbers freeze it spray, but sounds more like you have a loose wire somewhere, check the battery terminals are on properly some times the tightern up but dont clamp the post.

boycie · Feb 13, 2021

brianp38dse said:
Normaly they start playing up when they get hot can be tested with a quick spray of plumbers freeze it spray, but sounds more like you have a loose wire somewhere, check the battery terminals are on properly some times the tightern up but dont clamp the post.

Gunnerhavesome · Feb 13, 2021

Sounds like the cam/crank sensor to me. I had a similar issue a few years ago. P38 4.6 Thor. Car would start and run fine then when hot refuse to start until cooled and then cut out once on the road, got to the roadside refused to start called a tow truck and when he arrived it started fine, Changed the sensor and never a problem since.

boycie · Feb 13, 2021

Thanks for the reply ,the battery terminals are tight .The fact it starts when it cools down was one of the reasons I thought it my be the sensor ,I’ve found some new old stock on eBay for £150 and I’ve ordered one I’ll check the connections when I change it .

boycie · Feb 13, 2021

Gunnerhavesome said:
Sounds like the cam/crank sensor to me. I had a similar issue a few years ago. P38 4.6 Thor. Car would start and run fine then when hot refuse to start until cooled and then cut out once on the road, got to the roadside refused to start called a tow truck and when he arrived it started fine, Changed the sensor and never a problem since.

That’s pretty much where I am ,I’ve done the crank sensor so I will change the cam sensor .Thanks ,I feel a bit happier now I’m not the only one to have this intermittent problem.Out of interest which sensor did you change ?.

Gunnerhavesome · Feb 13, 2021

boycie said:
That’s pretty much where I am ,I’ve done the crank sensor so I will change the cam sensor .Thanks ,I feel a bit happier now I’m not the only one to have this intermittent problem.Out of interest which sensor did you change ?.

Mine was the cam sensor

boycie · Feb 13, 2021

Gunnerhavesome said:
Mine was the cam sensor

You have cheered me up no end thank you Gunnerhavesome .

Gunnerhavesome · Feb 13, 2021

boycie said:
You have cheered me up no end thank you Gunnerhavesome .

Happy to help, just hope it solves your problem.

boycie · Feb 13, 2021

Gunnerhavesome said:
Happy to help, just hope it solves your problem.

My Wife Jackie thinks you guys are magicians anything that go’s wrong with the car any odd noises or warning light ,she says ask your friends on Landyzone they will know and you normally do ,I just told her about your post “I told you they would know “.

tomcat59alan · Feb 13, 2021

boycie said:
My Wife Jackie thinks you guys are magicians anything that go’s wrong with the car any odd noises or warning light ,she says ask your friends on Landyzone they will know and you normally do ,I just told her about your post “I told you they would know “.

Hey,Tommy Cooper was a magician you know.

boycie · Feb 13, 2021

tomcat59alan said:
Hey,Tommy Cooper was a magician you know.

She thought he was pretty good as well .

boycie · Feb 13, 2021

I’ve just had a look at the cam sensor ,should it have a metal fork like bracket with a bolt through it holding it in position,if it should my fork part is missing it’s a 1999 Thor engine ?.

Henry_b · Feb 13, 2021

Crank Sensor is very common, and almost always goes out when hot..
It is positioned at the lower left hand part of the engine, close to the gearbox.

boycie · Feb 14, 2021

Henry_b said:
Crank Sensor is very common, and almost always goes out when hot..
It is positioned at the lower left hand part of the engine, close to the gearbox.

Thanks Henry ,that was my first thought the crank sensor so I changed it a month ago but I had the problem again yesterday.This time there was a fault code stored related to the CAM sensor.

pwood999 · Feb 14, 2021

Check the connector as well. It's in an ideal position to get covered in coolant or oil. If the sensor is loose, then it will definitely cause misfire, and possible failed starts.

boycie · Feb 14, 2021

pwood999 said:
Check the connector as well. It's in an ideal position to get covered in coolant or oil. If the sensor is loose, then it will definitely cause misfire, and possible failed starts.

That’s SPOOKY I went out this morning disconnected the crank sensor cleaned the two halves of the plug replaced the orange silicone seal reconnected it and gave it a coat of silicone spray.The car starts and runs fine at the moment I’ve got a new CAM sensor on the way .

Marshall8hp · Feb 14, 2021

The cam sensor should not have a discernable effect on the engine running. RAVE notes that it may lead to the fuel injection being 180 degrees out of phase but that it is difficult for the operator to notice any difference in vehicle operation.

Mine had a dud cam sensor for 12 months before I got around to replacing it. Finally put a new one in and the only difference was the error for a dud cam sensor disappeared.

The symptoms you describe in #1 are usually CPS. It might not be the CPS, but could be related to poor connections, damaged wiring, poor connection at the ECU end etc.

boycie · Feb 15, 2021

Marshall8hp said:
The cam sensor should not have a discernable effect on the engine running. RAVE notes that it may lead to the fuel injection being 180 degrees out of phase but that it is difficult for the operator to notice any difference in vehicle operation.

Mine had a dud cam sensor for 12 months before I got around to replacing it. Finally put a new one in and the only difference was the error for a dud cam sensor disappeared.

The symptoms you describe in #1 are usually CPS. It might not be the CPS, but could be related to poor connections, damaged wiring, poor connection at the ECU end etc.

Thanks for the reply ,I we took the car out today and it ran fine .I’ll try the cam sensor as I’ve ordered it ,the trouble is in the past it will run fine for a month then you try to start it and it just turns over leave it for 10 minutes and it’s back to normal.

pwood999 · Feb 16, 2021

You could try unplugging the cam sensor and see how it runs. Assuming your Crank sensor is giving good signals, the engine should run ok . . . .but . . . The ECU will flag a fault, but will probably use default fuel timings, and not try to adjust. It also affect knock sensor operation. There are some posts on various vehicle boards that also mention impact on transmission changes impact, but that depends if the P38 ECU's talk to each other.

From RAVE:

Camshaft sensor P38

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