97 cps keeps blowing

Jmcbride · Oct 25, 2015

Hey all, I have a 97 7.3 and I keep blowing cps. Sounds crazy but only works with duralast brand from autozone. I order one from riff raff a while back and it wouldn't even start. Napa one won't start. O reilly one will run for a while with the hiccup. Autozone work for about 2 weeks, so.e times. Have chased the wiring harness and found some bad spots so I replaced it. No engine codes and cel. I'm bout to go crazy chasing this thing down..

Magnum PD · Oct 25, 2015

It's not hitting the camshaft gear is it?

Jmcbride · Oct 25, 2015

No when I Chang it the isn't any marks on the metal bracket

Magnum PD · Oct 25, 2015

I'm taking about the flat circle on the bottom of the sensor

Jmcbride · Oct 25, 2015

Thr sensor never has any marks on it anywhere. Just a little oil

psduser1 · Oct 25, 2015

Cam walk?

Jmcbride · Oct 25, 2015

Not exactly sure what that is but sounds bad

psduser1 · Oct 25, 2015

If the cam walks away from the sensor, the sensor will not be triggered.
In other words the pcm won't tell the idm to "fire", which means the injectors won't operate.
Short version. Opposite of the contact question asked by magnum.
I can't tell you the air gap tolerance offhand, but it's fairly tight, and with poor quality checks on some of the newer replacement sensors, it may be enough to cause an intermittent no start.
Might be worth buying a higher quality i.e. more expensive sensor.

Magnum PD · Oct 25, 2015

Do you see the tach moving when it won't start?

Jmcbride · Oct 25, 2015

Sometimes yes. Sometimes it won't bounce. If the cam has walked what does it take to fix that?

Jmcbride · Oct 25, 2015

Most of the time the tach does move

Magnum PD · Oct 25, 2015

You have to pull heads to get lifters out then cam. Not sure how to check for cam walk.

78f100 · Oct 25, 2015

I only use oem sensors. I had another shop bring me a 7.3 that had intermitten no start and skip issues. They had put 2 different cps sensors from oreillys in it and all new injectors with same issue. Would get cps fault on the ids so I installed a new motorcraft cps, issue was gone. First shop owner and customer couldn't believe that was the issue until they drove it. Try a mc one, unless the cam bearings are shot like already said but you should see marks on the end if the cam is moving.