misterp Posted April 6, 2009 Report Share Posted April 6, 2009 Does anyone know what happens if the crank sensor signal wire is cut? Does the PCM cut both the spark and fuel? Mr. P. Quote Link to comment Share on other sites More sharing options...
Fireman31 Posted April 6, 2009 Report Share Posted April 6, 2009 It will light your dashboard up like a christmas tree, but the truck will still run. Code P0335 will be set..... Quote Link to comment Share on other sites More sharing options...
blackbeast ss Posted April 6, 2009 Report Share Posted April 6, 2009 this happend to when i reinstalled my tranny,they got damaged and cut. the truck wouldnt start it would crank but it would pop like a mofo....your timimg will be way offffff and cause the truck to backfire Quote Link to comment Share on other sites More sharing options...
zippy Posted April 6, 2009 Report Share Posted April 6, 2009 You will get codes and a no start. I've never gotten one to fire with no crank signal Quote Link to comment Share on other sites More sharing options...
misterp Posted April 6, 2009 Author Report Share Posted April 6, 2009 (edited) You will get codes and a no start. I've never gotten one to fire with no crank signal I understand it won't start - was more concerned with what will happen *while running*. Here is why I ask - I am wanting to create a fuel pressure safety switch; when fuel pressure drops below 58-psi have a relay interrupt the crank signal, I may also use a double-pole relay so that both crank and cam sensors are cut. The idea being, I want the PCM to stop sending spark and fuel to the motor until safe conditions return. DAN - after what you've said. I'm thinking I would have to interrupt both crank and cam sensors... Mr. P. Edited April 6, 2009 by Mr. P. (see edit history) Quote Link to comment Share on other sites More sharing options...
Fireman31 Posted April 6, 2009 Report Share Posted April 6, 2009 I understand it won't start - was more concerned with what will happen *while running*. Here is why I ask - I am wanting to create a fuel pressure safety switch; when fuel pressure drops below 58-psi have a relay interrupt the crank signal, I may also use a double-pole relay so that both crank and cam sensors are cut. The idea being, I want the PCM to stop sending spark and fuel to the motor until safe conditions return. DAN - after what you've said. I'm thinking I would have to interrupt both crank and cam sensors... Mr. P. Had this issue on an '05 Astro here at work, van was in at the local dealer for some warranty trans work. While at the dealer, the 3 wires that go to the sensor were completely severed, and the truck still ran. I got about 8 blocks away from the dealer after the warranty work was complete when the dash went haywire, and the truck started to buck. Upon my return to the dealer they brought it right in and onto a lift, scanned it quick, code P0335 was thrown. The tech put the truck up in the air and found the crank harness severed. I know he wasn't BSing me because I stood there and watched him like a hawk(the things I do as fleet supervisor ). I guess this was just an oddball case then. Quote Link to comment Share on other sites More sharing options...
mike1booth Posted April 6, 2009 Report Share Posted April 6, 2009 is you kill fuel and spark itll shut down the motor... y not just interrupt the ignition? Quote Link to comment Share on other sites More sharing options...
misterp Posted April 6, 2009 Author Report Share Posted April 6, 2009 is you kill fuel and spark itll shut down the motor... y not just interrupt the ignition? Well cutting spark is ok but then the PCM would still send a ton of raw gasoline out the exhaust and load-up the muffler, and when spark returns *BOOM* no more muffler I could use a latching relay, but it would be ideal if both spark and injectors were stopped. Mr. P. Quote Link to comment Share on other sites More sharing options...
mike1booth Posted April 6, 2009 Report Share Posted April 6, 2009 guess that could be trouble... good to know Quote Link to comment Share on other sites More sharing options...
zippy Posted April 7, 2009 Report Share Posted April 7, 2009 I understand it won't start - was more concerned with what will happen *while running*. Here is why I ask - I am wanting to create a fuel pressure safety switch; when fuel pressure drops below 58-psi have a relay interrupt the crank signal, I may also use a double-pole relay so that both crank and cam sensors are cut. The idea being, I want the PCM to stop sending spark and fuel to the motor until safe conditions return. DAN - after what you've said. I'm thinking I would have to interrupt both crank and cam sensors... Mr. P. Sounds like a problem waiting to happen when you're just driving around normal. I assume you're looking to do this during a nitrous or boosted situation since dropping fuel pressure when N/A really isn't likely to hurt anything. You could just fire the truck up if you wanted to find out and disconnect the sensor with it running. You planning to spray or make boost? Quote Link to comment Share on other sites More sharing options...
misterp Posted April 7, 2009 Author Report Share Posted April 7, 2009 Sounds like a problem waiting to happen when you're just driving around normal. I assume you're looking to do this during a nitrous or boosted situation since dropping fuel pressure when N/A really isn't likely to hurt anything. You could just fire the truck up if you wanted to find out and disconnect the sensor with it running. You planning to spray or make boost? Yes the circuit is only active when the second Walbro is running; when running on one fuel pump there is no difference from stock, that way you can start the truck like normal. Yes this is intended for use only during boost/nitrous. Mr. P. Quote Link to comment Share on other sites More sharing options...
zippy Posted April 7, 2009 Report Share Posted April 7, 2009 I know there are systems that you can hook to a wideband sensor to shut off nitrous if your afr gets over a selected number. That wouldn't be cutting off the fuel and spark, but it would be cutting off the dangerous part if you had a fuel pressure loss. Under boost and losing pressure you could also tap into the tps signal to the tac module which would put you into reduced power mode instantly. Quote Link to comment Share on other sites More sharing options...
misterp Posted April 7, 2009 Author Report Share Posted April 7, 2009 ... you could also tap into the tps signal to the tac module which would put you into reduced power mode instantly. Thanks for the suggestion, will crack the manual and check it out Mr. P. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.