Help us help you. By posting the year, make, model and engine near the beginning of your help request, followed by the symptoms (no start, high idle, misfire etc.) Along with any prevalent Diagnostic Trouble Codes, aka DTCs, other forum members will be able to help you get to a solution more quickly and easily!
I have a 2006 Ford e150 4.6 liter v8 engine. No trouble codes at the moment. It had a p0152 code (02 sensor circuit high voltage bank 2 sensor 1) but the check engine light turned off on it's own a week or 2 before the problem started.
Since the no start problem started I have put in a new fuel pump, new fuel pump driver module, new fuel rail pressure sensor, and had 2 junkyard computers in it from identical vans (no change in the problem so they will be returned)(original computer is back in).
I tested voltage on the connector removed from the fuel rail pressure sensor and it read 5v on the ref wire 4.9v on the signal wire and had a good ground wire all with the key on. When connected back to the frps the signal wire reads around 2.84v with the engine running at idle.
When the van is running it seems to be running fine with no rough idling or reving. when I let it sit for a while usually overnight it will have the crank no start problem. I checked the voltage on the connector removed from the fuel pump driver module with key on and I read 12v on the thick white wire. Once connected to the fpdm the voltage on the same wire dropped a volt or so and was fluctuating up and down about a volt or so.
I have a 2006 Ford e150 4.6 liter v8 engine. No trouble codes at the moment. It had a p0152 code (02 sensor circuit high voltage bank 2 sensor 1) but the check engine light turned off on it's own a week or 2 before the problem started.
Since the no start problem started I have put in a new fuel pump, new fuel pump driver module, new fuel rail pressure sensor, and had 2 junkyard computers in it from identical vans (no change in the problem so they will be returned)(original computer is back in).
I tested voltage on the connector removed from the fuel rail pressure sensor and it read 5v on the ref wire 4.9v on the signal wire and had a good ground wire all with the key on. When connected back to the frps the signal wire reads around 2.84v with the engine running at idle.
When the van is running it seems to be running fine with no rough idling or reving. when I let it sit for a while usually overnight it will have the crank no start problem. I checked the voltage on the connector removed from the fuel pump driver module with key on and I read 12v on the thick white wire. Once connected to the fpdm the voltage on the same wire dropped a volt or so and was fluctuating up and down about a volt or so.
testing the quote feature as one of you used it and it is horrible! lol
If this works properly, here is the order, and it must be followed exactly
#1 hit enter
#2 uncheck the " box at the top
#3 start typing as normal
I hate the way this is and we are aware of the problem and are working on a more user friendly format
It turns out the grounding strap to the frame was severed. I replaced it with a good wire. Now there is good ground on the frame and the condition has improved greatly. So far the van has been starting up and running fine for 2 days now. Thanks for that. I checked for a duty cycle on the 2 signal wires going from the driver module to the pcm and I read 98% on one of them and 100% on the other. From what I understand one should have 50% and the other should have between 25 & 50%.
It turns out the grounding strap to the frame was severed. I replaced it with a good wire. Now there is good ground on the frame and the condition has improved greatly. So far the van has been starting up and running fine for 2 days now. Thanks for that. I checked for a duty cycle on the 2 signal wires going from the driver module to the pcm and I read 98% on one of them and 100% on the other. From what I understand one should have 50% and the other should have between 25 & 50%.
Interesting. :huh: Were your readings taken with the engine running?
Are there any codes that set now that you've replaced the ground strap?
It threw a p2197 code today but after erasing it did not come back after running a while and several restarts. When I was checking the duty cycle the engine was running. The voltage reading on the lt blue/red wire (pcm) was jumping wildly from around .5v to around 11.5v. The other wire brown/orange (also pcm) was reading pretty steady at 2.28v and up every few seconds to 2.29 or 2.30v. Both readings with engine running.
I wanted to mention that when taking these readings I had my negative test lead on the frame and the positive on the appropriate wire for both voltage and duty cycle readings. However when I connected my test leads positive and negative to both pcm wires I got a duty cycle reading that looks more like what the control signal should be (25-50%).
I just remembered that while soldering on a new connector for the driver module I noticed that the ground wire going from the frame to the module had green powder within the strands of the wire (corrosion). I have been showing voltage drop on the negative circuit to the fuel pump and narrowed the drop to the wire between the module and the frame. I will put in a new wire asap. Is it possible that this corroded wire could be affecting the duty cycle?
I rechecked for voltage drop on the ground wire going from the module to the frame, and there wasn't any (maybe only .01v). I also checked the ground wire going from the module to the pump, also no voltage drop (.01v).The voltage drop (9.75v) only occurs between the ground wire from the frame to the module and the ground wire from the module to the pump measured at the connector with T pins.
