Engine wont start - no fuel pressure

[jneal]

Probably not as big of PITA as not running as it is now. At the FRP sensor I am recieving 5 volt at the 5 volt ref .01v at the low ref and 5 volts at the middle wire (sensor) Is that normal?

This is not normal. IMO you have a electrical problem. The fuel rail pressure sensor has a 5V supply, Ground, and Signal wire. You should not have 5V on any 2 wires at anytime unless you have 29,000 plus psi of rail pressure. Cranking is definately not one of this conditions. Now that being said, you need to find which wire to the sensor is the 5V reference which should be pin A or 1 on the connector , pin B or 2 should be ground and pin C or 3 should be signal. Now without looking at a wiring diagram (I am going off memory here) most manufactures will run a common 5v reference and common grd to several sensors. If one sensor shorts internally it can cause 5v to go to both the common 5v reference wire and the common ground wire. The easiest way to troubleshoot this is to check the wiring at the fuel rail pressure sensor, find which wire has 5v on it that shouldn't (ground or signal) and begin unplugging other engine sensors while monitoring voltage at the fuel pressure sensor. When voltage drops to .02 or less you have found the bad sensor. It could also be a short in the wiring harness. Easiest way to find this possible problem is to perform a wiggle test, which is just what it sounds like, wiggle the wiring harness while again monitoring voltage on the wire at the rail pressure sensor that should have not voltage, when it drops you have found the general loacation in the wiring harness that the problems lies.

What all did you have off during the injector swap? Is it possible that a wire got pinched under the valve cover during the valve cover swap? Have you checked the wiring harness on the passenger side where the LLY's have the harness rub issue.

But again IMO you don't have a mechanical issue, it is electrical.

Hope this helps.

Good luck,
Jerrod

 

[sweetdiesel]

Simon, his pressure is 190psi to 220psi.

After reading through my GM manual the rail sensor should show this 190-220psi (1.1-1.4 mpa) with key on and not cranking or running

Just means that his Rail sensor is good

As far as checking the reluctor wheel it should not move...Duh
But it will effect starting

Crank and cam sensors need to be checked also And also unplug the ECT sensor and compare it with ambient tempif it is off more than 5 degrees C
It can mean a bad resistance in the sensor circut and can mean other issues with the fuel system

Inspect fuel press reg 12 volt circut for intermintent short to ground


What codes was Mick showing?

 

[mick]

This is not normal. IMO you have a electrical problem. The fuel rail pressure sensor has a 5V supply, Ground, and Signal wire. You should not have 5V on any 2 wires at anytime unless you have 29,000 plus psi of rail pressure. Cranking is definately not one of this conditions. Now that being said, you need to find which wire to the sensor is the 5V reference which should be pin A or 1 on the connector , pin B or 2 should be ground and pin C or 3 should be signal. Now without looking at a wiring diagram (I am going off memory here) most manufactures will run a common 5v reference and common grd to several sensors. If one sensor shorts internally it can cause 5v to go to both the common 5v reference wire and the common ground wire. The easiest way to troubleshoot this is to check the wiring at the fuel rail pressure sensor, find which wire has 5v on it that shouldn't (ground or signal) and begin unplugging other engine sensors while monitoring voltage at the fuel pressure sensor. When voltage drops to .02 or less you have found the bad sensor. It could also be a short in the wiring harness. Easiest way to find this possible problem is to perform a wiggle test, which is just what it sounds like, wiggle the wiring harness while again monitoring voltage on the wire at the rail pressure sensor that should have not voltage, when it drops you have found the general loacation in the wiring harness that the problems lies.

What all did you have off during the injector swap? Is it possible that a wire got pinched under the valve cover during the valve cover swap? Have you checked the wiring harness on the passenger side where the LLY's have the harness rub issue.

But again IMO you don't have a mechanical issue, it is electrical.

Hope this helps.

Good luck,
Jerrod

Thanks Jerrod - I have .02v on the ground wire, 5v on the 5v ref wire and also 5v on the centre (signal) wire. You saying this is not right? If so you may be onto something No doubt I could have broken or squashed one of those so small wires somewhere. Im waiting on a set of injectors from Guy at the moment.

 

[LBZ]

I thought the reference should read low voltage at low pressure and high voltage at high pressure?

 

[mick]

After reading through my GM manual the rail sensor should show this 190-220psi (1.1-1.4 mpa) with key on and not cranking or running

Just means that his Rail sensor is good

As far as checking the reluctor wheel it should not move...Duh
But it will effect starting

Crank and cam sensors need to be checked also And also unplug the ECT sensor and compare it with ambient tempif it is off more than 5 degrees C
It can mean a bad resistance in the sensor circut and can mean other issues with the fuel system

Inspect fuel press reg 12 volt circut for intermintent short to ground


What codes was Mick showing?

Only a couple of codes relating to turbo boost press and map Simon. Crank and Cam Sensors are ok. If the same guy built your engine he didnt leave the reluctor plate off the cam too did he?

 

[LBZ]

I don't think so Mick-Simon got the truck running.

It just started for some reason after he put the road runner back in and threw some swear words at it!!:rofl:

 

[mick]

I thought the reference should read low voltage at low pressure and high voltage at high pressure?

Sparky is My weakest subject Dale. I hate things I cant see namely electricty. But I think the low reference is earth and all my other sensors at that particular point read app .01v/.02v but Im not sure about that sensor point as Jerrod mentioned....

 

[mick]

I don't think so Mick-Simon got the truck running.

It just started for some reason after he put the road runner back in and threw some swear words at it!!:rofl:

Thats all good then Those Canadian Swear Words would get anything going - my brother was up there for 30 years and I know :rofl:

Happy for you Simon

 

[LBZ]

Thanks Jerrod - I have .02v on the ground wire, 5v on the 5v ref wire and also 5v on the centre (signal) wire. You saying this is not right? If so you may be onto something No doubt I could have broken or squashed one of those so small wires somewhere. Im waiting on a set of injectors from Guy at the moment.

Did you measure this with the sensor unplugged or did you back probe it Mick?

 

[Fingers]

You should get 5 volts from 5 Volt reference to ground. Those are the two outside wires on the sensor. The Pressure Signal is from the center wire. Take that reading from between the center wire (yellow) and ground (Tan). While cranking, it should work its way to about 1.1 Volts which is ~4000PSI. Any movement means the pumps are at least pumping, but the ECM want pressure in the thousands before it fires the injectors.

You are not making pressure in the first place IMO. Without that, the engine will not even attempt to fire.

However there are some other basic things to check:

• 
  You need to check that you have connected ALL of the grounds. That is 4 on the right side of the engine and two on the left.
  
  The Crank and Cam signals are easy to check. On the Crank sensor, with the ignition on, check the voltage from the Dark Blue wire with a white stripe to ground. It should pulse as you turn the crank by hand. The Cam sensor signal is the brown wire with white stripe coming out of it. Check from there to ground while you turn over the motor by hand. It should change too, but only a couple times every two rotations. That is, one revolution should show nothing. the other it will change.
  

 

[Fingers]

Oh, and make sure the damn ECM and TCM and FICM connectors are all fully engaged.

 

[mick]

You should get 5 volts from 5 Volt reference to ground. Those are the two outside wires on the sensor. The Pressure Signal is from the center wire. Take that reading from between the center wire (yellow) and ground (Tan). While cranking, it should work its way to about 1.1 Volts which is ~4000PSI. Any movement means the pumps are at least pumping, but the ECM want pressure in the thousands before it fires the injectors.

You are not making pressure in the first place IMO. Without that, the engine will not even attempt to fire.

However there are some other basic things to check:

• 
  You need to check that you have connected ALL of the grounds. That is 4 on the right side of the engine and two on the left.
  The Crank and Cam signals are easy to check. On the Crank sensor, with the ignition on, check the voltage from the Dark Blue wire with a white stripe to ground. It should pulse as you turn the crank by hand. The Cam sensor signal is the brown wire with white stripe coming out of it. Check from there to ground while you turn over the motor by hand. It should change too, but only a couple times every two rotations. That is, one revolution should show nothing. the other it will change.
  

You may have something here John, I only remember 2 on the right side. I'll check that. Thanks.

 

[jneal]

Yes definately check all your grounds. Most electrical problems are related to grounds or lack there of.

Thanks John for the pin clarification, I was strictly going off memory.

 

[mick]

You should get 5 volts from 5 Volt reference to ground. Those are the two outside wires on the sensor. The Pressure Signal is from the center wire. Take that reading from between the center wire (yellow) and ground (Tan). While cranking, it should work its way to about 1.1 Volts which is ~4000PSI. Any movement means the pumps are at least pumping, but the ECM want pressure in the thousands before it fires the injectors.

You are not making pressure in the first place IMO. Without that, the engine will not even attempt to fire.

However there are some other basic things to check:

• 
  You need to check that you have connected ALL of the grounds. That is 4 on the right side of the engine and two on the left.
  
  The Crank and Cam signals are easy to check. On the Crank sensor, with the ignition on, check the voltage from the Dark Blue wire with a white stripe to ground. It should pulse as you turn the crank by hand. The Cam sensor signal is the brown wire with white stripe coming out of it. Check from there to ground while you turn over the motor by hand. It should change too, but only a couple times every two rotations. That is, one revolution should show nothing. the other it will change.
  

I can only find 2 on the r/h side plus the main battery ground. Is there another one I am missing?

 

[Fingers]

Gonna make me look......

 

[mick]

Gonna make me look......

I'll look in my book tonight but couldnt see anyy extra wires hanging around down that side. Mines up on the hoist so its probably easier for me

 

[mick]

Recieved a new set of 100% over Injectors from Guy yesterday so will be installing them the next day or so and see how we go on getting it started - meantime I bought another toy - 2007

 

[Kat]

Congrats :rockon:

 

[Turbo Buick 6]

Sweet Mick:cool2:

 

[mick]

Thanks Kat and Paul. Shouldnt hijack my own thread but I sold my 05 and my 65 and my 71 - too many trucks around