7.3 no start part deux.

[philos]

Got my new IPR replaced, and also took the time to build my own regulated return.
Got all buttoned up today, and I can only get it to crank over.
It gave a code for the exhaust pressure sensor, unplugged it and still just cranks.
Went to ICP and unplugged it, at which point she starts up.
Plugged the ICP back in and back to cranking. Unplugged, and around the block I went.
Injectors are cold, and the limp-mode pressure setting was making them noisy, but I'm sure they'd quiet back down with correct pressures.
Anyway, it starts/runs with it unplugged, but it's not running perfect.
I did fill the HPOP reservoir with some oil after the IPR was replaced, but I didn't check the level.
Also, I replaced the ICP with a motorcraft part within the past several weeks, so I'm doubt in its bad. I feel like it's related to the work I just did, but I can't say how or what...
Help?


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[Ozrockrat]

Sounds like low ICP. I do not have any of the data with me but I think its around 500 to start and 600+ to idle. Do you have anyway of checking it. Since you put in a new Motorcraft sensor I would probably eliminate that and check the wiring etc.

Noisy injectors are usually a sign of fuel starvation. Check the fuel pressure. Just as a point of interest there is a filter mesh inside the mixer/pickup in the fuel tank. Stupid bloody place to put a filter and a PITA to get it out. If you do remove it put an inline sediment filter on the chassis rail and check my old postings about making a new pickup/return. There is also a heap of info out on the web when you know to ask for it specifically.

Given you have played with the regulated return I would also suggest you check the rail pressure.

 

[philos]

Pressure at the regulator is at 62 psi +\- so it's definitely getting fuel (regulator is on the return/front side of the heads). I'm wondering if only putting one quart of oil in the HPOP reservoir could be the issue?
Low oil pump seems to work; pressure gauge on dash comes up after cranking for a few seconds.
Wait to start light works and comes on before cranking.
I'm done futzing tonight but I'll have another look in the am.
I'm also going to triple check my wiring on the new pigtail for the IPR. I matched the wires by color as well as by checking orientation, but I do make mistakes on occasion. Like I said, I'll check that tomorrow.
I'll also have another look at the oil level in the HPOP res...
And I'll also plug the ICP back in one more time to see if a second spin up the block has done anything, but I'm done for today.


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[philos]

And thanks for the reply!



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[Ozrockrat]

Sorry I just read your other thread. I didn't know you had done all the work to the fuel supply system.

I think you are on the right track. Its called "maintenance induced failure" ( fix it until its f*$ked). Backtrack what you have worked on and what you may of disturbed by working around those areas. I used to deliver white papers on this phenomena and yet it still bites me on the ******** way to regularly.

 

[philos]

Fix it til it f#@%@D, sounds like me... hehe.

Checked the HPOP reservoir, and filled it to the brim with fresh oil.
Triple checked the orientation of my wires to the IPR sensor/pigtail.

Still no start.

 

[Ozrockrat]

Do you have a data logger of any type that hooks to the engine. I am still thinking ICP is low or the system thinks it is low. Having some way of monitoring the following parameters would help. (The numbers I am suggesting are pulled from my worn out memory banks so I would recommend checking them elsewhere)

IPR duty cycle (cold 12-15, idle 9-12 %, higher numbers means its trying harder to get the amount of fuel it needs)
ICP pressure (around 500 to start, 700 idle and over 2000 wide open under load)
Volume of fuel desired (relative to throttle input)
Engine RPM (somewhere between 650 - 700 at idle I think)
Voltage (low voltage does weird things on these engines)

Also since you mentioned noisy injectors a buzz test would be beneficial. If you don't have the tools to perform a buzz test you can pull the valve covers and just check they all look to be pushing the same amount of oil around (PITA on a van). But this should be after you sort the low ICP.

 

[philos]

Sadly, I've only got a cheap scanner that barely pulls/clears codes... I should save some pennies for auto-enginuity and in turn save myself some headaches.

I think I'll try and look up the voltage values are supposed to be for the ICP and check with my multimeter, pretty certain they're in the factory manual somewhere.
I'm also going to test my splices/connections I made for the IPR pigtail... I crimped instead of soldered, so I'll check while I've got the multimeter out.

And, thanks again for the replies

 

[Ozrockrat]

I don't have access to the wiring diagrams but you should be able to measure the output voltage of the ICP sensor but it will need to be connected (3 wire sensor from memory). The 1st check should be the wiring from the sensor connector to the ECM. I have a healthy respect for Motorcraft parts and cannot remember any of their sensors ever being bad out of the box.

So just to make sure you don't get too far into the weeds.

1. Check your voltage while cranking the engine. Needs to be over 7.5V at the ECM to keep it happy.
2. If you can unplug the ICP sensor and it runs it is highly likely that the issue is low ICP reading.
3. Since you have replaced this sensor with a know quality part we can assume it is probably reading OK.
4. You could measure the voltage out from the sensor and see if you are getting the same at the ECM input.
5. Or you can just meter wires from the ICP sensor to the ECM
6. Alternatively you can put a gauge on the ICP and make sure it is over 500 at crank/start. Be very careful!!!! These things operate at very high pressure and at full pressure a pinhole leak can cause you damage.
7. Sadly a new sensor that works unplugged will probably equate to the ICP being low for mechanical not electrical reasons. The main thing you have going for you is that it was working OK before you fixed it so it will probably be something you have touched.

 

[philos]

Broke down and bought ANOTHER new ICP sensor, dropped it in (easy job without the fuel bowl in the way!) and she fired right up.
Went straight into a rough-ish idle and another P1211 code (IPR sensor!!!!), so I cleared the code and went for a drive.... first 4-5 miles it was waaaay down on power and the IPR code came back. Cleared it again and it started to smooth out a tad.
Put a few more miles in, and it's improving as I drive. No more codes either. WOOT!!!
So, I'm hoping that the last bits of trapped air will find their way out and the world will be right in dieseltown again.

I also took the time to wrestle with the EBP sensor, more fun!
Got my 9/16" wrench on the underside of the bracket, got my big socket on the EBP sensor, and it broke off in the bracket. Joy.
got the rest of the tube off with a healthy dose of wrestling and foul language, then I just cut the effing bracket off the HPOP gear cover. ****** it.
Cleaned it all out and dug the broken brass out of the fitting before putting it all back together. I've got a new EBP sensor en route, and the old broken one is hanging on by it's remaining 2.5 threads until then. I'm re-doing the bracket support for the EBP tube so that it isn't so lame.

Anywho, seems like my troubles are past for the moment.