|Topic Review (Newest First)|
|12-05-2019 04:38 PM|
The lift pump on the 7.3 is a dual pump system -- the low pressure side pulls from the tank and flows thru the filter to the High pressure side
So, yeah you could use the drain valve or remove the cap to check the low pressure side
but you need a gauge to check the high pressure side -- 55 psi
There are 2 weep holes on the pump to leak out fuel if the diaphragm or high pressure seals leak
may want to use a mirror or snake cam to look while the engine is running for leaks
Found this vid that explains the pump pretty well:
|12-05-2019 03:37 PM|
Thanks for the replies guys!
The tach needle definitely goes up when I'm cranking, so from what I've read that should mean the CPS is functioning, right?
There was no oil that I could see in the ICP connections. Disconnecting the ICP didn't seem to make any difference either.
I did fill up both tanks during the brief period it was running (barely) last night. So it has fresh fuel in it.
I don't have the tools to check the fuel pressure at the bowl. Is there a simple way to see if the lift pump is getting fuel from the tanks to the engine? Could I open the drain valve, drain the bowl, then leave the drain open and see if more fuel comes out when I crank it? I'm going to pull the fuel filter out tomorrow and change it to make sure that isn't the culprit. Is there other filters to check besides the main one? I assume its not easy to get to the screens inside the fuel tanks right?
Oh - I should mention that I noticed a minor fuel leak over the last couple weeks. Just a few drips from underneath that would stop 10 minutes or so after shutting off the engine. Would leave a small puddle on the driveway. Like maybe a 1/4 cup of fuel max. It looked a bit wet in the valley but nothing else noticeable. I was suspecting the o-rings on the bowl drain valve and even ordered them but hadn't had a chance to change them out yet. Now I'm wondering if the leak could be related to the current issue. Would a failing fuel pump leak?
|12-05-2019 03:23 PM|
Sounds like either a fuel issue or a hpo issue after the truck is warm.
Install a gauge at the Schrader valve for fuel pressure, and you'll need a scanner to watch ICP and IPR numbers.
|12-05-2019 10:31 AM|
Scan for codes?
I would add 5 gallons of fuel to one tank and try it again if you don't have a good scan tool.
A CPS would be a good guess, but I hate guessing. Sure would like to see codes and ICP pressure when cranking.
|12-05-2019 03:29 AM|
The fuel bowl cover must be on when cranking.
If the fuel bowl and HPOP reservoir are full after cranking and you are getting white smoke then your injectors are firing.
I would throw in a new CPS, cheap and easy to rule out.
Does the ICP connector have oil in it? Have you checked fuel pressure while cranking?
|12-04-2019 06:57 PM|
Sounds like you are not getting fuel -- are the filters clean?
Mechanical lift pump on that engine, I think -- not my knowledge zone
The fuel pump may have gone out -- could remove the filter and crank over to see if fuel is pushed up
not sure on your model, but may be a valve port on the fuel bowl to check pressure with a gauge
Need some of the other guys to pop in on this @bismic
|12-04-2019 06:09 PM|
Okay...so here's an update to my previous post. I typed that up yesterday. Tonight I was able to get it to start up after disconnecting the ICP sensor and cranking it for a long while. It ran for a while but seemed to be really low on power. I was able to drive it around to the corner and fill up with fresh fuel. On the way back home I gradually lost all the rest of the power and stalled out 50 feet from my driveway. Tried disconnecting the ICP sensor again and cranking for a while, but it wouldn't start. Any ideas??? - Andy
|12-04-2019 06:04 PM|
1997 F-250 7.3 - Cranks but no start
Hi Folks! I'm new to this forum, having just recently purchased my first 7.3 powerstroke diesel truck. It was running great for a few weeks, just drove it 800 miles to North Carolina and back with no issues. Yesterday though, I started it up and left it to idle and warm up in the driveway. It started up easy on the first try (had the block heater plugged in, a little chilly out), but then I heard it die about 5 minutes later. Almost sounded like it ran out of gas. At first I thought maybe it had run out of gas, but was still showing almost 1/4 tank on the rear tank. Switched it over to the front tank (also about 1/4 tank) but still wouldn't start. The starter cranks and the engine turns over, but it just won't fire up. Sounds like its just on the edge of starting but won't. I get a little bit of white smoke from the tailpipe but that's it. I've read up quite a bit on the forums and tried some trouble-shooting but I'm stuck. Any ideas?
So far I have checked/tried:
- Oil level, coolant, air filter all good
- Fuses all good
- Disconnected ICP sensor
- Batteries are nearly new and seem to be giving plenty of juice
Before I bought the truck, the previous owner recently had a bunch of work done including:
- Replaced HPOP
- Replaced HPOP pickup tube
- LPOP resealed
- Oil cooler resealed
- Replaced IPR
- Replaced EPS
What should I try next? Or should I give up and take it to my mechanic??