85_305
In the Brig (Banned)
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Or invest in the stancor relay that will last your truck out.
cranks but wont start
- Thread starter Bigsexy
- Start date
SBMCCUNE
New member
Hell of a lot better that the cheap ass NAPA? Price seems ok.
85_305
In the Brig (Banned)
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Ummmmmm ya. Look @ google comparisons. The stanor is twice-3x the size of the stock one lol.
Arisley
Moderator
I am using a relay I bought from Western Plow, cost 15 bucks delivered to my door. Been working for 5 winters (I believe) now.
Bigsexy
New member
How do you know if theres a bad ground? Is t here away to test it?
Bigsexy
New member
Does anyone know where I can get what voltage the icp amd ipr should see?
The ground for switched side of relay is what the PCM controls.
If you want to see if you relay works, remove the small wires. Turn key on and test to see which one is hot with key on. Reconnect. Use jumper wire to ground other terminal. The relay will either click on, or not.
On your hydraulic pressure stuff, if it is working but not starting you should here Solinoids clicking. Testing voltages won't give you much info. If you want to know what's up with it install a gauge on a rail. The ipr works off of duty cycle, or percentage of On time. One wire is always hot with key on, other is ground side switched by PCM. If truck is cold PCM can command up to maximum pressure to start (2700ish) So if you were able to watch duty cycle, it will jump up to roughly 30%. A warm engine idling around 500 psi should net a duty of around 11-13%.
But you can either hear or not hear Solinoids. If you do, you know it has hydraulic pressure, if not, then you know it isn't making at least 460 ish. If the PCM doesn't see at least around 450, it won't make everything happen with idm. Mechanically injector needs around 425 to overcome spring pressure internally, but PCM wants to see more. But also, if rail sensor is throwing out a bad reading, who knows. Hence the mechanical gauge.
Your rough running could be an injector, which now has the oil plunger stuck in the drain position, leaving the system not making any pressure at all.
If you want to see if you relay works, remove the small wires. Turn key on and test to see which one is hot with key on. Reconnect. Use jumper wire to ground other terminal. The relay will either click on, or not.
On your hydraulic pressure stuff, if it is working but not starting you should here Solinoids clicking. Testing voltages won't give you much info. If you want to know what's up with it install a gauge on a rail. The ipr works off of duty cycle, or percentage of On time. One wire is always hot with key on, other is ground side switched by PCM. If truck is cold PCM can command up to maximum pressure to start (2700ish) So if you were able to watch duty cycle, it will jump up to roughly 30%. A warm engine idling around 500 psi should net a duty of around 11-13%.
But you can either hear or not hear Solinoids. If you do, you know it has hydraulic pressure, if not, then you know it isn't making at least 460 ish. If the PCM doesn't see at least around 450, it won't make everything happen with idm. Mechanically injector needs around 425 to overcome spring pressure internally, but PCM wants to see more. But also, if rail sensor is throwing out a bad reading, who knows. Hence the mechanical gauge.
Your rough running could be an injector, which now has the oil plunger stuck in the drain position, leaving the system not making any pressure at all.
Bigsexy
New member
Ive checked and double checked the glow plugs and relay. My icp right now sees .2 in one side which should be dc and the other side is reading 4 volts. If im not mistakin it should only see more volts with more pressure. Which could mean my problem is the ipr. The ipr sees somewhere around 11 and .2, all them while the just the kry on no cranking.
Key on not cranking won't tell you much. But your .2 on Icp sensor is its output side, and yes more pressure means more volts. It range is like .2-3.3 volts.
Ipr's don't normally die in a 7.3, if you have no hydraulic pressure it's probably something else. The ipr has enough restriction when cranking and it in full drain position the system will still make 150 psi roughly.
Put a gauge on it, your chasing your tail trying to look at voltages.
Ipr's don't normally die in a 7.3, if you have no hydraulic pressure it's probably something else. The ipr has enough restriction when cranking and it in full drain position the system will still make 150 psi roughly.
Put a gauge on it, your chasing your tail trying to look at voltages.
Bigsexy
New member
Checked the fuses, relays, glow plugs, alternator, idm, and put new batteries and cps in it and she still does wanna start. Any other suggestions?
Bigsexy
New member
Im not sure if it has anything to do with my hpop. the oil pressure gauge on the dash kicks up when Im cranking. Being it all started when I disconnected the batterys to change the bolts and clean the posts. Im kinda think it might have something to do with the alarm on it. My buttons also not working either. The only thing I really use it for is the remote start in winter.
Bigsexy
New member
So finally brought the modus home and plugged it into the truck. The right bank isnt showing anything and im getting a few normal cpdes but had a p0605 internal control module rom error. Im thinking this means its time fpr a new pcm, any thoughts?
pilot4life
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Are we certain there is not a blown fuse? PCM power issues/communication have been traced to the fuel bowl heater circuit frying the fuse.
Last edited:
Bigsexy
New member
I had the fuel bowl heater blowing fuses a couple months ago so I disconnected it and havent had fuse blow since
Arisley
Moderator
If you are getting codes, I would think that means the Modus is communicating with the PCM.
Bigsexy
New member
Yeah I switched the pcm with the same nvk3 box. It didnt change a thing. I also ran a buzz test and im npt getting any thing on the right side. When am I suppose to see voltage in the harness that plugs in the uvch?
POWER-STRUCK
New member
sounds like a bad IDM or disconnected wiring harness
