Here's the symptoms, when cold the truck will crank and then blip then crank then crank then blip and so on and so forth. i've had to use ether a couple times. But once i get it started it will run real rough for a bit(5-10 min if sitting, a mile or so on road), then it clears up and runs like it always has. Last night i plugged the block heater in, and this morning it fired right up and ran fine. Although 5 hours later i tried to start it, and it started but raaaan really rough with barely enough power to move on flat ground. Then it cleared up and ran fine.

On saturday i put a different IPR in thinking that might be it. But it was not. I was able to run a buzz test off a buddies scan gauge, and all injectors were heard. But the gauge could not run a contribution test. Anybody else have issues with the cont test?

I would appreciate any help. Could it be the injectors poppets are messed up?

 

Don't use ether ..! you could cause some real damage.. Did you pull any fault codes ? Did the SES light come on when running rough ?

 

no ses light, and no codes. When using ether i do at least wait till the glow plug relay clicks off. But sometimes i still have to use it.

 

Did you buzz the injectors with a warm or cold engine Austin? You really need to buzz them on a cold engine when you're having your problems. Then buzz test it about 6 or 7 more times and see if the buzz gets better the more you do it (poppet issue).

How many miles on the engine oil and is it full? If you get it up to operating temp and shut it off, does it start right back up? What if you remove the chip? Make any difference (other than no fun to drive)?

 

I pulled the chip sunday, and tried to start it yesterday morning to no avail. The oil has less than 1k on it, and as soon as it gets to operating temp i have no problems starting it back up. At idle my DC % is 12-14, and the pump psi is around 600. Thats according to the scan gauge. I will try the buzz testing when its cold. i did it when it was hot, and there was one injector that had a little higher pitch to it than the others. Got any thoughts on that?

 

If it was a slight miss I'd say pull the valve cover and watch the oil discharge from the weak injector or watch rotational velocity numbers to see how that cylinder is acting.

I've seen these motors start on 4 cylinders, so one weak buzz won't affect starting the way you're describing.

Have you got a scan gauge for at least a little bit? How many readings have you cycled through and checked? EOT reading seem accurate? What does ICP psi and IPR % reach while cranking with a no start? Any smoke out the tailpipe while cranking?

 

EOT? sorry its been a long day and im drawing a blank on that. lol i will check the % and psi on a cold start tomorrow. And i get white smoke big time with a no start. but the glowplugs have been fowled for a while now. It pretty much seems like it is starting on 4 cylinders.

 

Engine oil temp. If the EOT sensor goes bad, it might set the glow plugs, timing, and all that other stuff wrong making it difficult to start. If it's 80 deg in the morning and EOT reads 105, you've got a problem. Within 5 - 7 degrees of outside temps in the morning is within the good range.

 

heres a vid of it trying to start the other morning. after some of this and ether it will start rough.

Truck trying to start

 

Have you been under the valve covers to make sure that the wiring harnesses are plugged in, injectors torqued properly, etc?
Also have you tried unplugging the injection pressure sensor to see if it starts up better than in your video?

 

Im gonna pull the VC's on friday and check out the harnesses. Thanks for all the help guys.

 

swap your CPS just for the heck of it, could be a timing issue too but that does sound horid!

 

Hey guys, Austin has my Scanguage and is more than welcome to use it for whatever tests y'all need him to run. For some reason it will do the CCT on my OBS, but not on his SD. Don't know whats going on there, but here is what I remember from working on it Saturday if it helps at all. I have no clue whats wrong with his truck or what to look at now..

With the chip installed the IPR DC% does some really stupid crap. Don't know if it changed when he pulled the chip or not, but just cruising down the highway the DC was full tilt at 64.7%. Let of the accelerator and it drops down then touch it a little to hold speed on the highway and boom right back to 64.7%, but when I drove it after we changed the IPR it did not do that, it drove normal and had normal power. Switched drivers then after a couple runs it started doing that and had hardly any power at all. Before we changed the IPR it seemed normal, but DC% would drop off every so often and you would lose power, then it would come back up and power would come back.

ICP was low with the chip. 400-600psi at idle, normal cruising even with DC% peaked at 64.7%, and bounced around between 1900-2300psi @ WOT.

EOT seemed normal and showed 195* @ operating temp. Austin, I need to you check the ambient temp when you get up tomorrow before you start the truck, turn your key on, and see what the Scanguage says your oil temp is. If it's close to or the same as the ambient temp then that's perfect.

The buzz test we ran Saturday sounded funky. I actually heard a couple of injectors that I didn't really like, but i'm used to have a nice, loud, crisp buzz from my single shots. He had a couple that were loud like my single shots and the others were soft and quiet..

Pulsewidth from his truck is also something I'm not used to. Scanguage showed me 2.8 MS of pulsewidth at an idle. What should the PW be at idle for split shots? My singles are at 3 MS @ WOT and like 1 MS at idle.

Austin, if you need help with messing around under the VCs bring it to the house. I will supervise. LOL

Also, the truck has a new ICP sensor, we cleaned the IPR that we put in there prior to installation, and y'all need to see the pictures of the IPR that came out of his truck, never seen anything like it before and still can't believe it. haha

 

Isn't there a setting on the Scan gauge for different years on the 7.3? I'd have to go push a bunch of buttons and see if I get lucky (don't like to read directions) but it seems like there was an up to 95 or 96 option, and then a later model option. If yours is set for the 95, he may have to set it up differently to get accurate readings or to run the CCT.

Does Cody or someone have AE? Seems like watching rotational velocity numbers for all 8 cylinders at once would be helpful.

I'd have to check pulsewidth readings on my gauge for comparison, but my IAT and EOT usually are off up to 10 degrees in the morning for reference.

 

I think you may be right Chris and I had forgotten about it. All the readings on the SG seemed right, but wouldn't run that CCT.. I will call Austin and tell him what to do with the guage if I remember how to do it. DOH!!!