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Hello, I am pretty new to Diesel engines in general, I am working on my 99 7.3 with my father in law. It started as the engine was hard to crank, whether hot or cold. So we narrowed it down to the injector o rings. We pulled and changed the O rings on all 8 injectors. We also changed the Glow plugs while we were in there. It is still very hard to start cold. It will crank which is an improvement, but it takes a while. After the engine is warm it will start after about 4-5 cranks, but cold it takes somewhere between 10-20 cranks before she boots up. Any suggestions as where to look next as to what might be causing the hard start?
again I am new to Diesel engines in general, my father in law has worked on tractor engines but that’s about the extend of our knowledge. Thanks
What brand of glowplugs did you use and where did you get them? Also if you haven’t it might not hurt to install a new GP relay as the contacts get worn out with age and won’t carry enough current. There are upgrades for that too.. I’m running the White Rogers and so far I really like it.
The reason I ask is most everyone will tell you Motorcraft/Beru only for glow plugs and sensors etc. And watch out for fakes they’re out there. Same Motorcraft packaging and everything—yuk!
You came to the right place these guys are a great help when it comes to getting these vehicle sorted out—helped me out more times than I can count.
What brand of glowplugs did you use and where did you get them? Also if you haven’t it might not hurt to install a new GP relay as the contacts get worn out with age and won’t carry enough current. There are upgrades for that too.. I’m running the White Rogers and so far I really like it.
The reason I ask is most everyone will tell you Motorcraft/Beru only for glow plugs and sensors etc. And watch out for fakes they’re out there. Same Motorcraft packaging and everything—yuk!
yes, the only thing that has changed is it starts easier after it’s been running
Originally Posted by jonest1027
I used AC Delco. The higher end ones from Napa.
So the thing is.. running anything other than genuine Motorcraft glow plugs is a major gamble. They may work for a time but when they fail the tips can swell up which makes removing them a nightmare. You don’t want a plug too swollen to remove from the head—ever trust me.
That said I really bet you’re either dealing with doa glowplugs or your relay is weak. Starting good when warm is a really good sign so it’s good to hear the o-rings helped I know how big of a job that is to do!
I hate to throw money at a vehicle that isn’t mine but I’d lean towards Motorcraft plugs and a known good relay.
Also where do you live? If it gets cold there you might consider switching to a 5w-40 oil it’ll help a lot with cold starts.
Just my $.02 hopefully someone else chimes in to point you in the right direction. Take care,
I would not put anything but motorcraft glow plugs in either but being that you are still having to crank the engine 4-5 times after the engine is at operating temp I don't think glow plugs are your issue. It would be a really good idea to get forscan lite on a android and a OBD2 Bluetooth dongle so you can monitor pids. Without this you are usually going to be guessing and throwing parts at the truck. These 2 things are one of the most valuable tools you can have for these trucks and it's all for under $25. Have you checked the oil level in the h-pop when the engine is cold or warm? Does the truck run well once it's warmed up and running?
THere is a small plug right on top of the hpop, unscrew that preferably when the engine is cold and check the oil level, should be about 3/4 of a inch below the plug whole
I'll third or fourth that motion on OEM glow plugs. It's a PITA to change them again already but could be much worse later. Do you have a scanner? If not, get yourself set up so you can read your sensors and I'd start with injector control pressure (ICP). RPM's while cranking too, since slow cranking is an frequent problem and will make starting tough.
You need 150+rpm, 470PSI+/- ICP, and at least10.2V+ from the batteries to fire. That being said long start when cold but fires right up when warm usually points to clearance issues in the injectors. When the oil is cold and thick, you have issues with it being able to make it through the poppets. Shimming them will help immensely. You may be able to go to a synthetic 5w/40 weight oil short term to get you by, but the shimming of the injectors, and/or new/rebuilt injectors will be a not too distant future if it's poppet clearances.