Could timing have burnt out my G.P.'s???

[Josh Carmack]

I bought two 1990 7.3's in the same week about a month or so. I was tired of gasser problems and wanted to go the diesel route for more than one reason. I grew up on a farm, around tons of diesel engines, and then we quit farming so I spent most of my mechanic years on gassers. I know most of the big stuff to know about diesels, but the details are what get me. So i'll pose this question for people that have more 7.3 IDI experience. My big truck was running and cranking perfectly when I purchased it last month. I have put a couple thousand miles on it, and it has ran and started perfectly til last Thursday. The original owner stated he believed one glow plug was bad when he sold it to me as he was noticing the Wait to start light would extinguish faster than normal. It was still starting fine in less than 5 seconds of cranking even on a 20 degree night. Last WED I got in it in the evening after work and noticed the WTS light went out very quickly and it was a PITA to start. The next morning it started better but not as good, the next evening after work it took about 30 seconds to crank. Friday morning it would not start at all even after enough cranking to make the starter sweat and scream at me. One little half second shot of either fired it right off, and it has taken ether pretty much ever since. This morning and afternoon it required ether to get it running. My question being, this truck sounded hot from the very beginning, it had been some many years since I had been around any IDI fords, but it seemed louder than most. Then I recently read that advanced timing cam burn out GP's and cause loud idling. I checked yesterday and found three bad GP's on one bank and quit looking because I knew that was enough to make the controller not light the rest.

My questions are, is it normal for several glow plugs to go out in a short two or three day period, as mine seemed to do in less than a week. It went from starting good to not at all almost.
And can advanced timing burn them out quickly, or does it take a long period of time. In other words, can advanced timing burn out plugs in a very short time, say a few months, or does it just shorten their lives by say 10 to 20 percent. The original owner stated the I.P. was only a year or so old. SO there was the opportunity for the truck to get out of time. The truck is a 1990 f-350 Crew cab long bed with 350,000 miles. Truck still runs fine and has plenty of power and starts great after the first start, it is only a problem to start once the engine has cooled. Hot starts are sub one second cranking times.

 

[stumiister]

The timing of the IP being advance in my opinion has nothing to do with the gp's not working or burning out sooner than they should.
If you replace the gp's sue Ford ZD9's or Beru. Any others swell and are hard to come out or the tips break off.
The only purpose the gp's have is to start the engine when it is cold.
You should have the timing checked it should be about 8.5* to 9.5* BDTC at about 600rpm for a auto tranny and cold idle should be about 900rpm I think for a manual it is set about 650rpm
There is a good write up in the tech section.

 

[Hydro-idi]

If engine timing was too far advanced, the glow plug tips would be burnt off.

 

[Mulochico]

You should have the timing checked it should be about 8.5* to 9.5* BDTC at about 600rpm for a auto tranny and cold idle should be about 900rpm I think for a manual it is set about 650rpm
There is a good write up in the tech section.

The timing is 9.5* btdc (because of the uls fuels) at 2000 rpm not 600 rpm. just want to clarify.

 

[icanfixall]

Welcome to the forum. I see you just signed up here this month.. Depending on what advance your running and what glow plugs you have in the engine can tell us plenty. Its been kicked around here lots that timing more than 10.5 btdc does burn out the plugs faster. We also know that the best... Last word in glow plugs is the Beru ZD9.. they are sold in the Motorcraft bags most anyplace. Plenty of auto parts sells them. Figure around $10.00 each. Once in a while you can find them a little cheaper than that too. Just need to ask the collective where the best deal is.. When several people search it done so much faster. Same with asking questions here.. Many are here wanting to help. So please order up a set of Motorcraft ZD9 berus. Using ether to start wont hurt but please disconnect the glow plug controller. Find the fender mount solenoid. On the hot side there is a double wire in one connecter. Usually its yellow. That two wires feeds the power to the controller. Once thats done using ether will not hurt the engine but use only what you need. Very small sprays are all thats needed.. The timing needs to be corrected too. About the easiest way to know if the advance is too much is listen to the cold engine sound. Your needing to hear the sound of a psd engine. Then when the fast idle and cold advance shuts off listen again... What you want to hear is some rattle like a psd but not much. Running a jumper wire to the advance on the injection pump to the positive of any battery will make it rattle a lot. So you just want to hear some. Might want to back off the advance till its as soft sounding as a gasser. Then add the jumper wire. If it sounds good with the jumper then its running right and needs to be advanced some. Its a lot of work but its the best way without a meter.

 

[gatorman21218]

in short yes. I had mine about 20* BTDC and I probably have 3 working glow plugs now. Ill post up some pics when I pull them out

 

[Josh Carmack]

Yeah, I plan to go with the motorcrafts, they were only a dollar higher than the autolights at 10.79 at my local AZ. Years back I put about 100 to 150 K on my uncles mid to late 80's F-350 and F-450, one was a 6.9 and the other 7.3. I t has been many years, but I made dozens of trips every summer hauling tomatoes as far south as Houston, and as far north as great lakes Michigan area. they both seemed much quieter at idle than this one, but also 10 to 15 years younger than this one is now. The cold start advance is working, because it quietens down at operating temperature and idles a little smoother as well once you hear the advance drop off. I'll pull the GP's this weekend, I'm still working ******* getting my black diesel setup going. I'm not bragging, but I'm fairly good at mechanics, just have little experience with diesel engines. I thought it was a little strange that the WTS light went from normal warm up time to almost nothing in two days, almost like I lost to or three GP's in a two or three day period, but I also don't know how many bad gp's it takes to throw the controller out from still lighting the others. As the original owner already stated he believed at least one was bad due to shortened time on the WTS light, it may have only been one more possibly two that caused it to go out too soon to light the remaining good ones.

Anyone know about how many bad ones it takes to keep the controller from properly heating up the rest?



As far as ether goes, no need to worry, I'm not the type of guy that dumps half the can in a diesel and then wonders what happened as I watch the rods fly out the side of the block. A little bitty half second squirt fires it right off. I start it from under the hood by jumping the solenoid and then giving it a small squirt. I have actually seen the damage done to a John Deere 750B dozer when the "operator" dumped half a can in it when all it needed was a new fuel filter. Rod piston and all found it's way to the belly pan of the dozer. Dozer had about 2000 hours of life left in the UC and Finals etc, but the engine was toasted. I'm guessing it pooled in the breather and then ran away once it fired off.

 

[Josh Carmack]

Also, I am very good with electronics, opamps trigger circuits etc, I don't know if or how well it will work, but I am kicking around the idea of using a piezeo sensor attached to the IP lines to trigger a normal timing light. I just need to find a shop that has a IDI timing light to compare its delay in triggering to the real deal if will trigger at all. if it works, I'll post the schematic to it for any others that are electronically inclined.

 

[TronDD]

I also don't know how many bad gp's it takes to throw the controller out from still lighting the others.

In my recent experience, all it took was one. It was a plug someone mickey moused in to a hole in the intake and it wasn't grounded well. The plugs didn't come on at all until I got a good ground for that one plug.

Tim.

 

[redneckaggie]

1 bad glow plug or dirty/loose connection will compromise the whole system

In my experience the glow plugs do not graudually go out, they go just as you saw them work one day and not the next, and one bad plug can make the others go to.

generally people will suggest replacing all 8 but I like to test my plugs in ohms since that is what the controller works on. anything not wihin .1 or .2 ohms of the rest gets replaced.