Hard to start 3B: no smoke, starter OK, battery OK, glow OK (1 Viewer)

deaddrift

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All of a sudden my 3B is taking three or four attempts to start. The starter cranks fine. The busbar has 12v dropping to 4v during the first stages of the glow cycle. Three of the four glow plugs have continuity, and one does not, which sucks because it is only a year old. I will be replacing that when I can get one, i.e., not today. I didn't adjust the valves, but dry compression on the warm engine is 400, 415, 405, 440 from front to back. There is no smoke of any color during starting attempts. Earlier when I was having glow problems I did see a lot of white smoke.

After a few tries the truck does start OK and then runs normally with no apparent loss of power. When I first experienced this problem my fuel gage was low so I assumed the tank was empty. I filled 3 gal in there and then pumped through and bled the injector lines at the injectors. No bubbles from the fuel filter, but when the engine is running and I crack the injectors they kinda spit all over the place, hard to tell if any air is coming out or not.

Could an air leak or trapped air cause hard starting that goes away after 3-4 attempts? I run biodiesel, B99 or B50 (winter mix) exclusively and have for seven years using the original fuel lines. The hoses appear fine, no sponginess. Could it be a fuel pump problem? Is one bad plug enough to cause this to happen?

Thanks for looking. Happy New Year.
 
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I had a similar problem with my 1HZ a few years back. Cranking times were getting longer , but once started would be fine for the rest of the day until it sat overnight. Finally discovered a bad fitting on the fuel line near the pump ,although no fuel was leaking out ,it was letting air in.
Overnight the fuel inside the pump would run backwards to the tank.
I would fix the glowplug , just one can cause a problem in cold climes.
 

deaddrift

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Joined
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I had a plug go last year and got a single (expensive) nippon denso to replace it. I also ordered online Rockauto 6 new (dirt cheap) NKG plugs, as MUD research told me that people recommended replacing all the plugs at once since once one fails, the others often follow.
During the time that I had the one denso plug in, (about a month) a second one of the original plugs failed, backing up the wisdom that I had found on this website.
Replaced all the plugs when they arrived in the mail, and no worries with the glow system since...

If you do replace only one plug, at least make sure the voltage is the same as the other plugs...
 

RufusTheDufus

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Question: Is there any harm in replacing one plug only, especially if it is from a different manufacturer than the other three?

It's not a problem as a quick fix, but not ideal either. Glow plugs act like variable resistors. Their resistance goes up as they heat up and a plot of the change in resistance vs. temperature will be a curve. Manufacturer A's plugs will likely have a different curve than Manufacturer B. The current is going to want to follow the path of least resistance. So the odd-brand plug may heat faster/slower than the others. If it's the correct voltage plug and your glow system is operating properly it shouldn't be a situation that causes any damage. All the plugs will eventually heat up. You might might burn up another plug sooner but at least you'll be starting better in the mean time.
 

deaddrift

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There is a lot of info of varying usefulness about glow plugs for a 12V 3B with Superglow. In particular I keep seeing Bosch part numbers that start with "GPT". However these never match up with suppliers' lists; their Bosch part reference numbers look like this: 0 250 202 058.

Anyone know why both the Toyota 19850-68050 AND Toyota 19850-68051 are listed as appropriate parts? Haven't been able to find specs for these. I have found the 68051 for sale and would like to get OEM if possible.
 

deaddrift

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Oh yeah and BTW the three good plugs have carbon around the circumference but the bad plug has carbon on only one side, other side bare metal. I assume that is relevant? Had the injectors rebuilt last year by a shop with a good rep locally.
 

deaddrift

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Ha, I'm talking to myself here today.

The parts guy at the dealer says that a single digit change, like 68050 to 68051, indicates a change in the supplier, so: same part, different outfit making it. Second number is the good one. I will add this info to lostmarbles' glow plugs thread.

I found the part at bochtoyotasouth.com for $25, hopefully it will get here soon. Still looking for feedback about the carbon pattern on my plugs if anyone has any.
 
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Certainly agreed to get your plugs in order as the most important first step. Also make the very quick check that your EDIC or overinjection magnet pushrod moves to the start position when your starter motor is engaged. You or an accomplice should be able to see the rod move toward the injection pump when the motor is cranked.

EDIT ... Rod moves away from injection pump for overinjection mode for both EDIC equipped and overinjection magnet equipped 3B engines.
 
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deaddrift

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New plugs solved the problem, fires right up first go. The OEM plug part number for my 10/85 12V 3B with superglow is 19850-68051. Thanks all for the advice, and happy trails.
 

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