Pre-Power Stroke Diesel (7.3L IDI & 6.9L)Diesel Topics Only
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I have just installed a rebuilt 6.9 L rebuilt engine in my 1986 Ford F250. I removed the injected pump from the old engine that had been equipped with a ATS turbocharger. We then installed it on the new engine and set the timing marks as instructed in the service manual.When we started the new engine it smoked excessively, and was very difficult to start. We took it out and drove it for approximately 10 miles and it continued to smoke excessively when driving or even idling. if this were a gasoline engine with a carburetor I would think it was flooding, that's what it acts like but not being a diesel expert, we are stumped.
My question is: Is there an adjustment on the fuel injection pump to reduce the volume of fuel flowing to the injectors? Also is it possible that this is a timing problem with the pump?
if there is a sticky that addresses this please provide it to me.
Sounds like the timing is off, and probably also over-fueling. Overfueling wont make it start any harder though, or smoke at idle. On the right side of the pump under a little triangle plate is the fuel adjustment screw.
My question has to do with the volume of diesel flowing through the injector pump. Is there a screw adjustment on the pump like there is on a carburetor that adjusts the volume of fuel flowing through the pump to the injectors or is that preset when they build the pump?
If it is smoking at idle, It is more than likely due to the IP timing rather than too much fuel. The idle fueling should be similar between the pumps as the turbo will not be spooled at this rpm. I recommend checking timing first as this is more than likely the cause.
Here is a link on turning up your pump, just do the opposite. You will want to turn it down to where it barely smokes when lugged at full throttle, or better yet invest in a pyrometer and adjust it so as to keep temps below 1200.
88 Bronco II
86 F250/350 6.9IDI N/A 2300# BB codes
83 F150 4WD with 351 Cleveland
78 Ranchero with 400
Engineer's Motto--If it isn't broken, take it apart and fix it.
First off, there are a couple of things to remember:
In a gasoline engine, the carburator attempts to keep a constant mixture(i.e. air/fuel ratio).
In a diesel, the ratio is not kept constant at all. At low throttle levels, the ratio can be 100:1 or something extremely high like that. At WOT, it is (hopefully) around stoichiometric, or you get smoke.
Our pumps are of the 'governor' sort: The throttle lever controls the governed speed, the governor then controls how much fuel is dispensed.
At idle, the pump will attempt to maintain the given speed by increasing fuel if the speed is low, or decreasing it when high. This is why you can put far more load on our engines at idle(only really applicable to a manual transmission) without them dying, compared to a gas engine.
In your case, the timing is far enough off that it's not burning well, so the pump has to add lots more fuel to keep it running.
I suspect you need to advance the timing a bit.
Rotating the pump counterclockwise when viewed from the front of the engine is advanced(top of pump towards the passenger side).
I'd honestly just adjust it until it starts to give a bit of rattle(check youtube videos to see what I mean), and see how it drives. I think the best results are gained by advancing it until you start losing power, then retarding it slightly and calling it good.
These engines are *very* hardy and hard to break; "too" advanced by a few degrees won't do any damage, but will hurt your power and fuel mileage somewhat. Too retarded will hurt your power and fuel mileage quite a lot.
I think it is the timing all so it is very sensitive, I strongly recommend obtaining a proper timing tool to set it correctly. with a ferret timing tool with todays low cetane, fast burning diesel 6.5-8 degrees BTC at 2000 rpm(mine reads 12.5 at idle, and 6.5 at 2000) under light loads and if you never tow, more advance can be tolerated, however if you tow and will have long periods of full throttle, less timing is better. as the engine can thermal forward under prolonged high egt's . diesels never idle to Rich. they can be smelly if an injector is bad, (weeping) on pressure build up. hence fuel in cylinder at the wrong time, incomplete burn means smelly, smoky, exhaust, get it timed, then see how she runs, then adjust fuel rate. my .02
Wanted 93 crew cab f350 idi... Democracy is two wolves and a lamb voteing on what to have for lunch, Liberty is a well-Armed lamb contesting the vote. Benjamin Franklin... My Boy is a MARINE.... 72 F250 390 HI BOY 4speed.... 91 E350 7.3 idi..KF7POL
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