G188D fuel pump timing

The engine starts hard when under 50F. When it starts, it runs a bit rough for a couple minutes. There is raw fuel smell for a long time. Perhaps until the engine warms and the thermostat opens. It has new fuel injectors as of last year when I had them checked for spray pattern and found them wanting. The engine does not run strong, but runs smooth when operating.

Upon checking the fuel timing after giving it a "tune-up" as suggested in the service manual, I believe the fuel pump timing is off a bit. I know the engine has been worked on by a previous owner but not who. A couple push rods have been replaced.

As I stated, I checked the fuel pump timing and I want someone more experienced than I to check my thoughts. I am unfamiliar with the timing marks on the flywheel and am not positive on the marks. I assume as the engine turns counter clockwise the first mark is 8 Degrees BTC, next may be 4 Degrees BTC and finally...TDC.

From the valve cover, I get the fuel timing should be 8 Degrees BTC.

I turn the engine counter clockwise until the fuel pump marks line up and took the pictures of the fuel pump:

Without moving the crankshaft, the flywheel (TDC?):


I believe this is 4 Degrees BTC:

And this is what the timing should actually be...8 Degrees BTC:


I'm thinking the fuel timing is currently at TDC and needs to be changed to 8 Degrees BTC. Am I correct?

Thank you

SOME timed at 0*.. Some at 8*.. if your valve cover says 8*.. move it to 8*..
IF its at TDC NOW.. that would account for the raw fuel.. The inj. pump is telling the injectors to inject the fuel, TO LATE to burn..
Good luck.. BTW> how long has it been running like that.??
U better check the condition of the engine oil.. it might be REAL THIN.??

Turn the engine the direction that the fan indicates, or hit the starter a spit second to see which way it turns. Only turn the engine forward to line up timing marks, if you back it up because you went past, you have to go back 90 degrees to remove the gear lash and turn it back around forward.

No big deal to mess with the timing, if it's already messed up or not, scratch a line on the pump mounting flange and the engine at that spot so you can put it back to the same place if needed.

I have the service manual, but it's image of the flywheel does not look like what I have.

All I can see are three lines with what looks like 0.0, 4 and 8. Not what I'm accustom to looking at when i look for timing marks as I come from a gasser background as far as engine mechanics.

@thepumpguysc

Thanks for your reassurance of what's happening. It's been running like this since we bought the machine a few years ago.

I know if it's smelling like this, something is not correct, but I cannot do everything at once. Priorities prevail and I had not worked diesels until now. I did not know what was happening. I was thinking it was low compression and it was needing a rebuild. I had a someone look at it once who works as a diesel mechanic at a local truck shop. He shrugged his shoulders and said it was old and needed to be rebuilt and didn't seem interested in extra work. I was putting off the rebuild until after we built our house and was going to put up with it running like this until I could get to it next year. But I should have known that diesel mechanics can be as knowledgeable (or as trustworthy) as gasser mechanics (I don't know why I would have thought otherwise).

Anyhow, I had a bit of time and found the service manual online and said what the heck and dove in! I broke a $75 nut fastener on the head, but I may have found why my machine has run like crap for a couple years and why the previous owner gave me a good deal. I knew the raw fuel is an issue with going into the oil. I checked it regularly (Including the smell test). The oil level did not change. That meant that the fuel was keeping up with the oil burning or leakage to keep if full. OR that the rings are so tight that the raw fuel does not get past them (keeping them free in the pistons at the same time?) I never smelled fuel in the oil, so i think I'm good on the condition of the rings and cylinders. Besides, It's on it's second quality battery in three years. The compression must have worn them out having to turning the engine over forever to start the bloomin' thing. The starter is still good. I have disassembled, cleaned, checked the brushes and lubed the bushings before reassembling. With about 200 hours over three years, I have changed the oil three times.

@Delmer

Thank you for the memory boost. I have a background in gasoline engines and know of backlash. We all need a nudge to our memories about some time or another at times.

Those marks on the flywheel sure look like 0,4 and 8 to me. Are the other marks supposed to be on the front pulley?

You can bump the timing and see how it does. As long as you marked the flange, you can put it back close enough.

How is the blowby on the engine when it's warmed up and you've run it awhile? that's pretty subjective, but if it's blowing oil mist all over everything, then you have a pretty good idea. If an engine needs an overhaul, I'd expect it to be using oil and have noticeably excessive blowby.

Have you tried priming the fuel system before starting to see if that makes a difference. Diesels start really badly when air gets in the wrong places, and there are lots of old, brittle rubber pieces that can let air leak in over night.

@Delmar

There is blow-by. I was a heavy equipment operator for years and it is not noticeably different than other equipment I have operated. In fact, it is much better than some. There is no oil mist being blown out.

I have gone through the fuel system to clean out the tank, remove the water and replaced seals in the return lines. The sealing surfaces of the fittings all appeared to have been very clean with no nicks and are taut. The only thing I might still do is replace the in-line valve and the water drain valve, but I double that either of those could ve a air infiltration offender as the drain nor valve leak when turned to its limits.

There is only one thing to do now...Go adjust the fuel pump to 8* BTC!

I will be back soon to give a report.

I moved the timing to 8* BTC. The engine did not start. I scratched my head then opened fuel shut-off. The engine turns over quick enough but requires starting fluid still to start. It is definitely stronger now as the tractor will rock slightly when the throttle is tapped. There is much less smoke/raw fuel out the exhaust. The stream does not burn my eyes, but I still smell fuel. Perhaps only 1/4 as strong as before.

OK, I'm not thrilled, but I'm happy there is an improvement! Perhaps the fuel pump is weak, maybe the rings are not sealing as well as they should, the new injectors I installed last year pop at the wrong pressure or there is carbon build-up on the end of the injectors. I do not have testing tools for fuel pressure so if I can find time, I can pull the injectors to take them to be cleaned, spray pattern tested and pop pressure checked.

You could try 12 degrees if there's room in the bolt slots.

Do you get white fog/mist out of the exhaust right from the start when trying to start it? does the starter spin the engine over fast enough? Is the diesel relatively fresh, or been in the tank for years?

1 more thing & I hate to say this... its possible that someone put the pump on 180* out of time..
I've seen'm start like that & smoke something awful..
If u know your way around cars then it shouldnt be much of a stretch to remove the valve cover to make sure your on #1 compression stroke & the lines are in the pump window..
Theres another way to check it.. but u have to remove the pump..
On the end of the pump drive shaft there's a DOT... & inside the pump theres a DOT.. the pump is installed correctly if u see its DOT to DOT.. If it is, great.. if not, u found your problem.. just reach inside the pump w a long flat blade screwdriver or a kitchen knife, whatever is handy. lol.. & rotate the inside of the pump to the dot on the driveshaft..
BTW> when u remove the pump, the drive shaft will stay in the engine..

IF your going to go the pump removal route, TIE the THROTTLE BACK to the wide open position BEFORE touching any nuts on the pump..
and once its off, use your finger to check for ANY gouges in the brass pilot tube in the front of the pump.
If there are gouges, the front one means dirty engine oil, the back one means dirty fuel..
No sense putting the pump back on w those gouges present..
They will catch the drive shaft seal & flip it.. THEN your looking at fuel in the oil..

Temperature here is 47-51F after 40F overnight.

Prior to adjusting the fuel timing, at idle, the engine would always lope like it was hunting for the proper amount of fuel or engine speed. After adjusting the fuel timing, that lope or hunting was no longer present. Still, to rid the tractor of it's annoying vibrations and rattles so I could listen for engine noises, I adjusted the idle speed the idle speed to about 800-850 instead of the 625-675. I ran the engine for 5 minutes at various rpm because it sounded stronger and got that strong diesel ignition sound as well as the exhaust was cleaner except for the quick black puff of smoke until the rpm leveled with the throttle demand. After shutting off, I immediately started it up again to check it's starting performance. It started nearly instantly.

I left it to sit for 30 minutes. The engine use to start up after a couple revolutions for a couple hours to all day depending on the temperatures and the wind. This time, it would just turn over without starting. All the while, just blowing white smoke from the first revolution or two. RPM was in excess of 200 rpm for ~15 seconds. Opening the throttle somewhat started the engine.

@Delmer
There may be room to turn the pump further. I have been wondering if it might be off by a tooth. How many degrees is a tooth? It was pretty stiff to align the marks. Maybe I should pre-stress the fuel lines to relieve the tension.

I have fresh fuel in the tank. Even the oldest fuel prior to adding the latest fuel could only be two months old from the retailer. It does puff white smoke within two revolutions.

@thepumpguysc
I could believe the pump could be any number of teeth out of synch. I know many different people could have had their fingers in the engine and I don't know how much they knew or how sober they were. But to be 180* off and still run? Interesting. So it would start with the fuel just sitting on the top of the piston or on the dome of the combustion chamber. I could see how difficult it would be to get the fuel to ignite laying on something that potentially cold and boy would it smoke!

I have taken the valve cover off (I don't want to remove the pump if I don't want to) and checked for proper synchronization of the gears. It appears good. I have taken @Delmar's suggestion of increasing the timing to 12* BTC. Also, while the return line is off to adjust the pump, I am re-checking the cleanliness of the check valve on the top of the pump. It appears good, but I'm going to run some copper wire beyond the ball to be sure it's clean.

Thanks for the heads up about the pump removal caveats.

I'm eating dinner right now. If it's light enough when done, I'll do more tonight.

The timing was advanced to ~12* BTC and the check valve is clean and everything is reassembled. The engine will not start without starting fluid, but would not stay running. Good thing I made marks for the original setting of TDC, 8* BTC and now 12* BTC so I do not need to spend a lot of time going back to another setting.

TDC : Engine started OK with starter fluid, ran weak, started good after a 30 minute rest

8* BTC : Engine started OK with starter fluid, ran strong, started after a 30 minute rest with throttle open

12* BTC : Engine did start with starter fluid but would not stay running

Sadly I would consider taking the front valve cover off and see if some Bozo has a timing gear off one tooth. Go by the book for the IP timing.

I'd try 6 and 10 degrees.

I don't understand why it wouldn't start at 8 after running for a bit, if it was too advanced, I'd think it would lock up for a second, but not just turn over without firing.

I think we've established the outside limits of where it runs good, now narrow it down to a happier balance.

Tinkerer, if it was off one or two teeth, that would reflect in the timing marks inside the pump, wouldn't it (or not being able to make them align). The TDC is measured by the crankshaft, and the pump timing is measured by the lines inside the pump, only wear inside the pump would change the timing outside of that alignment.

Looking at images, I find the crank gear has 24 teeth and the fuel pump drive gear has 48 teeth. That makes sense since the crank turns twice for every one turn of the fuel pump (and camshaft). If the pump were off one tooth, it would be off by 15* (360/24) one direction or the other. Since correct timing is *8 BTC and assuming timing is off by one tooth, the now "correct" timing without any disassembly would be 8*+/- 15*. Timing will be either be 23* BTC or 7* ATC. That is ... assuming an error of one tooth. I'm now associating the combination of ignition timing AND gasoline entry into the one process of diesel fuel injection. Like ignition timing in gasoline engines, if the distributor is off by a gear, there isn't a true necessity to remove the distributor and turn it to engage in the proper position to get a good running engine. At least the vehicles I could afford to drive.

Advancing the timing to ~12* did nothing good for me. Going up to 23* BTC most likely will not get any better results. Besides, I would have to disassemble the pump and gear to get it to that measurement. If I would go that far, I would make it correct. So, I am left with turning the timing from the 8* I know will work, back beyond the TDC I know works and possibly backward to the 7* ATC. Does anyone see a reason why this would harm me or my engine?

I do not have a diesel to compare the sound of a good running diesel to. It was a long time ago that I was on a piece of equipment, that the only sound I can remember is the sound of my father's voice telling me I was fired and to go home because I was on a 580 Super E and he was in a Case 780, both wide open throttle, both digging rock and he could not hear what I said correctly and he got mad. Told me to go home right then and there. Then he felt bad. Not for firing me, but he realized I rode to work with him.

Back to where I was going with this statement. When the timing was at TDC, the engine wasn't strong sounding and spewed white smoke (fuel). At 8*, it sounded strong and rocked the tractor a little when the throttle was tapped. I also realized that the stabilizers were down so now I am more impressed that the engine would do that. It smoked 1/4 as much as when the timing was at TDC. I still don't understand why it would not start up easily after a short break unless the throttle was opened. Here is what sticks in my mind about the 8* timing. It sounded good! Standing next to the tractor and opening the throttle sharply made that really sharp RAP that a good diesel makes.........and I just remembered I do have a diesel to compare it to. Right in my own darn yard. I completely forgot I have a International with a 10 liter cummins that makes that very same RAP that the G188D made. I feel sad that I forgot my own truck. My mind has been on the backhoe and I haven't thought of much else unless my wife had me doing something.

I think I have to move on from where I am now. I have spent too much time on this problem. I will have to set it at a position somewhere north of 0 up to 8* BTC and live with it until I can take a rain day or something. For now I have propeller shaft seals, brake pad/shoe/seal and a hydraulic manifold bypass for the swing frame/boom manifold to work on so I am not leaking hydraulic oil all over when I dig our foundation, french drain, pond. It's already April, the temperatures are hitting 50 and we are on lock-down from the COVID-19 virus. I have to build a house this summer...no ifs and or buts. It's going to get done.

Thank you for your input gentlemen. I will be back to update this thread as changes happen and most likely I will be back to one of the forums here for something or other I am sure. I have rock and soil processing plant to make, rocks to crush and firewood to process. Oh, and a house, greenhouse, barn, shed, garage, utilities barn, wood-fired boiler,,,,,,,,,,,etc. Good night all and thank you!

Sorry about the length of the previous post. I was tired and tend to blither. I hate to admit that.

Delmer; Ordinarily it would, but with the difficulty he is having getting any success rotating the pump I just have to wonder what all has been done.

It sounds as if u didn’t know.. your SUPPOSED TO INCREASE THE THROTTLE OFF OF IDLE TO START THAT MACHINE..
Then bring it back down slowly, to low idle or above to warm up the engine AND TRANSMISSION..
It hope that helps your thought process..

@thepumpguysc
When cold, I always up the throttle to start to give a little more fuel and to help warm things up. I was not aware I should do the same after the engine had some heat built up. So, I should go back to the 8* BTC timing where it sounded nice.

Last year the injectors were new. Since then, the filters have been changed.
I plan to build an injection pop tester to check the injectors for proper opening pressure and pattern. Until then, I will be happy to be using less fuel to do my work and not have to smell as much fuel in the exhaust. Though, for the cost of building a tester, I could easily save that dollar amount in fuel over the summer. Plus...less pollution settling on my land and other's. But, we are not allowed to drive right now. We are in a lock-down and are being ticketed for unnecessary travel because of the COVID-19 virus. Our county currently has the fastest illness growth in New York.

I live in a very small rural county in SC.. u know the ones where the gas station is also a restaurant and hardware store.??
Anyway, I can go months w/o seeing a cop car.. but yesterday I was working out in the yard/garden all day & the police sirens were unbelievable.!! I guess they were pulling over everyone that was in a car, asking what they were doing & giving tickets..!!