Hurley88E9

Today I ran the truck with a boost gauge hooked up. A heavy up hill pull only made 18-19 psi, that was the most i could get out of it. The relay valve is probably still supplying 10psi of air pressure to the puff limiter when the engine makes 18 psi of boost. Truck still does not smoke at all since i put added the additional .020 shim to the PLE dimension. Im wondering if the relay valve is the issue.

I checked that the throttle was going full and the stop cable was fully retracted before i did anything. I will pop the cap off the other rack and see what i have.

My 1988 Superliner with an E9 and V style pump does not seem to run like it has the advertised 500Hp. I just put new injection nozzles in it a few months ago. It does not smoke at all under any circumstances other than when the parking brake is set and you floor the accelerator pedal. I have never seen EGTs get much over 900 on a heavy pull. There also does not seem to be a lot of whistle from the turbo when its under a heavy load like it could stand to have more fuel. Today I pulled the puff limiter out. The PLE dimension stamped on the pump housing is 1.086. The set PLE dimension Measured 1.010. I would think that being that much shorter would allow the rack to travel fully. I decided to throw a .020 shim in it just to see what would happen so my current PLE is .990 and its supposed to be 1.086. Also I removed the air line that supplies the puff limiter. With the truck aired up and the parking brake released air comes out of the reversing valve. My reversing valve is mounted on the manifold and has one air line that supplies air to the valve, one port connected to the manifold and then the port that supplies air to the puff limiter. I removed the valve from the manifold and connected a pressure tester to the port that connects to the manifold. I also inserted a test fitting in the port that goes to the puff limiter. When the manifold pressure was set at 15 psi the valve supplied 15 psi to the puff limiter. When manifold pressure was increased to 20 psi, 8 psi was supplied to puff limiter. When manifold pressure was increased to 25 psi, 4 psi was supplied to the puff limiter. Puff limiter would fully extend when 20-25 psi was applied. Does all this data sound correct? My concern is the reversing valve is allowing to much pressure to go to the puff limiter causing the fuel rack to not go full throttle. I have not checked boost pressure but i did install a test fitting so the next time its driven i will record boost pressure. I dont think there are any leaks in the intake due to the fact i have no smoke.

I adjusted the RPM to 625 @ idle and I also adjusted the engine brake switch so it would come on when the throttle is decelerated, it took all the adjustment i had left for the switch.

I failed to mention this engine has a v style injection pump. Is the idle screw still by the throttle linkage?

I have an E9 that idles around 450RPM and I am wondering what is the proper adjustment procedure? I think the low idle rpm should be around 750, is that correct? Thanks

Just to follow up, I had the injection nozzles rebuilt at Columbus diesel supply. They asked if i wanted to go with a low flow nozzle, they said it would make more power but i decided to just keep them factory. The injection nozzles were extremely dirty and all of the orings were deteriorated. I was hoping it would run a little better, the power seems the same, but there is less white/grey smoke, more than likely due to poorly atomized fuel. There really wasn't much white/grey smoke in the first place but i do think it cleaned up. After driving it a few times and checking the oil level it seems to be fixed. Thanks for the advice everyone.

I call them injection nozzles because injection pressure is created in the injection pump, an injector creates injection pressure in the injector itself. So the way i look at it this engine doesn't have injectors. I know that is getting pretty technical, but even if you look in a mack service manual you wont see them called injectors. You are correct though, all injectors do have nozzles. Thanks for all your help. I will give an update after I get it fixed.

The Engine has an Ambac V style pump, did all of these engines use bosch injection nozzles? I would rather have new nozzles if they are available because i could install them right after I pull the old ones. Then i wont have to wait a week for them to get back from what ever shop i send them to. Im located in Ohio, does anyone have suggestions for where i should have the original nozzles cleaned and tested?

So this weekend i had some time to look at the engine. I pulled the valve covers and nozzle plugs and found that 4 of the nozzles had fuel on top, 2 had oil on top, and 2 were dry. So still not being 100% convinced that i was getting that much fuel in the oil from the return fuel i decided to reinstall the plugs and pressure test them. I applied 15psi to the return line on the left side of the engine and nozzle 4 started pouring fuel out around the cap. So I switched to the right side of the engine and tested it. 5,6,7, and 8 all poured fuel out. So now that my problem is pinpointed to the nozzle orings, I think i should go ahead and replace the nozzles while I have them out. What is a good replacement nozzle? Are OEM nozzles still available? Is it worth having my nozzles cleaned/tested or rebuilt? Is there a better performing nozzle?

I might try to pull the valve covers and pressure test the return lines before pulling the caps off of the nozzles. Does that sound like a good idea? The truck has around 400k miles on it. We have owned it since 1990. For as long as I can remember the truck loses prime after a couple days of sitting, it will crank 3-5 seconds before starting and it starts kind of rough. Once it starts though it will fire instantly when you turn the key when it is restarted. It does seem like it looses prime slightly faster now that fuel is getting into the oil, but its not much faster. I changed the oil again today and it was about 2 or 3 gallons over full. I forgot to look at the speedometer but im guessing that oil had 400-500 miles on it. I will check tomorrow to make sure.

AZB755V8 sorry i meant bypassing fuel into the oil and i edited my post. As far as the pressure check that was the lift pump i was checking, not the injection pump.

I have a 1988 Superliner with an E9, it has the V style injection pump. I noticed the engine oil level was high and kept monitoring it to find out that it was continuing to rise. The coolant level has not moved and im positive it has to be fuel getting into the oil. The first thing I did was isolated the lift pump and applied 45psi of air pressure to the inlet and capped the outlet, after an hour i had only lost 1 psi. Next i capped the inlet and applied 45psi to the outlet and i let it sit for 14 hours, I lost 6psi. To me that does not seem like a leak that would cause my engine to be 3-5 gallon over full after 1000-2000 miles of operation. There are no new lift pumps available or rebuild kits for that style of pump. Im leaning torwards the injection pump is bypassing fuel into the oil somehow. The engine runs ok and seems to have goood power, which makes me think an injection nozzle would have nothing to do with it and by the nozzle design it would have to leak fuel past the upper oring and im sure that would cause a noticeable miss. What troubleshooting steps can i take to prove the injection pump is failing and if it is bad what are my options as far as rebuilding or replacing?