BigBlue12V
New member
- Joined
- Apr 27, 2008
- Messages
- 237
Hey guys, I have a 96 that was swapped to a p-pumped 24 valve before I got it. I've been slowly fixing some things that were not done correctly or cosmetically pleasing. It seemed very stock when I got it. The plate and starwheel were adjusted but that was it. It had a carter electric lift pump on the frame, identical to a stock 24 valve unit. I replaced that with a Holley 12-920 pump which is way more than adequate in flow and pressure for a P pump and Holley claims it is compatible for use with diesel fuels. There's a 32 micron fuel filter before the lift pump, no fuel heater bowl. The line goes straight from lift pump to fuel filter on engine (stock 12V style) then to the injection pump.
The engine is out of a Freightliner best I can tell.
A friend located and arranged the purchase of some 75hp 8 hole nozzles online, we installed those and it ran better. Upon removing the stock ones we noticed they were incredibly clogged up. I had already removed the plate and messed with the starwheel a little more before this.
Then a couple weeks ago I installed an HX40 with a 14 cm exhaust housing. With stock gov. springs I could barely get any spool from it. While doing that I also gasket matched and ported the exhaust manifold and turbo inlet/manifold flange. took it for a test drive, then installed PacBrake 4k RPM GSk, removing stock shims, then 1 soft click and 4 hard. Checked with caliper, measurements are good. At the same time, we also advance the timing. We were shooting for 22* but knowing the 24V injector pop pressure is different, we needed to add about 6.5* so we set it to 28* at the pump, which should give us 21-22 final. Upon firing it up from this, the truck idled great, but pops badly in neutral and some under load. Throughout the next week I changed the fuel filters which weren't very old, and added a fuel pressure gauge and installed a Tork Tek overflow valve. I get 40 psi of fuel pressure to the injection pump. I adjusted the AFC more as well, ground the foot and did the washer mod. I had also had a couple problems with the truck occasionally dying when coming to a stoplight and the throttle would kinda hang when starting it. So we tightened the gsk one more click each. That seemed to fix those problems. The popping persists. We checked the timing to make sure it hadn't slipped and it was still at our same setting. While doing this I remembered to check my coolant as it occasionally needs topped off, rarely takes more than a pint or so. My heater core leaks so it didn't concern me. But this time when I checked it, it was a lot lower than normal. What made me check the coolant is the fact that my temp gauge hadn't been reading anything. So we topped it off and got to wondering if the popping and more than usual coolant disappearance wasn't coolant making its way into the combustion chamber. So I replaced the head gasket and adjusted the valves. The popping was no better in neutral, but seems to be less noticable under load. Then it still wasn't registering anything on the temp gauge so I pulled the thermostat and a odd looking rubber thingy on it had gotten loose and stuck the thermostat wide open. I'm not familiar with 24V thermostats, but the aftermarket replacement one did not have this rubber piece. I installed that and all is well with the temps now.
But through all this I still have the popping. Going to mess with timing again this weekend but I'm very baffled at this point. It has to be in the timing or GSK. I know if the timing was retarded this would definitely happen but it didn't seem to have slipped. I've not really ever had or heard of this problem with GSK either, but then again I've never used or known anyone to use PacBrake kits. I've always had good luck with TST kits in the past and I'm about to rip the PB ones out and swap in TST ones for peace of mind if the timing don't fix my problem. I've done a lot of research and searching to try and find the solution to my problems.
Between the timing, head gasket, valve adjustment and all this other stuff something should have fixed it. I know ten million of ya are gonna say timing, and I hope you're right. I hope somehow we messed it up and didn't catch it when we checked it again. We kinda stopped partway through checking it because it dawned on me that my disappearing coolant was disappearing too quickly to be heater core and not making puddles so I immediately figured that was the popping problem. And BTW, the gasket was already seeping a tiny bit of oil in the front, so it wasn't done for nothing. And its good peace of mind that its new and torqued good n tight especially with more fuel and turbo going to it.
Any other ideas on what it could be, if the timing is ok? And BTW if the timing is still right where we set it, then I will drop it down some n see if that helps as a friend suggested that maybe I don't have enough fuel for that much timing (which is possible I suppose). My smoke isn't quite as black as it should be either. And my EGT's are pretty high even once I get the turbo going, I buried it at 1600 to make almost 40# of boost this evening while I was messing with it.
And while I got ya reading this (hopefully your ADD didn't kick in yet and make you hit the back button) is there any point to modifying the AFC if ya don't have a fuel plate? A friend asked me why I was modifying the AFC if I don't have a plate and it got me thinking. I'm not quite familiar enough with the insides of the P pump to really truly know the answer outright but it seems he is correct?
Thanks for all the help and sorry for the long post but figured it makes more sense to provide you with ALL the info and details now than waste your time thinking about it and typing a wrong answer or more questions.
The engine is out of a Freightliner best I can tell.
A friend located and arranged the purchase of some 75hp 8 hole nozzles online, we installed those and it ran better. Upon removing the stock ones we noticed they were incredibly clogged up. I had already removed the plate and messed with the starwheel a little more before this.
Then a couple weeks ago I installed an HX40 with a 14 cm exhaust housing. With stock gov. springs I could barely get any spool from it. While doing that I also gasket matched and ported the exhaust manifold and turbo inlet/manifold flange. took it for a test drive, then installed PacBrake 4k RPM GSk, removing stock shims, then 1 soft click and 4 hard. Checked with caliper, measurements are good. At the same time, we also advance the timing. We were shooting for 22* but knowing the 24V injector pop pressure is different, we needed to add about 6.5* so we set it to 28* at the pump, which should give us 21-22 final. Upon firing it up from this, the truck idled great, but pops badly in neutral and some under load. Throughout the next week I changed the fuel filters which weren't very old, and added a fuel pressure gauge and installed a Tork Tek overflow valve. I get 40 psi of fuel pressure to the injection pump. I adjusted the AFC more as well, ground the foot and did the washer mod. I had also had a couple problems with the truck occasionally dying when coming to a stoplight and the throttle would kinda hang when starting it. So we tightened the gsk one more click each. That seemed to fix those problems. The popping persists. We checked the timing to make sure it hadn't slipped and it was still at our same setting. While doing this I remembered to check my coolant as it occasionally needs topped off, rarely takes more than a pint or so. My heater core leaks so it didn't concern me. But this time when I checked it, it was a lot lower than normal. What made me check the coolant is the fact that my temp gauge hadn't been reading anything. So we topped it off and got to wondering if the popping and more than usual coolant disappearance wasn't coolant making its way into the combustion chamber. So I replaced the head gasket and adjusted the valves. The popping was no better in neutral, but seems to be less noticable under load. Then it still wasn't registering anything on the temp gauge so I pulled the thermostat and a odd looking rubber thingy on it had gotten loose and stuck the thermostat wide open. I'm not familiar with 24V thermostats, but the aftermarket replacement one did not have this rubber piece. I installed that and all is well with the temps now.
But through all this I still have the popping. Going to mess with timing again this weekend but I'm very baffled at this point. It has to be in the timing or GSK. I know if the timing was retarded this would definitely happen but it didn't seem to have slipped. I've not really ever had or heard of this problem with GSK either, but then again I've never used or known anyone to use PacBrake kits. I've always had good luck with TST kits in the past and I'm about to rip the PB ones out and swap in TST ones for peace of mind if the timing don't fix my problem. I've done a lot of research and searching to try and find the solution to my problems.
Between the timing, head gasket, valve adjustment and all this other stuff something should have fixed it. I know ten million of ya are gonna say timing, and I hope you're right. I hope somehow we messed it up and didn't catch it when we checked it again. We kinda stopped partway through checking it because it dawned on me that my disappearing coolant was disappearing too quickly to be heater core and not making puddles so I immediately figured that was the popping problem. And BTW, the gasket was already seeping a tiny bit of oil in the front, so it wasn't done for nothing. And its good peace of mind that its new and torqued good n tight especially with more fuel and turbo going to it.
Any other ideas on what it could be, if the timing is ok? And BTW if the timing is still right where we set it, then I will drop it down some n see if that helps as a friend suggested that maybe I don't have enough fuel for that much timing (which is possible I suppose). My smoke isn't quite as black as it should be either. And my EGT's are pretty high even once I get the turbo going, I buried it at 1600 to make almost 40# of boost this evening while I was messing with it.
And while I got ya reading this (hopefully your ADD didn't kick in yet and make you hit the back button) is there any point to modifying the AFC if ya don't have a fuel plate? A friend asked me why I was modifying the AFC if I don't have a plate and it got me thinking. I'm not quite familiar enough with the insides of the P pump to really truly know the answer outright but it seems he is correct?
Thanks for all the help and sorry for the long post but figured it makes more sense to provide you with ALL the info and details now than waste your time thinking about it and typing a wrong answer or more questions.
