I have a 1999 Peterbilt 330 dump with a single axle and a 20k pusher. The engine has about 200k miles on it and runs smooth it just doesn't have any power. It is rated at 300hp on the label on the engine. The oil is clean and replaced the 2 fuel filters. I guess I am wondering what people would recommend as the next steps. When I have the truck loaded (about 8yards of stone) and the engine is under load I don't hear the turbo spool at all but when Im unloaded I can hear it spool up when I get above 1500rpms. Wondered if it was a air to air issue or turbo issue? I haven't checked my fuel pressure yet but plan to do that this weekend. Any suggestions would be greatly appreciated. Justin
I've never heard of a 3206, are you sure it's not a 3306 or 3406..? Checking fuel pressure would be a good idea, checking turbo boost with the truck under load would be the next step. Need an engine Serial Number to let you know what the specs are.
Maybe it's a 3208 with two bad pistons?
My guess 3126.
Sorry it's a 3126 it was late and I wasn't thinking at all 3126 Sn# 7AS60627 Thank you
OK, for that particular engine - fuel pressure specification 74psi @ 2200RPM. Boost pressure 20.5psi @ 1500RPM under load.
Thanks nige, where would you locate the sensor for the boost pressure? Right before the turbo? You don't happen to have to fuel pressure spec at idle would you? Could I take that off the fitting where the fuel filter is located on the engine? There is a housing there with a plug. Thanks Justin
There is no fuel pressure spec at Low Idle, only High Idle (2200) which is what I gave you. Testing at the fuel filter should be good so long as you're connected at the outlet side of the filter. There are 2 plugs located on the air inlet cover where you can measure boost pressure. In all probability you'll have to knock up some sort of adapter to connect a pressure gauge because the plugs are quite large in diameter.
Are there any fault codes??? I've seen the fuel pumps go on these 3126's, cheesy little pump they are but they do last. One was very worn but the truck would still pull for a few minutes if you let the fuel pressure build up idling, then watch the fuel pressure drop to zero and try to find a good place to pull over! Wouldn't even pull in the lowest gear but also wouldn't stall! I'd check your ICP (Injection Control Pressure) after checking fuel pressure and the turbo, you'll need some fittings and a 5000psi hose and gauge. Should peak around 3500psi under full load. I've seen a few faulty ICP sensors that send bad info to the ECM that would not trigger a code. Also the ICP regulators go bad every now an then but should set a code if the sensor is operating correctly. Could be a faulty boost sensor, but it would set a code as well. Seems to me like it's in limp mode... I just realized I used International Navistar terms for the Heui system. Cat calls it IAP (Injection Actuation Pressure) and International calls it ICP (Injection Control Pressure) Sorry for any confusion ha ha!
I just found the procedure for it so I'm going to have to try it this weekend when I'm home. I'm going to check my fuel pressure as well. I ordered a boost gauge and I don't think it will be here by this weekend so I might have to wait on that till the following weekend. Thanks for the help. I guess a code of 55 would indicate that there are no fault codes? Justin
I have a diagnostic code when I checked of 39 does anyone know what that is or where I can look it up? Thanks, Justin
That sounds like an Event Code rather than a Diagnostic Code, but I can't find any mention of it. Closest I can find is 35 which is an engine overspeed warning.
This engine doesn't have a lot of low end torque. It only produces 850 lb/ft at 1500 rpm. High idle is 2650 rpm. If you're down under 1500 rpm don't expect a lot. It's only 7.2 litres. I guess what I'm trying to say is if it's been low power since you got it it may be normal. Still a good idea to check boost and fuel pressure though.
Engine S/N 7AS60627. Rated power 300BHP @ 2200RPM, torque 860ft.lb. @ 1440RPM. HINL 2650RPM.
In my book... Flash Code 39 (Fault Code 164-11) ---- Injection Actuation Pressure Sensor I've seen quite a few of these sensors fail, one even blew apart and made a mess... I'd check the wiring first, they like to rub through the harness right behind the HEUI pump..
I know that this one turned out to be a 3126 but yes, they did make a 3206 at one time although they only made 3 before scrapping the whole thing.
Wow. A lot of money wrapped up there that never got out the door. It might have been good for something.
No advantage over an inline six I don't think. The 3208 is beloved by many but I view it as a complete waste of iron, in most cases it's short lived and problematic. YMMV
A scanner would allow you to monitor injection control pressure while driving. With a load on I would want to here a turbo, the turbo is spun by heat, heat is from fuel, in this engine fuel injector is fired by oil pressure. Oil is moved by high pressure pump, resistance causes pressure, icp solenoid controls that pressure. And the computer modulates that pressure with the icp, and monitors it with the pressure sensor on the head. So low oil volume, icp malfunction or a leak in system will affect performance, each injector has O rings that hold oil pressure, and the injector internally has to hold pressure. Remember, resistance causes pressure not the pump, there is a regulator in the back of the head that regulates fuel pressure. I have seen icp sensors bad (I carry a spare on my service truck) injectors leaking, bad pumps, fuel regulators and a bad computer. Step 1 air filter/fuel filter Step 2 injection control pressure Step 3 fuel pressure Step 4 is there oil in fuel tank? A Hail Mary at home play would be new icp sensor, and a fuel pressure regulator, a scanner helps a lot in this case, I do use a pressure gauge for a crank no start, but you need a loaded pressure. I may be using IH terms vs Cat but engines are similar.
I prefer to use a mechanical gauge plumbed into the high press oil rail to check ICP, the reading on the scanner is only as good as the pressure sensor... I also carry a known good ICP sensor in my service truck. Since he has the flash code 39, which I've seen many times, My bet is it's a bad ICP sensor or wiring problem..
I sent the OP a message offering him the diagnostic procedure for his IAP sensor code.
Perfect! I'd like to know how he makes out.
Hey all, thanks for all of your replies! I only get to look at the truck on the weekend because its about 4 hrs from me so Im going to try to get up there this weekend to take a look. It has all new fuel filters and I don't see any oil in the fuel. The oil is full and everything seems normal minus the lack of power and no turbo spool under load. I found a hole in my wastegate vacuum line and that seemed to help a little bit. Also, I thought the redline was 2300rpms so I have been shifting at 2000-2100 which puts me at about 1400rpms in the higher gear and she is a dog. Not to jump subjects before working this out but when the truck is idling Im having a hell of a time getting the truck into gear, does anyone have a procedure for adjusting the clutch? Could it possibly just be worn and needs to be replaced? if so, how could I tell? Thanks, Justin
Don't forget to send me your email address by PM and I'll fire you off the Diagnositc Procedure for your IAP Sensor fault.
Some people block off the waste gate line to get a little extra boost. Depending on what type of clutch you have it will probably have a clutch brake to stop the trans from spinning to make it go into gear without grinding. That brake could be worn and need adjustment or replacement. Any truck mechanic could tell you in a few minutes what you need to do.
Nige, I thought I sent you an email but I'll send you another message with my email thanks. Mobiltech, thanks for the heads up I'll have to try to get some time to drop it off down in town and see what the guy says. It's kind of annoying and I don't want to damage my tranny.
I'm guessing you have an Eaton Fuller trans with a pull type clutch? If so clutch adjustment is very simple, take the cover plate off the bottom of the bell housing, bar the engine over until you see the 5/8 hex adjuster (could be an old style ring type adjuster or an "auto-adjust", you have to push in on the adjuster and turn to release the lock, have a helper or a stick to hold the clutch pedal down, turn the adjuster clockwise to obtain 1/2" between throwout bearing and clutch brake, and you should have 1/8" clearance between release fingers and throwout bearing (you check these measurements when the clutch pedal is up). Make sure the adjuster pops out all the way to lock it when your done. and grease the throwout bearing good! Grease on the clutch brake is fine! There are two tabs on the clutch brake that slide in grooves on the input shaft, they will shear off if you push the clutch down hard while the truck is moving in gear, hopefully that's not the case! They make 2 piece clutch brakes that you can install without pulling the trans if it happens...
What scanner tool do you guys recommend? If I was able to get one it would have to be affordable bc I would only use it occasionally and can't justify spending 3-4k on one. With that said if that is what you had to do to get a decent one then I would like to know that as well. Thank you Justin
Do you want one just for this truck? The only time I use a scanner on these 3126's is to do injector cut out tests. For any other problems I just use flash codes and mechanical gauges plumbed in, oh and my eyes and brain! But then again i'm a bit old school... I don't like computers haha
Is the 3206 the engine CAT was trying to develop in conjunction with GM to install in the pickups to replace the 6.5L?
I guess if you're doing the adjustment yourself first check the linkage to make sure the clutch brake is contacted just before the pedal hits the floor. This can be set in the linkage rods. You will want to do this before you check the free pedal clearance as said above.
I've seen way too many clutches outtawack from people miss adjusting the linkage rods, if you adjust the clutch internally to obtain the 1/2" clearance between the throwout bearing and clutch brake, the release finger clearance should be approx 1/8" and it should all function fine with about 1 1/2" to 2" free pedal, if not then someone has messed with the linkage rods. I've always done the 1/2" internal clearance as a baseline first, then if I have to adjust the free pedal to obtain the 1/8" clearance, I adjust that with the linkages, then check the operation. Depends on how the linkage is set up and of course wear on cab/engine mounts etc..
I see your point but you have to account for cab mount wear and any wear in the linkage just as you saidI've seen a lot of cabs move enough to lose your clutch brake.
Yeah I know what you're talking about! Doesn't take much movement to throw things off. Usually need to tweak the linkage after a truck has been flopped on it's side. Poor trucks are never the same!