rev limiter
 

Guys i gotta problem....my 02 6.6 dmaz ended up with water and maybe dr pepper soda in the fuel tank. After replacing the fuel filter i got running again but it wouldnt restart. It did run ok on the way home but wouldnt restart. It ended up at a dealer and they literly tore it apart starting with the fuel tank then into the injectors and pulled a cup and then broke off 2 glowplugs and walked away from it.myself and a buddygrubbed out the broken glowplugs reassembled it with gm injectors and all the other needed parts. The rev limiter now kicks in at 2k. With it running ok before the tear down im scratching my hesd..i dont get a check engine light or error code. Is it posssible the computer nreds to relearn cuz the batterys were disconnected improperly or maybe does it have a air pocket...ive yet to get my hands on it .my buddy just called about the problem after only driving it about 4 miles...thought id ask and get a jumo on things before ho brought it over. I have a oppertunity to get it scanned tomorrow but id have to drive it 2 hrs and im hesitant. Whatcha's think?

2k rpm sounds like limp mode. need to read the codes to see why. disconnecting the battery won't always reset it.

Ive determined it is in limp mode. Got a p0088 code which is fuel high pressure. Scannef the pressureat a idle and its coming in at over 24 k. Does anybody have a idea what a 02 lb7 idle high pressure should be? Im leaning towards the fuel pressure regulator. All connections and reference voltage checked ok. I believr the high pressure sensor is ok because at a idle when you plug it the engine really falls off. Thoughts??

check the connection to the pressure regulator on the CP3. if unplugged or if one of the wire is broken, etc then the regulator will default to max pressure. it is also possible the regulator is stuck.

does it run loud at idle with more knock then normal? it normally will when running at max PSI during idle. if it is then your pressure sensor is likely fine and it is the regulator and connection that needs to be looked at. if it still runs quite then it may be the sensor

at idle it should run somewhere around 5k PSI. max PSI is upwards of 23K PSI.

Thanks for the feedback...my partner checked the connection and voltage...i believe it was 5 volts coming out of the cp3 plug. Does this sound right? It is running loud and rough at a idle. Can you clean the regulator? I bought a new one but I'm just wondering also I'm wondering if a bad pressure sensor will put it in default max pressure? Bought new one of those to....got 750.00 into the both of them. Thats why I'm curious if they're cleanable.o

haven't bought a pressure sensor yet but the regulators should only be about $150. $750 seems like a lot to me. anyways back on track here

the 5 volts you are measuring will be misleading as it is a pulse width modulated current. it is using 5 volts turning it on and off at high frequency. you would need to use an oscilloscope to see the single properly and not a DVM.

0% duty cycle will be max pressure and 100% will be minimum pressure. in the programing of the ECM there is constraints as to the minimum and maximum duty cycle that can be commanded so there will always be 5 volts on plug

regulators can be cleaned but it is generally advised to replace them since cleaning it seems to be temporary and won't fix bad solenoids or wear and tear to the metering valve

bad sensors will usually give weird pressure readings or a fixed reading. the sensor/ECM relationship works kind of backwards. 0 volts = 0 PSI and 5 volts (it is actually only 4. something) = max pressure. but if the sensor is not putting out anything then the ECM will open the regulator to up the pressure and if the sensor is stuck at 5 volts then the ECM will try and close the valve to reduce the pressure. so in this sense it is backwards.

try not to get too caught up in that though. if you unplug the sensor and the reading shows 0 PSI and the engine starts to run a little loud and a little rough then when you short out the pins (5v to sense wires) and the reading goes up to approximately 23K PSI and the engine quiets down and possibly dies then the regulator is likely fine.

if you have already purchased both parts then i would just replace then and be done.

Thanks wrench!! Ur a pillar of knowledge....I'll take ur advice and replace them both....with 5k already invested in injectors, and all the related parts what's another 750 ugh!! But yeah 419 for a regulator and 279 for a sensor was the best I could find at the area oreilly's,advance,auto zone. Glad I didnt go to the dealer like I did for the injectors,hardlines,and rubber fuel lines.... I still have a hard time sitting down after they got done with me...thanks again though! I'll post the outcome.

i bet one of the dealers here could have beat that

pressure regulator
 

Hey fellas I replaced the high pressure regulator and my truck runs like a dream...gotta question though...how many of you guys and do you reccomend doing a cyl contribution test after replacing all the injectors with good quality one and the lines. Ive been limited driving 400 miles until i replaced the regulator last nite and dont se to have any leakage in my oil...just wondering if it'd be worth the 300 mile rd trip to drive to a scanner.thoughts??

are you referring to a balance rate test? if so i would do it after replacing any injector. i have my own scanner so it is no big deal to me. it is more for finding problems and to verify that everything was done correctly. it is used more often before replacing injectors then after.

if it runs good and not making any oil then drive it and dont worry. 300 miles is a long way for a balance rate check.