redline8300 Report post Posted July 2, 2016 I have a 1997 Beaver Marquis and I'm having major problems with no low end power or top end power. The problem started out on a drive from Baton Rogue to Terre Haute. It was going down the road at 65 one minute then it was struggling to maintain 45 mph for the duration of the drive. I've changed all the filters and have ran a temp fuel hose on the outside of the RV to verify that the one under it isn't my problem. I just replaced the transfer pump and rebuilt the check valve and the injector pressure jumped from the 780's to 860's. The only code the engine throws a 232.4 when you rev it up. The turbo seems tight but it's not reading any boost pressure right now and the other week I could get it to read up to 10 lbs. The RV is 6 hours from home and the drive here is getting annoying trying to fix it. Share this post Link to post Share on other sites
wolfe10 Report post Posted July 2, 2016 redline8300, Welcome to the FMCA Forum. 10 PSI of boost at WOT is no where near enough. Assume you have checked your air intake and air filter for bird nests, wet filter element, or other severe restriction. What is your air filter minder reading. Next would be to check for a leaking boot or gasket, then check the CAC (Charge Air Cooler) for leaks. Give the Caterpillar RV Hotline a call (877 777-3126). Don't know that they will have service people working over the weekend. But certainly on Monday you can confirm proper boost and they can also tell you what the 232.4 code is (I don't have my manuals handy). Share this post Link to post Share on other sites
garyreed Report post Posted July 2, 2016 Have the CAC hoses and clamps been checked? Gary Share this post Link to post Share on other sites
kaypsmith Report post Posted July 2, 2016 Last time that happened to my coach, one exhaust pipe from the right manifold cracked, it looked fine, but when revved up the crack would open up, causing lack of boost. Just something else to look for in case. Share this post Link to post Share on other sites
wolfe10 Report post Posted July 2, 2016 35 minutes ago, kaypsmith said: Last time that happened to my coach, one exhaust pipe from the right manifold cracked, it looked fine, but when revved up the crack would open up, causing lack of boost. Just something else to look for in case. Good thought. Exhaust leaks are pretty easy to identify on a diesel. LOTS of black soot around the leak! Check head to exhaust manifold, exhaust manifold itself and manifold to turbo. Share this post Link to post Share on other sites
redline8300 Report post Posted July 3, 2016 Right now the intake tube is disconnected while we checked for fuel leaks but I have checked the filter and it was clean. The 232.4 came up as the 5+ volt issue. My google foo came back with one of the 5 sensors that run the engine is causing that error or a bad ECM. That is why the jumping boost pressure is bothering me. I had it downshift a few drives ago and it jumped up to 16 but came down to 10 and today it isn't reading at all. With the trans in neutral it is slow to rev. I checked around all the boost hoses and squeezing around them I couldn't feel any splits. Not the best method, but at that time we figured that we had a fueling issue. When running don't hear the sound of pressure blowing off. Couldn't see any soot around the exhaust manifold. We found an diesel shop not that far away and will try to get one of their guys to swing on by next week. Share this post Link to post Share on other sites
garyreed Report post Posted July 3, 2016 Did you check all of the battery cables and all the small wires connected to the starting batteries? If it comes and goes that easy, at best it could be a loose wire or plug. It could be that the harness has rubbed a hole where it is tied to the block or a bracket. Gary Share this post Link to post Share on other sites
jleamont Report post Posted July 6, 2016 Brett, would a 1997 have a MAP sensor? i don't recall if that year is the B or E of the 3126. When the OP mentioned 5v usually it's an ECM reference voltage sensor problem. MAP sensor open circuit will cause no boost. Share this post Link to post Share on other sites
DaveAtherton Report post Posted July 6, 2016 Good morning gentleman, I guess term MAT Sensor comes from terms other than Caterpillar tech info. Term that I am going to go with boost pressure sensor which is part of group of 5 volt sensors. The voltage with this sensor group is strict 5 volt power range. If any of the of group diagnostic code share active 232-03 5 volt supply above normal and 232-4 5 volt supply below normal. What this is telling problem is a wiring or pin terminal problem. Do not replace the sensor or ECM. Note: if the sensor has an integral connector the pin Connector cannot be removed. Only replace the socket terminal in wiring harness. My suggestion before going into depth on problem first check the turbo wastegate for movement, check little rubber hose that actuate the wastegate Rod. Last note: do not try to induce power to the 5 volt sensor group because the sensor group is all tied in together and go direct to ECM unfuse. Dave Atherton Retired Cat Mechanic Share this post Link to post Share on other sites
DaveAtherton Report post Posted July 6, 2016 Gentleman, coming in on this problem and answering to above post . Checking turbo wastegate arm and Rod movement is there is full range of movement. Next move I would suggest with low power is the fuel system from fuel tank to engine, which a temp bypass was made. Did you check fuel pressure going into the engine fuel rail 60 to 65 psi high Idle. Being fuel transfer pump rebuilt you should but needs to be checked ( low fuel pressure will cause low power ). Next place to look real close at is the fuel pressure regulator on the back of head, in time the check valve will not hold back pressure in fuel rail. Connect a clear plastic hose to the return to fuel tank hose on discharge end of fuel pressure regulator for clear stream of fuel coming from engine while engine at idle and high idle. If you have lot of air or foam in fuel clear line returning to fuel tank than that would cause low power. Dave Atherton Retired Cat Mechanic Share this post Link to post Share on other sites
manholt Report post Posted July 8, 2016 I guess the OP got it fixed! Carl Share this post Link to post Share on other sites
redline8300 Report post Posted August 18, 2016 Turns out it was the HEUI. I will type out a more elaborate explanation of what all we did before we came to that conclusion but I just got back from driving it home and have only had 2.5 hours of sleep in almost 2 days. Share this post Link to post Share on other sites
redline8300 Report post Posted August 18, 2016 Early on I disconnected the waste gate arm and the actuator thinking I may have had something bad on that end and wired it what I thought was closed, turns out I wired it open. Before we changed out the transfer pump we could get it to idle, still low power but it would idle. After we changed it out it barely ran and then stopped all together. We put an electric pump sucking fuel through the filters and the existing lines and the beast screamed to life. When we disconnected the pump and fired it up it roared to life. The hope that it was a trapped air bubble finally working out was dashed when it died about 30 seconds later. Both filters were still filled with fuel. Thinking that the issue was the transfer pump it came back off and moving the plunger you could hear it pumping but when it went back on the HEIU it wasn't building any suction. The mechanic changed out the HEUI and it drove great. Not sure what was wrong with the drive lobe on the original HEUI but for some reason it would drive the original pump but not enough fuel was getting to the engine. Share this post Link to post Share on other sites
manholt Report post Posted August 18, 2016 Glad your back on the road again! 6 weeks is a long time to be down... Carl Share this post Link to post Share on other sites
jleamont Report post Posted August 18, 2016 Redline, was it the HEUI pump or Regulator? Most mechanics will replace both on a 3126 while you are in there. Share this post Link to post Share on other sites
hermanmullins Report post Posted August 18, 2016 Cummins person here, what is the "HUEI"? Just trying to improve my knowledge. Herman Share this post Link to post Share on other sites
jleamont Report post Posted August 18, 2016 Hydraulic Unit Electronic Injection CAT, Navistar and Ford all ran it at one point or another. Oddly most of the components all appeared to be almost identical on similar years. Cliff note version; engine oil is pressurized to around 3000 psi and sent to the fuel injectors (via HEUI pump) it uses that high pressure oil to push a piston inside the fuel injector (oil on top, fuel on bottom of piston) to atomize the fuel, the injectors are controlled by a solenoid on top of each. The CAT design only has one solenoid where the Later Navistar design in the video has two. common problems; engine oil consumption via leaking piston sealing inside injectors. low power, oil breaks down and cannot be pressurized any more or is aerated. injector o-ring failure, causing cross contamation of fuel and oil, usually oil ends up in the fuel tank. oil leaks, at that psi you can really leak oil. pump failure and or pump regulator failure. Here is a later design (Navistar) that explains it. Hope that helps understand. Complex system that worked well, high pressure common rail replaced this design on all three OEMs later to help better control emissions. Share this post Link to post Share on other sites
manholt Report post Posted August 18, 2016 Darn it. After looking at the women, I forgot what I wanted to say! Don't even remember the video... Carl Share this post Link to post Share on other sites
five Report post Posted August 18, 2016 After watching the video, it's amazing any of these things run. Share this post Link to post Share on other sites
jleamont Report post Posted August 18, 2016 31 minutes ago, FIVE said: After watching the video, it's amazing any of these things run. I know...right? I'll take an Old school mechanical diesel any day over a new one. Share this post Link to post Share on other sites
rsbilledwards Report post Posted August 18, 2016 THEY CALL IT PROGRESS BillE Share this post Link to post Share on other sites
redline8300 Report post Posted August 18, 2016 6 hours ago, Manholt said: Glad your back on the road again! 6 weeks is a long time to be down... Carl I only need the RV when I'm on a job and I just wrapped up rehab from knee surgery. Share this post Link to post Share on other sites
jleamont Report post Posted August 18, 2016 1 hour ago, rsbilledwards said: THEY CALL IT PROGRESS BillE I call it over engineering, which bleeds my wallet Share this post Link to post Share on other sites
jleamont Report post Posted August 18, 2016 38 minutes ago, redline8300 said: I only need the RV when I'm on a job and I just wrapped up rehab from knee surgery. Get some rest.. Share this post Link to post Share on other sites
rsbilledwards Report post Posted August 18, 2016 J, I agree. Today it is BLING that gets the attention and the idea that it is new and without problems or issues. It is just like everything else these days, who can I impress, how good can I look...and then you ask is it paid for...nope, the bank owns it! It looks like all the real coachers are driving the older and best of the bunch built and own them outright! There must be something I am missing. My mother thought I was a spend thrift, yet today comfortable and living the dream with no help from her and we own it all except the cabin!!!. all the way to the bank! Huffy keep rolling, nice to see you back, enjoy. I still like going back and watching the roll out up the Siskiyou Mountain pass out of Ashland, Oregon. gonna do it in the Panther next time we are out there. It is home ground, grew up in Medford. Porsches are not the same either...it's a money game! BillE Share this post Link to post Share on other sites
