Author Topic: 3126e not starting  (Read 326 times)

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Offline Dennis

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3126e not starting
« on: March 08, 2020, 11:21:09 AM »
NEW GUY   I have a 2002 3126e  serial# ckm35557 , it will not start cranks fine it will start with a snif of either and runs great ( with intake heater disconected)   will start on cold morrings 20-30 deg but once the day warms up it will not fire, 175000 miles on it I have had it for 1500 miles  put a new IAP valve, have power to valve,tried the IAP  solenoid trick buy disconecting still no start, had a truck garage look at it they put there scaner ( not a cat one) and said my starting pressure on heui was 1800 psi  , 1100 at idel , I pulled valve cover off saw no spraying oil from o-rings cranking and running put a mechancal gauge  on the head plug  and it read 15000 psi at cranking.  fuel pressure at cranking was 50 psi  all new (full) fuel filters and new oil and filter when truck runs it runs great no smoke,  I plow with this truck and she did not use a drop of oil all winter about 86hours this season, had oil tested by cat all good there are other things I tryed , NEED HELP PLEASE    The truck is graged all year Thanks Dennis

Offline David.e.atherton

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Re: 3126e not starting
« Reply #1 on: March 09, 2020, 04:45:40 AM »
Dennis, understanding your problem correctly with information posted.you are over looking or being
given and not understanding how the caterpillar electronic engine operates. First of all use of starting
fluid is not recommended ( even with intake heater disconnect ). Looking at startup cranking engine oil
pressure, engine will start and idle at 870 psi  oil pressure. Engine will run at 1800 psi oil pressure.
Diesel fuel pressure cranking is ok cranking and will increase when engine starts. What you have
over looked is the Injection Actuation pressure Regulator is not operating correctly after engine has
been running. Which will present a fault code of 42-11.  Ask Dave, Dave Atherton Retired Cat Mechanic

Offline Dennis

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Re: 3126e not starting
« Reply #2 on: March 09, 2020, 05:12:32 AM »
Hi dave  I know about useing either I have been working around heavy equiptment all my life I don't like useing it  but when I do very little. I have flash codes 18 , 15, 39, , I made sure no broken valve springs, with that heui pressure it should start, I do not have a coolant level sensor on my expantion tank , just a harness to tank thats has a blank plug, I did see that my fuel rail in the head will not hold any pressure after shut down, I tryied to hand prime before trying to start and no change,could the fuel pressure regulator be a probblem,

Offline Dennis

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Re: 3126e not starting
« Reply #3 on: March 09, 2020, 05:16:40 AM »
Dave I am going to pull IAP valve and clean and try again.

Offline Dennis

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Re: 3126e not starting
« Reply #4 on: March 09, 2020, 12:26:21 PM »
no start,  heui pressure at 1500 while cranking, I build snow plow trucks for my self, from ground up,   I build all the hyd's system's for the last 40 plus years all ways had ford f 800's with the good old GAS 429  this is my first deisel truck,   I have case, kubota tractors with deisel never knew this cat was going to be a pain in my butt    With the heui pressure good why won't this start,   I AM  LOST PLEASE HELP  DENNIS

Offline Dennis

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Re: 3126e not starting
« Reply #5 on: March 09, 2020, 12:41:44 PM »
DAVE     I have heard a bout the dead-head pressure test on the heui pump , I have seen small hyd pumps split because of dead-heading what do you think   thank you  dennis

Offline Dennis

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Re: 3126e not starting
« Reply #6 on: March 09, 2020, 03:21:08 PM »
Dave I got a new gauge and this is what I got     on the heui test port on head,  1000 psi cranking, 1250 psi with IAP sensor disconnected ,  with IAP sensor still disconnected I also disconnected the IAP valve and got 100 psi . I am thinking to dead head heui pump but want to  hear from you first  Thank you Dennis

Offline David.e.atherton

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Re: 3126e not starting
« Reply #7 on: March 09, 2020, 08:39:51 PM »
Dennis,  one question where did you locate the injection actuation pressure regulator because with your
Engine serial number location of the IAPR valve is located inside the Heui pump housing that is a non-
serviceable and requires exchange Heui pump . This requires removing HEUI pump. Would suggest
taking snow plow to a service shop that has been schooled on caterpillar Heui injection systems. Yes I understand
you have been around Caterpillar equipment but if you never been schooled with electronic caterpillar
engines with Heui injection systems and do not have access to caterpillar engine diagnostic service tool
called Cat ET you are only guessing and throwing parts at engine. Area of concern from my post this am.
I mentioned the use of starting fluid and problems that can happen . What you did not understand how the
caterpillar 3126 E Heui pump and use of starting fluid do not mix. The reason the gear that drives the HEUI
pump is a pressed on a number 2 Morse taper shaft on pump and is held in place by a bolt and washer.
Yes there are service bulletins pertaining the gear on Heui pump slipping but will still drive the Heui pump.
The shock of engine start up with starting fluid can loosen the gear on Heui pump. Again my suggestion
It is your best interest to take snow plow to a service shop that understands caterpillar engines. Sorry I
Cannot help you further but you need to connect Cat ET to find out where problem is located .ask Dave,
Dave Atherton Retired Cat Mechanic

Offline Dennis

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Re: 3126e not starting
« Reply #8 on: March 10, 2020, 05:25:26 AM »
Dave thanks for your help  ,     and my heui pump has a round top with IAP valve on side  of pump ,and either has been used twice , I have had the heui pump out for mounting o-ring replacement , gear look good.    THANKS for your help Dennis

Offline Dennis

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Re: 3126e not starting
« Reply #9 on: March 10, 2020, 09:30:50 AM »
hey dave   I know you said you wouldn't help me any more but I put the dead-head pressure test  with IAP connected only got 1000 psi it held there on total cranking,  disconnected IAP harness and got 0 psi  , just wanted to tell you  Thanks for your help  Dennis

Offline Dennis

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Re: 3126e not starting
« Reply #10 on: March 10, 2020, 10:07:47 AM »
hey dave    forget last post I had the IAP sensor unplug while I did the test, well I plug in the IAP sensor and I got 4000 psi dropping to 3800 psi as cranking got slower .  Thank you for your time   Dennis