Cat engine 3126

Albemarle, NC

#441 Jan 19, 2011
I forgot to mention either is needed only when engine is warm or at operatin temp.Engine cranks without either when cold or has been sitting a while
rom Maxwell

Big Spring, TX

#443 Jan 21, 2011
1997 freightliner w/3126 no oil pressure reading on dash gauge changed out sending unit, same problem, swaped wires same problem. Suggestions?
1997 Holiday Rambler endeavor LE

Since: Jan 11

Franklin, MA

#444 Jan 23, 2011
Does anyone know if a ecap nexg4522 scan tool is compatible with a 3126 sn#7AS25581 in a 1998 GMC T6500. The CAT manual seems to indicate it can be used for engine years 89 to 98, including the 3126 series. The scan tool has been used in the past for a 3406 engine. Would I need an adapter cable or extra software? The GMC service manual only shows the ODB2 connector as the interface to the CAT ECM, does this seem correct or should I be looking for another connector to talk to the CAT ECM. Also does anybody know if my engine is a 3126a,b,e,... by the serial # listed above. Thanks, Ken
Rick Love

Barrigada, Guam

#445 Jan 26, 2011
CatTech wrote:
any electronic Caterpillar engine questions i can help
I have a 2000 FL-80 with a 3126 cat engine , it just shut down on the road ,I replaced the shut off solenoid , that was not the problem ,I even ran 12 volts direct to the soleniod , still nothing , will run on starting fluid then die , any ideas

Thanks Rick


#446 Jan 27, 2011
shuts down abruptly or slowly dies off?
Can it be restarted easily or do you have to crank it much before starting?

serial prefix#?

Durham, NC

#449 Feb 7, 2011
I've got a 3126b on a 01'freightliner and its been shuting down on me while im driving down the road and starts right back up immediatly after shuting down.My fluid is nice,clean and full and just replaced 2 censors on it.ICPS and Low coolant censor.Can anyone help me.


#450 Feb 8, 2011
Check grounds, power supplies and ignition on wires to ecm.

Dunnellon, FL

#451 Feb 9, 2011
Bought a tree truck from Ken Oresky at All Florida Truck Sales/ in Florida 2010 with the Cat 3126 and have had nothing but trouble. This purported reputable dealer sold us this truck knowing that it had a cracked block - we had problems with cold starting and many of the issues in this blog but when you get down to it, this guy is not reputable and will sell you a problem without batting an eye. We spoke with him after the purchase and he verbally admitted knowing about the cracked block but we got so much crapola info from the computer readings as this guy manipulated and fed us a total line of BS. He said he'd give us a new head for our mechanic to install - NOT - he never returned our calls or emails - just a sorry dealer! We are running our old truck as its dependable and all I can say is if you're buying a truck with this engine, don't buy from Ken Oresky at All Florida Truck Sales, hes a piece of work.

Seattle, WA

#452 Feb 10, 2011
I have a 2000 3126 250 HP Hi Torque with 3060P Allison. It ran perfect for 250,000 miles, the #6 injector came apart and destroyed the engine. I did have a warning as the engine for about 1 week before it blew ran rought and smoked when started for about five minutes, then cleared up and ran fine. If you have this problem get the injectors checked out imediatly do not wait! I bought a used 330 hp from a wrecked rv with up graded Allison transmission. Fuel transfer pump is bad I suspect the seals have dryed up from sitting. Will replace next weekend. Wish me luck!

Adair, OK

#453 Feb 15, 2011
I Have a 3126 Cat that the block is bad any ideas,what the best way to fix it

Pikesville, MD

#454 Feb 16, 2011
looking at an 04 fl 70 w a 3126 cat motor is there anything I need to be looking for as far as the motor any type TSB that can be checked on ?the motor has 300k on it should it need any type of service at this mileage thanks for any input.

Corpus Christi, TX

#455 Feb 22, 2011
I have a 1999 Beaver with 330 hp 3126B and the maintenance is a nightmare. It's an electronic engine and the dealers avoid then like the plague except to sell parts and labor.

Henderson, NV

#456 Feb 22, 2011
I just lost my 3126B at 265K miles. I don't know exactly what happened but, my mechanic said something let go in the top of the engine! I just had it into Cat a month ago to have all of the O-rings on the injectors replaced and a complete service done the day before it let go. I run quite a few miles, about 3000 a week and service it religioously at 6000 miles. I believe the main problem is the engine was NOT properly maintained by its former owner. Now I'm without a truck but hopefully can retain my customer base.

Henderson, CO

#457 Feb 24, 2011
3126e with 20K, very rough idle cold and throws a 3-9 code. Starts fine when warm.

Memphis, TN

#458 Mar 3, 2011
CatTech wrote:
any electronic Caterpillar engine questions i can help
i have a 3126 cat thats in the cat shop now been in 2 shops the last month neither one can figure problem out we are not getting fire to the injectors they say do you know what might be the cause they have tried everything they know and still cant fix this is a big part of my living i need help bad can you give me some insight on the problem please thanks so much karl


#459 Mar 3, 2011
Rich wrote:
3126e with 20K, very rough idle cold and throws a 3-9 code. Starts fine when warm.
What's your serial?

United States

#460 Mar 3, 2011
Per wrote:
<quoted text>
What's your serial?
serial# CKM41410


United States

#461 Mar 5, 2011
Per wrote:
<quoted text>
What's your serial?
Also neglected to mention, won't start if outside temp below about 65 degrees F unless block heater for about an hour first. Then usually idles very rough - the warmer it is outside, the less chance of rough idle. I've verified that input air preheater is working (I can hear the solenoid click and Fluke 36 clamp meter measures about 95 amps when energized.)


#462 Mar 5, 2011
Does it make any difference at all if you prime it manually before attempting a cold start?

United States

#463 Mar 5, 2011
Per wrote:
Does it make any difference at all if you prime it manually before attempting a cold start?
I don't have a manual fuel primer.
Book says 39 code is IAP fault. Could that be caused by a plugged fuel filter? Only about 500 miles on new filter (single 2 micron filter with fuel/water separator.) BTW, how are cable connectors removed from the engine sensors. Is it a squeeze or turn or push to unlock?

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