Medium and Heavy Trucks
Working on a Caterpillar 3126 (eng# 8YL76928). Getting a code 164-2 (Injection actuation pressure signal erratic). New
Expert's Assistant chat
Customer: Working on a Caterpillar 3126 (eng# *****). Getting a code 164-2 (Injection actuation pressure signal erratic). New actuation pressure sensor and new engine harness from ecm to sensors. Can you point me in the right direction.
Answered by yellowman99 in 8 mins 8 years ago
yellowman99
Auto Mechanic
16,260 satisfied customers
Specialities include: Auto Body Technician, Heavy Equipment Repairs, Heavy Duty Engine Repairs, Brake and Transmission Repairs
Hi. Thanks for asking your question! I will try and help you out.
There are four things that cause a 164-2 code.
The first is a faulty IAP sensor. Which you have already replaced.
Second is a faulty IAPCV. Injection actuation pressure control valve. It's screwed into the Heui pump and has a two wire connector connected to it. I have replaced many if these for this problem. I would change this next.
Third is a faulty Heui pump.
Lastly is a leaking injector.
Please reply back if you need more help or have more questions. I am happy to assist.
There are four things that cause a 164-2 code.
The first is a faulty IAP sensor. Which you have already replaced.
Second is a faulty IAPCV. Injection actuation pressure control valve. It's screwed into the Heui pump and has a two wire connector connected to it. I have replaced many if these for this problem. I would change this next.
Third is a faulty Heui pump.
Lastly is a leaking injector.
Please reply back if you need more help or have more questions. I am happy to assist.
Customer
Is there any way to test or tell if the IAPCV and the HEUI are bad before replacing them?
Yes there is.
To test a 5000 psi gauge needs to be connected to the outlet of the Heui pump. While cranking the gauge should read 4000 or higher without dropping below 4000. It's best to get the engine warm before doing this. Cold oil may not show problem. If pressure is below 4000, you then replace the IAPCV first then Retest. If the pressure is still below 4000. The Heui pump is faulty.
4 out of 5 times the IAPCV is the problem.
Let me know if you need more help.
To test a 5000 psi gauge needs to be connected to the outlet of the Heui pump. While cranking the gauge should read 4000 or higher without dropping below 4000. It's best to get the engine warm before doing this. Cold oil may not show problem. If pressure is below 4000, you then replace the IAPCV first then Retest. If the pressure is still below 4000. The Heui pump is faulty.
4 out of 5 times the IAPCV is the problem.
Let me know if you need more help.
Customer
Would Cat ET be an accurate way of monitoring the ICP? If not, where would be the best place to tie in the gauge. It is a metal line so I cannot tie in to the line itself. Is there a port on the output side of the HEUI that I could easily tie into. Sorry, not very familiar with the 3126's.
No problem Scott. ET will identify the pressure is fluctuating by not what is causing the 164-2.
To install a 5000 psi gauge. You need to remove the metal line and connect the gauge where the metal line connects to the Heui pump.
Please be careful, this system has high pressure oil and can be very dangerous. Oil pressure from a leak can cause personal injury.
To install a 5000 psi gauge. You need to remove the metal line and connect the gauge where the metal line connects to the Heui pump.
Please be careful, this system has high pressure oil and can be very dangerous. Oil pressure from a leak can cause personal injury.
Customer
Now I am getting a code 164-11 actuation pressure system fault. Is this something additional or is it common to log these codes together.
Hey Scott.
It's common to see these codes together. Both of these codes are caused by the same items. 164-2 is defined as an erratic all over the place pressure. 164-11 is defined as a system fault. Normally indicating the system can not make the required pressure is needs. For example, the engine ECM may want 2100 psi but the IAP sensor is only detecting 1200 psi. Whenever the actual and desired pressure are more than 200 psi different for more than 3 seconds. A 164-11 code will go active.
Let me know if you need more help.
It's common to see these codes together. Both of these codes are caused by the same items. 164-2 is defined as an erratic all over the place pressure. 164-11 is defined as a system fault. Normally indicating the system can not make the required pressure is needs. For example, the engine ECM may want 2100 psi but the IAP sensor is only detecting 1200 psi. Whenever the actual and desired pressure are more than 200 psi different for more than 3 seconds. A 164-11 code will go active.
Let me know if you need more help.
Customer
on the guage, remove the line and dead man the gauge coming out of the pump (gauge with a plug on the back side)? Fluid does not need to flow through the gauge. Sorry for the stupid question but that's a lot of pressure, don't want to screw anything up.
Yes that sounds correct. It's a dead head test. A 5000 psi gauge is needed for safety. Please be careful. High pressure oil is dangerous.
Read less
0 Likes
Backyellowman99
16,260 satisfied customers
Auto Mechanic
yellowman99
Auto Mechanic
16,260 satisfied customers
Ellen
Licensed mechanics
14 Mechanics are online right now.
Related Car Questions
I have a 3126 cat. Code 164-11. I've replaced 6 pack
7.7.2022
Daniel Wilson
Car Specialist
6,648 Satisfied Customers
I have an 03 rv freightliner chassis with cat 3126 engine
2.27.2022
Wayne
Journeyman
5,816 Satisfied Customers
2002 kenworth with a CAT 3126 engine- crank no start. I am
9.17.2021
Nich1019
Diesel Technician
117 Satisfied Customers
Yeah I have a 3126 cat engine. It is throwing code 39, 15,
6.30.2021
Nich1019
Diesel Technician
117 Satisfied Customers
I have an 2002 model 330 Pete with a C7. showing codes 164-2
5.3.2021
Daniel Wilson
Car Specialist
6,648 Satisfied Customers
I have a 3126 cat. Code 164-11. I've replaced 6 pack
7.7.2022
Daniel Wilson
Car Specialist
6,648 Satisfied Customers
I have an 03 rv freightliner chassis with cat 3126 engine
2.27.2022
Wayne
Journeyman
5,816 Satisfied Customers
How it works
Ask for help, 24/7Ask for help, 24/7
Members enjoy round-the-clock access to 12,000+ verified Experts, including doctors, lawyers, tech support, mechanics, vets, home repair pros, more.
Expert will respond in minutesExpert will respond in minutes
After you reach out, we match you with an Expert who specializes in your situation. Talk, text, chat, whichever you prefer.
Save time & moneySave time & money
No scheduling hassles, missing time from work, or expensive consults.
A JustAnswer membership can save you significant time and money each month.
Sarahesq and 87 other Automotive Mechanics are ready to help you.
Disclaimer: Information in questions, answers, and other posts on this site ("Posts") comes from individual users, not JustAnswer; JustAnswer is not responsible for Posts. Posts are for general information, are not intended to substitute for informed professional advice (medical, legal, veterinary, financial, etc.), or to establish a professional-client relationship. The site and services are provided "as is" with no warranty or representations by JustAnswer regarding the qualifications of Experts. To see what credentials have been verified by a third-party service, please click on the "Verified" symbol in some Experts' profiles. JustAnswer is not intended or designed for EMERGENCY questions which should be directed immediately by telephone or in-person to qualified professionals.
Last Updated: 12-20-22
“I had a resolution within 15 minutes”
— Erin, JustAnswer customer
Why you’ll love JustAnswer
JustAnswer is the best way to get expertise on-demand from doctors, lawyers, vets, mechanics and more. Since 2003, we’ve helped more than 9 million people in 196 countries and have an A+ rating with BBB and a 9.6/10 rating with TrustPilot.
Highly rated, verified Experts
We pride ourselves in our 8-step verification process including license and credential checks. Vetted by us and rated by customers, like you.
Free expert tips & articles
By Robyn
By Carolyn Hauck
By Jessica Klimczak
Ask-a-doc Web sites: If you've got a quick question, you can try to get an answer from sites that say they have various specialists on hand to give quick answers... Justanswer.com.
JustAnswer.com...has seen a spike since October in legal questions from readers about layoffs, unemployment and severance.
Traffic on JustAnswer rose 14 percent...and had nearly 400,000 page views in 30 days...inquiries related to stress, high blood pressure, drinking and heart pain jumped 33 percent.
I will tell you that...the things you have to go through to be an Expert are quite rigorous.
Web sites like justanswer.com/legal ...leave nothing to chance.
Tory Johnson, GMA Workplace Contributor, discusses work-from-home jobs, such as JustAnswer in which verified Experts answer people’s questions.
