We recommend Torque Pro. Consult the relevant manual for the exact value of the voltage variation that will set code P for the application being worked on. VVT and VCS systems use pressurized engine oil to act on actuators that control variable valve timing. The image below shows a typical VVT control solenoid.

The most common cause of code P by a large margin is a low engine oil level, followed closely by low oil pressure issues and incorrect, or unsuitable lubricating oil. Other common causes of code P include. Failed, or failing PCM, which is even more rare, but not altogether impossible.

isuzu npr rough idle

Although the symptoms of code P are much the same on all vehicles, the severity of one or more symptoms may vary from vehicle to vehicle. Below are some common symptoms of this code. Significantly reduced engine power at some engine speeds. In some cases, engine misfiring may be present at some engine speeds. Note that in these cases, other codes that are closely related to P might be present. NOTE: When diagnosing code P, start the procedure by inspecting the engine for oil leaks that could have reduced the engine oil level.

Repair oil leaks as required, top off the oil level, clear the code, and operate the vehicle. Rescan to see if the code returns. If the code persists, proceed as follows. Check the engine oil level, and adjust the level to the correct mark. Clear the code and operate the vehicle to see if the code returns.

NOTE: At this point, it is important to determine if the engine is filled with suitable oil. Replace the oil and filter if there is any doubt about the type, grade, viscosity, or age of the engine oil. If the engine oil is at the correct level, and of the correct type and grade, perform an oil pressure test to verify that the oil pressure is within specification. Low oil pressure is major cause of code P If the oil pressure does not conform to specification, locate and repair the cause before commencing with the diagnostic procedure.

If the oil pressure is within specification, perform a thorough inspection of all related wiring and connectors. Repair all defects as required, but be sure to check the circuit for reference voltage, continuity, and ground contact.

Be sure however to disconnect all control modules before commencing continuity checks. Consult the relevant manual to determine the color-coding, location, and function of each wire in the connector, as well as the exact values of the reference voltage. If the code persists, there may be an intermittent fault present, and you may have to allow it to worsen before an accurate diagnosis can be made. Clean all components as required, and test their operation before re-installing them.

NOTE: With some scanners and code readers, it is possible to operate the actuators or control valves manually.The U. Chamber of Commerce shared its insight on the Paycheck Protection Program. Click here to learn more. Discussion in ' Mechanic and Repair ' started by gulfjoeOct 28, Log in or Sign up. Sign up now! Pandemic Unemployment Assistance is effective from January 27, until the end of this year. Messages: 1, I have been on the hunt for a nice used Isuzu NPR I am starting to learn what a Nice BOX truck cost I found one in Atlanta, NPR.

The guy said it needs 4 injectors. I called a few diesel mechanics I my area, but they needed ALOT of info off the truck, stuff I don't think the seller would give me Soooooooo, I am asking what is ball park cost to replace 4 injectors on a NPR. Thanks in advance. Messages: 5, What engine you have. Landrus2Oct 28, He didn't say I am looking for a ballpark on what 4 injectors Cost to replace. It's a diesel non dpf according to for sale ad Posted via Mobile Device. There are usually a lot of these trucks available.

Have you checked with Penske or Ryder? I bought mine 4 years ago and still get emails about available trucks from Penske. For reference mine was 16 K with miles diesel engine and fiberglass box. Might also check with Rush truck centers. I bought mine from them. Very easy to deal with. You must log in or sign up to reply here. Share This Page Tweet. Your name or email address: Do you already have an account?

No, create an account now. Yes, my password is: Forgot your password?NPR came in with rpm idle when in park or n. Goes to stock idle in gear. Had codes for regen too often and over boosting. Found turbocharger bypassing oil and wastegate frozen. Installed OE turbocharger and replaced map sensor I broke the original taking it out to clean No vacuum leaks detected. Codes causing to default after 2 block of driving. I cannot find the source of high idle. I think this will solve my code issue since turbo is spooling at a high rate at the rpm idle.

Any suggestions? Can you do a log file of the truck while its happening and post it please? Can you show it as a excel file? If so have you checked it to make sure it is not turned up? I was called for a bus that wouldn't start last summer. I asked the driver if it was in Park or neutral.

Driver got a little offended with me. Showed up. Put it into park and started it up. Walked away and called bus owner. So that is a very good question. I don't work on these very often so it's a good thing to know. I could kick myself. I completely forgot about the idle knob until your response.

Thank you, Now I can finish testing. I second Rickys suggestion.

isuzu npr rough idle

I had one on Monday that the driver would hit the knob with his knee and not bother to turn it down. Info Topics User Groups. Heavy Duty. Reply Bookmark 0. Michael Diagnostician. Champaign, Illinois.

Michael Default. Ricky Technician.

1999 ISUZU NPR Technical Service Bulletins

Wilton, Connecticut. Ricky Default.Search our online idle control valve catalog and find the lowest priced discount auto parts on the web. We sell wholesale to the public. We specialize in a wide-variety of high-quality car parts and accessories for your car, truck or SUV. Call toll free to order or place your order online via our secure checkout system. Our online parts catalog uses real-time inventory, so you can be assured the parts you buy are in stock at the time of ordering.

Most orders are shipped the same day. They are available for the following Isuzu NPR years:,, 02, 01, 00, 99, 98, 97, 96, 95, 94, Thank you for the quick and acurate service. The parts came well packaged and 2 days before promised. Your prices were better than any I had found on those parts.

I will ckeck your site for parts Close X. To return a part, simply submit a support ticket within 30 days of ordering and we will issue you an RMA number to return your product. See customer service page for refund and return details. We scour the web to make sure PartsGeek always has low prices. You can buy with confidence!

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isuzu npr rough idle

Replacement Idle Control Valve. Shipping Options: Free Ground Shipping. Read more reviews. Catalog: E.

isuzu npr rough idle

Catalog: B. Catalog: C.The truck was shutting off so I changed fuel filter and then I bled the lines. I got it to run thinking I fixed the problem but it started shutting off even more frequitly. I need help this truck needs to be on the road. Do you. Hello, These trucks Diesels had a problem with the secondary fuel pump going out causing the engine to stall out. Here are diagrams to help you remove the pump and get back going again.

Check out the diagrams Below Please let us know if you need anything else to get the problem fixed. Cheers, Ken Images Click to enlarge. Was this answer. Rebuilt the engine, runs well but stalls in drive or reverse when you take your foot off the brake. Idle is controlled through the injector pump. Was there any issue prior to the re build? Roy Was this answer.

The guy bought it broken so we do not know. I guess that is the best place to start? Most likely a failure in the injector pump. Oh, and thank you! Was fuel pressure checked? Was accelerator pedal OHM checked for dead spot? We have paid for several tow trucks. Sometimes it starts back up after a few minutes of Embarrassment with a Trailer full of Equipment and a Four Man Crew standing on the side of the road, that pushed the rig out of a busy intersection only to Leave them Stranded again later and possibly farther from home.

Men are stranded on their way to work! I have two of these Sweet Trucks and they have under K on them because no employees are willing to be stranded in them any longer!Gray or Blue Smoke from Diesel Exhaust. Newer, low mileage truck owners can skip this paragraph, but many of us like to have a worn out beater truck laying around, or maybe your teenager bought their first car from a not-so-honest guy. Blue usually means one thing: you are burning oil.

Common issues include piston rings, valve seals, PCV valves, injector o-rings, turbo seals or the turbo itself; depending on the vehicle. Besides jumping into an engine rebuild, many owners try to narrow the cause down by starting at the lowest cost and working upwards. Stiction Eliminator is a smart place to start. It helps remove the built up coked and varnished oil and soot, prevents future coking, helping the rings and seals do their job, which in turn restores compression.

The cleaning of the turbo, camshaft and other internals that oil comes in contact with reduces friction in the engine, helping to lower engine operating temperatures and making the engine run more efficiently and smoother.

Stiction Eliminator belongs first on the list due to its money back guarantee and ease of installation. Next, many auto parts stores offer compression test units for rent, and you receive your money back when you return the tool.

PCV valves are usually the next cheapest, these can go bad and suck oil into the intake, depending on the vehicle.

Consult your mechanic if unsure on your next step, many manufacturers have an acceptable amount of oil that might be burnt during normal operation as the vehicle ages. White Smoke from Diesel Exhaust.

2006 ISUZU NPR Technical Service Bulletins

White smoke in diesel engines is usually the last color you want to see, particularly on gas cars. If the smoke is thin, and goes away relatively quickly, than it is merely condensation. However, thicker, longer lasting smoke is a much larger headache. Your engine is more than likely burning coolant. This can be the result of a blown head gasket, damaged cylinder head, or cracked engine block — none of these are easy on the wallet. Diesels can also put out white smoke when fuel passes completely through the engine and reaches the exhaust without having been burned.

This might be caused from the engine being too cool to burn the fuel, low compression in cylinder sfuel injection timing, defective fuel injector, burnt out glow plugs, clogged air filter or poor quality fuel.

Diesel Extreme is the go to solution for this color smoke since it attacks many of these issues.Toggle Navigation Nalley Isuzu Truck. Categories About Us. Select a Vehicle. Search Go. Select Your Vehicle. You can edit the name of your vehicle by clicking the pencil icon on the right. Something went wrong. Please try again. Select your vehicle below:. VIN Go.

No vehicles found. Your Cart. Continue Shopping View Cart. Welcome to Nalley Isuzu Truck. Isuzu Truck Parts. Select a Model. Your Isuzu truck deserves the very best upkeep. Because it helps you do your job right. This is a real truck that needs real parts. As an official distribution channel of a comprehensive inventory of Isuzu Truck Parts and price-savvy FleetValue Parts, we have everything you need to keep your truck in working order.

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