Why is my Duramax fuel rail pressure so low?

This is a very common problem that we hear about from our Duramax customers. Actual fuel rail pressure is not keeping up with desired fuel rail pressure. This may only happen in high fuel demand situations like towing or racing but it can also happen with everyday use.

Can a low fuel rail pressure cause a Mil?

Low rail pressure may or may not cause an MIL (check engine light). This is a very common problem that we hear about from our Duramax customers. Actual fuel rail pressure is not keeping up with desired fuel rail pressure.

When to change the fuel filter on a Duramax?

Dirty fuel filter is the most common issue we see when fuel rail pressure is low. The filter should be changed in the 8,000-10,000 mile range if good fuel is being purchased and running mostly low HP tuning, much sooner if running competition/race style tuning.

How does FRP sensor work on Duramax diesel engine?

The FRP sensor uses a 5-volt reference circuit , a signal circuit, and a low reference circuit to monitor fuel rail pressure. This information is sent to the engine control module (ECM) to assist in the fueling of the engine. • DTCs P0090, P0192, P0193 are not set.

What causes a Chevy 2500HD to lose power under load?

Probably P0087. Check the fuel hoses at the side of the trans– they can get kinked, weak and collapse. I’ve just experienced a very similar situation with my 2005 2500HD. After driving about 2 hours, over varying terrain, I had to stop at a light (not the first on the trip).

What’s the code on the Check Engine light?

Pulling the code when the Check Engine comes on would help, too. I’ve never had a check engine light and there’s only ever been 2 codes found. In 2012 there was a P1093 code and the dealer invoice states “…low rail pressure during enrichment. Command high fuel rail pressure, pressure drops.

What are the diagnostic parameters of a Duramax diesel engine?

2005 6.6L (LLY) Duramax Diesel ENGINE DIAGNOSTIC PARAMETERS SENSED PARAMETER FAULT CODE ACCEPTABLE OPERATING RANGE AND RATIONALITY PRIMARY MALFUNCTION DETECTION PARAMETERS SECONDARY MONITORING PARAMETERS AND CONDITIONS MONITORING TIME LENGTH AND FREQUENCY OF CHECK MONITORING METHOD FAULT CODE STORAGE AND MIL ILLUMINATION

How long does it take to repair a Duramax fuel rail?

Inspect the unit as well as the fuel tank and remove the offending particles or repair the separated pickup tube. Tools needed: fuel line quick disconnect kit, can be the cheap plastic ones sold at the local parts store. Approximate time is 3-4 hours. Cost: is less than $20.00 unless the pickup/sending unit is damaged.

What’s the low fuel pressure code on a Duramax?

Duramax LBZ and LMM P0087 Low Fuel Pressure code Summer comes, temps rise, and the working trucks with relatively high miles start to set a P0087 code and go into limp mode while towing. I am on the receiving end of continuous calls over the past few years inquiring what to do.

How long does it take to fix Duramax fuel rail pressure?

Approximate time for the DIY’er would be 6-10 hours. Installing a lift pump may help fix the symptom and is a good modification for the future even if a new CP3 is needed. If a mechanic is out of the question, then installing a quality lift pump would be my first recommendation. High injector return rates.

What should the rail pressure be on a Duramax LBZ?

The dealer can use his Tech 2 scan tool to control the injection pump and increase desired rail pressure to max of 160mpa at idle. The observed actual pressure should follow desired or at least be quite close. If not then step 3 is necessary to eliminate the rail pressure relief valve as a possible leak. Step three: Bottle test.

Where is the CP3 on a Duramax engine?

This CP3 is under high demand, sucking fuel from the tank through the filter and then converting this to pressures up to 26,000 psi.It is a mechanical pump and does wear with use. This is a big job to do as the CP3 is gear driven off of the camshaft and is located in the valley of the engine.

What’s the code for low fuel rail pressure?

Have a gmc sierra 2500 duramax. When towing or with a load the engine light comes on and the code is for low fuel rail pressue. No power on accleration … read more I HAVE A DTC 1093 (FUEL RAIL PRESS LOW DURING ENRICHMENT) ON A 05 DURAMAX.

What’s the low fuel code on a Duramax?

After warm up and under a load the engine goes into limp mode, sends a code of 1093- low fuel … read more Vocational, Technical or Tra… My 2003 6.6 diesel Duramax will not start in cold unless it is plugged in. I have replaced the glowplugs, air intake heater, and temp. sensor. but still it won’t start. Could you please tell me my pro … read more

What is the proper fuel pressure for a Duramax?

Use common sense safety practices when servicing any diesel system: While maximum control oil pressure on a Power Stroke can reach nearly 4,000 psi, the Duramax fuel system is pressure-relieved at a blistering 27,550 psi. Cracking a fuel line loose on a running Duramax engine could easily be fatal.

What causes low fuel rail pressure?

Some of the most common causes of low fuel rail pressure can be a dirty fuel filter, leaking fuel filter head or a cracked water separator, a weak fuel pressure relief valve, a collapsing or cracked fuel line, a blocked or broken fuel tank pickup, or a sign of fuel delivery trouble.

What is the normal fuel pressure at the rail?

For a GM, this pressure is usually set to 58psi (factory fuel pressure in the rail). The vacuum/boost referenced regulator will help to change the pressure in the rail based on the pressure in the manifold. When an engine is idling, it may be pulling 20 inHg of vacuum, which translates to roughly 10psi.

What is a Duramax lift pump?

Whether you own a Power Stroke, Cummins , or Duramax-powered rig (or something else altogether), a lift pump can simply be defined as a low-pressure supply pump that is used to transmit fuel to a high-pressure pump. In the case of most mechanical engines, fuel pressure is fed to an injection pump,…

What to do if your Duramax engine won’t start?

Replaced the Injecton pump with ac delco pump, replaced the fuel filter, replaced the 2 fuel lines from filter to engine, replaced ecm and reprogrammed, performed all vacuum test through fuel rail and filter housing and holds 25″ vacuum. The pump sucks down to 10″ vacuum with the return blocked off. still won’t start any help would be appreciated.

Why does my 6.6L crank no start?

Possible someone shimmed the valve and lost parts– COMMON. Pull the “U” hose from the fuel rail– plug the hose. Connect a hose to the nipple on the fuel rail. Crank the engine— any fuel coming out of the fuel rail nipple — the FPRV is leaking fuel– IT WILL NEVER START.

How can I tell if my Duramax fuel rail is leaking?

Weak fuel pressure relief valve (fprv) for 2004.5-2010 model years. This can be tested by doing the “bottle test” This is an easy, cheap way to see if the fprv is leaking. If any fuel is leaking past the fprv, then the internal spring will need to be shimmed.

What to do if your Duramax crank wont start?

Buy a new filter head– little over $100, and comes with a new filter and WIF sensor. i replaced the fuel hose to/from the filter head with clear line from the hardware store and then pressurized the fuel tank to 15 psi with a compressor and found the system full of air from a leaking quick connect fitting on the fuel line near the fuel tank.

What should vacuum pressure be on Duramax diesel engine?

Attempt to start the engine. ⇒ If the engine does not start, refer to Engine Cranks But Does Not Run . Install the J 44638 to the fuel rail service port and slowly increase the engine speed until reaching wide open throttle (WOT). Vacuum should be less than 5 inches Hg of vacuum.

What’s the fuel pressure on a GMC Duramax?

The actual fuel pressure today is 4.2 mpa while cranking. I just ordered a fuel supply diagnostic hose to make sure the volume is coming up from the tank and without sucking in air. Yeah thats about 610 psi and you need about 1400-1500psi to start easy..

What is the low fuel pressure code on a Duramax LBZ?

Duramax LBZ and LMM P0087 Low Fuel Pressure code Summer comes, temps rise, and the working trucks with relatively high miles start to set a P0087 code and go into limp mode while towing.

Can a low pressure fuel system cause spark plugs to wear out?

A low-pressure fuel system will destroy the spark plugs that ignite the fuel in an engine’s cylinder. If by chance you are replacing them and you find they are worn out before their time, you might be looking at a problem with your fuel system.

What kind of pump does a Duramax cp4.2 use?

Like all Duramax engines from ’01-’10, the LML was also void of a lift pump from the factory. This means that not only does the CP4.2 have to pressurize fuel as high as 29,000 psi before sending it to the rails, but it also has to pull its low pressure fuel from the tank.

What causes the injector on a Duramax to fail?

The two primary failure points of the factory injectors are internal cracking of the injector body itself and corrosion-induced failure of the internal ball seat. The solenoid style Bosch units found in the LB7 employed a non-hardened internal ball seat to seal the injector.

How can I Keep my Duramax Diesel pump healthy?

However, there are measures you can take to keep the pump happy and healthy, the first being to always buy your diesel from a high-traffic, reputable filling station that’s known to dispense good, clean fuel. Second, always change the fuel filter at or before the recommended service interval.

What does check engine light on fuel rail sensor mean?

Check Engine Light comes on The fuel rail sensor, commonly referred to as the fuel pressure sensor, is an engine management component that is commonly found on diesel, and some gasoline injected vehicles. It is a part of vehicle’s fuel system and designed to monitor the fuel pressure that is present at the fuel rail.

What to do if your fuel tank is low?

Run the fuel level down as much as possible, then the tank will have to be dropped. The fuel sending/pickup unit will then need to be pulled out. Inspect the unit as well as the fuel tank and remove the offending particles or repair the separated pickup tube.

Why does my GMC Truck have a low coolant light?

The truck now has about 35,000km on it and the low coolant message is appearing at almost every start up. The tank is not low but I topped it off right to the cap and the message still pops up. I stopped by the dealership and they said this is common as the sensor is in the surge tank and the fix is to replace the surge tank to the tune of $600.

Can a PCM turn off a low coolant light?

Yes. If the light goes out then the switch is bad. If not then you could possibly have an open wire and the pcm isn’t seeing that the switch is closed thus keeping the light on. A multi-meter can tell you if a wire is open. Yes.

What to do if your coolant level is low?

Try the paperclip first to rule that out. You’ll need to find the wires at the PCM that come from the switch. Then with a multi-meter set on ohms you put one lead on the wire at the PCM and the other lead on the wire at the switch.

When did the coolant message come on on my Silverado?

Bought my 2017 GMC denali 2500 HD 6.6L on 5/6/17 and that night the coolant message came on….Brought the truck back the next day, service writer opened the coolant cap which turned off the message for two days and they/he didn’t “see” the message on the dash or in the scan tool history.

What are the most common LMM Duramax engine problems?

1 DPF system & active regeneration 2 Leaking transmission lines 3 Fueling / low fuel pressure 4 Piston / crankshaft failure 5 Allison 1000 power limitation

Why is my Duramax 6.6L engine not working?

Overtime, both of these parts are prone to normal wear and tear which can reduce fuel rail pressure. Injectors can get clogged or the fuel pump can simply weaken. As mentioned, this is most common when its hot and when towing heavy which requires the engine to work harder and therefore more fuel to be used.

Why does my Duramax 6600 have no oil pressure?

IF NO METAL, Brent wants to put on a Certified AC DELCO filter with the anti bleed off valve. This filter was designed for the well known issue on some motors which had the leak back issue of losing oil in the filter causing priming issues like what I have now.

1 DPF system & active regeneration 2 Leaking transmission lines 3 Fueling / low fuel pressure 4 Piston / crankshaft failure 5 Allison 1000 power limitation

What happens if your Chevy Silverado has low oil pressure?

May 27, 2019 by Jason One of the most serious issues that can happen to your Chevy Silverado ‘s engine is if it ends up with low oil pressure. Low oil pressure will cause the engine to seize up. When the oil pressure light on, it should be assumed that the engine locking up is imminent.

Can a low oil pressure cause engine to seize up?

Low oil pressure will cause the engine to seize up. When the oil pressure light on, it should be assumed that the engine locking up is imminent. We advise not running the engine until the issue can be properly diagnosed. There are many things that can cause low oil pressure. Below, we’ll review the most common causes:

Why does the P1093 code keep coming up?

Made it out of the drriveway and engine lost all power and I couldnt go faster than about 23 mph. Changed tunes to 1 Simon send ahile back (I have used before) and towed about 200 miles at about 5mpg (yeahh). For some reason I can not get this code to go away now and stay away. 3 diff tunes with the same result.

Is there a problem with the LLY P1093?

The P1093 is the oldest of the LLY performance problems, and we know shimming/race-valve fixes 99% of trucks with this problem. My racing tunes won’t “limp”, but that does not stop the valve from dumping rail pressure.

What are the P1093 codes for Duramax trucks?

9,659 satisfied customers 2005 chevy: duramax cranks but wont start,checked fuel filter 2005 chevy 2500 duramax cranks but wont start,checked fuel filter by opening bleeder on top as soon as i pushed prime ball,fuel squited out.truck dont even try to start. Codes p0700,p1093… read more jmbenedict02 22 satisfied customers

What are the error codes on my Duramax truck?

Codes p0700,p1093… read more jmbenedict02 22 satisfied customers have two error codes on my truck – chev duramax 6.6L p0203..rev have two error codes on my truck – chev duramax 6.6L P0203 and P1262 – anyplace to find what these codes mean? and is it just the truck going into safe mode – will not go out of @nd gear, and when I s…

Why is my Duramax fuel rail pressure so low?