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Andy
Andy, Technician
Category: Heavy Equipment
Satisfied Customers: 857
Experience:  310s and 310t technician licenses, 17 yrs experience, International Diamond Certified Tech 7 yrs
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We have a 1995 International School Bus DT466 engine. How do

Customer Question

We have a 1995 International School Bus DT466 engine. How do I check the fuel pressure on this and what are the specs on how much pressure the system should have?
Submitted: 4 years ago.
Category: Heavy Equipment
Expert:  Andy replied 4 years ago.

Hi there! My name is XXXXX XXXXX I think I can help you resolve your problem!

 

11. FUEL PUMP PRESSURE

 

 

 

Measure at bleeder valve on filter header

 

 

 

 

Minimum 150 RPM cranking speed for 20 seconds.

 

 

 

 

Instrument

Spec.

Actual

 

 

 

 

0-160 PSI

20 PSI

 

 

 

 

 

Gauge

minimum

 

 

 

 

 

 

 

 

 

 

 

 

? If pressure is low, replace fuel filter, clean fuel strainer and retest.

 

 



Edited by Andy3221 on 5/4/2010 at 6:12 PM EST
Expert:  Andy replied 4 years ago.

also 20 psi minimum at high idle . If you need anything else , don't hesitate to ask ! I'll be in and out if you need me!

Customer: replied 4 years ago.
Thanks Andy,
Our mechanic left early for the day. I printed out your answer for him, he will see it tomorrow morning. Will keep you posted.
Expert:  Andy replied 4 years ago.
Ok thanks
Customer: replied 4 years ago.
hi - mechanic here. i just checked the fuel pressure at the outlet from the lifter pump, the needle was bouncing between 28 - 30 psi . my question is - is that the amount of pressure that goes into the engine or is there another pump that increases the pressure ? if there is, how do I check that pressure ? if there is not what else can be my problem with no power. i checked my exhaust and intake for restriction and the turbo is sucking fine. i just have no power to go uphill. its a school bus 1995 dt466 international.

Another thing to note, when being started when cold, the engine idles rough and white smoke is emitted until engine warms up.
Thanks
Moses.
Expert:  Andy replied 4 years ago.
Have you tried measuring fuel pressure at full load ? Leave gauge connected and road test and make engine work hard and see if fuel pressure remains above min of 20 psi. while also checking boost. Should be able to develop minimum 20 psi and up to 30 psi

Also should check fuel lines from tank to make sure nothing is kinked that could cause excess restriction before lift pump. Should not have more than 8 " hg. If there is more , check k for blockage between pump and fuel tank.

Did you clean the strainer and replace the filter ?

Also , is the fuel clear ? no air bubbles ?

For the intake restriction, should be measured after the air filter at full rpm , no load . You should not have more than 12" H2O

You can also check the turbo actuator for proper operation and also for leakage. Here is how:

1. Remove actuator boost line from turbo compressor housing.

2. Connect an air regulator with a 0-60 PSI gauge to the actuator boost line. Figure 2.42

3. Mark actuator shaft with paint pen. Spray leak detector or soap solution around the actuator housing

4. Spray leak detector around the actuator housing and slowly apply air pressure to the actuator. Actuator (shaft) movement (indicated by position of paint mark) should begin to occur between 28-30 psi.

If a significant amount of actuator shaft movement occurs and no air leaks are detected at actuator housing, actuator is OK. If little or no shaft movement occurs or air leaks are present at the actuator housing, the turbocharger must be removed from the engine. You may be able to replace just the actuator alone if it is leaking air .

 

 

 

 

Andy, Technician
Category: Heavy Equipment
Satisfied Customers: 857
Experience: 310s and 310t technician licenses, 17 yrs experience, International Diamond Certified Tech 7 yrs
Andy and 3 other Heavy Equipment Specialists are ready to help you
Customer: replied 4 years ago.
Hi, Moses my mechanic has some more questions for you. (He has been busy with other buses - hence the delay).
I will quote what you write and pose his question
You: "Have you tried measuring fuel pressure at full load ? Leave gauge connected and road test and make engine work hard and see if fuel pressure remains above min of 20 psi. while also checking boost. Should be able to develop minimum 20 psi and up to 30 psi"

Moses: Yes it is above 20 psi - although I don't know what you mean by checking boost. How is that done?

You: "Did you clean the strainer and replace the filter ? Also , is the fuel clear ? no air bubbles ? For the intake restriction, should be measured after the air filter at full rpm , no load . You should not have more than 12" H2O"

Moses: Yes, the strainer the filter the fuel all look OK. Yet the bus has almost ZERO power going uphill. There's also the white smoke that is being emitted all the time now. When i take a sniff at the tailpipe it seems to me that the fuel is not getting burnt properly.

If possible, can you call Moses direct? His cellphone # XXXXX XXXXX maybe he can call you? I don't know how this would work with JustAnswer's policies as I am new here. We will give you a bonus once this thing gets resolved.


Expert:  Andy replied 4 years ago.

I am sorry but phone calls or e-mails are not allowed according to just answer's policies but we can continue this way . Just have to catch each other at the right time of day to keep going with diagnose

 

Expert:  Andy replied 4 years ago.
Can I have the last 8 digits of the vin please ?

Edited by Andy3221 on 5/11/2010 at 9:31 PM EST
Expert:  Andy replied 4 years ago.

Fuel pressure must remain above 20 psi minimum ,in all conditions -whether at idle no load, high idle no load and high idle full load .

 

If fuel pressure is good in all conditions, then we proceed to check boost pressure :

 

1. Remove plug from boost pipe, install adapter fitting and connect a line as shown in Figure 2.40 . If no plug is provided on boost pipe, remove hose which supplies manifold boost pressure to Manifold Absolute Pressure sensor at intake manifold/valve cover. Install a tee fitting and connect the removed hose from MAP sensor and the test line to fitting.

NOTE: MAP sensor must be connected during boost pressure test.

2. Route the line so it is not crimped or in contact with a hot engine surface inside the cab of the vehicle.

 

Figure 2.40 Boost Pressure Tap Location

 

3. Temporarily install a 0-30 psi gauge to the line routed from the boost pipe or tee at MAP sensor line to the appropriate pressure gauge.

4. Drive vehicle on road till engine reaches operating temperature. Find an open section of road and select a suitable gear. Depress the accelerator pedal (full depression) to the floor and accelerate to rated speed and 100% load.

NOTE: If boost pressure is within specifications, the engine is functioning properly. There may be chassis or application concerns.

5. Record intake manifold boost at full load rated engine speed

 

Should be able to develop at least 20 psi at full load.

 

Let me know how it works out !

 

 

 

Also would like to know if you have a warn engine light on ?(active faults)



Edited by Andy3221 on 5/11/2010 at 9:52 PM EST
Customer: replied 4 years ago.
Hello
Last 8 of VIN: SH681283

Note this is an older vehicle ('95) so doesn't have turbo actuator
Customer: replied 4 years ago.
By the way Andy, the link to Figure 2.40 gets me to a Navistar page that requires a login. and the picture you provide (view full image) is not being shown (although this maybe my host's internet filter which is in a very strict mode)
Customer: replied 4 years ago.
No warning lights on.
Expert:  Andy replied 4 years ago.

 

 

Just was wondering if you had a warn engine light or not . Thanks!

Here is the picture of the port if you have it . If not , you can tee off the map sensor to check boost .

Also , any exhaust leaks before the turbo will definitely affect the amount of boost developed by the turbo. Also any leaks in the piping after the turbo, going through the charge air cooler , and then into the engine should be repaired too (loose clamps, rubbed out hoses, cracked pipes or damaged charge air cooler ).You can use a soapy water solution in a spray bottle to spray everything down and check for leaks with engine reving at about 1500 rpm so that turbo is spinning and creating some boost to make leaks bubble up .

 

Also should check wastegate actuator . Here's how:

 

 

12. WASTEGATE ACTUATOR TEST

 

 

 

Apply regulated air to actuator

 

 

 

 

Inspect for leakage

 

 

 

 

Inspect actuator for movement

 

 

 

 

Instrument

Spec.

Actual

 

 

 

 

0 - 60 PSI

Gauge

28 - 30

PSI

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

PURPOSE

To determine operation of actuator in conjunction with turbocharger operation.

TEST PROCEDURE

1. Remove actuator boost line from turbo compressor housing.

2. Connect an air regulator with a 0-60 PSI gauge to the actuator boost line. Figure 2.42

3. Mark actuator shaft with paint pen. Spray leak detector or soap solution around the actuator housing

4. Spray leak detector around the actuator housing and slowly apply air pressure to the actuator. Actuator (shaft) movement (indicated by position of paint mark) should begin to occur between 28-30 psi.

If a significant amount of actuator shaft movement occurs and no air leaks are detected at actuator housing, actuator is OK. If little or no shaft movement occurs or air leaks are present at the actuator housing, the turbocharger must be removed from engine. Refer to engine service manual for further wastegate diagnosis.

Figure 2.42 Wastegate Actuator Test

 

let me know if you need anything else!

Customer: replied 4 years ago.
Andy! You already posted how to check the actuator last week and yesterday again.
PLEASE READ THROUGH OUR WHOLE REPLIES NOT JUST THE LAST LINE OF IT!
THIS IS NOT AN ELECTRONIC ENGINE!!!!!
(We already stated that above) so this vehicle does not have a turbocharger, Actuator nor any Engine Warning Lights!!!
Also please guide us in the right direction as to the white smoke.
Thank you
Customer: replied 4 years ago.
I tapped into the boost pressure line and the gauge reading was as follows:
at full idle at 3000 RPM I had about 8 PSI. When I tried to go uphill my RPM wouldn't go above 1500 RPM and my boost pressure was at zero.
Expert:  Andy replied 4 years ago.

Sorry about that , I must have gotten mixed up with another question I was working on with another customer!

 

Did we check the ECM and Injector driver module power cables yet ? These are smaller gauge wires that leave the batteries and run all the way to the Ecm just above the starter. The inline fuse holders in battery box are marked : ecm and idm. We need to check there to see if the terminals are melted from not enough tension on the fuse . This causes resistance and then heat and eventually , lack or loss of power to ecm and idm. Let's make sure that is all good there and do a good visual of the wires going to the ecm for any rubout , corrosion or fraying. There is a connector above the starter that should be tug tested to make sure there is no corrosion there . The most common is the inline fuse holders in the battery box though . They are notorious for causing low power problems. Engine could still start fine but with problems like we are seeing.

 

Also , we need to try and check injection control pressure(ICP).

 

The system utilizes hydraulically actuated electronically controlled injectors to deliver fuel to each injector. The hydraulic fluid used to actuate the injectors is engine oil.

Oil is drawn from the oil pan thru the pickup tube by the engine oil pump. The engine oil pump is a gerotor type pump driven by the crankshaft. Oil is fed through passages in the front cover to an oil reservoir located in the front cover.

The reservoir makes available a constant supply of oil to a high pressure hydraulic pump mounted to the front cover. The high pressure pump is a gear driven swash plate pump. High pressure oil is delivered by the high pressure pump to the high pressure oil supply manifold and into oil passages machined into the cylinder head.

When an injector is energized, a poppet valve is opened by an electronic solenoid mounted on the injector. Oil pressure is allowed to flow into the injector and act on the amplifier piston. When injection is ended, the oil pressure on top of the amplifier piston is vented by the poppet valve thru the top portion of the injector.

Pressure control in the Injection Control Pressure System is a closed loop. It is controlled by the IPR valve (Injection Pressure Regulator), the ICP sensor (Injection Control Pressure) and the strategy in the ECM (Electronic Control Module).

ICP pressure ranges from 3447.4 to 20684.2 kPa (500 to 3000 psi). The regulator valve is mounted in the high pressure pump and achieves injection control pressure regulation by dumping excess oil into the front cover and back to sump.

 

 

The injection control pressure system is a closed loop operating system. The system consists of the (ECM) Electronic Control Module, (ICP) Injection Control Pressure Sensor and the (IPR) Injection Pressure Regulator valve.

The ECM is programmed with an injection pressure control strategy which determines the correct injection control pressure at each engine operating condition. The ECM receives a 0-5 volt d.c. analog feedback signal from the ICP sensor located in the high pressure oil supply gallery on the left cylinder head that indicates Injection Control Pressure information. The ECM processes this signal and controls Injection Control Pressure by controlling the ground to the IPR regulating valve.

 

Now that you know a little about icp, let's try to disconnect the icp sensor and road test to see if it is any better with the sensor disconnected.The sensor is located on the left side of the engine #17 at the front or in the middle on the left side of engine like in the 2nd picture(#4 in that pic)

 

It is a 3-wire sensor.

 

 

 

Do this only after you've checked the supply power to ecm from the batteries . Let me know how it goes!

 

 



Edited by Andy3221 on 5/13/2010 at 2:14 AM EST
Customer: replied 4 years ago.
Andy
How can I make this any clearer...... THIS IS NOT AN ELECTRONIC ENGINE!!!!!!!!!!!!! NO COMPUTER ON BOARD HENCE NO ECM NO ICP OR ANY OTHER SENSORS!!!!!!!!!!

THIS BUS HAS A STRICTLY MECHANICAL ENGINE - YOU ALREADY ASKED FOR THE VIN
Expert:  Andy replied 4 years ago.
sorry but the vin doesn't tell me that! I will try and dig up some more info for you on that but there are various injection pumps that went on those engines back then. Is there any way youcan help narrow it down by looking on your injectionm pump to see what make it is or any info on a data plate?Sorry about the mixup!
Customer: replied 4 years ago.
OK here-goes. The manufacturer of the injection pump is BOSCH.
I will post the numbers and the spaces in between them exactly as I find them on the tag:

PES6P110A320L S3330

0 402 046 857

66300 04861
Expert:  Andy replied 4 years ago.
will try and send diagnostic forms that i found for that particular engine but trying to find specs
Customer: replied 4 years ago.
Any luck?
Expert:  Andy replied 4 years ago.
HERE IS THE DIAGNOSTIC SHEET THAT WE WOULD USETO HELP US TO DIAGNOSE THAT PARTICULAR ENGINE WITH A BOSCH PUMP! STILL LOOKING FOR SPECSgraphic
Expert:  Andy replied 4 years ago.
After digging through our manuals online, I can find performance specs for everything else but the bosch "P" style pump which is what you have . Are you certain there is no turbo at all mounted on the exhaust manifold? I am running out of luck on this one. All I've been able to find is specs on other types of bosch pumps on engines with turbo. Almost everyhthing I have worked on has either a turbo or a blower. Sorry about the delay but this is a very old unit and info seems limited on it .
Customer: replied 4 years ago.
This bus does have a turbo. I made a mistake on Wednesday when I wrote otherwise - sorry. It only doesn't have a turbo actuator but it definitely DOES have a turbocharger
Expert:  Andy replied 4 years ago.
Ok then , I'll give it another lookup but I am only finding bosch pumps of another style on those engines .I can't seem to find the bosch "p"style pump engine specifications.
Your engine develops 190 hp at 2300 for your info.So I have to find those specs.

Edited by Andy3221 on 5/17/2010 at 3:48 PM EST
Expert:  Andy replied 4 years ago.
We should do the turbo wastegate and turbo tests mentionned above to see what we come up with > I gather you could not hear the turbo whistling sound so it seems to be that your turbo needs to be inspected thoroughly for exhaust leaks and also need to pull piping off on intake side to inspect turbo fins for damage and see if turbo is spinning freely . Also should check all intake piping for rubout or loose clamps . Anything after the turbo, going through the air cooler and then into the engine has to be leak free or you will lose boost pressure going into the engine , and therefore , lose power and have unburnt fuel .
Customer: replied 4 years ago.
But when you mentioned "wastegate" above you always mentioned it together with "actuator" which this bus does not have.
Expert:  Andy replied 4 years ago.
If you LOOK under the turbo , you will see the small diaphragm type actuator mounted under the turbo . It has a small line that hooks up to the compressor side of the turbo .

Have you inspected the turbo fins yet ? Pull the piping off that comes from the air filter and goes to the turbo . Then inspect the fins inside to see if there is damage or fins rubbing against the walls . ALSO , SPIN THE FINS , the turbo should spin freely and not jamming up
Expert:  Andy replied 4 years ago.
Are you sure that the first 5 digits of that injection pump info is "PES6P"? I can't find that . I can only find "PES6A" or PES6MW"?
Expert:  Andy replied 4 years ago.
Please let me know how things go and what you find and I will try to continue to help as best as I can
Customer: replied 4 years ago.
We'll keep you posted! Mechanic took half a day off. Should be back later or tommorow
Expert:  Andy replied 4 years ago.
Ok hope to get this resolved soon !

Edited by Andy3221 on 5/17/2010 at 5:56 PM EST

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