p38 diesel poor running between 600rpm - 1000 rpm

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roddy4

New Member
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664
Location
banbury,oxfordshire
after this speed fine real headache but have changed fuel filter to original,air filter,changed oil and filter,it is in tomorrow (tuesday) being hooked up to an oscilloscope and then driven around with a laptop to see what is going on,it is going to be at best a sensor,at worst it will be the injection pump, or maybe no.4 injector with the wire on.
will let you know.

it is a 1995 model maybe airflow meter? if it has one
 
after this speed fine real headache but have changed fuel filter to original,air filter,changed oil and filter,it is in tomorrow (tuesday) being hooked up to an oscilloscope and then driven around with a laptop to see what is going on,it is going to be at best a sensor,at worst it will be the injection pump, or maybe no.4 injector with the wire on.
will let you know.

it is a 1995 model maybe airflow meter? if it has one


95 pre EGR no airflow meter. Just air temp sensor under front of manifold.
It should not be running at 600 rpm it should be ticking over at 750 rpm. Have you had the top of the pump off?
 
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95 pre EGR no airflow meter. Just air temp sensor under front of manifold.
It should not be running at 600 rpm it should be ticking over at 750 rpm. Have you had the top of the pump off?
no haven't touched any part of the pump at all.don't understand it so left well alone.
 
no haven't touched any part of the pump at all.don't understand it so left well alone.

Sliding the pump top backwards or forwards sets the fuel quantity servo to it's initial setting when the pump is calibrated. If it has been undone and has moved that could be the reason the tickover is low. If it is that is, but you did mention 600 RPM and that is too low. Unless the pump is totally cacked, but if it runs ok at all other speeds that will not be the case. Number four injector measures start of injection for timing advance servo to change start of injection at higher engine speeds.
 
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Sliding the pump top backwards or forwards sets the fuel quantity servo to it's initial setting when the pump is calibrated. If it has been undone and has moved that could be the reason the tickover is low. If it is that is, but you did mention 600 RPM and that is too low. Unless the pump is totally cacked, but if it runs ok at all other speeds that will not be the case. Number four injector measures start of injection for timing advance servo to change start of injection at higher engine speeds.

it looks as though it could be a sensor?
 
the story so far,it has been semi diagnosed,it has 16v at ecu,temp sensor on engine says -30 even when warm,going to eh douglas (tomorrow) and they have a full diagnostic system,and will tell me what is going on,my thoughts are still on injection pump,or if i am extremely lucky a sensor,the hot start is pants at the mo.but maybe thinking it is -30 could be a factor.
alternator could be chucking out too many volts.
 
Number four injector measures start of injection for timing advance servo to change start of injection at higher engine speeds.

Sorry to hijack this thread but Wammers could you elaborate on the above please
 
Sorry to hijack this thread but Wammers could you elaborate on the above please

Not really a lot to elaborate on. Needle sensor in number four injector detects start of injection. Signal from that tells ECU together with signal from crank position sensor, to adjust timing solenoid to change cam angle, to set timing to a nominal setting for engine speed at the time.
 
I will try to explain how I see the system working.....(and I could be very wrong - which wouldn't be a surprise...)

The Crank Position Sensor (CPS) picks up a signal from the flywheel(?) which has a number of sensing positions on it at various different angles.

The Injector 4 Needle Lift Sensor, indicates when the N0. 4 injector is squirting....

The ECU measures the crank Position depending on when it last recieved a pulse from the Flywheel so it knows where abouts on the piston movement it is....it then calculates the time it opened No.4 to when it closed No.4 to where the crankshaft is...

When the engine speed increases, it needs to inject the fuel a little bit earlier in the cycle to ensure it is fully atomised, swirled and burnt before the piston gets to Top Dead Centre (TDC).

In order to do this, it measures how fast the engine is turning according to the CPS, then it opens the injector a fraction earlier to ensure a good burn. it then monitors the No.4 injector to ensure it is starting the injection cycle at the right time based on CPS signals recieved.

The timing of the injection sequence is conducted by movement of the FIP to either advance of retard the timing of the fuel squirts.

It then measures the CPS signals to ensure constant fuelling is maintained for the engine speed by ensuring the No.4 start of sequence is correct....when the engine slows down again, the CPS calculation instructs the FIP to retard the timing to prevent the fuel being injected to late in the cycle and causing unburnt fuel to be ejected through the exhaust. Again No.4 injector is used to measure when in the crankshaft cycle the fuel is being injected and adjustments are made accordingly.

Clear as a glass of Thames Water....
 
I will try to explain how I see the system working.....(and I could be very wrong - which wouldn't be a surprise...)

The Crank Position Sensor (CPS) picks up a signal from the flywheel(?) which has a number of sensing positions on it at various different angles.

The Injector 4 Needle Lift Sensor, indicates when the N0. 4 injector is squirting....

The ECU measures the crank Position depending on when it last recieved a pulse from the Flywheel so it knows where abouts on the piston movement it is....it then calculates the time it opened No.4 to when it closed No.4 to where the crankshaft is...

When the engine speed increases, it needs to inject the fuel a little bit earlier in the cycle to ensure it is fully atomised, swirled and burnt before the piston gets to Top Dead Centre (TDC).

In order to do this, it measures how fast the engine is turning according to the CPS, then it opens the injector a fraction earlier to ensure a good burn. it then monitors the No.4 injector to ensure it is starting the injection cycle at the right time based on CPS signals recieved.

The timing of the injection sequence is conducted by movement of the FIP to either advance of retard the timing of the fuel squirts.

It then measures the CPS signals to ensure constant fuelling is maintained for the engine speed by ensuring the No.4 start of sequence is correct....when the engine slows down again, the CPS calculation instructs the FIP to retard the timing to prevent the fuel being injected to late in the cycle and causing unburnt fuel to be ejected through the exhaust. Again No.4 injector is used to measure when in the crankshaft cycle the fuel is being injected and adjustments are made accordingly.

Clear as a glass of Thames Water....

Mine was the expergated version. Can tell you write drawing notifications. Turn tap to left, water flows, turn tap to right, water stops. Bet you could do a few paragraphs on that one. :):):)
 
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1). Scale with Caution as Distortion can occur

2). All Contractors and their clients must ensure compliance with all local legislature in place at the time the works commence.

3). All permits must be in place priror to any works starting.

4). The Contractor must be in receipt of the Site Induction information and have a copy of the site emergency proceudures to hand at all times whilst on site.

5). This Landyzone Forum Reply is for information only and the Author nor the Company will be held to account for any works based solely upon this Reply. All other replies must be consulted and the most recent revision to be checked prior to any works commencing.

6). Any site specific H&S regulations will be provided during Site Induction.

7). Instructions for Use:

a. Water is suuplied to Tap outlet at mains pressure +/- 0.4bar
b. At all times Tap is to be maintained in the Closed Position to prevent further wastage.
c. To provide Water at a constant flow first ensure sink and plug hole are clean and clear of all debris and pubic hair remenants.
d. If it is required for the sink to be filled, ensure plug is inserted squarely into the plug hole first.
e. Ensure all PPE is in place prior to Tap operation.
f. Slowly turn Tap anti-clockwise, to permit water to flow, beaware of any splashes that will effect the front of the trouser area, as this may result in ridicule and much micky taking.
g. Monitor Tap outflow to ensure clean and clear water is delivered.
h. If the sink is being filled, constant check on water level is to maintained at all times.
i. In order to cease water flow, it is necessary to turn the Tap in a clockwise direction until such time that resistance is felt against the sealing 'O' Ring and water flow has ceased. (some minor dripping can be expected at this point)
j. Monitor facet outlet for un-expected drippage, should this continue for longer than the permitted tolerance of drips (usually in the 5-6 range) Tap seal may be comprimised. Further assitance maybe needed if this is the case.
k. In Order to empty sink, first ensure all interconnecting pipework for the drain is secure and inplace with no visible defects.
l. Slowly pull plug from plug hole, ensure reasonable force is used to overcome water pressure, but ensure care is taken as over exertion could result in the embarrasing trouser frontage splashes once again.
m. Ensure all water is drained from sink within the permitted time frame, any slowing of water flow could indicate a blockage, which will require further investigation.
n. Ensure toilet seat is down at all times and turn off bathroom lights on exiting the facility.
 
1). Scale with Caution as Distortion can occur

2). All Contractors and their clients must ensure compliance with all local legislature in place at the time the works commence.

3). All permits must be in place priror to any works starting.

4). The Contractor must be in receipt of the Site Induction information and have a copy of the site emergency proceudures to hand at all times whilst on site.

5). This Landyzone Forum Reply is for information only and the Author nor the Company will be held to account for any works based solely upon this Reply. All other replies must be consulted and the most recent revision to be checked prior to any works commencing.

6). Any site specific H&S regulations will be provided during Site Induction.

7). Instructions for Use:

a. Water is suuplied to Tap outlet at mains pressure +/- 0.4bar
b. At all times Tap is to be maintained in the Closed Position to prevent further wastage.
c. To provide Water at a constant flow first ensure sink and plug hole are clean and clear of all debris and pubic hair remenants.
d. If it is required for the sink to be filled, ensure plug is inserted squarely into the plug hole first.
e. Ensure all PPE is in place prior to Tap operation.
f. Slowly turn Tap anti-clockwise, to permit water to flow, beaware of any splashes that will effect the front of the trouser area, as this may result in ridicule and much micky taking.
g. Monitor Tap outflow to ensure clean and clear water is delivered.
h. If the sink is being filled, constant check on water level is to maintained at all times.
i. In order to cease water flow, it is necessary to turn the Tap in a clockwise direction until such time that resistance is felt against the sealing 'O' Ring and water flow has ceased. (some minor dripping can be expected at this point)
j. Monitor facet outlet for un-expected drippage, should this continue for longer than the permitted tolerance of drips (usually in the 5-6 range) Tap seal may be comprimised. Further assitance maybe needed if this is the case.
k. In Order to empty sink, first ensure all interconnecting pipework for the drain is secure and inplace with no visible defects.
l. Slowly pull plug from plug hole, ensure reasonable force is used to overcome water pressure, but ensure care is taken as over exertion could result in the embarrasing trouser frontage splashes once again.
m. Ensure all water is drained from sink within the permitted time frame, any slowing of water flow could indicate a blockage, which will require further investigation.
n. Ensure toilet seat is down at all times and turn off bathroom lights on exiting the facility.

:hysterically_laughi:hysterically_laughi Absolute class.
 
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ok so it has been on diagnostic,no fault found,only a fault with cruise control which it does not have,so no further forward, ffs,apart from being financially raped by the stealer,
i am going to give up driving!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
 
1). Scale with Caution as Distortion can occur

2). All Contractors and their clients must ensure compliance with all local legislature in place at the time the works commence.

3). All permits must be in place priror to any works starting.

4). The Contractor must be in receipt of the Site Induction information and have a copy of the site emergency proceudures to hand at all times whilst on site.

5). This Landyzone Forum Reply is for information only and the Author nor the Company will be held to account for any works based solely upon this Reply. All other replies must be consulted and the most recent revision to be checked prior to any works commencing.

6). Any site specific H&S regulations will be provided during Site Induction.

7). Instructions for Use:

a. Water is suuplied to Tap outlet at mains pressure +/- 0.4bar
b. At all times Tap is to be maintained in the Closed Position to prevent further wastage.
c. To provide Water at a constant flow first ensure sink and plug hole are clean and clear of all debris and pubic hair remenants.
d. If it is required for the sink to be filled, ensure plug is inserted squarely into the plug hole first.
e. Ensure all PPE is in place prior to Tap operation.
f. Slowly turn Tap anti-clockwise, to permit water to flow, beaware of any splashes that will effect the front of the trouser area, as this may result in ridicule and much micky taking.
g. Monitor Tap outflow to ensure clean and clear water is delivered.
h. If the sink is being filled, constant check on water level is to maintained at all times.
i. In order to cease water flow, it is necessary to turn the Tap in a clockwise direction until such time that resistance is felt against the sealing 'O' Ring and water flow has ceased. (some minor dripping can be expected at this point)
j. Monitor facet outlet for un-expected drippage, should this continue for longer than the permitted tolerance of drips (usually in the 5-6 range) Tap seal may be comprimised. Further assitance maybe needed if this is the case.
k. In Order to empty sink, first ensure all interconnecting pipework for the drain is secure and inplace with no visible defects.
l. Slowly pull plug from plug hole, ensure reasonable force is used to overcome water pressure, but ensure care is taken as over exertion could result in the embarrasing trouser frontage splashes once again.
m. Ensure all water is drained from sink within the permitted time frame, any slowing of water flow could indicate a blockage, which will require further investigation.
n. Ensure toilet seat is down at all times and turn off bathroom lights on exiting the facility.

You obviously spend alot of time compiling method/risk assessments and I liked your elaboration on my initial question.
So to follow on if cps or injector 4 aren't communicating quick enough (i.e you stamp on gas or kickdown) and the ecu isn't getting the correct information,is it possible the ecu would restrict the correct fuel amount to a lower level because it wouldn't know what to do (i.e a safe default mode ) and when engine is back to lower rev range it would self rectify.
 
In theory, your statement is correct....the system does have a default 'safe' mode if it thinks the readings from the CPS and N0.4 injector don't seem to match any of the fuel maps it has.

This usually only happens if the CPS or the No.4 injector aren't delivering correct information to the ECM (there are many other sensers in the system too BTW..but these two are the main culprits for crap running problems)

I don't write RA's or Method Statements, although I do work closely with those that do, my role is a Design Engineer....part of my job is to also write the technical documents to accompany the parts/components I am involved in, also penning the Maintenance, service, repair and testing documents too....
 
ok so it has been on diagnostic,no fault found,only a fault with cruise control which it does not have,so no further forward, ffs,apart from being financially raped by the stealer,
i am going to give up driving!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

So when on diagnostic machine did the values for the CPS and injector 4 match the general setting for engine idling
 
In theory, your statement is correct....the system does have a default 'safe' mode if it thinks the readings from the CPS and N0.4 injector don't seem to match any of the fuel maps it has.

This usually only happens if the CPS or the No.4 injector aren't delivering correct information to the ECM (there are many other sensers in the system too BTW..but these two are the main culprits for crap running problems)


Cheers Saint, its given me a better insight into a intermittent problem i'm having :)
 
give up with the bag of **** now,just use and abuse it til it goes no more,if the fault does not show up,points to mechanical? can't be arsed with it now,cost £2000 so far that is it for now,could of bought a toyota surf,saving pennies now for a different 4x4.
if the guys with the equipment cannot find it what chance have i got,i take it the diesels run like like a bag of **** on the overrun.
 
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