Heater low temperature, lack of power, connected?

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Russell Marlow

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Surrey
I posted yesterday about low heater temperature but re post having learnt more in the hope a TD5 expert can help!

I have previously been trying to sort out a lack of ooomph! up hills it is gutless and I suspect top end though it is not pushed fast on the whole. It does seem over 70 is just runs out of steam if I try it and I know over 16 yrs we had it she will if pushed carry on way past that.

I have recently noticed the heater is only warm...not nice and hot, of course it may have been this way for some time and not noticed until cooler weather!

I am sure the heater is fine, no airlocks etc...it gets warmish.

Today I drove with hawkeye on and the coolant did not get over 81 degrees assuming the car sender is correct. All hoses in the car were no more than 50 ish degrees. Both heater hoses similar temperature.

I now wonder if the power loss and cool running (though gauge is midway) are connected? Thermostat??

I believe it has a bypass valve which if faulty can cause strange issues.
 
Russell Marlow said:
I now wonder if the power loss and cool running (though gauge is midway) are connected? Thermostat??
Click to expand...
It's the other way around... with low coolant temp and fuel temp input it should be more "nervous" than at normal operating temp.... see the fuel temp live input, at around 80*C coolant temp it shoudl be at least 10 dergrees lower...if the FT input is high the ECU is reducing the fuelling which is the same for high coolant temp too when the gauge goes to the red one which is not the case here
 
I think I understand that thanks....so I need to look at fuel temperature too? Are there any things I could look at for its gutless performance?
Turbo boost seems fine.
Coolant temp is low 80 degrees so thermostat to do.
Not had EGR for many years.
Only fault I pick up is EGR of course and for years high manifold pressure I cant fathom out but it always drove fine like that.
No other obvious issues though I am not knowledgable enough to know what readings some live data should give.
I love the old truck.....but really need to sort it.
 

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I will do thanks...may be a while, have a funeral to deal with. It always drove fine even with the high pressure reading which without the Hawkeye would have been unknown. Thanks again.
 
sierrafery said:
Then read all live inputs at idle and the manifold pressure under load and post here the results
Click to expand...
Hi, just picking up on this now. The distractions are sorted and I had a few other jobs to do before getting to the gutless performance. Thermostat done and it warms up now and maintains temperature BUT the heater is still only mlldly warm on full heat....it used to burn skin off in the past! Front propshaft repaired too.
I will get onto the readings with Hawkeye soon now and come back with results.....it remains gutless but seemingly turbo boost fine.
 
I have been lazy on the gutless truck with other family cars etc to sort...but it potters around. Yesterday I got to it proper using on a longer run and playing with Hawkeye along the way. I was alone so not easy.
Using the list kindly provided.
MAF seems good. A little high at idle 65-70 but seems to be fine up to maximum throttle/load.

Ambient Pressure AAP seems good, maybe 101 dropping to 98/99 as revs build.

Inlet Air Temp.....high, 30 plus rising to 42 grinding slowly due to lack of power up long motorway hill.

Coolant Temp spot on in range having done thermostat.

Fuel Temp yes acceptably less than coolant temp.

I am not sure about the Hawkeye pressure readings, it has two more. on the tool. One reads about 230 at idloe or coasting and immediatly exactly 100 if the throttle is touched at all.

Also throttle pedal readings. assuming these are Driver demand on hawkeye.
1 is 0.53v to 3.76v
2 is 4.52v to 1.28v
3 is static at5 and bit V but not sure its for my car??
So these are bit off the range given on the list kindly provided.

The truck for many years has code for high manifold pressure after every drive, a new sensor did not cure it BUT it has always driven fine. The loss of power was relatively sudden. In context it is smooth, chugs around, does not smoke or burn oil, had super clean mot fast pass.

Power under load is shocking, 70mph is hard work give it a long motorway incline and it can grind down to 50 max 4th gear!

I can push the accelerator up and down and nothing happens not even a change in note.

Sorry its a long post!
 
Last edited:
So there are 4 pressure readings on Hawkeye. The pressure high fault code again was present as it has been for many years to no ill affect. It has EGR delete too by the way so always get EGR fault code haha!

Just read these on the drive running but no load....seemed similar driving.
Ambient Pressure 96.7kpa
Ambient Pressure Raw 97.2

Manifold Pressure 220 idling drops using throttle to exactly 100.0 as it did driving, 220-230 coasting down hill, dropping back to exactly 100 throttle depressed.
Manifold Pressure Raw 221.7 at idle but this one seems to climb a bit building revs off load to 247.
 
Russell Marlow said:
Manifold Pressure 220 idling drops using throttle to exactly 100.0 as it did driving, 220-230 coasting down hill, dropping back to exactly 100 throttle depressed.
Manifold Pressure Raw 221.7 at idle but this one seems to climb a bit building revs off load to 247.
Click to expand...
So that's definitely a big problem, now unplug the MAP sensor and read that way, eventually drive test it with sensor unplugged.... as you replaced the sensor seems that it's a wiring issue on that path or the ECU has a fault
 
sierrafery said:
So that's definitely a big problem, now unplug the MAP sensor and read that way, eventually drive test it with sensor unplugged.... as you replaced the sensor seems that it's a wiring issue on that path or the ECU has a fault
Click to expand...
thanks, ok I shall do that over coming days and report back. As I said the fault codes have for many years said the manifold pressure has been high but it drove just fine.
 
Russell Marlow said:
thanks, ok I shall do that over coming days and report back. As I said the fault codes have for many years said the manifold pressure has been high but it drove just fine.
Click to expand...
Maybe things got worst in time cos based on the actual MAP reading it's obvious that it instantly goes to overboost so the lack of power is normal for that default
 
Hi, done a bit more then...its so frustrating. Real tidy truck but just cant get to bottom of this issue.

First....two faults showing now. Inlet temperature high.
Manifold pressure high.
Once it showed turbo has overboosted...but not after a few more drives.

Readings with the MAP sensor disconnected.
Absolute pressure 101ish
Absolute pressure raw 102ish
Manifold pressure 100 dead
Manifold pressure raw 653.7 to 654.0

Drives no better disconnected, but fault code changes to air inlet temp hi and manifold pressure low rather than high when its connected.

Reconnect and back as I previously posted in terms of fault codes and readings

The inlet air temperature is stuck on 120 degrees so thats wrong!

I agree it does drive like it has overboost limp mode but it does not show an overboost fault......I recall adjusting the wastegate after work years ago to a little under where it overboosted and went into the limp!

to add to my frustration it threw that wierd little recangular sign in the lcd today with no indicators etc!
 
Russell Marlow said:
The inlet air temperature is stuck on 120 degrees so thats wrong!
Click to expand...
That's classic IAT signal(part of MAP) failure code... if you are 100% certain that the MAP/IAT sensor is good i must insist that it's a wiring issue on that circuit or the ECU has an internal fault... check if the red plug is free of oil and well connected
 
sierrafery said:
That's classic IAT signal(part of MAP) failure code... if you are 100% certain that the MAP/IAT sensor is good i must insist that it's a wiring issue on that circuit or the ECU has an internal fault... check if the red plug is free of oil and well connected
Click to expand...
ok, I changed the harness before but having owned it 17 years that was likely an age ago! I will go back to the ECU and big plug by the battery and start again there. The MAP sensor was replaced when this issue started and nothing changed.

Is there any guidance as to the loom/checking wiring?

Should I open up the ECU if oil is found on plug to see iniside?
 
If oil got inside the ECU it could have made damage which you can't repair only swappig the ECU with known good one can rule it out... on such old vehicle the only 100% certain way to fix an intermittent wiring issues is to replace the whole engine harness with a new one or at least rewire the MAP/IAT circuit from plug to ECU if you are skilled enough to do that
 
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