HELP please!

[BatleyBoy]

I have a problem with strange pod readings.

The story is that I’ve fitted a replacement 4.0 speed six to my T350. All went ok with installation, but I am now getting strange pod readings. For example, yesterday the engine pod readings were reading ok to start with, then after about an hour the readings started look odd on tick over:

Water oC : 98
Oil T: 97
Oil P: 8 (dropping to 6) psi
Battery: 13.0v
Fuel: 28L
Air Temp: 34 oC


After another 10 mins they got worse, and importantly the water got to 108oC and the oil pressure dropped to 3 and the warning light flashed on. At this stage we checked the water temp with an infrared temp gauge. We measured the temp on the block close to the temp sensor. It read at 82oC on the temperature gauge (when the pod reading showed 108oC).

After the water temp reached 108 oC we left the car for 5 mins and then restarted the engine, and the readings were as follows on tick over:

Water oC : 79oC
Oil T: 74oC
Oil P: 14psi
Battery: 13.2v
Fuel: 28L
Air Temp: 28 oC

The car was only stood for 5 mins therefore I find it strange that the readings had dropped so much in such a short time.

As far as the oil pressure is concerned, the readings are all over the place. As I say it showed at 3 psi at one stage, but when I increased revs slightly in second to third gear it was approaching 50 psi. In general oil pressure bar gauge the pressure is either at the bottom or at the top of the gauge and nothing in between.

To be honest I don’t believe for a second we actually have an oil pressure issue, but I would rather not take a risk. I’ve been through Graham Saggy manual and checked various stuff including the earth’s, but the strange readings continue.

Any thoughts would be appreciated.

Thanks. BB.

[Targarama]

So when you replaced the engine did you keep the unknown sensors from the new engine or replace with nice shiney new ones?

[BatleyBoy]

Targarama said:

So when you replaced the engine did you keep the unknown sensors from the new engine or replace with nice shiney new ones?

We changed the chip in the ECU to the Saggy chip that came with the engine, but we left all of the sensors. The oil pressure sender is reletively new...fitted May 2009.

[Geoff Ashcroft]

Plumb a mechanical oil pressure gauge in the pressure line to confirm oil pressure readings. If it were mine, I'd change all the sensors for new ones - you've spent enough dosh on the motor, after all. Don't know if you need to program sensors on the pod (someone will say for sure). I would have thought they're plug and play, but I don't know if they need calibrating like a data logger.
And I take it you had the front of the car raised to allow all air locks to be removed from the cooling system when refilling????

[BatleyBoy]

Geoff Ashcroft said:

Plumb a mechanical oil pressure gauge in the pressure line to confirm oil pressure readings. If it were mine, I'd change all the sensors for new ones - you've spent enough dosh on the motor, after all. Don't know if you need to program sensors on the pod (someone will say for sure). I would have thought they're plug and play, but I don't know if they need calibrating like a data logger.
And I take it you had the front of the car raised to allow all air locks to be removed from the cooling system when refilling????

Thanks for your thoughts Geoff.

To be honest all the pod readings are all over the place, not just the water temps.

The new rad was fitted at the garage so I am comfortable with the installation aspect. But as for the water temp readings, they are all over the place to be hoest. For example one second thay are at 90oC and then upto 97, then back to 94, then upto 98, back to 95 then upto 108! They just flit up and down; big changes within seconds, the readings are never stable (the oil pressure is fluctuating in the same eccentric manner also).

Please note also that we checked the water temp with a infra red temp gauge and it read 82oC on the block when the pod reading was showing 108oC.

In addition, I would think that at a water temp of 108oC we would have some visible signs of distress in the engine bay?

Cheers. BB.

[Targarama]

Sounds like you might have an air lock in the engine, try a good bleed session.

[BatleyBoy]

Targarama said:

Sounds like you might have an air lock in the engine, try a good bleed session.

Air lock in the engine?

[Kaplaah]

i had a similar problem with mine and just replaced all the sensors. sorted it all straight away

[Targarama]

BatleyBoy said:

Targarama said:

Sounds like you might have an air lock in the engine, try a good bleed session.

Air lock in the engine?

In the cooling system, in the engine, by the coolant temperature sensor

[nightSpirit]

Does sound like an air lock in the cooling system somewhere...not having done a bleed on a TVR before I can only go off my track car which is very different. Why not try and new sensor (this would need a bleed on fitting?). If the engine was running at those temps genuinely I'd expect you'd see more warning than a few digits on the pod display!

[Dr John]

I've had water temp readings like that when the water level is low. If the sensor becomes uncovered then it reads the temperature of the steam above the water which can easily be 108 then water sloshes over it and it suddenly drops then rises again.
However as the other pod readings are erratic I'd suspect a problem with the loom or the pod itself, it might just be a poor connection. A failure of ALL the sensors at the same time is unlikely (but possible).

John

[blackiepaul]

Hello,

Never had readings like that.

I would run the car and then jack the front up and squeeze the water hoses as it sounds like you do have a air lock. I am sure I am telling the two of you how to suck eggs but remember to check to see if there is a air at the top of the swirl pot as much as when you check the water at the fill point.

If you were getting temps like that then you would be getting water coming from your water filler cap as it is made to release water at that temp as it would have created alot of pressure.

Paul......

[BatleyBoy]

Thanks for all comments / thoughts.....please keep them coming!

I really don't think the water temp or oil pressure are actually a problem. I beleive its something thats causing probs with the pod readings, as BOTH the water temps and oil pressure readings are all over the place.

To support this statement, when the pod said the water temp was 108oC, the hand held laser temp gauge said the actual temp (measured on the block by the sensor) was 82oC. So I doubt its a problem with air in the system.

The oil pressure readings are also all over the place also. For example we had low readings yesterday (see my comments in earlier post), and then this morning it showed 65psi on tickover when engine was cold.

[Kaplaah]

i had exactly the same problem with mine when i first bought it. the numbers on tick over would flicker from 0 to 50 on tick over with oil pressure.it just blurted out what ever number it felt like. same when driving too and with the water temp as well. was just all over the place. car drove absolutely fine and had no problems at all. those dash duzzers get annoying after a while!

Edited by Kaplaah on Friday 16th July 14:59

[shep1001]

Have you had it plugged into a laptop? maybe the EUC tells a different story to the display? Also would a poor earth not cause erratic readings as they work off resistance?

Shep

[Blue-Lightning]

I had a very similar problem with my T350c a year or so ago.

The oil pressure would drop to next to nothing and the water temp reached over 110 on some occasions.

The problem was the earth cable between the enginge block and chassis. Even tho the bolts were done up tight, the connection to the block had corroded. I cleaned this up and reconnected it, then everything was back to normal.

Hope this helps. BL

[5yearstobuyatvr]

Yes I had the same problem, a new earth strap from chassis to engine should sort it.