Tamora troubles... engine cutting out when warm

[JockyWilson]

Looking for some advice on the Tamora as me (and two mechanically minded mates) are out of ideas!

Brief history:
12 k service at end of October, driven straight to France (put a few hundred miles on it, no issues)
Second or third drive after that, engine cut out while driving. Managed to restart it and get it home.
On the next attempt a week later, started fine from cold, idled for 10 mins then cut out when put in first gear and tried to pull away.
Called the service garage and was recommended to change the coil pack. This is all detailed in this thread:
http://www.pistonheads.com/gassing/topic.asp?h=0&a...

So, have recently got a replacement coil pack and fitted it. Following the coil pack change, this has happened on 2 cold start attempts:

Started from cold (started first time, no extra throttle required)
Idled fine for 9-10mins
After about 10 minutes, with water temp at 65 deg, oil around 26 deg, the engine briefly struggled and cut out.
It's possible to restart it, but it needs a constant foot on the gas. As soon as you remove the slight pedal pressure, it cuts out.

Troubleshooting since:

Have increased the engine idle - still cuts out when it gets warm.
Have checked all the high temp leads with a multimeter - resistance fine.
Checked all spark plugs - look fine (and new at the service).
Checked resistance across the ECU water temp sensor - measured around 795 then 1118 five minutes later when slightly cooler (so guessing it's doing its job)
Disconnected the ECU water temp sensor and started the car. EFI Fault - Warning Code 4. Engine was still warm when started and needed a foot on the gas to stay running.
Disconnected the fuel hose going into the fuel rail to check for residual fuel pressure straight after the engine died - no fuel came out.
Did the same after having the engine running and turning the ignition off - again no fuel came out of the pipe.

Listened to the fuel pump priming in the boot - seems to be doing its job when the car is turned on.

Have been trying to get the speed 6 diagnostic software running but have failed so far. Can't get hold of a laptop with a sufficiently old enough version of windows to run the software. I have read this thread on it (http://www.pistonheads.com/gassing/topic.asp?h=0&f=152&t=1051057&nmt=)

So, we're thinking it's still looking like a fuel or electrical issue but now out of ideas. Has anyone had these symptoms before?

A mate suggested the throttle pot, but looks like you need to take the bonnet off to properly get at this.

The car's been off the road for two months now as have been fiddling with it when I've had the time. Getting pretty frustrating now though, especially straight after a big service.

All suggestions welcome!

[Andy_mr2sc]

Have you tried evoOlli's software? This will work on later versions of Windows and is much easier to read than the original offering.

http://www.pistonheads.com/gassing/topic.asp?t=136...

Edited by Andy_mr2sc on Sunday 14th February 11:57

[NWTony]

I'm no expert,but could it be the coil pack breaking down as it gets hot? It sounds like it is not firing on all cylinders which could be the injector loom as well.My T350 was losing random cylinders and it turned out to be the wiring to the injectors. They are batch fired 1-3 and 4-6 but individually wired, so you can splice from 1 into 2 and 3 if need be to test it.

Also, a friend had a kinda similar issue with an Esprit - drove fine on a run out, then misfiring / wouldn't run, which turned out to be fuel injectors.

Caveat - I have a friend who understands these things and I just try to remember what he says!

[TVRinBFG]

Change the Fuel crank sensor, especially if it comes out look gungey. And for the small money involved, change the fuel pump relay.

[JockyWilson]

Thanks for the suggestions and thanks for the evoOlli software link Andy, I wasn't aware of it before, looks good! I've got a new crank sensor / fuel relay on the way and the software is downloaded to have a play this weekend. Will update on progress..

[ChazUwe]

Or contact Olli and see if he is still making his mobile version for permanent mounting in car with real time info!





Like to be able to get the ECU temp reading as well as the dash reading which can be inaccurate.

[JockyWilson]

That does look like a quality set up, will do just that...
How have you managed to attach it? Guess it might also fit in the glove box if only used for troubleshooting etc

[ChazUwe]

Have a look through these links, I have just used a couple of metal brackets with some velcro. Would like to power from the radio so it kills the power with the ignition. Not got round to that yet... You can make your own if you have some soldering skills....

http://www.pistonheads.com/gassing/topic.asp?h=0&a...

http://www.pistonheads.com/gassing/topic.asp?h=0&a...

[JockyWilson]

So troubleshooting is ongoing. Got the software working now but haven't changed the crank sensor yet as the parts only recently arrived. Car started fine today but on initial start up the passenger side exhaust seemed to be pumping out much more puff then the driver's side.

Would the data below point more to a faulty throttle pot rather than crank sensor? Will still likely replace the crank sensor next as I have the part, but wondering whether it's looking like the throttle pot is the main culprit. Looks like £115 for the two parts.

Does anyone know how hard the throttle pots are to change? Is it a bonnet off job?

[Englishman]

Before you change anything, do both throttle pot readings change with throttle movement? If so, it'd suggest to me that the throttle balance is way out.

[K4TRV]

Snippety..........the passenger side exhaust seemed to be pumping out much more puff then the driver's side." snip.

It is "one" single pipe after the Cats............a some stage check your box is not blocked? Cats breaking up after running wrong mixtures can do this??

When did you last "balance" the throttle bodies, as in using an Air meter???

When all is balanced then look at Throttle pots? Certainly not looking good one that read out.

Deffo take the bonnet off to do any more work etc!!

Hope that helps?

T

[JockyWilson]

Englishman said:

Before you change anything, do both throttle pot readings change with throttle movement? If so, it'd suggest to me that the throttle balance is way out.

.. both throttle pot readings change with throttle movement yes. On driving, I reset the adaptive maps and things seem fine for 10-20mins then the same issues reappear (engine hesitant then cuts out). I've never balanced the throttle bodies myself, but it's recently back form the full 12k service at a very well known TVR dealer.

[JockyWilson]

K4TRV said:

Deffo take the bonnet off to do any more work etc!!

T

Never taken the bonnet off before... heard it can be tricky to get back in the right alignment. Proving to be quite a learning curve this issue

[shep1001]

JockyWilson said:

So troubleshooting is ongoing. Got the software working now but haven't changed the crank sensor yet as the parts only recently arrived. Car started fine today but on initial start up the passenger side exhaust seemed to be pumping out much more puff then the driver's side.

Would the data below point more to a faulty throttle pot rather than crank sensor? Will still likely replace the crank sensor next as I have the part, but wondering whether it's looking like the throttle pot is the main culprit. Looks like £115 for the two parts.

Does anyone know how hard the throttle pots are to change? Is it a bonnet off job?

The adaptives are massively different & those throttles look well out of balance or the sensor is knackered. they should be the same - Aprox 15.5% at idle (which yours is in that pic) 95% fully open & they should track each other +/- 0.5% over their range.

When you do the crank sensor there is a little spacer on it. Its very important you don't loose it or forget to put it back in. Without it the sensor sits to close to the spiny things in the engine and it will foul the end of the sensor and lop it off!!. The front t-pot is easy, the back one has to be done by feel. (pinch the mrs vanity mirror so you can see what you are doing) its two philips screws that hold it in place. They may need trimming to get them to fit perfectly too. The t-pots are not identical but they are colour coded. Ford parts I believe

Here is a shot of mine idle for reference just taken

Edited by shep1001 on Sunday 28th February 18:34

[anonymous-user]

You appear to have a problem, that I can't help with. Can't stop myself thinking though...why would you want to leave your car at idle from cold for 10 minutes at a time, throwing fuel down into the exhaust on cold idle can only bring premature cat failure??

[shep1001]

TVRMs said:

You appear to have a problem, that I can't help with. Can't stop myself thinking though...why would you want to leave your car at idle from cold for 10 minutes at a time, throwing fuel down into the exhaust on cold idle can only bring premature cat failure??

I wouldn't normally cold idle either, just fire her up and go. The cat issue is not a problem for me. Moglet checked them just before Christmas & confirmed they were OK..... now back in the loft for another 12 months.

Edited by shep1001 on Sunday 28th February 18:35

[K4TRV]

JockyWilson said:

Never taken the bonnet off before... heard it can be tricky to get back in the right alignment. Proving to be quite a learning curve this issue

Pop off the strut from the stud on the bonnet (you really need another pair of hands!!). What you remove is the single nut either side - don't remove the three bolts holding the hinge to the bonnet.

Then squeeze the hinges slightly inwards and off the stud - this where the 2nd person supports the bonnet, suggest you drop a sheet/towels oner the engine and wings to prevent scrapes. The other hinge should easy pop off the other stud. It is not too heavy, so help the helper to place the bonnet against a wall with two towels on the ground (nose upwards). Job done and you'll be amazed at the access you now have!!

T

[shep1001]

K4TRV said:

Pop off the strut from the stud on the bonnet (you really need another pair of hands!!). What you remove is the single nut either side - don't remove the three bolts holding the hinge to the bonnet.

Then squeeze the hinges slightly inwards and off the stud - this where the 2nd person supports the bonnet, suggest you drop a sheet/towels oner the engine and wings to prevent scrapes. The other hinge should easy pop off the other stud. It is not too heavy, so help the helper to place the bonnet against a wall with two towels on the ground (nose upwards). Job done and you'll be amazed at the access you now have!!

T

If you mark round the bolts its easy to line them back up. You do need a second pair of hands but its a simple job. I trust the Mrs to help me lift mine on and off with no drama

[Englishman]

JockyWilson said:

Englishman said:

Before you change anything, do both throttle pot readings change with throttle movement? If so, it'd suggest to me that the throttle balance is way out.

.. both throttle pot readings change with throttle movement yes. On driving, I reset the adaptive maps and things seem fine for 10-20mins then the same issues reappear (engine hesitant then cuts out). I've never balanced the throttle bodies myself, but it's recently back form the full 12k service at a very well known TVR dealer.

Ok, can I suggest another test - you can do this without actually starting the engine. Connect up the computer and turn the ignition on, what do each of the pots show? Then press the accelerator slowly until fully open. They should start about 15%, finish about 94% and progress roughly in step. If you reset the throttles and repeat is there any change?

[shep1001]

If you have a syncrometer check the throttle balance for yourself. I had it once where the lock nut on the grub screw had not been tightened so it went out of balance within about 50 miles of being checked. Its quite easy to check and adjust so long as you do them in sequence. Once all 6 pots are balanced, set the idle then re-set the throttle zero & adaptive maps on the software.