Strange engine behaviour?

[easylife]

My TII cab started doing this on the way back from Brooklands at the weekend (although mine seems to run for longer than 5 minutes normally before going into limp home mode).

Are we saying from the thread you highlighted that the only real fix is to source a new OMP and ECU?

[Mazzyrx7]

The car doesn\'t go into limp mode until the car is fully warmed up as some of the sensors are by pasted until then. Restarting the car put\'s it back into warm up mode for a short time then back to limp mode.

You\'ll need to use the FSM for some of this. http://www.rotaryheads.com/PDF/2nd_gen/

See what fault codes the car has stored. You\'ll need an analog multi meter to read the pulses from the ECU. Down near the battery and leading coil pack there are two green connectors. Ground the single one to the negative on the battery. Then plug the multi meter into the larger connector. One of the connectors is ground (top middle) then top left is positive and that is the ECU fault output. The bottom middle point is to test another control unit. Once all connected up turn the ignition on. Multi meter will display  3 second pulse then it\'ll display the fault codes. 1 long pulse is 10 (2 long pulses is 20) then you\'ll get short pulses, 1 pulse is one (5 short is 5) that code would = 25. The FSM gives all the fault codes in fuelling the part.

If the OMP shows as a fault. Unplug the two connectors and check resistance of the OMP. This will show if it\'s the pump or bad wiring back to the ECU. All is explained in lubrication on the FSM

The ECU doesn\'t always fry it depends how the pump has failed. My stepper motor had a short and this burned the OMP part of the ECU. Your ECU might be fine. I could smell my ECU frying itself, when I first got the car running again. Check the picture in the previous link that I posted. It shows you what part of the ECU burns out. Or just fit a new OMP and then take the car for a good drive if no limp mode the ECU is fine.

I bought my OMP off Tim at RXmotors for a tenner. ECU is going to be £50. So not too bad.

[easylife]

Great advice thanks

[Prof]

If it is the OMP, it\'s basically a stepper motor and the likely hood is that the insulation on one of the coils has failed and it\'s shorted.  This is basically bad news as it toasts a transistor pack in the ECU as the outputs aren\'t really short circuit protected.  The part is no longer available (typical) but could be replaced by a 4 discreete power transistors - bit of a bodge but will work.  I did go through an excersize a couple of years back to see if I could find a pin compatible pack that could be used - but drew a blank.

[Prof]

Having said that,
 
I had similar \'under load\' issues like mis firing and loss of power when accelerating and it was caused by a lose alternator belt - since this is such a quick check and a cheap fix - it\'s worth ruling out - and you\'ll get no error codes from it either !

[easylife]

Cheers Prof, looks like I\'ll have to get my hands dirty for once. Shame you missed Brooklands but definitely not the place to be if you had a cold!

[Mazzyrx7]

I did find these for sale. http://www.plccenter.co.uk/Buy/TOSHIBA/TMP4501

I might have a go at repairing the ECU at some point but looking at buying that Pansport ECU thats up for sale. As the car has had the cat removed and I don\'t think the turbo wastegate will have been ported. I\'m guessing that with the increased boost of the pansport ECU the car will less likely over boost and hit fuel cut. Also I\'m guessing the car will run a bit richer which has got to better than lean. Or it\'ll just blow up!

[Prof]

I did find these for sale. http://www.plccenter.co.uk/Buy/TOSHIBA/TMP4501
 
I might have a go at repairing the ECU at some point but looking at buying that Pansport ECU thats up for sale. As the car has had the cat removed and I don\'t think the turbo wastegate will have been ported. I\'m guessing that with the increased boost of the pansport ECU the car will less likely over boost and hit fuel cut. Also I\'m guessing the car will run a bit richer which has got to better than lean. Or it\'ll just blow up!

You\'ll probably still get boost creep - but at least the ECU will be mapped for it and avoid the dreaded fuel cut. The Boost creep is much worse if you change the air filter as well as the exhaust, and a boost controller won\'t stop it either.
 
Oh and good find on the Tosh\' transistors - if you have to order a bulk load, i\'ll take a couple.  could never find anyone who had stock when I looked for them.

[turbointhebrain]

mmm this is interesting, my fc is giving the same problem.  thanks for shedding a bit of light on this for me.  hopefully my redom ecu isnt fried!eep

[bumpstart]

this is almost certainly an EOMP fault if s5 car and the best solution is quite likely the US rtek chipped ECU which will ignore the EOMP and thus allow you to set it at fixed rate and supplement premix

in my experience the initial fault is sometimes oil built up around the plug socket on the pump itself or also in the feedback sender
.. a few times the issue has been in the wiring pigtail up to the water pump neck

and it is no good swapping the ecu for another until you track this fault down , as some of the faults can ruin the new ECU

as for the self protect , the ecu does do a resistance check.. but should log this fault .. if its not logging it then the fault is often in the feedback sender or wiring

the other options the OP have are the obvious full standalone ECU .. some of which can use the EOMP in a modded output format ... consider that your EOMP needs to be checked still for faults
cheaper ECUs wont do it as it ties up too many outs and one input .. but there is the eomp controller that will run off a map sensor or a mapped ecu output
 ( should you wish to run in from a custom 2 or 3D table )




NB
a similar 3000 rpm / load fault is in the s4 cars,, but has nothing to do with limp mode or a restart
.. the issue relates to engine and sensor grounds and is quite often a fault in the loom just out from the ECU plug where all these earth,, and the shield wiring ties together in two metal crimps
adding supplementary ground to chassis from here,, and resoldering the joints will sort that issue

[Mazzyrx7]

To conclude my problem. New ECU fitted today and car is running perfectly.

Just got a few more small jobs to do and get an MOT on it. Found insurance for £200 for the year which I think is pretty good.