Rough running

[Jefers]

Hi all, talking of chips anyone got a tornado chip for a 4.0. Going to run with a map 2. Tired of shunting!

[QBee]

It doesn’t work like that. Best guess chips are just that.....best guess.
The best way to cure shunting and get the car to run much better is to get the ECU mapped to the car.
The 14CUX ECU wasn’t mappable 10 years ago, but a few people have worked it out now and can sort your car out for you for not a lot of money.
My recommendation is a guy called Jools. He is based in Chesterfield and will map it while you wait if you ask.
His website is HERE

Lots of us have had our cars mapped by him, he is a great guy and all reviews are positive.

[Jefers]

Thanks for reply. I'm 4 hrs from jools. Was going to get a best guess map and get it mapped locally. Shunting has gone but as I understand it the map2 is a range rover map?

[QBee]

Not many 14CUX mappers - there may be one in your area. If you say what area perhaps someone on here will know.
I cannot answer your other question.

if you go for a Tornado chip, you need one specifically for your engine....which is?

[blitzracing]

Dont bother with best guess at great expense. You could try running the green map that you have to start with, as all the shunting is at light load so you cant do much damage. You can try altering the CO trim on the side of the AFM to see the effect, as this will alter the mixture up to around 2.5 k rpm. At least this way you wont spend silly money on a chip that may or may not work. The Eprom is a 27C256, next to nothing to buy, and your remapper should have facilities to copy the chip to have to start with, then you can generate a new map. Personally I copy the TVR white tune into the green location and then alter that. Better than starting with a RR map. You do need very specific hardware to reprogram the 14CUX as its not got a programmable chip it in. This is a Moats Ostrich that costs about £200 that looks like an Eprom, but can be flash programmed with Tuner Pro, or its own utility.

Ive remapped my green tune on my 3.9 and it works very well, but I dont have catalysts to worry about. Problem is shunting is caused by lots of factors, so I try GOC' s vacuum advance mod first off. This is basically block the air hole by the throttle plate that feeds the distributor vacuum, and then drill a hole in the side of the plenum and fit a pipe you can fit the rubber tube to. It will fail the emissions test come MOT but make it s you can swap it back easily before you go. Otherwise Im happy to blow you a copy of my green map if you want to give it a go? Where are you in the country?

Edited by blitzracing on Sunday 6th October 18:19

[Paulprior]

Hi Blitzracing, i see that RG will show the injector duty cycle, but it seems to be for both banks, can i read and understand something from that ??
As it seems that a Lambda sensor fault (disconnection anyway) will not throw up the misfire are there any other circumstances possible that might overdose one bank??, the only other possibilities i can imagine at the moment are a short term short circuit on one of the injectors itself or on the cable back to the ECU, but i think that this would be erratic in nature, while my problem is very consistent at least on correcting itself, just inconsistent on when it happens.

Just off for an MOT now and then i will take the car off the road for the winter where i will primarily tart up the engine bay along with a few other little bits and pieces so just wondering if there was anything usefull i might do at the same time ?,otherwise i guess it a 2 channel scope connected full time on the injectors for next year

Any thoughts greatly appreciated as always

Paul

[blitzracing]

I have to assume that the injector timing in RoverGauge is likely to be the time set by the map, as this will be the same on both banks, and the lambda trim is added afterwards. In terms of why it would suddenly over fuel on one bank, then yes a short on the injector -ve side to ground will cause the injectors to stick open, and Ive come across this once where the loom had chaffed through, so woth giving the loom a wiggle and see if you can create the fault. It will highly over fuel the one bank- and if you suspect something this drastic a noid light is definitely the way to go. Mind you a total short would have showed at around 12v on the injectors all the time.

[Paulprior]

Unfortunately i previously measured the injector supply voltage and from ECU output to earth, obviously on my DVMs, i will do it differently next time, i think a 2 channel scope with recording ability will be the way to go due to the erratic nature of this problem, one thing that suggests to me that its not an shorting problem is that it has been there probably a very long time without getting worse, 3 years with me as well as having the previous owners invoices from TVR specialists trying to track down random ignition system problems.

I have no previous experience with a V8, would anyone know how it feels with one full bank not running ??, if im driving at 50 to 60 and it happens i can continue to drive but cannot really accelerate, just trying to understand if my current thoughts are somewhere near on track ??

[Penelope Stopit]

Easy innit

Wire switch to open circuit injectors negative signal to whichever bank you want to switch off

Drive car at 50 to 60 MPH and operate switch