5 litre chip in 4 litre

[mootown]

hi all
i am a pistonhead virgin lol i need your great wisdom and experience.ive had a 2000 4 litre chim for three years. recently my ecu started acting like it had mind of its own turned out to be the processor was the culprit ended up getting new one of ebay works fine but lacking in mid range power and acceleration. now here is my question to you all,in my old ecu (which is a recon)the chip has 5.0 on it in marker pen, so is it recommended to run a 4.0 litre with a 5.0 litre chip in it?? ive asked around and been told it will fit but it will supply too much fuel which will make the mixture too rich, but mine has cats which as lambda sensors that apparently checks the mixture and send info to ecu chips which alters the mixture.it was running fine before tick over a bit lumpy. any input is welcomed

[SILICONEKID340HP]

I will run very rich ,after 3500 RPM it goes on to the fixed map so it will be a waste of time..

Does any of the Chips have Tornado or Mark Adams on them?

[blitzracing]

The big issue with the wrong chip is its mapped for a much bigger range of airflow, as a 5ltr car draws a load more air than the 4ltr, so the air flow scaling is wrong, so you end up only using part of the map. The ECU can make some pretty massive fueling changes to compensate for it being wrong, which is why your car is running at all, but its not ideal for power, economy or drive-ability. Drop me a mail if you want a second hand 4 ltr chip, or you could get one from TVR power- I think they where about £80 last time I looked.

[mootown]

thanks guys for reply its now got a 4 litre chip in it from camco .it runs a lot better when it idles and is running cooler but the limiter now kicks in at 5500 rpm and acceleration not as responsive unlike when it had the other chip in it.

[SILICONEKID340HP]

mootown said:

thanks guys for reply its now got a 4 litre chip in it from camco .it runs a lot better when it idles and is running cooler but the limiter now kicks in at 5500 rpm and acceleration not as responsive unlike when it had the other chip in it.

Who is camco ? what was wrong with your original chip.

[blitzracing]

mootown said:

thanks guys for reply its now got a 4 litre chip in it from camco .it runs a lot better when it idles and is running cooler but the limiter now kicks in at 5500 rpm and acceleration not as responsive unlike when it had the other chip in it.

I suspect thats a 4 ltr range Rover chip then- a completely different animal to the TVR spec one. Apart from fuelling differences the TVR one has a much higher rev limiter, and the Range Rover mapping is too lean for best power. Never heard of Camco either (?)

[mootown]

Hi silicone
camco is a company in warrington that do ecu's got a new one for £280.00 through ebay which is for a 4 litre. the ecu that was in prior to having to change it because it created a fault had a 5 litre chip in it. car runs fine with the 4 litre chip but has'nt got the grunt that it had with the 5litre chip in it. just was contemplating if i should put the 5L chip in the new ecu. Cheers

[mootown]

I think you could be right noticed a smell of fuel when its running and the rev limiter comes in at 5500 rpm could i put the old chip in the new ecu. cheers

[blitzracing]

You need the correct fuel map for that engine- end of story. If you are hitting the rev limiter and its a Range Rover map, its like hitting a brick wall, it simply cuts the injectors so the engine gets no fuel at all, a truely horrible experiance when overtaking something!. Also if they have fitted a Range Rover map it will lack power due to the leaning off of the mixture as the RPM rises. Whats physically written on the chip? TVR used to just write 3.9 cat or like on a lable on the chip. Range Rover ones have a just a version number printed on them, no other info. Lucas did put a black plastic box over the Eprom origionaly that clips off, but I guess thats gone if you have been swapping chips? Obviously if you have the chip from the defective ECU and its marked for your engine size that will be fine to swap into the new ECU.

Edited by blitzracing on Thursday 28th June 12:13

[brett84]

sorry to jump on this thread

is the issue going to be the same running a 5ltr chip with a 4.6?

thats what mine has, runs rich but seems to still pull like a train, lumpy at about 30mph.
i am going to get an MS ECU in a few months, but in the mean time i'm not going to do any damage am I?

[blitzracing]

Difficult to say, and a good 4.6 probibly draws as much air as a 5ltr anyway so the airflow scaling wont be miles out. The problem is the ECU sets the overall fuel mixture platform at idle and as the airflow charateristics at idle will be different between the engines, the basic fueling level may be set incorrectly. The ECU then makes small fuelling trims from that point onwards as the rpm rises, and if the basic fueling level is wrong it runs out of correction range and can make the car snatch as the ECU tries to compensate (this is up to 3400 rpm.) However I would think as long as your plugs are not running sooty black, you wont do any real harm, you just will not get the best MPG or power from the engine. The differences between a 4 and 5 ltr map are going to be much larger.

[brett84]

thank you
puts my mind at ease, previous owner ran it for ages and plugs seem healthy.

(sorry to jump on this thread)

[SILICONEKID340HP]

All you needed was a second hand 14CUX ,they are in many vehicles,then just fit your old chip back in ..


There are guide lines when handling and storing the chip, something to do with static.

[Andy JB]

Interesting thread...

So if i have a Camco ECU on my 5 litre with a 5 litre chip, in theory it should perform as TVR intended ? or does it not work that way.

I have good consumption for a 5 litre and no issues with power or torque over 7 years of ownership, good plugs tec if a tad rich at times, or am i missing out on a TVR ECU ?

[mootown]

cheers blitzracing
the ecu is acting as you say ive also read that the top speed is limited too so when i get home tomorrow im taking it for a spin to see if this is the case also problem is if i open the ecu to check the chip the guarantee will be void so ill will have to slog it out with camco it definitely sounds like and feels like a land rover chip as anybody else out there had dealings with camco.

[blitzracing]

The speed input on the ECU is a fixed 36 mph signal- so it wont limit on top speed. As for what chip was fitted I cant really answer without plugging the chip into an Eprom reader and looking at whats inside. I would really hope that a company dealing with chipping would be bright enough to use the correct fuel map.

[mootown]

Thanks for input hope your right blitz decided to get it dyno tested just to make sure the chip is what its suppose to be and also to make sure the engine is running ok will be back with results soon as cheers all for input.