Runing rich after decat?
Discussion
I've recently had my pre cats taken out and an ACT decat Y piece fitted. The car runs great and certainly feels more eager to rev.
However I noticed today (when I had the roof off; it was raining when I brought the car home last week) that it smells as if it is running rich.
When I walk behind the car, it smells like it has just started from cold even when it is fully warmed up, very 'petroly' (new word just made up
)
No changes were made to the lambdas (still in) and no coloured resistors were added. I do note however that in the service notes it does say 'Air Flow set @ 3 volts' if that means anything to anyone.
PS - It's a 97 450 running standard ignition
However I noticed today (when I had the roof off; it was raining when I brought the car home last week) that it smells as if it is running rich.
When I walk behind the car, it smells like it has just started from cold even when it is fully warmed up, very 'petroly' (new word just made up
)No changes were made to the lambdas (still in) and no coloured resistors were added. I do note however that in the service notes it does say 'Air Flow set @ 3 volts' if that means anything to anyone.
PS - It's a 97 450 running standard ignition
Search for Blitzracing using the forum search facility and PM him. Lovely guy, will know straight away.
The lambdas still in is correct, and you would only need a change of resistor if you had removed them.
My suspicion is that your bigger trumpets may be confusing the AFM into ordering more fuel to be injected.
Mine is decatted, and I was told by more than one expert, includng Mark Adama himself, that the decatting itself was not an issue. I cannot say I have detected an excessive fuel smell. Indeed, the only odd aroma occurs when I have a passenger on a track day.....
However I did have various fuelling issues around that time, due to changing the engine, AFM, injectors etc etc, and in the end had to have it remapped to resolve the issues. Also, my stepper was heat sensitive, causing hot stalling, which only showed up after the decat.
You might set your mind at rest by taking it to a rolling road and asking them to run it up with an AFR connected (air fuel ratio gauge). At which time I would be rude not to do a power run, which at some RRs will also give you a graph plot of your air fuel ratio. This will tell you for definite if you need a remap, or not.
The lambdas still in is correct, and you would only need a change of resistor if you had removed them.
My suspicion is that your bigger trumpets may be confusing the AFM into ordering more fuel to be injected.
Mine is decatted, and I was told by more than one expert, includng Mark Adama himself, that the decatting itself was not an issue. I cannot say I have detected an excessive fuel smell. Indeed, the only odd aroma occurs when I have a passenger on a track day.....
However I did have various fuelling issues around that time, due to changing the engine, AFM, injectors etc etc, and in the end had to have it remapped to resolve the issues. Also, my stepper was heat sensitive, causing hot stalling, which only showed up after the decat.
You might set your mind at rest by taking it to a rolling road and asking them to run it up with an AFR connected (air fuel ratio gauge). At which time I would be rude not to do a power run, which at some RRs will also give you a graph plot of your air fuel ratio. This will tell you for definite if you need a remap, or not.
A900ss said:
Glad you're happy with yours also
I don't know its running rich but the fact I can smell petrol suggests to me it is.
It will go on a rolling road either next week or the week after and that should tell me the AFR to confirm either way.
Mine wasnt fuelling properly under load anyway, even before the new bits so I have booked it in for a full remap, new injectors etc etc and dropped it off today. Looking forward to reporting back on progress in the next couple of weeks.I don't know its running rich but the fact I can smell petrol suggests to me it is.
It will go on a rolling road either next week or the week after and that should tell me the AFR to confirm either way.
Currently I have 303 bhp and 360 lb of torque. I have a number in mind I would like it to be but lets see!
TV8 said:
Mine wasnt fuelling properly under load anyway, even before the new bits so I have booked it in for a full remap, new injectors etc etc and dropped it off today. Looking forward to reporting back on progress in the next couple of weeks.
Currently I have 303 bhp and 360 lb of torque. I have a number in mind I would like it to be but lets see!
If you have 303/360 I take it you have a 5 litre?Currently I have 303 bhp and 360 lb of torque. I have a number in mind I would like it to be but lets see!
I look forward to the update though. Do you have an aftermarket ECU or are you using something like a tornado chip as a remap?
Removing the cats will make the car smell- its not something we are used to these days, but you get unburnt hydrocarbons that give it the petrol smell as there is not catalyst to ignite them. Having said it should not really smell that bad once the engine is up to temp. The ECU is designed not to let the car run rich, even if you modify the exhaust, by using the lambda probes to reset the mixture, and it has a pretty wide adjustment range. The ECU could be in limp home mode if something is wrong, and the MPG will be poor, and most of the ECU warning lights dont work on the TVR's because the British version of the ECU has it disabled in the chip. The Americans get a working version. You really can only tell if you have fault with a fault code reader / RoverGauge or ECUmate to plug in.
The CO trim on the side of the AFM is ignored as you have lambda probes (at least as far as I can tell) but if you want a voltage it should be between 1 and 1.3 volts. 3 volts would be a highly rich setting if there was no lambda probes, and you where running on the green tune resistor. Dont forget bad MPG can be ignition related as well- no vacuum advance will loose a couple of mpg.
The CO trim on the side of the AFM is ignored as you have lambda probes (at least as far as I can tell) but if you want a voltage it should be between 1 and 1.3 volts. 3 volts would be a highly rich setting if there was no lambda probes, and you where running on the green tune resistor. Dont forget bad MPG can be ignition related as well- no vacuum advance will loose a couple of mpg.
Mine is smelly too and during the summer, I could smell fuel a couple of times when the fans kicked whilst stationary… this transpired to be loose lambdas. Sorted that and the then getting rich smell on overrun… turns out to be broken flexible joint on exhaust/ y-piece connector. Once done it should be good. TBH, I quite like the smell. As Alun said, "remains me of the cars of old", and it certainly beats the horrible, acrid diesel smell. If it continues whilst driving, double check the fuel hoses that run from the inlet manifold (near the heater rails) down the back of the engine. I replaced mine, but they apparently have a habit of splitting and cracking over time.
Sleeved and no cats though… smells great and sounds like Hades on wheels…
Sleeved and no cats though… smells great and sounds like Hades on wheels…
A900ss said:
If you have 303/360 I take it you have a 5 litre?
I look forward to the update though. Do you have an aftermarket ECU or are you using something like a tornado chip as a remap?
I am keeping the Lucas system. There is a post on here about remapping the 14cux and one the guys involved has remapped a few now and is going to re-scale for the 20am and remap to suit. Looking forward to it though if I had my time again, with what I have ended up doing to this car, I wish I had kept my old one and up-graded that instead! I look forward to the update though. Do you have an aftermarket ECU or are you using something like a tornado chip as a remap?
TV8 said:
QBee said:
Then he is correct - the torque is about right, but the bhp s coming up short.
Anthony is on the right lines. In fact he was stood next to me when it was on the rollers!Hi. Anthony,
I was recommended someone else than mark Adams and contacted him through Pistonheads after the work he and a few others put into this thread. http://www.pistonheads.com/gassing/topic.asp?h=0&a...
He has his own rolling road and is a decent guy to deal with. He also has a connection to Triumph Stags I found out today!
I am already looking forward to the drive home at some point in the next couple of weeks.
I was recommended someone else than mark Adams and contacted him through Pistonheads after the work he and a few others put into this thread. http://www.pistonheads.com/gassing/topic.asp?h=0&a...
He has his own rolling road and is a decent guy to deal with. He also has a connection to Triumph Stags I found out today!
I am already looking forward to the drive home at some point in the next couple of weeks.
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