strong smell of fuel,white smoke and engine light after decat????
11 September 2010, 10:25 PM
#1
strong smell of fuel,white smoke and engine light after decat????
I removed the cat downpipe from my twin scroll jdm 2003 sti. last week and fitted my decat 3" decat downpipe and 3" cat back team ice from roger clark. and it is being remapped next week and i have been driving it for a week off boost very gently all week with no issues. i went to start my car this morning and it was ticking over eratically and wouldnt rev and when the engine was warmer it drove fine and the white smoke and smell of fuel cleared. however coming home from work the white smoke was there all the way home and my engine light came on and off and it stunk of fuel in the cabin so i have now parked it up till it gets remapped and ecu reset next week. is this normal issues when not remapped yet as i nursed it home and now have no car as to not damage anything,. i have no knocking just a strong smell of fuel and white smoke and pops bangs and eratic idling. any help cheers 
11 September 2010, 10:50 PM
#2
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as normal i stand to be corrected but to my knowledge the reason why you are having these problems is due to the mods + no remap,if you can make some time to put mods on then remap straight after,same day with no or very little driving inbeweetn putting mods on and the remap.Thats the way ive done it with my 05 jdm sti.
Dan
05 jdm sti
400/400
Dan
05 jdm sti
400/400
11 September 2010, 11:24 PM
#5
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Yes it will mate,a decat and no remap = trouble as it causes det wich can lead to engine failure.they are a few good well known mappers registered on here-simon aka jollygreenmonster,juggers,andyf,duncan at racedynamix i think its called just ask around on here for details of mappers,they will be happy to have a chat and help you with your choice of remap.
dan
05 jdm sti
400/400
dan
05 jdm sti
400/400
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12 September 2010, 12:05 AM
#9
One of your lambda sensors is possibly on the blink. The smell of fuel is exactly as you've said, over fuelling.
If either of the Lambda sensors go then the ECU defaults to the failsafe fuelling map and throws a CEL. Failsafe map runs pretty rich so that may be what's happening.
Get a handheld diagnostic device plugged in just to see what error code is being generated, at least you'll know then.
If either of the Lambda sensors go then the ECU defaults to the failsafe fuelling map and throws a CEL. Failsafe map runs pretty rich so that may be what's happening.
Get a handheld diagnostic device plugged in just to see what error code is being generated, at least you'll know then.
12 September 2010, 12:47 AM
#10
What's got me worried is White smoke is usually linked to either head gasket or water getting into the cylinders coming out the exhaust. My water level is fine Inc anti freeze but it idles eraticly with a strong smell of fuel and I don't know if it was fuel or water dripping from the exhaust I hope it's just a remap issue but why the White smoke?
12 September 2010, 12:56 AM
#12
If I accelerate more onto a bit of boost then the smoke goes. Fuel smell goes and drives and pulls ok but this was only brief to test of course oh and I get a couple of pops and bangs of unburnt fuel I presume
Last edited by fordrsrickc; 12 September 2010 at 12:57 AM.
12 September 2010, 04:43 AM
#14
Cars over fueling the cats before used to burn the femaing fuel in the cats now your d cated there is excess unburnt fuel in system witch would explain the smell and White smoke ok that's my theory but I might be wrong lol get it mapped asap
12 September 2010, 10:54 PM
#18
i always thought white smoke was water related or steam and i thought blue smoke was oil, got mixed answers here from lambda to maf to oil to water to remap to fuel so im as you can imagine getting a bit paranoid and just want to get to the route of the problem and buying a diagnostic checker to see what the fault code is just need to find a suitable one now
13 September 2010, 12:08 AM
#19
Firstly, stop worrying, it will be fine 
With a decat, my car was smoking white every time it was cold, enough to have me worried on more than one occasion. As mentioned, it's something to do with what the cats do to the fumes, so don't worry about that.
Your check engine light is probably down to the rear lambda sensor now reading incorrect values - mine did the same until remap (i.e. threw a CEL). Your mapper can sort that one out no problem.
With a decat, my car was smoking white every time it was cold, enough to have me worried on more than one occasion. As mentioned, it's something to do with what the cats do to the fumes, so don't worry about that.
Your check engine light is probably down to the rear lambda sensor now reading incorrect values - mine did the same until remap (i.e. threw a CEL). Your mapper can sort that one out no problem.
13 September 2010, 01:02 AM
#20
I drove it the other day and it was smoking very badly even when warm and didnt clear and the smell of fuel was inside the cabin it was that bad i just parked it up for a week. so not to cause any damage i have borrowed a car from a friend at work an old Astra L reg Auto which i have to drive in 1 2 and 3 because DRIVE is buggered lol but it gets me to work and back and beats walking lol cant wait till remap day and ive still got to fit my headers, up pipe, pipe up my FMIC,fit my walbro 255 fuel pump and change the spark plugs and fuel filter for good measure and i only have 2 five hour windows to do this with work and days off wish me luck lol
13 September 2010, 01:40 AM
#21
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Hmmm, there's a lot of well meaning bad/reckless advice in this thread. One of the problems with internet forums is that it's easy to ignore the simple fact that often, the worst way to try and diagnose a problem with a car is via the internet. Especially when it comes to noises, smells, smoke colours an' ting. A certain amount of smoke under certain circumstances can be normal, but you need to be able to see it to tell what's normal and what isn't.
Fordsrickc, it certainly is possible that what you are experiencing is nothing more than the natural consequences of fitting the decat parts + a bit of weather. It's possible, for example, that the white smoke is merely condensation and that by leaving the car parked up, you're actually causing more of it to build up than you'd see under "normal" usage circumstances.
However, the symptoms you are describing sound like there is a problem of some sort, or, at very least, that you need to rule a problem out. Have you, for example, checked whether the coolant level (i.e. the one in the header tank on the inlet manifold) and oil levels are normal? If you're losing either in significant quantity, then there's going to be a level drop, so that's a handy bit of diagnostic info you can check yourself.
Similarly it's difficult to see a scenario where fitting the exhaust components, alone, would cause the car to "stink" of fuel to the point you are saying it's easily noticeable inside the cabin. Sure it'll run better after a remap but it should run properly on a light throttle beforehand.
If there's any doubt in your mind, if I were you I wouldn't wait until the car is mapped to get it looked at. Is there a good specialist within local driving range?
Fordsrickc, it certainly is possible that what you are experiencing is nothing more than the natural consequences of fitting the decat parts + a bit of weather. It's possible, for example, that the white smoke is merely condensation and that by leaving the car parked up, you're actually causing more of it to build up than you'd see under "normal" usage circumstances.
However, the symptoms you are describing sound like there is a problem of some sort, or, at very least, that you need to rule a problem out. Have you, for example, checked whether the coolant level (i.e. the one in the header tank on the inlet manifold) and oil levels are normal? If you're losing either in significant quantity, then there's going to be a level drop, so that's a handy bit of diagnostic info you can check yourself.
Similarly it's difficult to see a scenario where fitting the exhaust components, alone, would cause the car to "stink" of fuel to the point you are saying it's easily noticeable inside the cabin. Sure it'll run better after a remap but it should run properly on a light throttle beforehand.
If there's any doubt in your mind, if I were you I wouldn't wait until the car is mapped to get it looked at. Is there a good specialist within local driving range?
13 September 2010, 12:06 PM
#22
YIPPPPPPEEEEEE!!!!!! found out what the problem was on my car it has an LPG conversion and the LPG ecu is plumbed into the car ecu and because the LPG ecu is programmed to let the car run on petrol until warm then switches to gas and if on LPG and the gas runs out it is programmed to switch back to petrol and if i give it beans it will switch back to petrol also,....so it is bridged into my cars ecu and i unplugged the LPG ECU to reset it and the car is now fine no smoke and the strong smell of fuel has gone and it runs spot on so they are conflicting with each other even when the lpg is not being used or switched on but the LPG ecu must have been telling the car ecu to add more fuel so i am having the LPG either removed or looked at as i dont want to have to pay all the money for a remap only for the LPG ecu to conflict and mess my car ecu map up. I feel much better now and thanks for all the comments guys who would have thought it would be the LPG lol when i dont even use it, as it was on the car when i got it.
bit like buying a teapot to make coffee ...
13 September 2010, 01:23 PM
#24
I think of it as more like putting liqourice shoelaces in a smart pair of shoes lol it was on the car when I bought it and it is 650.00 to remove it so I just left it and don't use it. I thought the LPG was a good idea at the time of purchase with it only being £20 to fill up but has no power so don't bother using it and just stick to fuel.
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