Cars running boggy does it require a remap?

[Mi11ar]

Hi guys my old engine seized so I got a newer one fitted (70k miles) I then got it serviced and a new cam belt, while this being done I got my old S2000 air filter put onto the new engine, fitted a FMIC, 3'' down pipe and de-cat. (I already had a stainless steel exhaust on it think it's 2'' or 2.5'')

Car was fine for a few days then it ran boggy, it was happy if I slowly accelerated but if I put my foot down it would bog and miss fire, I changed the spark plugs thinking I may have got some dodgy ones and this solved the problem for about a week then it came back, I plugged it in and it came up with a error with a Temp Gauge switch so I replaced that, which solved the problem for a few days, I then plugged it in again no errors, no lights on the dash board but still it's boggy and miss firing! I can't get my head around it as sometimes it's fine and then other days it's dodgy.

My thoughts were that since I've changed so much on the Car it may be over fuling or something due to the lack of a map what are your thought can anyone shed some light?

 

[antwan64og]

As I don't have Vagcom I use the below process

Clear any codes with a VAG scanner.
Unhook the -ve battery terminal, leave it 20 minutes. (reset the ECU)
Hook battery back up.
Turn key to first position, leave for 10mins in this position. (should reset the throttle body).
Start car and let idle for a few minutes.
Switch off and drive as normal.

If you have VAGcom you can reset the throttle body and see what the fuel trims are like anyway.

The car should drive ok with the decat as the O2 sensor would read a little lean at first during idle and add a % more fuel.
The S2000 filter needs a remap though to get any gains, I'd stick with the stock airbox for now and see if that helps

 

[Nilz]

Are you getting any more fault codes since changing the temp switch?

Have you checked all the coilpacks are in secure?

I would check for any split pipes, try driving with the N75 disconnected and see if that makes a difference too.

 

[dusty]

Maybe also check the coilpack wiring loom mine was in a right state after 110,000 miles insulation cracked and missing on multiple coilpacks

 

[<tuffty/>]

What engine code did you have (I assume its an AGU) and what did you replace it with? when was the last time you know the MAF was changed? if you have access to VCDS can you log airflow?

Is it a misfire or just die on its ****?...

The fact its ok for a while then goes funny is nothing to do with the mapping... the MAF compensates for the increased airflow to a degree... if the MAF is tired it can under/over fuel under hard acceleration as its a narrow band lambda so fuelling is under lambda control on idle/cruise (closed-loop control) but lambda has no say under acceleration (open-loop control)... fuelling is airflow/rpm controlled and if the MAF is not reading right then fuelling won't be right

A remap won't help... you have a hardware issue somewhere so need to fix that first...

Difficult to diagnose on your current description tbh... need logs

<tuffty/>

 

[Mi11ar]

I'm not a mechanic (far from it) so I'm just describing what I've seen, I know for sure the air flow was checked and everything was fine but that was only when idle and it's always been fine in idle anyway.

it doesn't die on it's **** it will go it just will splutter and jitter like the engine is being restricted or something, hard to describe haha

it has been plugged in since having the new sensor put on and still nothings coming up, I'll get a new MAF and then see if that helps.

I'll also give what Ant suggested ago

Oh and yes I think it's AGU lol

 

[<tuffty/>]

Throttle body reset info for an AGU can be found here..
Throttle Body Alignment (TBA) - Ross-Tech Wiki

<tuffty/>

 

[Mi11ar]

Car came off the road and needed major repairs, that's now out the way and the Cars driving again, went a week without this problem but it's now back, I'm taking it my friends garage to get a TB reset on Friday if that doesn't solve it I'll buy a new MAF, if that doesn't solve it what else could it be!? lol

 

[Mi11ar]

Done a throttle body reset and the Cars still the same miss firing and the computers showing up no problems and the MAF is reading as normal....

 

[Mi11ar]

Someone suggested this - HONDA MAZDA NISSAN TOYOTA EXHAUST DE CAT O2 LAMBDA FOOLER TRICKER SENSOR SPACER | eBay thoughts?

 

[Mi11ar]

Anyone?

 

[Nilz]

Not actually seen that before or heard of anyone on here using it.

I dont think it would be that causing the issue though.

Have you had a visual check of all the pipes or are you able to do a smoke test or pressure test to see if there are any leaks anwhere?

 

[david7m]

As I don't have Vagcom I use the below process

Clear any codes with a VAG scanner.
Unhook the -ve battery terminal, leave it 20 minutes. (reset the ECU)
Hook battery back up.
Turn key to first position, leave for 10mins in this position. (should reset the throttle body).
Start car and let idle for a few minutes.
Switch off and drive as normal.

Think you need the bonnet open to reset the throttle bodies by turning ignition on, should make a whistling noise and then stop.

Dave

 

[Mi11ar]

Not actually seen that before or heard of anyone on here using it.

I dont think it would be that causing the issue though.

Have you had a visual check of all the pipes or are you able to do a smoke test or pressure test to see if there are any leaks anwhere?

Yes I've had a new FMIC fitted and had everything checked over we can't find any issues every time we plug it into the diagnostic system no errors come up and all the sensors are reading perfectly fine, even if we watch the readings while we rev the engine and it's miss firing and bogging out all the sensors are still reading perfectly fine.

Think you need the bonnet open to reset the throttle bodies by turning ignition on, should make a whistling noise and then stop.

Dave

Yea we done this the other day it didn't make a difference



I'm at a loss really lol, going to put the old CAT back on to see if that solves the problem we think it may be an issue with the ECU after doing so many mods and not mapping them in, funny thing is the Car runs perfect when cold but once it's warmed up it starts miss firing and going really boggy again....

 

[<tuffty/>]

Someone suggested this - HONDA MAZDA NISSAN TOYOTA EXHAUST DE CAT O2 LAMBDA FOOLER TRICKER SENSOR SPACER | eBay thoughts?

That won't fix your problem...

Get it to a specialist and get it logged on a dyno...

<tuffty/>

 

[JUS3IN]

i reckon its coilpacks, mine never threw a code and it ran like crap kangarooing and missing before the pack died completely.

 

[lol4fun]

Someone suggested this - HONDA MAZDA NISSAN TOYOTA EXHAUST DE CAT O2 LAMBDA FOOLER TRICKER SENSOR SPACER | eBay thoughts?

If yours is an agu which I think you said it was it won't be anything to do with the o2 sensor, they just use the maf to work out fueling.

Mine isn't happy either, its not the coil packs so I'm going to try cleaning the injectors next but need to get/borrow an ultrasconic cleaner.

 

[daz-20vt]

It does sound like a coilpack. Do you have traction control and if yes does the tc light flash at the same time as it misses. Also are you using oem sensors etc. Cheap parts can fail extremely quickly. Also as said check the loom coming from the coil packs. Cracking is common.

 

[Mi11ar]

Not the coil packs as I've replaced them, going to put the old cat on I was told that may fix the problem?

 

[s5joe]

Have you checked the temp sender unit or on a agu engine they have a ignition amp on the air box that could be faulty

 

[lol4fun]

How would you test for a faulty ignition amp?

 

[JUS3IN]

sometimes new coilpacks are faulty, especially cheap knock offs...

 

[s5joe]

How would you test for a faulty ignition amp?

i think you can with a multi meter google is the way forward for that

 

[Mi11ar]

The CAT can't go back on as the Lamdba is securely stuck into the de-cat pipe, only way it can be removed would include damaging the lambda and I needed to drive 300miles so couldn't afford to risk it.

I'm going to get the Car mapped because after plugging the Car into the diagnostics machine countless times and performing every sort of test the Cars reading up perfectly, I've replaced most sensors apart from the MAF but since that's reading up perfectly fine I don't see the point, I'll just be throwing money away until the faults found otherwise.

 

[Freeman_1986]

The CAT can't go back on as the Lamdba is securely stuck into the de-cat pipe, only way it can be removed would include damaging the lambda and I needed to drive 300miles so couldn't afford to risk it.

I'm going to get the Car mapped because after plugging the Car into the diagnostics machine countless times and performing every sort of test the Cars reading up perfectly, I've replaced most sensors apart from the MAF but since that's reading up perfectly fine I don't see the point, I'll just be throwing money away until the faults found otherwise.

Have you tried unplugging the MAF? Just to confirm? My s3 misfired with it plugged in (pretty much the same symptoms as you have) but ran spot on with it unplugged. Will only take you 5 mins, and deffo eliminates it then.

 

[Mi11ar]

Have you tried unplugging the MAF? Just to confirm? My s3 misfired with it plugged in (pretty much the same symptoms as you have) but ran spot on with it unplugged. Will only take you 5 mins, and deffo eliminates it then.

Runs exactly the same with MAF unplugged