AEM cai + top secret cat back = CEL :(

[kashy]

I installed my exhaust, gutted the precats and installed the AEM CAI,

It was fine for a week. however it just through a CEL on its 1 week anniversary.

However during the week it did seem to stutter now and again around 3000-4000rpm, revs would rise eratically and car would take time getting upto speed.

I have tried cleaning the MAF, o2 sensors, tightened Intake clamps, reseted the ecu several times. Howver i dont seem to be getting anywhere.

I have read some other posts which seem to indicate that the AEM CAI could be possibly causing the CEL. However i have tightened this.

I was gonna take toyota to get cel read however ive been advise that the j-spec cars are different.

anybody have any other ideas?

thanks

[kanujunkie]

where do you live Kashy?

there may be someone near you with a J-spec code reader

[aaronjb]

Or a MAF you can borrow (that would be my next port of call, if you can't pull the codes)

[kashy]

where do you live Kashy?

there may be someone near you with a J-spec code reader

im from edinburgh, Will give a call round some places in the next few days to see if any1 has one.

Any of you guys think it may be worthwhile to put back in the stock airbox to see if the CEL goes away?

[Anonymous]

AEM CAIs don't cause a CEL if installed correctly (e.g., no air leak).   Since you changed intake and exhaust at the same time, it is harder to tell what the cause is.  I forget the codes, but some of them can be caused by an air leak in the intake -or- exhaust according to the BGB, so even with the code(s) you may not be able to narrow it down.  Swapping back to the stock intake takes some time, but may help narrow it down.  Before doing that, I'll look at the intake and exhaust very carefully.

As I recall, cars in the UK don't have the Vacuum Switching Valve (VSV) that goes to the intake like ours do in the US, so you are supposed to plug the nipple on the AEM intended for a 1/4" hose between the intake (near MAF) and the VSV.  Make sure no air gets in there because it will be unfiltered air.  An intake air leak that would cause a CEL would be UPSTREAM of the MAF, though.

[kashy]

Hey everyone,

Jus an update on the CEL problem,

Not been able to find a code reader just yet however i did change the intake back to standard. After reset the CEL light remined off for a while then turned on later.

I also took out the o2 sensors cleaned them and put them back in a couple times. I did notice them getting covered in black soot very quickly.
Would this indicate over fuelling?

I have also double checked the exhaust for leaks and rechecked bolts.

I have a feeling it is MAF related since it seems the exhaust system seems fine and the intake has been swapped back to original without little effect on cel light.

Any1 have further suggestions?

[Anonymous]

You are right... black soot means it was running too rich.  Something could be indicating more air than there really is.   Did you say that you cleaned the MAF?  Let's see... an exhaust leak before the O2 sensor would put more oxygen in and cause the ECU to try to compensate by adding more fuel.  So an exhaust leak could be the problem.  It could be right at the manifold.. where it bolts to the head.  Did you put new studs in or reuse the ones you had?

[kashy]

Thanks for the Reply Beanie,

i reused old studs plus bolts and reused the old manifold gasket with a sealant. I have noticed the engine bay to be a lot hotter than normal but then again i have also removed the manifold heatsheilds.

Possibly gonna be a good idea to buy another manifold gasket im guessing then.

ive been driving it some today and noticed it also stutters a lot more in high gears, low revs. The revs rise suddenly then there is a lag before the car actually gains momentum.

[aaronjb]

The revs rise suddenly then there is a lag before the car actually gains momentum.

If you mean the revs rise out of proportion to the speed, and then the speed gradually catches up, then that sounds like a totally different problem - your clutch is on it's way out (or contaminated with oil, same difference - it needs replacing).

[kashy]

If you mean the revs rise out of proportion to the speed, and then the speed gradually catches up, then that sounds like a totally different problem - your clutch is on it's way out (or contaminated with oil, same difference - it needs replacing).

Hmmm could be that too, but just seems weird that CEL is popping up aswell. If i can work out what the CEL is caused by then ill get clutch changed aswell. However its proving difficult finding a j-spec code reader. So therefore i was just taking guesses on what it could be.

[Anonymous]

This sounds suspiciously like a duff O2 sensor to me.

Shoot me down in flames if I'm wrong though...

Richie

[kashy]

Can the o2 sensors be checked in anyway to check if there duff??

[Anonymous]

if you have a spare one, you can swap them out to rule out the problem. as your car is a jspec, unfortunately you dont have a 3rd one after the main cat to swap with.

I dont know if you can measure the resistance across one, or if you can substitute one with a resistor for the purposes of fault finding.

perhaps somebody on here could comment further??

[aaronjb]

I dont know if you can measure the resistance across one, or if you can substitute one with a resistor for the purposes of fault finding.

You can if it's the heater circuit that's up the spout, yes (there are posts on here if you search around), but not if it's the actual sensor..

IIRC the heater circuit bypass post also has details of the resistance specs across the heater wires.

I think, though, that a heater malfunction lights a CEL immediately - anyone able to back up/refute that statement?

[kashy]

Finally found the problem source,

Car was in at Mr T getting my leaky roof checked out. Told them to see if they can read the j-spec ecu, and they managed to but did charge me £30 to do it.

But test shows the Oxy sensor Bank 1 is faulty. Am i right in sayng this means all i have to do is replace the faulty one?

anybody know which is bank 1 and which is bank 2?

thanks

[markiii]

they read teh code but couldn't tell you which bank was which?

[Anonymous]

I think bank 1 is on the right.  That would be the driver's side on your side of the pond.

[kashy]

finally got round to sorting this out.

bought a universal o2 sensor from ebay for only £19.50 delivered  s:D s:D  Mr T wanted £135 inc labour.
CLICK HERE FOR LINK

Managed to wire it in easily by splicing the wires.
Got rid of my CEL and noticed car is a lot perkier now  s:twisted: :twisted: s:twisted:

Bank 1 is the sensor on right - Thanks Beanie

[GSB]

Bank 1 = Cylinders 1 and 4
Bank 2 = Cylinders 2 and 3