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94 N/A Aerotop - lacking power problem please help!


Guest Jamesgregory

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Guest Jamesgregory

Hi All, I have just bought a 94 aerotop N/A Auto. It needs some work and I am stripping it down to do something I think will be totally original with the styling so watch this space..

However in the meantime I have some faults to resolve. Lucky for me my freind has an Aristo with a 2JZ GTE and Auto gearbox so he has helped me quite a bit, but we are both stumped with this current problem: so here goes.

 

The engine seems pretty solid and is running very smoothly and idling perfectly, I have replaced all the spark plugs HT leads, changed the oil and thats about it so far on the engine.

The problem is that when accelerating the car is really lacking power (no jokes about it being Normally Aspirated thanks LOL:p) it's taking ages to get to 60/70 mph and i doubt it will ever reach a 100 in the current state of play, so we have been trying to diagnose the problem.

I have checked the error codes and I am getting a 24 for the IAT, could this be a simple problem to fix?

 

In Neutral the engine revs just fine and smoothly, no backfiring, smoke or misfires, it seems solid.

The guy I bought it off has an aftermarket air filter cone and has removed the original airbox and IAT.

 

Should I replace this IAT and if so anyone know the best place to get one?

 

Would really appreciate any help thanks guys!

 

James

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Guest Jamesgregory

Hi buddy, thank's ill try there, yes it is all a bit odd. I did wander at first perhaps a Tranny issue, but up to about 30/40 mph it pulls really well and changes gear fine, feels like the TorqueC is transferring power properly and everything fine. then it just feels like the engine is being starved of fuel or something trying to get it from 40 to 60+ takes an age, the acceleration just becomes really lame, perhaps I might do a video to try and explain better... ?

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Guest Jamesgregory

Oh ok yeah I know this guy I found him on ebay. cool ill try there, thanks for the tip on the fuel fliter will check that too.

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Guest Jamesgregory

Thanks for the reply Jason. Perhaps, I have been reluctant to try anything involving removing or changing the exhaust as I know this can have other implications on the Lambda sensors and might create other faults on the ECU, my car has 2 Lambda sensors pre cat and 1 after, so these could also be an issue perhaps? I have seen the cleaning procedure on here so might try that too!

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Thanks for the reply Jason. Perhaps, I have been reluctant to try anything involving removing or changing the exhaust as I know this can have other implications on the Lambda sensors and might create other faults on the ECU, my car has 2 Lambda sensors pre cat and 1 after, so these could also be an issue perhaps? I have seen the cleaning procedure on here so might try that too!

 

No problem, this is a great forum so you're in good hands :D I would definitely clean or replace the sensors anyway tbh. My NA ran slightly rich and it was the lambda sensor.

 

I don't think it would make it run that poor though unless its running in limp mode?

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Guest Jamesgregory
No problem, this is a great forum so you're in good hands :D I would definitely clean or replace the sensors anyway tbh. My NA ran slightly rich and it was the lambda sensor.

 

I don't think it would make it run that poor though unless its running in limp mode?

 

Thanks Jason and Listy, will try the things mentioned above and report back in the next few days. Yes indeed the Forum is very useful!

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  • 1 month later...
Guest Jamesgregory

Hi Jason,

 

After a busy few weeks, I have managed to crack on with some more bits on the Supra, today we took the whole exhaust apart and sure enough the hot side of the catalytic converter was totally messed up like a messed up thing. After an hour or so and an assortment of: an SDS power drill with a foot long drill bit, a hammer, a cro bar and some pliars I managed to totally hollow out the Cat, so the exhaust is effectively straight through now. And seems to have massivly improved the power! Just got to do a general service put some new plugs / oil and filters and I think she will be perfect again.

 

Thanks for the advice, top tip!

 

James

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Cats usually fail because the fuelling goes up the swanny and they get burned. I think something else might be amiss and the cat is just a symptom rather than the route cause.

 

Anyway, as he's just bashed it out the problem has gone away (until the next emissions test :) )

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I'm amazed nobody has said, its slow because its a N/A :p

 

Still glade you managed to find out that it was the CAT mate. :)

 

For once i think people listened to the "Please no NA jokes" in the first post ;)

 

I had the same problem with my old NA thinking about it now, except my 2nd cat caught fire! Luckily I was outside Spar when i noticed, ran in, grabbed a bottle of water, shouted "I'll pay in a minute" ran to the car, and put it out! Then went back in to pay and explain :)

 

Once I put a decat in, never had a drama again. However, I did find out later the exhaust manifold was blowing, but dont know if it was connected or not.

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Just to clarify a previous post the NA has two lambda sensors in the manifold pre first cat. The sensor in the first cat is the overheat sensor. Have you reset the ecu and tried running again to see if the code comes back? i would be surprised if the cat was the route cause but i did once own a car that the back box collapsed and restricted power

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Guest Jamesgregory

Hey fly,

Yes reset the ECU, code keeps coming back because there is no intake air temp sensor. However the guy I bought it off said it ran perfectly until the Cat had collapsed so I am hoping this has fixed the problem, we won't know for sure though until I fix the sticky brake problem.

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Guest Jamesgregory

Hey Digsy,

 

Yes this is a concern she does seem to be running a bit rich, smelling a bit petrolly at the minute which might have cooked the Cat, which could be a result of the aftermarket air filter and no air intake temp sensor.

 

I am still trying to find a stock airbox. I think Keron might have one.

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