intercooler and loss of power

[BIG-JOHN]

Hi everyone,
My terrano t2 on an O3 plate i noticed yesterday the intercooler sounds to be running all the time plus i twice had loss of power, vehicle would not go through the 2000 revs range, stopped vehicle checked under bonnet to see if there was anything obvious ( there wasn't ) there were no warning lights on the dash, so turned off engine then restarted which seemed to clear the loss of power but the intercooler still runs/ you can hear it quite clearly, anybody got any ideas is it an easy to fix am i in any danger of any damage to the engine etc.....

 

[Terranosaurus]

Its not your intercooler that running John. They don't move or make a noise

 

[scubadude]

I'm no expert but it sounds like the MAF sensor is playing about, i had the same thing with my diesel car. I'm only guessing but i might be worth having a look at the EGR valve as well (if it has one).

Since i had the problem with the car i religously clean out the EGR valve as it get quite clogged with black coot.

Hope that helps

 

[Thomas-the-Terrano2]

Hi everyone,
My terrano t2 on an O3 plate i noticed yesterday the intercooler sounds to be running all the time plus i twice had loss of power, vehicle would not go through the 2000 revs range, stopped vehicle checked under bonnet to see if there was anything obvious ( there wasn't ) there were no warning lights on the dash, so turned off engine then restarted which seemed to clear the loss of power but the intercooler still runs/ you can hear it quite clearly, anybody got any ideas is it an easy to fix am i in any danger of any damage to the engine etc.....

as per TRS, are you referring to the turbo. mine occasionally has a flat spot as if turbine
stuck, feels like alot smaller engine, well guess is as is a 2.7 n/a vs 27 with a turbo.

 

[lacroupade]

BigJohn, as Tsaurus says, its your viscous fan that you're hearing - the intercooler is the radiator matrix mounted on top of the engine under the bonnet intake - it cools air between the turbo and the inlet manifold. Since colder air is denser, this gets more into the engine, plus more fuel, and enhances the burn process.

But I've just had a thought and need to ask a question of the more technically-minded folks here....the MAF is basically nothing more than a couple of wires in the air intake, pre-turbo, that sense the temperature of the air coming in - it then says to the engine management system...."ah the air being shoved into the turbo is colder so more will be going into the engine so lets squirt more fuel in" or vica versa.

But if the intercooler is doing a terrific job and really getting the air temp down, I assume the MAF is only sensing a temperature drop as a result of more air rushing past it into the turbo, and I wonder if its directly proportional to the temperature (and pressure) drop at the other end of the intercooler, which of course it can't sense - or is there another sensor there as well?? Or is it just that the turbo is able to shove more air in simply because back-pressure reduces with temperature, and the MAF-sensed cooling effect from that additional airflow over it is sufficient feedback?

Confused? You will be....:doh

 

[lacroupade]

Also check other threads but don't think an 03-plater will have a EGR, but its not a given so do check!

 

[Thomas-the-Terrano2]

I'm no expert but it sounds like the MAF sensor is playing about, i had the same thing with my diesel car. I'm only guessing but i might be worth having a look at the EGR valve as well (if it has one).

Since i had the problem with the car i religously clean out the EGR valve as it get quite clogged with black coot.

Hope that helps

as per TRS, are you referring to the turbo. mine occasionally has a flat spot as if turbine
stuck, feels like alot smaller engine, well guess is as is a 2.7 naturally aspirated vs 2.7
with a turbocharger. after all the intercooler lifts output on 2.7td from 100 bhp to 125 bhp
with tdi. guessing turbo adds a fair old bit of bhp to a straight di. (fx4 taxi output anyone).

 

[scubadude]

The experiance i had was the MAF was giving false readings to the engine management. The MAF senses air temp and flow, if either or both of these are not working correctly the engine management adjusts the amount of fuel sent to the injectors incorrectly hence power change. It maybe worth checking the whole air intake circuit for debris (air filter should catch most of it) and also checking the intercooler for oil (be careful with that one).

 

[lacroupade]

To be more precise, the MAF in a T2 is the hot wire type and doesn't actually measure airflow as such - it simply assumes a given airflow, derived from the ability of that airflow to reduce the temperature of the hot wires, i.e. if the wires cool faster, more airflow is assumed so more fuel pumped in.....in other words it only monitors the temperature of the wires. Thats why the wires need keeping clean, because if they are sh*t up (technical term!), that tends to insulate and keeps them warmer than they should be.

Thats why I asked that slightly windy question above but when I think about it, its not about the temperature of the air finally entering the manifold, but the volume - and that will be seen by the MAF as the turbo ups its game and squirts in more air..

There are other, more sophisticated MAFs that do measure other elements, but Nissan has applied KISS principles for a change (!).

 

[lacroupade]

And one simple check BigJohn - if your temp gauge in the car is reading higher than normal that could be whats keeping the fan going....new thermostat? And if its not, then something else is afoot....

 

[Deleted Member S]

Hi i'm wondering if it could poss be your air con fan (if you have air con) thats is constantly running

 

[coachmanking]

Reading through the thread - reference is made to keeping the wire clean on the MAF. Is it possible to clean the wire and if so with what?
Many thanks

 

[Jocky]

Going right back to the start of this thread, we don't now if its a 2.7 or 3.0ltr engine:nenau

I agree the noise sounds like the viscous fan.

I personally wouldn't waste my time cleaning the MAF, in my opinion its a total waste of time and money buying the cleaner.:augie

If its a bosch Maf they don't cost that much:clap

I don't think the MAF will stop the Rev's going above 2000rpm. I suspect the flyby wire throttle pedal is needing cleaned with a blast of air.

Easy test is unplug the MAF, no change and its unserviceable (knackered) if its working you'll feel the difference when its unplugged.

 

[BIG-JOHN]

thanx chaps

for those who asked its a 2.7tdi the vehicle will still travel at around 50 to 60 mph but thats it if i slow down any more it really does struggle to pick up speed again, also it is the viscous fan that is making the extra noise ( didnt know the intercooler was basically an air intake ) as i took the vehicle back to the garage as i had to have a new water pump fitted and the mechanic did say the fan is still a little stiff and will need to bed in ( is this correct? ) so the question is guys do just change the maff sensor, and also how do i find the fly by wire accelerator wire to clean it, the other thing is when it does loose power turning the ignition off resets or clears the problem temporarily, so what should i do?????

cheers john..........

 

[extreme-4x4]

for those who asked its a 2.7tdi the vehicle will still travel at around 50 to 60 mph but thats it if i slow down any more it really does struggle to pick up speed again, also it is the viscous fan that is making the extra noise ( didnt know the intercooler was basically an air intake ) as i took the vehicle back to the garage as i had to have a new water pump fitted and the mechanic did say the fan is still a little stiff and will need to bed in ( is this correct? ) so the question is guys do just change the maff sensor, and also how do i find the fly by wire accelerator wire to clean it, the other thing is when it does loose power turning the ignition off resets or clears the problem temporarily, so what should i do?????

cheers john..........

fan could be rubbing not put back right

 

[Jocky]

Hi John, it does sound like the MAF now,50/60 mph max
The MAF is just after the air filter, with a wire plug on the top or side, should say Bosch on it.
Easy test is to unplug and see if there is any change, no change and its shot. Don't be scared to unplug it, won't cause any damage.

When mine went on my T2 it sort of went slowly no sudden failure then on long run it felt gutless, 60 mph max and it took a week to get there:lol

I got one from 1st nissan garage I found and it cost £34+VAT, changed it in the dealer car park, 10mm spanner and a screw driver, its that easy

You can get some strange various prices for MAF's from nissan, so phone a couple of dealers, yours is a late model so it might be expensive:sly

The fly by wire throttle is at the top of the throttle pedal, have a look you'll see it. Check connections and that its not covered with dust etc, you can give it a short blast with air, DO NOT SPRAY it with WD40 etc.

 

[Deleted Member S]

You mentioned that you've had a new water pump fitted, I had a prob with the 1st one I fitted in that the fan was engaged all the time:dohafter 2 weeks I went back & had it swopped under warranty & the 2nd one has been fine most of the time just it seams to engage to much on motor way trips:augie

 

[BIG-JOHN]

water pump and viscous fan

You mentioned that you've had a new water pump fitted, I had a prob with the 1st one I fitted in that the fan was engaged all the time:dohafter 2 weeks I went back & had it swopped under warranty & the 2nd one has been fine most of the time just it seams to engage to much on motor way trips:augie

good news the viscous fan finally disengaged today so I now dont have the roar and wind noise coming from the fan seems to have freed itself greeeaat........ but still not as pokey as I would like there is still a definate power difficiency, have cleaned the maff sensor, also checked the air filter which is brand new have put it all back together and it still dont knock my socks off, when ya say blow out the fly by wire accelerator do i have to disconnect it or can it be done in situ???????? ( am still going to order a maff sensor ebay has em for about £43.00 is this reasonable??? )

cheers john........

 

[Jocky]

Don't unplug it no need.

Have you tried the MAF unplugged test?

And £43 is not a bad price. Make sure its the right one

 

[Deleted Member S]

Got my MAF from a main dealer in Newcastle for £45 with a full Nissan 1 year warranty:thumbsI did the unplug Maf test & the engine just died then checked the voltage & it was only .1 volt down but after taking the plunge & fitting a new MAF I had a new hot hatch