Ford Ranger Powertrain Problem

[Nereus]

if the intercooler has sprung a leak, you will hear it as you accelerate, with some loss in power.

Please remember, I am a complete mechanical ignoramus.

Saying you will hear it, makes my ears prick up. Could this be the whooshing I've been reporting? The same whooshing they replaced the original turbo for?

When did they replace the turbo? Or are you referring to the original warranty replacement?

As for a "whooshing" sound it depends entirely on where it may be leaking. If its at the intercooler, as it appears that component is mounted in front of the radiator, then I doubt very much you will hear it in the cab. If it is leaking from a blown hose, yes it MAY be heard from the cab. Different turbos can and do make different sounds, even when they are operating normally. As I posted previously, the turbo is an air compressor, driven by the exhaust gas from the engine, and by definition there will be pressure in the system. The electronics, in this case it seems that Ford call it "Power Train", will monitor the "boost pressure" and report a fault if the boost pressure(air) is less than that set in the electronics.

As there is pressure involved, there has to be some form of "limiter" to prevent over pressuring the both engine and the hoses. It is called a "waste gate", and is more of a relief valve than a regulator, although that is its function. These can and do fail, which will also lead to an alarm light if the boost pressure drops too low. There is also a device called an "EGR valve". This is "exhaust gas recycling" and can ALSO fail leading again to a fault condition.

But of course, Ford Hua Hin will keep this in reserve, so when the next fault occurs they have something to blame it on!

[Big Boy]

The turbo was the original warranty replacement.

I noticed the whoosh was very prominent Tuesday. Didn't get a single warning light yesterday.

[Nereus]

The turbo was the original warranty replacement.

I noticed the whoosh was very prominent Tuesday. Didn't get a single warning light yesterday.

I am not sure just which model engine you have in your car. Some models use "variable geometry" inlet vanes on the turbo, in place of a waste gate. The device is controlled by the engine electronics, which it seems everybody except Ford, call an ECU. The linkage that operates the vanes can and does "stick" or become worn and not operate correctly.
That COULD lead to intermittent noise, but I would also expect it to be felt through either rough running, or "surging" of the engine.

Such a fault SHOULD be recorded in the electronics and be read with their test book / laptop.

[Big Boy]

Most of what you just said went straight over my head

However, before changing my turbo, they had all sorts of devices attached to my car, and even brought over a team of specialists from Pattaya. I had to drive the car, indicating when I heard the noise, and this was recorded alongside the sensor readings. However, I don't think any of it made much sense to the specialists,or at least, they didn't show much reaction with each whoosh.

[Nereus]

Most of what you just said went straight over my head

However, before changing my turbo, they had all sorts of devices attached to my car, and even brought over a team of specialists from Pattaya. I had to drive the car, indicating when I heard the noise, and this was recorded alongside the sensor readings. However, I don't think any of it made much sense to the specialists,or at least, they didn't show much reaction with each whoosh.

I will be in town next week if you would like me to have a look at it with you and try and explain what is what. The following is a varibale vane turbo, which I am now suspecting that you may have.

turbo.jpg (32.72 KiB) Viewed 555 times

The round component with a small black hose going to it and a long rod running left to right operates the variable vanes of the turbo that are inside the housing with the red cover over it on the right. (the red cover is NOT used when on the car)

[Big Boy]

Hopefully, there won't be a problem to look at next week. But I won't say no just yet.

[VincentD]

Having had only a petrol turbo engine (but I would assume the principles of operation are similar), when the turbo spools up, pressure builds up in sync. Most wastegates are of the recirculating type, that is, the excess boost overpressure is vented back into the intake. The purpose is mainly noise reduction so you won't hear the psssht! noise after every gear upshift coming off boost. (Though the boy racers love it.)

If you have a leak in the pressure side of the turbo, that hissing (whooshing?) sound will get louder and more prominent the harder you push the engine. Doesn't matter whether variable vane, solenoid valve or check valve, if there is pressure and it is leaking, you will hear it.

Remember. No leak, no hiss. And only when there is boost pressure, i.e. the engine is under load. Turbos only work if there is enough exhaust gas to drive them.

Do hope it gets sorted out soon.

[Nereus]

Hopefully, there won't be a problem to look at next week. But I won't say no just yet.

I wasn't looking to fix anything, rather just show you which parts are which.

[Dannie Boy]

Hopefully, there won't be a problem to look at next week. But I won't say no just yet.

I wasn't looking to fix anything, rather just show you which parts are which.

BB wrote:
Most of what you just said went straight over my head

Now you get a chance for some of it to hit just below the forehead!!

[Big Boy]

Hopefully, there won't be a problem to look at next week. But I won't say no just yet.

I wasn't looking to fix anything, rather just show you which parts are which.

HaHa, sorry - thought you wanted to give me your opinion of what the problem was (didn't expect you to fix anything ). It really would be wasted on me

If they fail this time, I will refer it to the garage you suggested.

[Nereus]

Most wastegates are of the recirculating type, that is, the excess boost overpressure is vented back into the intake.

Hmm, I have worked on turbos from small diesel engines on earthmoving equipment, right up to marine engine turbos bigger than a complete Ford Ranger engine, and I have yet to see one that vents back into the inlet manifold. I would be interested to know which one you are talking about?

The exhaust gas turbine speed, and hence the compressor side speed, HAS to be regulated to control the pressure. if it was not the turbine speed would become excessive at higher engine RPMs and associated increased exhaust gas flow.
Allowing the charge air back into the inlet manifold would completely negate the purpose of the turbo and very likely blow out the intercooler, or damage the compressor side.

The purpose is mainly noise reduction so you won't hear the psssht! noise after every gear upshift coming off boost.

The purpose has nothing to do with noise, entirely connected with controlling the boost pressure.
Big marine engine turbos exhibit a phenomena known as "barking", when in rough weather the load suddenly comes off the propeller. If you have never been close to one when it happens I can assure that when you stop running away it will just be to change your underwear!

I have no experience with petrol engine turbos, so my comments relate to diesel engines.

[VincentD]

A quick explanation for Nereus. I used to play around with Saab turbos and did a fair bit of modification of which the turbo was one of them.
1. Wastegate spring controls base boost. The (vacuum operated) wastegate actuator is not attached when testing this.
2. We increase boost with an electronic valve that is connected to the wastegate actuator, so we delay opening of wastegate, thus increasing boost.
3. there is a recirculating valve that dumps excess boost back into the inlet on sudden throttle closure so as not to cause a shock wave against a closed throttle plate that could stall the turbo

Yes, petrol turbo systems are a bit more contrived. You're right about the noise reduction not being the main purpose.
I tried a manual boost control valve as a first mod, better spoolup and slightly higher boost than stock, but sensitive to the weather. Second mod was an ecu reflash; combined with a few other mods had the car up to 285 hp, up from the factory 185.
Sold the car at 16 years old when I could not get comprehensive insurance in Thailand for a car that age.

[Nereus]

You are taking the thread off topic talking about both petrol engines and race cars. I have not played around with any of them, but I was paid to maintain diesel engines. What you are talking about is as quoted on Wiki:

Anti-surge/dump/blow off valves
Main article: Blowoff valve

Turbocharged engines operating at wide open throttle and high rpm require a large volume of air to flow between the turbocharger and the inlet of the engine. When the throttle is closed, compressed air flows to the throttle valve without an exit (i.e., the air has nowhere to go).
In this situation, the surge can raise the pressure of the air to a level that can cause damage. This is because if the pressure rises high enough, a compressor stall occurs—stored pressurized air decompresses backward across the impeller and out the inlet. The reverse flow back across the turbocharger makes the turbine shaft reduce in speed more quickly than it would naturally, possibly damaging the turbocharger.
To prevent this from happening, a valve is fitted between the turbocharger and inlet, which vents off the excess air pressure. These are known as an anti-surge, diverter, bypass, turbo-relief valve, blow-off valve (BOV), or dump valve. It is a pressure relief valve, and is normally operated by the vacuum from the intake manifold.

It does go on to mention about petrol injected engines that use a MAF type of sensor having to employ what you are referring to.

The first thing that you have to accept is that although both a diesel and petrol engine turbo are basically the same, the air intake is vastly different. A diesel engine does not have any throttle valve, the air has a clear intake into the cylinders. The speed of the engine is controlled solely by the metering of the fuel. ALL diesel engines have to have some from of controlling the boost pressure via the exhaust gas flow. It may be a waste gate, variable vanes or some other means, but it is not via dumping the charge air back into the inlet.

If you want to have a thread about your experience with turbo petrol engines, then I am sure that there is room for it on here.

[VincentD]

Cheers. Back to topic and hopefully a happy conclusion.

[Big Boy]

Well, the car is back, and all seems well. I got the call to collect 3 hours earlier than expected. The whoosh sound has gone, so maybe a leaky intercooler has been the problem all along.

Not sure when the next decent run will be to test the repair. Although the last time the light came on it was about 5 miles from home.