In 2007, Fiat introduced its 1.4-litre T-Jet turbo-petrol engine. This 1.4 T-Jet engine did it 3 years earlier than VAG with its 1.4 TSI.
The 1.4 T-Jet engine found its way into the Fiat Punto, Bravo, Lancia Delta, as well as the Abarth 500, Punto and Grande Punto models. We will be dismantling the 1.4 T-Jet engine taken from a 2009 Fiat Bravo 2.
But the Italian 1.4 T-Jet engine was created on the basis of the old design of the 1.4 FIRE engine family, which dates back to the mid-1980s.
Therefore, the cylinder block of this 1.4 T-Jet engine is cast iron, although the lower crankshaft bearings are cast into the aluminum lower half-block, fuel is injected into the intake manifold in front of the valves, and a toothed belt is used in the timing drive.
The Italian 1.4-liter turbo engine produces from 105 to 200 hp. in several rare charged versions. The most common 1.4 T-Jet engines develop from 120 to 150 hp.
These engines do not have a special cylinder head with a MultiAir throttleless intake mechanism; such engines appeared in 2010.
Problems And Reliability of the Fiat 1.4 T-Jet engine
The turbo-petrol Italian engine is reliable and durable. It does not have serious systematic problems and does not upset with costly breakdowns.
This 1.4 T-Jet engine has a resource of at least 300,000 km, it can easily go 500,000 km or more. Still, it’s an old-school engine.
However, the famous Italian build quality and “love for little things” often upsets small troubles in the form of fluid leaks and other troubles. Next, we will tell about everything in detail.
The generator installed on the 1.4 T-Jet engine serves well, but if it fails, it cannot be repaired with non-original parts.
So, the symptoms of a faulty alternator are very clear: a no-charging indicator and an inoperative electric power steering (EUR). Also, these problems can appear sporadically.
The generator can be repaired, but experience shows that only the original Denso relay-regulator should be installed. With a non-original regulator, the malfunction will persist.
2. Uncertain engine start
An uncommon but well-known problem with 1.4 T-Jet engines is starting the engine on the second try. The problem occurs due to insufficient fuel pressure.
The culprit can be one of three components: the fuel pump check valve, the fuel pressure regulator on the rail, or the injectors.
The first step is to check the pressure in the rail after stopping the engine – it should be about 3 bar and not drop below 2.5 bar after a few hours.
The working pressure in the rail at idle should rise to 3.5 bar. Most often, it is the fuel pressure regulator that fails.
There is also a fuel filter in the fuel pump in the tank. If the filter is clogged, the 1.4 T-Jet engine pulls poorly or accelerates jerkily.
The fuel filter is sold together with the fuel pump, which is not cheap. The owners of Italian cars have found a way out: they turn on the gasoline supply bypassing the standard fuel filter, and install a suitable fine filter under the hood in the supply line.
3. Turbocharger and boost control
The Fiat 1.4 T-Jet engine uses IHI RHF3 turbochargers. On the 120-horsepower version – the VL37 model, on the 150-horsepower version – the VL36.
These turbochargers create an excess boost pressure of up to 0.9-1.0 bar, they serve well, according to experience they can go up to 250,000 – 300,000 km without repair or replacement.
Premature replacement of the turbocharger may be necessary if cracks appear on the “hot” cast iron part. This is a fairly common problem with these IHI turbines.
In some cases, exhaust gases can escape through the crack, which naturally reduces the turbine performance.
It has been noticed that gas leakage can occur at high pressure, then the engine works normally at medium loads, and pulls weakly at high loads.
In some cases, the appearance of cracks does not affect the performance of the turbocharger.
Also, these turbochargers sometimes require attention due to oil leakage through the supply pipes and oil drain into the cartridge. Oil leakage can be eliminated by replacing the rubber seals on the tubes.
The turbocharger wastegate is driven by a vacuum actuator controlled by a conventional electro-vacuum valve.
Also in both versions of the 1.4 T-Jet engines with a power of 120 and 150 hp. there is a bypass valve (bypass) that bleeds excess boost pressure.
Most often, it is the bypass that fails, in which the rubber diaphragm bursts. In this case, the engine pulls worse, because the generated boost pressure after the compressor is again sent to the intake. With small air leaks, usually no errors are recorded.
With significant leakage of inflated air, error P0240 appears. The same error appears due to the failure of the solenoid valve, when the wastegate does not open at all and the performance of the turbocharger is not regulated.
Also, both valves can fail due to loss of contacts in their connectors.
4. Oil separator
The oil separator, also known as a breather, of the crankcase ventilation system is equipped with a rubber spring-loaded membrane that regulates the outflow of crankcase gases.
Depending on the engine operating mode, crankcase gases are removed into the intake manifold in one of two ways: before the compressor or after it.
The membrane, of course, is not eternal and may burst over the years. In this case, a whistle or hiss will be heard under the hood.
With a large crack in the membrane, a lot of oil vapor will enter the intake, traces of which can get on the air filter. The membrane can be purchased and changed separately – there are non-original parts on the market.
It also does not hurt to clean the oil separator at least once every 5 years, because. the emulsion of moisture and oil vapor that accumulates in it can freeze in winter.
In this case, the crankcase ventilation system will be clogged. There have been cases of oil squeezing through the dipstick tube.
There are also isolated cases of loss of almost the entire amount of oil due to improper operation of the oil separator and its valve when the membrane is destroyed. In this case, the engines reached the welding of the liners to the crankshaft journals.
5. Ignition coils
The ignition coils on the 1.4 T-Jet engine generally perform well. If misfires occur, as evidenced by alternating dips in power and kicks, as well as a blinking Check Engine light, then worn or broken spark plugs are usually to blame.
Of course, due to worn spark plugs, the load on the ignition coils increases. As a rule, in the first place, the insulators of the coils do not withstand. Penetrating cracked insulators can be changed separately.
6. Pump leak and o-ring
At the inlet to the cooling system pump, a sealing rubber ring is used, which eventually loses its elasticity and allows oil to leak. This ring should be preventively changed along with the pump when replacing the timing belt.
7. Heat exchanger
The heat exchanger used to cool the oil may leak oil through the bolt located in it. To eliminate the leak, you need to unscrew the bolt and replace the two rubber rings, which harden over time and cease to fulfill their function. It is better to do this when changing the oil, when all of it is drained from the sump.
8. Timing belt
The timing belt kit is the same as on other engines of the FIRE family with a volume of 1.0 to 1.4 liters. The timing belt should be changed every 60,000 km – this interval is set for difficult operating conditions.
There are no marks on the timing belt. The timing belt is replaced in a position where all pistons are at the same level.
To do this, unscrew the two spark plugs and insert two “rulers” into the vacated holes. Then the crankshaft and camshafts are fixed through specially provided holes.
9. Cylinder head
The cylinder head of the 1.4 T-Jet engine, like other engines of the FIRE family, consists of two parts. In the upper part is the bed of both camshafts and the camshafts themselves.
There is no valve cover as such. At the bottom of the cylinder head are valves and related parts: pushers, springs, valve guides, and more.
The cylinder head of a 1.4 turbocharged engine is original, it has differences from the cylinder head of atmospheric versions. Camshafts on 120- and 150-horsepower 1.4 T-Jet engines are different.
10. Engine block
The cylinder block of the 1.4 T-Jet engine is cast iron, the cylinders are bored right in the block. There is one repair size of the piston group.
The cylinder block of the T-Jet engine is different from the block of naturally aspirated engines of the same family.
This block has more developed channels of the cooling system, as well as the height of the block is increased by 0.8 mm.