NISSAN SKYLINE – LAUREL R34 - C35 with RB20 DE NEO L/B engine – “Loss of power, poor dynamics

07.12.2008

NISSAN SKYLINE – LAUREL R34 - C35 with motor RB20 DE NEO L/B –
“LOSS OF POWER, POOR DYNAMICS”

An increase in the vehicle fleet in developed countries always puts the issue of ecology as a top priority. Tightening emission standards is one of the reasons forcing automakers to produce new engines and car owners to update their vehicles. For this purpose, there are various insurance mechanisms, including the purchase of outdated cars, surcharges and the purchase of modern ones that meet new toxicity standards. This is the development of the scientific industry, mechanical engineering, technology, economics, etc...

Undoubtedly, the constant race to raise standards pursued by the governments of developed countries is also an attempt to limit the import of foreign manufacturers, especially from developing countries, whose cars, due to a lack of technology, cannot fit into certain standards (including “crash tests” ), but are successfully sold in other developing countries.

This approach is understandable - the government cares about preserving jobs, economic stability, protects its market from low-quality goods (and not just cars), but at the same time, the fuel in this country corresponds to the highest class at all gas stations, roads are called roads and speed limit comply with EVERYTHING without exception. It’s not entirely clear when there are no roads, instead of gasoline - ....., the rules are not written, but EURO 4 for the elite was introduced as a pass at customs, although no one strives to achieve it, and it is impossible. Simply “separate financial flows” - this is possible.

Some of the leading companies, anticipating the tightening of toxicity standards, are investing a lot of money in advance in scientific research, developing technologies that will later help them survive and compete.

One of these TOYOTA, the LEARN BURN series of engines was an intermediate stage

transition from stoichiometric to lean combustion engines. If we differentiate them by the A/F ratio, then these are:

1. A/F =14.7

2. A/F ≈ 24

3. A/F ≈ 40

In the second and third cases for different models You can put the sign “approximately” instead of “equal”.

The second case includes LEARN BURN motors, and the third is D4 and all analogues of NEO Di, FSI, etc.

Such “transitional” motors of this period of group 2 include the motor RB20DE NEO L/B(Learn Burn) which NISSAN produced from approximately 1998 to 2002, until the NEO Di series came to replace it.

What is cardinal about this engine, in contrast to its predecessor RB20E and its contemporaries RB25DE NEO, that it received the L/B prefix? The main thing is combustion chambers, timing systems and phases, installation of an ignition system with higher energy, introduction of mechanical dampers SWIRL for lean mode. Introduced deep feedback according to DC and one HF rotation sensor was added. All this made it possible to “remove” 155 horsepower from the two-liter inline six, meeting the 2000 toxicity standards for Japan. Many may ask - why so little? But the question here is not the number of “horses”, but how to keep track of the toxicity of the exhaust. After all, all declared cars with their declared power must comply with these standards - otherwise they cannot move on public roads on their own - only on a tow truck. Please - there are tracks, I brought the car, paid for the emissions of the overpowered engine, burnt the tires - back to the trailer and to the garage, "tuning" further. But on the streets you can breathe. In general, there are many ways to improve the ecology of streets (but all of them involve high quality gasoline for starters).

This modification of the engine required changing the intake manifold - it became composite - to accommodate the dampers SWIRL , stopping access of the fuel-air mixture to one of the intake valves. (this engine has 2 intake valves per cylinder).

Since the injector is located in front of the intake valve, then fuel-air mixture is formed in intake manifold, but the nozzle is located in front of one of the intake valves, so blocking one channel increases the flow rate and improves mixture formation. In fact, the damper only blocks the air for one of the intake channels, since mixture formation is carried out in the second channel, where the nozzle is located. The dampers operate discretely - or are closed for idling(low loads) or completely open. A malfunction of this system leads to a sharp decrease in engine power. But the main thing is that with the introduction of such a manifold, NISSAN received one problem that is not typical for engines of this series. Since the car uses separate “grounds” and grounding points for power and signal circuits, in this engine the signal ground of the sensors has always been located on the intake manifold in the area of ​​the coolant temperature sensor on the ECU (output to the upper radiator pipe). The manifold is always bolted to the block and this connection has never caused problems on the RB series. It is noteworthy that, in order to save money, NISSAN used three-wire DCs, in which the signal “ground” was the sensor body. All this led to a change in the DC signal relative to a given one, namely, the appearance of a threshold.

Consider Figure 1, which comments on the appearance of code such as DTC P0131 – Heated Oxygen Sensor 1 (FRONT) – LEAN SHIFT MONITORING

In the left picture ( rice. 1-1) - everything is normal, the DC signal exceeds the level of the rich mixture RICH, the threshold of which the ECU set to 0.6 volts (for reference - the threshold lean mixture 0.35 volts)

If the DC voltage is above 0.6 volts - a “rich mixture”, less than 0.35 - a “poor” mixture. Such a hysteresis loop makes it possible to accurately distinguish between operation in transient modes, as well as determine the inactivity of the DC. If the DC signal is constantly in the area of ​​lean mixtures, it means there is a problem, the solution to which includes checking the DC, injectors, air leaks, fuel pressure, etc. In addition, due to the savings on the 4th wire of the DC, its signal “ground” is determined by the quality of the contact in the threaded connection of both the DC and the exhaust manifold, and the exhaust manifold itself. Why is this so - it’s all because of the separation of power and signal “grounds”. If a bad contact occurs in the DC thread (resistance increases), then a certain part of the DC signal drops at this resistance, lowering its value to a constant level. This leads to a downward shift of the oscillogram - Rice. 1-2(the signal amplitude does not change), but the positive half-wave ceases to overcome the upper threshold of the trigger hysteresis in the ECU. The management decision is to “retighten” the DC. Let's put it this way - " This Not Always Just" not only because of accessibility, but also because of the impossibility of unscrewing the DC without damaging it (dents on the body are unacceptable).

Another reason for P0131– poor contact in the signal ground – it is also recommended to retighten it. Installing a 4-wire DC solves some of the problems - the signal does not depend on the state of the exhaust manifold, but you have to lay an additional wire.

All this is very good if your car diagnostics comply with EURO OBD, which has codes for such cases. And if you have a car with a 14 pin connector, the ECU of which does not contain such codes - but in DATA STREAM mode, graphically you determined that the DC signal level was insufficient, retightened the signal ground and DC bolts - but it did not help, then for this motor you need to “ground” ” the very point of the signal ground. To do this, it is enough to connect two points with a wire whose cross-section is not lower than 3 mm².

Photo 1 Grounding point for the signal part of electrical equipment

Photo 2 The point on the intake manifold to which the signal ground must be connected.

How to check the need for such an operation without a scanner that displays the real date - turn on the ammeter between these two points. If the current exceeds 0.2 A, then the design needs to be modified.

What customer complaints have we encountered:

- « loss of power after engine warms up" – this is the main reason for contacting. After the temperature reaches 60 degrees, the fuel correction is significantly taken into account according to the DC readings, and the owners complained that after warming up while driving, “they let off the gas - pressed it, and it was as if the car had been hitched to a trailer.”

- “The revs are rising, but there is no acceleration “ etc.

Another rating: - “Very sluggish acceleration up to 3000 rpm, then nothing seems to happen.”

From messages in the forums, most of them changed spark plugs five times from simple to iridium APEXi 7 (with photo reports on the work done), all sensors in a circle (starting from MAF, etc., fuel pump, washing injectors, who knows...).

Some even managed to overhaul the automatic transmission, and I personally met such people. There was no limit to surprise. This is understandable - there are no errors (and there won’t be any on this engine), but the problem is unsolvable. It’s just that on the RB25 the manifold is solid, but here on the SWIRL flap spacer there are gaskets on which mass resistance increases over time due to oxidation . In DATA STREAM mode, when the O2 B1S1 signal is graphically displayed and the points on the collectors are connected, the signal immediately changes its appearance from NG to OK (Fig. 1) and the car receives full acceleration dynamics, and the owner is surprised by one wire.

Gadzhiev A.O
© Legion-Avtodata

Gadzhiev Arid Omarovich, Moscow, Ermakova Roshcha str. 7A, territory 14 TMP, www.nissan-A-service.ru tel. +79265256300, e-mail: [email protected], Union of Automotive Diagnosticians

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Books

• , . We bring to your attention a repair and operation manual Nissan car Laurel has been produced since 1997. The publication examines in detail the structure of the car and provides recommendations for…
• Nissan Laurel: Operation, maintenance and repair manual, A.V. Kondratyev. We bring to your attention a repair and operation manual for the Nissan Laurel car produced since 1997. The publication examines in detail the structure of the car, provides recommendations for…

The history of the Nissan Laurel car began in 1968. And it ended in 2002. During this rather long period of time, eight generations were released of this car. It was mainly sold in Japan. Although occasionally this model was exported to European and Asian countries. The car was really good, so it’s worth briefly talking about all its eight generations.

Start of production

Initially, the Nissan Laurel was produced as a 4-door sedan. But two years after the start of production, the company began releasing another version of the model. Namely, a 2-door hardtop coupe.

The model was offered with three various engines: G18 1.8, G20S 2.0 and G20T 2.0. Their power was 105, 110 and 120 “horses”, respectively. By the way, not only a 4-speed manual transmission was offered, but also a 3-speed automatic transmission. However, it was rear-wheel drive only.

The car looked stylish. Attention was drawn to the double round headlights, sparkling chrome radiator grille and a powerful hood. The rear view mirrors located on it gave the car special originality.

In 1970, an updated Nissan Laurel with a hard top was released. Dashboard also improved, and also added the executive GL package to the line. In 1972, the first generation was no longer produced.

Further release

Since 1972, the second generation of the model has been released. The appearance was somewhat transformed, but much more important was that the line power units became wider. The Nissan Laurel C130 was offered with engines of 1.8, 2.0, 2.6 and 2.8 liters, respectively. There was also a choice in terms of suspension. It could be either independent or with a continuous bridge.

The third generation, which was produced from 1977 to 1980, was very popular. It was a stylish, long and low sedan with a completely updated appearance. In place round headlights square ones arrived, and dynamic and clear lines became noticeable in the body itself. And in 1980 on latest models 3rd generation, a hatch appeared. Interestingly, a 2-liter diesel unit has been added to the engine range.

4th and 5th generations

From 1980 to 1984, a model was released that was available exclusively in a 4-door body. "Nissan Laurel" fourth generation was available with eight different engines. Of these, two ran on diesel fuel.

The fifth generation saw the return of the hardtop. The model itself has gone through significant tuning. Nissan Laurel began to look more elegant and respectable. The car was also equipped with a powerful 175-horsepower engine, known as the RB20DET. It was the best of all offered. It had 4 valves, 2 camshaft, electronic injection fuel and one turbine. True, the consumption was quite impressive - about 10.5 liters per 100 kilometers in mixed mode.

It is also worth noting that these cars were the first models to use active suspension.

C33

The sixth generation became known under this name. It was produced from 1988 to 1992. Sixth generation cars were offered exclusively in hardtop form. And quite powerful engines were installed under their hoods.

Take, for example, the 205-horsepower 2-liter engine. Nissan Laurel with such a unit was extremely popular and in demand. Not surprising, since it was the only one equipped with a turbocharger.

But there were also other options: 180, 155, 125, 94 and 91 liters. With. The engines were already offered with a 4-speed automatic transmission and a 5-speed manual transmission. Although the most powerful engines were also available with a 5-speed automatic transmission.

Nissan Laurel has undergone a significant technical transformation. So, for example, they started installing an independent gear in front shock absorber strut. And at the rear there is a multi-link suspension. This suspension was also independent.

Interestingly, some models were offered with the HICAS system. Thanks to it, the rear wheels were activated during sharp turns or drifts. In general, in terms of handling, the sixth Nissan generation has become significantly more advanced compared to its predecessors. Ventilated disc brakes and even an ABS system began to be installed on all wheels.

C34

The seventh generation was also produced for four years. And he was given special attention. It is not surprising that the C34 has become the main competitor of the Toyota Mark 2. Its design was radically redesigned, but it was decided to place emphasis on organizing the internal space, which did not go unnoticed. All Nissan Laurel parts and components were perfectly calibrated and adjusted. The ergonomics of the cabin turned out to be top level. As is the equipment. Airbags, ABS, climate control, air conditioning, velor interior - the car was equipped with everything possible.

And of course technical specifications They also became noticeably better. A powerful 2.5-liter 235-horsepower engine appeared, and the weakest was the one that produced 100 “horses.” Engines of 125, 150 and 190 hp were also available. With.

Gasoline models were offered only with an automatic transmission (4 or 5 speeds), and for diesel versions“mechanics” was also available.

Recent years

From 1997 to 2002, the eighth generation Laurel models were released. The engines remained the same, but a 280 and 200 horsepower engine was added. The popularity of the model began to fall, as many people chose the Toyota Mark, so the developers decided to focus on increasing the power of the units and technical characteristics in general. They even began to offer automatic transmissions with the function manual control. And an all-wheel drive version appeared.

The list of equipment has also been expanded. Appeared multimedia system(more precisely, a radio tape recorder with a video playback function), six powerful speakers, ABS, 3-circuit seat belts, parking sensors, electric mirrors with adjustments, a light sensor.

The rarest configuration is the Club S Type X. This car boasted a leather interior with suede inserts, a sports gearbox, xenon optics, factory tinting, electric seats and other additions.

The model was not delivered to Russia, but many people brought it themselves. Now it can be found in sales through advertisements. The normal price for a model produced in the late 90s or early 2000s is about 200-300 thousand rubles.