Toyota 1JZ Engine Problems And Specs

JZ-series engines were manufactured from 1990 to 2007. Thus, these engines date back to the “second wave” of Toyota engine manufacturing when the first wave of the engines (and earlier years, as in this case) was replaced with less reliable ones.

The more so that the series JZ was replaced by a series of M, which I think is the most successful in the history of Toyota! Also, you may know another famous JZ engine – 2JZ.

Toyota 1JZ Specs

What Cars Have A 1JZ Engine?

• Toyota Crown
• Toyota Mark II
• Toyota Supra
• Toyota Brevis
• Toyota Chaser
• Toyota Cresta
• Toyota Mark II Blit
• Toyota Progres
• Toyota Soarer
• Toyota Tourer V
• Toyota Verossa

Toyota 1JZ Engine Modifications

1JZ-GE

Output for the early non-turbo (1990-1995) 1JZ-GE was 170 PS (125 kW; 168 bhp) at 6000 rpm and 235 N·m (173 lb·ft) at 4800 rpm.
Later released non-turbo (1995->) 1JZ-GE had an output of 200 PS (147 kW; 197 bhp) at 6000 rpm and 251 N·m (185 lb·ft) at 4000 rpm.

The 2.5-liter 1JZ uses oversquare bore dimensions (86 x 71.5mm) and, in naturally aspirated guise, a 10:1 compression ratio.

With the aid of a DOHC, 24-valve head, and a dual-stage intake manifold. Like all JZ-series engines, the early 1JZ-GE is designed for longitudinal mounting and rear-wheel-drive.

These models also came with a 4-speed automatic transmission as standard; no manual gearbox option was offered.

1JZ-GTE

First Generation 1JZ-GTE in a 1991 Toyota Chaser

Third Generation 1JZ-GTE VVTi transplanted into a 1989 MX83 Toyota Cressida

The first generation 1JZ-GTE employs twin CT12A turbochargers arranged parallel and blowing through a side-mount or front-mount air-to-air intercooler. With an 8.5:1 static compression ratio, the factory quoted power and torque outputs are 280 PS (205 kW) at 6200 rpm and 363-newton meters (268 lbf·ft) at 4800 rpm.

The bore and stroke are the same as for the 1JZ-GE: 86 mm (3.39 in) bore × 71.5 mm (2.81 in) stroke. Yamaha may have had a hand in developing or producing these engines (possibly the head design), hence the Yamaha badging on certain parts of the engine, such as the cam gear cover. In 1991, the 1JZ-GTE was slotted into the all-new Soarer GT.

The early generation 1JZ-GTEs combined the inherent smoothness of an inline 6-cylinder engine with the revving capacity of its short stroke and early power delivery of its small, ceramic-wheeled turbochargers. Unfortunately, the ceramic turbine wheels are prone to delamination in high impeller rpm and local temperature conditions, usually a result of a bigger boost. Moreover, the first-generation 1JZs were even more prone to turbo failure due to a faulty one-way valve on the head, specifically on the intake cam cover causing blow-by gases to go into the intake manifold.

A decent amount of oil vapor flows into the turbos on the exhaust side, causing premature wear on the seals. The later second-generation engines had this problem fixed. There was actually a recall to repair the first-generation engines in Japan, though that does not apply to 1JZs imported to other countries. The fix is simple and involves replacing the PCV valve (2JZ); all parts are available through Toyota.

The third generation of the 1JZ-GTE was introduced around 1996, still as a 2.5-liter turbo, but with Toyota’s BEAMSarchitecture.[2] This included a reworked head, a newly developed continuously variable valve timing mechanism (VVT-i), modified water jackets for improved cylinder cooling, and newly developed shims with a titanium nitride coating for reduced cam friction.[3] The turbo setup changed from parallel twin-turbo (CT12A x2) to a single turbo (CT15B).

The single turbo is made more efficient by the use of smaller exhaust ports in the head. This allows the escaping exhaust gasses to have more velocity as they exit the head, spooling the turbo faster and at lower RPM. In addition, the adoption of VVT-i and the improved cylinder cooling allowed the compression ratio to be increased from 8.5:1 to 9.0:1.

Even though the official power figures remained at 280 metric horsepower (205 kW) at 6200 rpm, torque was increased by 20Nm to 379-newton meters (280 lbf·ft) at 2400 rpm. These improvements resulted in increased engine efficiency, reducing fuel consumption by 10%.

The adoption of a much higher efficiency single turbocharger than the twins and different manifold and exhaust ports were responsible for most of the 50% torque increase at low engine speeds. This engine was used primarily in Toyota’s X chassis cars (Chaser, Mark II, Cresta, Verossa), the Crown Athlete V (JZS170), and in the later JZZ30 Soarer, as the JZA70 Supra was long discontinued by this time.

1JZ-FSE

In around 2000, Toyota introduced probably the least recognized members of the JZ engine family – the FSE direct-injection variants. These FSE 1JZ and 2JZ engines aim to achieve minimal emissions and fuel consumption together with no performance loss.

The 2.5-liter 1JZ-FSE employs the same block as the conventional 1JZ-GE; everything up top, however, is unique. The ‘D4’ FSE employs a relatively narrow-angle cylinder head with swirl control valves that improve combustion efficiency. This is necessary to run at extremely lean air-fuel ratios around 20 to 40:1 at certain engine load and revs. Not surprisingly, fuel consumption is reduced by around 20 percent (when tested in the Japanese 10/15 urban mode).

Interestingly, normal unleaded fuel is enough to cope with the FSE’s 11:1 compression ratio.

The direct injection version of the 1JZ generates 147 kW (200 PS; 197 hp) and 250 N·m (184 lb·ft) – virtually the same as the conventional VVT-i 1JZ-GE. The 1JZ-FSE is always used with an automatic transmission.

Toyota 1JZ Engine Tuning

Fuel pump

It all starts with the fuel pump. In stock when the pump was new, he gave 180 L\h, and it is enough to approximately 1 bar. But what is your car’s age? That’s right! You can measure it, but how to do it correctly only a few know. Ideally, you should remove the pump for this procedure. The correct solution – replace it with a new one. If this is not done, and you wind the pressure when the pump can not cope with it = say hello to detonation and the engine’s death.

Today there is a huge range of pumps. The most preferred in terms of price/performance is, in our opinion, Walbro 255 l \ h. However, it is also slightly more expensive. You can take the pump from the American Supra 280 l \ h, Sard 280 l \ h, Tomei 280-300 l / h, etc. An alternative low-cost option is to use a pump from GTR, which gives about 240-250 l \ h, but it is already used, and it needs to be measured. There were many cases where these pumps come already dead or die after a short time of operation.

Boost Up

We meant that the pump had been replaced. Then boost up begins with the exhaust. Power releasing can not take place without the release of uniFLOW. In contrast to the widely accepted, the release is not “add” and releases the already available power. Standard Edition, including the catalyst, does not allow the exhaust gases to go out with sufficient speed, and therefore, the engine is “throttled.” Our task – to give it to “breathe.”

“Barrel” of catalyst must be removed and replaced with the desired pipe diameter. Often these machines are already up to the release of the catalyst, i.e. the pipe section to the larger of the “barrel.” So the simplest version of events is the simple removal of the barrel and inserting a piece of pipe in the place of transition between the diameter of the outlet itself and the receiving tube (that’s what comes from the turbines).

A better solution would be to replace and downpipe to a larger diameter. It is possible to buy a ready-made pipe and make yourself the benefit of any welder to deal with that. We need to find a thin-walled tube (2-3mm) and bend 90 degrees and pile this exhaust pipe. The cross-section of release for boost up is recommended from 76 to 80mm if the whole issue, including a reception pipe of this diameter, will be – perfect!

We recommend using resonators, one or two after the former “barrel” of the catalyst, to minimize noise on the issue. If this is not possible, use silencers (plug in a jar, reducing the diameter).

It is argued that the exhaust pipe can leave the standard, and then release should be as wide as possible—this misperception. To exhaust gas flow rate is maximum (and therefore purging), it is necessary that the maximum diameter was first “track” and not at the end.

After installing the overboost, i.e. the pressure peaks will jump to 0.9 bar, in rare cases, up to 1 bar. Stable pressure rises from 0.68-0.72 to about 0.85. That is, we have already received an increase in power.

Air filter. An essential device. It allows the engine to “breathe” more freely, as well as release. In our opinion, one of the most sophisticated and simple is Apexi PowerIntake (or SuperIntake). It’s simple to buy it, and maintain, and its characteristics are more than sufficient. It is not recommended to use foam rubber “fungi” such as the HKS because they are good in Japan, where the roads are washed with shampoo and clean, and we pretty much suck with the sand and dust that accelerates engine wear at times! If the car came with the filter, remove it immediately!

According to the pump replacement, inlet and outlet results, we get to the 1JZ-GTE (and on the same 2JZ-GTE) from about 320 to 330 hp.

Boost controller. Apexi AVC-R, Greddy Profec-e01, etc., devices are perfect and can regulate the boost pressure, struggling with over boost, etc., but are very expensive. Mid-range devices such as Blitz SBC Spec S or R also can cope with their tasks, and their cost is much more pleasing. The simplest and cheapest solution is to buy a used boost controller of the old type like Apexi or HKS EVC. They can be found for $ 100-150 and can also cope with the task, are simple to use, and reliable.

After the installation of the boost controller, we can build up pressure to stable 0.93 bars. Then there is a limit of fuel and ignition maps on a desktop computer. Then, a little more pressure and say hi to overboost and cut-off pressure, car jerking, etc.

Now it’s time to deal with ECU. We need the card for fuel and ignition with more than 0.93 bars. There are several solutions here, but the most common – is piggyback. That is a “snag” of a standard computer—two types: strip with a chip inserted into a standard ECU or external device appendage.

Front intercooler. A necessary thing to boost up. Especially in summer.

In such a configuration, we get about 380 hp on the 1JZ-GTE and 400 hp on the 2JZ-GTE if we have the full intake, exhaust, boost controller’s pump, ECU, and front intercooler, and the pressure of 1.2 bars.

Hey, since 1JZ and 2JZ are pretty much similar, you can find more information on the 2JZ page!

1JZ Engine Problems And Reliability

The engine will not start. The most common reason for this issue is because the spark plug has been flooded with oil or fuel, so drain the water out of it and clean it with a dry cloth or sandpaper.

The timing belt tensioner is a weak point. The factory claims the belt’s power source to be 100,000 kilometers, which isn’t bad, but the tensioner causes it to break early. All engines aside from the direct injection version are “non-stick,” so when the belt breaks, the piston and valve do not collide. However, regardless of whether or not there is an issue with the timing belt because of the tensioner, it’s never enjoyable.

The electronically controlled fuel injection system in the 1JZ was a revolutionary innovation at the time, allowing for precise control over the quality of gas combustion in a wide range of revolutions. When stepping on the accelerator, the vehicle responds promptly and has a sense of animation.

1JZ Fuel Consumption

The engine’s fuel efficiency is good, given the power. In urban driving, it consumes 15 liters per 100 kilometers, whereas on the highway it uses 9-10 liters per 100 kilometers, and in a combined cycle it utilizes 12.5 liters.

High petrol usage – normally linked to the lambda probe, which has broken. It’s a good idea to change both the oxygen sensor and the air filter, as well as the mass air flow sensor (MAF).

How Reliable Is 1JZ-GTE?

The most robust and durable 1JZ is a non-VVT-i 1JZ-GE engine. The longevity of these engines is over 200,000 miles (320,000 km), although they are now ancient, and finding one in good condition is not simple.

What To Choose 1JZ Or 2JZ?

In favor of 1JZ, the engine’s cost in the secondary market and the abundance of cars going with this engine. Based on the machine with 1JZ, you can get easier to do the engine with 500hp. However, the concept of “peak power” and “long-term operation” when tuning the fore. The first DJ has a serious problem with cooling while increasing power.

In the “native” for him 320-330 hp implicit configuration engineers cope, but as soon as we increase capacity in half, start to get out of the problem. Overheating of the 6-cylinder engine when operating in peak mode is no news. It is one thing to travel 402 meters in a straight line, and the other – to move tens of minutes at “sneakers on the floor.”

However, the concept of “peak power” and “long-term engine operation” when tuning is the main thing. The 1JZ has a serious problem with cooling while increasing power. In stock, 320-330 hp are normal for it, but as soon as we increase capacity in half, the problems begin. On the other hand, overheating of the 6-cylinder engine when operating in peak mode is normal. One thing is to travel 402 meters in a straight line, and the other – to move tens of minutes at “sneakers on the floor.”

Overheated oil, lack of cross-antifreeze channels, and the main limitation of the radiator all start to play a decisive “killer” role in the engine’s operation. Western experts usually say: «no replacement for displacement.» No turbines and tricks ever replace the volume. The smaller the engine forcing per liter, the more reliable all configurations will be and the longer it will operate. Therefore, if you have the budget and the possibility – place the 2JZ-GTE! It is stronger, bigger, and has a higher margin of safety.

But the choice is yours. 1JZ can cope with the peak power of 500 hp, but how you will exploit it – is another question.

The information provided in this article is for general informational purposes only. The author and publisher make no representations or warranties of any kind, express or implied, regarding the accuracy, adequacy, validity, reliability, availability, or completeness of any information presented. The reader is advised to consult a qualified professional, such as a mechanic or dealership, before making any decisions related to their vehicle's engine oil or maintenance.