Autopapyrus · KAMAZ-5320 10.85 V8 KAMAZ-740 (1986)
https://autopapyrus.com/guides/kamaz/kamaz-5320/fuel-injector-replacement/
https://autopapyrus.com/guides/kamaz/kamaz-5320/fuel-injector-replacement/
Compiled automatically from service literature and owner experience. Specs are for the typical configuration — check them against your exact car before you start.
KAMAZ-5320 10.85 V8 KAMAZ-740 (1986): Fuel Injector Replacement
On the KAMAZ-740, the injectors are mounted in the cylinder heads, one per cylinder, and are held down by a clamp. High-pressure lines from the injection pump and a fuel return (drain) line connect to them. The main goal is to keep dirt out of the fuel system and avoid damaging the injector seats. A new injector (or one calibrated on a test bench) must be installed with new sealing washers.
Parts
4| № | Part | Alternatives |
|---|---|---|
| 01 | KAMAZ-740 closed-type multi-hole fuel injector8 pcs (if replacing as a set, all of the same brand) | YaZDA, Avtodizel, Motorpal |
| 02 | Copper sealing washers for injector | |
| 03 | Copper sealing washers for drain fittings | |
| 04 | Injector gaskets or seal rings (kit) |
Tools
9- Open-end and box-end wrench set (mainly 17, 19, 22, 24 mm)
- socket set with a ratchet handle
- torque wrench
- injector puller (or a pry bar with a support block)
- plugs for fittings and holes
- clean container with diesel fuel
- brush
- degreaser
- lint-free rags
Step by step
14 steps- Shut off the engine and let it cool down. Disconnect the negative battery terminal. Thoroughly wash and blow out the area around the injectors, lines and fittings. Dirt must not get into the seats and passages.
- If you are replacing injectors to find a faulty one (smoke, rough running, knocking, increased fuel consumption), identify the cylinder first. With the engine running, loosen the high-pressure line nut on one injector at a time. If the engine speed and sound do not change, that injector is not working properly. Loosen the nut only 1-2 turns and place a rag under the nut.
- Disconnect the high-pressure line from the injector fitting and from the injection pump section. Immediately cap the open fittings with clean plugs. Do not bend the lines or change their shape, because even fuel delivery between cylinders depends on it.
- Remove the drain (return) line or hose from the injector, taking care not to lose the copper washers, and cap the fittings with plugs.
- If the cylinder head cover is in the way, remove it. Remove the nuts of the injector clamp, then remove the clamp.
- Pull the injector out of its seat by pulling straight out, without rocking it sideways. If it is stuck from carbon buildup, use a puller or rock it gently along its axis. Do not strike the nozzle and do not use pipe wrenches on the injector body.
- Inspect the seat in the cylinder head. Clean off carbon and dirt with a wooden or plastic stick and a rag. Do not scrape the seat with a metal scraper. Remove the old sealing washer from the seat, since it often stays behind. Two washers stacked together will give the wrong nozzle protrusion.
- It is best to test the injector on a test bench before installation. The KAMAZ-740 opening pressure is about 17.5 MPa (175 kgf/cm²). The spray should be a fine mist, even from all the holes, with no dripping or wetness after injection. The pressure is adjusted with shims under the spring on the bench. If you do not have a test bench, install injectors that have already been tested and adjusted by a shop.
- Install a new sealing washer and insert the injector into the seat squarely, without tilting, so that it sits on the washer. Install the clamp and tighten the nuts evenly, alternating, in 2-3 passes. The clamp nut torque is about 20-25 N·m (15-18 lb-ft). If your service manual specifies a different value, follow it. Overtightening or tilting can deform the body and cause the needle to seize.
- Connect the drain line with new copper washers and tighten the fitting moderately (guideline 15-25 N·m (11-18 lb-ft), without stripping the threads).
- Install the high-pressure line. First thread the union nuts in by hand all the way, without cross-threading, then tighten with a wrench (guideline 20-30 N·m (15-22 lb-ft)). The line must sit in place without tension. Tighten only with a wrench of the correct size, without extensions.
- Prime the system with the hand priming pump, with the bleed valve/plug on the filter and on the injection pump open, until fuel flows without bubbles. To bleed air from the high-pressure lines, with the engine running, briefly loosen the nuts at the injectors until the bubbles disappear, then tighten them.
- Start the engine and let it idle for 5-10 minutes. Check all connections for fuel leaks, and check the knock level and smoke. Retighten the fasteners if needed, then reinstall the cylinder head cover and any other parts you removed.
- After 50-100 km (30-60 miles) of driving, inspect the connections again for leaks and retighten if needed.
Common mistakes and warnings
- Fuel from an injector under pressure can penetrate the skin, so never test injectors with your finger or hand, and never keep your hands near the nozzle while the engine is running
- Wear gloves and safety glasses, and work away from open flames
- Check the exact torque values for your configuration against the KAMAZ-740 service manual
- If you have no experience with fuel injection equipment, it is better to leave injector adjustment and bench testing to a specialized shop