1
）
Cleaning instrument of cleaning under vehicle
2
）
Cleaning instrument of cleaning inside vehicle
7
．
Special tester
When check the engine control system, use diagnose tester to help finding source of fault is effecitive.
Currently, in the vehicle repairing market most diagnose tester are table type engine fault analysis meter. Also on
the market distributed portable type engine computer tester is applied. These tester usually has diagnose interface,
take the interface connect with engine inner cabin or the fault diagnose socket which under panel, then operate
key-indicate on the tester control panel, can test micro computer control system’s sensor , actuator and its circuit.
These testers’ advantage is, carry easy, operation simple, though price is high, about one engine control
comptuer’s average price, however it can avoid changing no damaged parts while maintenance ,also can
improve the speed and efficiency ,so to the buyer, economy benefit is obvious.
Portable engine computer tester has these function as following::
(1)Take dynamic testing on engine micro computer control system while engine running or car running.
(2) Read fault code from the engine computer’s memorizer.
(3)After checking , clear the engine computer saved fault code according to the operator’s order.
Now, some engine computer testers imported from America have already been sold in civil, different testers
suits for different engine microcomputer control system testing, also there is one suits for multi type engine
computer control system, called all-purpose computer tester. For example, Owatonna Tool Company sells the
computer tester called OTC monitor.
This monitor is a LCD ,showing in a way of menu type, operate control key by select menu item when
testing, simple and convenient for using, showing in simplicity, diagnosis data transmission cable which
connecting with diagnosis socket with multi-interface; used for plug diagnosis socket of multi-type vehicles. At
the end of monitor with PROM socket, use relevant PROM magnetic card when testing different veheicle.
Basic principles and attention items of failure diagnosis
1. Operation principle
1
）
Only digital multi meter (usually above 10M
Ω
)permit to check electric inject system.
2
）
Repairing work pls use quality goods parts, otherwise can’t guarantee electric inject system normal
operation.
3
）
During the maintenance , only can use lead-free petrol.
4
）
Please abide normative repair and diagnose flow ,to do the maintenance.
5
）
During the maintenance disassemble electric eject system parts is prohibited.
6
）
During repairing, take the electronic components ( electronic control unit , sensor and so on), shouleb
careful, don’t let them fall down on the floor..
2. Judgment principle
Engine microcomputer control system is a complex system, grasp systemic examine steps and methods when
diagnose the faults. From the principle of view, if diagnose and fix one engine fault which may referred to
microcomputer system, first , check the fault whether has relation with microcomputer system. When engine get
fault, but warning light not show light ( no display code) in the most time, this fault may has relation with the
engine micro control system . At this time , should take it like engine machine part, checking as basic diagnose
process .otherwise, may take lots of time to check microcomputer sensor, actuator , circuit for a fault no relation
with microcomputer, however the not get the real fault.
The cause of typical faults which no relation with microcomputer :
a
．
idle speed not steady(even flameout)
(1) Idle speed too low.
(2) Idle speed mixed air ration not correct or not average(vacuum leakage)
(3) Ignition time postpone.
