Basic DIY Diagnostics!

Here's some tips for DIY(do it yourself) tuning tips. reading this may actually save you
a trip to the Mistri.

Pretty basic..here Goes.
1.Checking your air filter element.
Remove air filter element.
Remove governer advance vaccum hose.(Carby)
Remove vaccum(either afm or map) hose (EFI)
Start er' up
Put the filter back in while she's running
If the rpms drop significantly or stalls-Replace filter element.
2.Cheking AirFuel Ratio
Take out the air filter;
Run engine at idle;
Slowly cover the carby with your hand or other appropriate apparatus.
If the engine rpm increase the mixture is lean & if it decreases it is rich
Repeat for 1500 & 2500 rpm.
(Oh yeah, stop sniffing those exhaust fumes)
EFI's usually display a fault code.
Short appropriate terminal and diagnose.
3.Checking Individual Compression-Leads-Plugs(Cylinders)
Start her up.
While she's running, remove spark lead to Cylinder one(Nearest the timing belt)
Ground the cable to the engine proper.
Note decrease in difference in rpmRpm amongst the cylinders. A drop off bw 50-80 rpm is okay.
If one or more cylinder drops the rpm more than that, thats usually the faulty one.
4-Checking Up of Internal Engine rattles and problems!
Before you actually proceed not that converting an old stethoscope with a welding filament
or a used screw driver makes a good audio isolator and helps you listen to the
internal goings on of the engine with fair clarity.
NOISY BIG END BEARINGS.
A loud thumping noise/knock emitting from the engine at idle usually means screwed
up big end bearings. A further characteristic of this noise is that it dissppears under load.
Ususally induced by using overadvanced spark or valve timing. Excessive full throttle
starts and engine neglect. A lighter sound usually denotes wrist pin (piston pin) damage
PISTON SLAP.
Sound caused by excessive freeplay of the Piston in the bore made by the piston skirt hitting
the cylinder wall on the power stroke. Retiring your timing should reduce this noise alongwith
a steady drop off in power accompanied by excessive intermittent blowby.
COLLAPSED VALVE LIFTERS(Diesel engines)
That excessive RAP-TAP you always curse especially in the winters!!
TICK TICKING.
Thats usually excessive LASH or excessive tappet clearance.
Happy Tuning