EA82T #1 & #2 Injectors staying on??

discopotato03 · Post by **discopotato03** » Wed Sep 21, 2011 10:53 am

Actually Gannon the 4 plug ones do have a crank angle sensor under the cover plate in the distributor .

I think the reason EA82s never had sequential injection was because they were able to pass the emissions levels of the day without it .
With sequential injection you have to have larger injectors because all the fuel has to be injected once per engine cycle not twice like semi sequential and batch fire does .
The advantage of sequential is that that the injection pulse can be timed to squirt at the most advantageous time in the cycle in regards to inlet valve opening . The curious thing is that its the end of the pulse or squirt thats timed not the beginning , logical if you think all the fuel has to be injected by a given point in the cylinders cycle .
Sequential systems lose any real advantage when the revs are up beyond say 2800-3000 revs because the gas speeds are high enough to ensure good mixing of the air and fuel , but its at light load/lowish revs/hot and cold starts where much of the perceived emission and consumption dramas are .

Direct injection is where it gets really complex mechanically (chamber temps/pressures) and they can have injection timing more like a diesel ( injecting towards the end of the compression strokes at light loads) to make late engines run on almost no fuel . Also amasing how much exhaust gas an engine can eat if its integrated into the overall package .

A .

YouTube · Post by **El_Freddo** » Wed Sep 21, 2011 1:52 pm

discopotato03 wrote:Also amasing how much exhaust gas an engine can eat if its integrated into the overall package .

You mean re-circulated into the chamber for re-burning like the ERG system works?

Cheers

Bennie

discopotato03 · Post by **discopotato03** » Wed Sep 21, 2011 11:49 pm

The theory is it acts like an inert gas to reduce combustion temperature and pressure to supress detonation when its desirable , for manufacturers , to have lean air fuel ratios .
Its not always possible to run retarded ignition timing to beat detonation so feeding in an inert gas is a way to be lean and advanced and partially avoid detonation .
This is why defeating EGR systems can be a backwards step if you don't have full control of fueling and ignition timing .

Gannon · Post by **Gannon** » Thu Sep 22, 2011 6:22 am

Isnt it a cam position sensor, seeing that it is driven at camshaft speed?

discopotato03 · Post by **discopotato03** » Thu Sep 22, 2011 8:46 am

All distributors turn at camshaft speed which is half crankshaft speed . It doesn't really matter if you have a 2:1 gear reduction to drive the dissy off the crank because it turns at the same speed relative to the crankshaft .
Anyway what it tells the computer is the cranks position because from there it knows where the pistons are in the four stroke cycle ie where they are in relation to top dead center on the compression strokes .
So , the computer can "read" crank speed and acceleration/deceleration and know when to inject fuel and dump the coils field .

It gets more interesting with variable cam timing because the relation of the cam/s and crankshaft changes .
The best system is the one wher you have a crank position sensor on the crank pulley and another either one or two on the cams because you need a reference pulse so the computer knows which side of the cycle the cylinders are in (remember two revolutions per cycle) and any change in cam timing with VCT .
When you have a single coil and batch or semi sequential injection , and a rotor button and cap or "distributor" , its much simpler than multi coil and sequential injection .

The reason EA82s have the dissy cam driven off the nearside head/cam is packaging , it would not have been easy to drive it off the front of an already short crankshaft and have it not foul on anything . These don't have a chain or gear case on the front like an EA81 does and lots of extras on the front which are packaged differently to 81s .

A .

RSR 555 · Post by **RSR 555** » Mon Sep 26, 2011 12:01 am

jaymoor wrote:Hey did you manage to fix your ea82t ecu, i bought off one ea82t to restore and in the process discovered the previous owner had messed the ecu. i one of the 3 transistors is missing T607(green in colour). the previous owner told me that the fuel pump failed and the techs told him its the ecu. would you help me with the part no for that green transistor so i could fix this ecu. thanks:)

Wow.. this is a blast from the past.. yes mate, I solved it with another ECU