Hi,
I just replaced the fuel pump cause it won't turn anymore

During troubleshooting I noticed that the injectors wires were not as per Buick Service Manual (car is a 1992 Buick Roadmaster with L05 350ci)


Uploaded with ImageShack.us

Here the green/red is on driver side. It has been like that for at least 2.5 years when I bought the car.
In Service Manual this is supposed to be injector #1 and wrining diagrams show that wires should be blue/red.
but blue/red is connected to injector of passenegr side

I have wired as per Service Manual and did not notice real change up to now but I only did a very short test drive ...

What should I do ???

 

Position of injector connectors makes absolutely no difference what so ever. Tried it before.

//RF

 

Well the experience I have is that engine still works OK but then why GM engineers would do two output from the ECM to the two injectors if not to spray gas exactly when needed on each side ??

Also I have an ECM with EBL FLASHER so I am wondering if this is not taking even more advantage of the two injectors ...

I understand the plenum is BIG and there is kind of inertia in the fuel delivery from the injectors to the cylinders so this would hide not-synchronised injection. Result would be poor economy ? no ?

 

TBI ECM fires each injector on alternative time bases. In other words it is normal for TBI ECM to fire one injector once it receives distributor reference pulse - synchronized with the spark plug firings. A TBI system typically fires the injectors every other spark plug firing. That is, 2 injectors, each firing alternately on each spark plug firing. From the overall scheme of things since intake plenum is interconnected below TB fuel - air mixture is shared.
//RF

 

OK but then if gas from injector 1 is expected in one cylinder - let's say cylinder 1 on alternator side - the time for gas to reach this cylinder will become longer if it is indeed the injector 2 that is commanded to fire instead of its mate, injector1 ...

I imagine that this time difference will have an effect.

A bit like if ignition timing was not set at 0° but at 4° for example.

So it is my understanding that if both injectors do not fire at the same time (I saw clearly them firing one after the other at idle with filter box removed) then it is of certain importance to know which one is correct, the Service Manual or the initial state of the car.

 

It doesn't make a difference. The ECM has no idea which plug is firing at any time anyway. It's a wet-flow manifold, the injector just has to keep it filled with a "fog" of fuel. The timing isn't important.

 

jeeezz this is far from rocket science

just pooring gas into a big cast iron block ...

 

What did you expect from 30 year old technology?