I removed the intake manifold and fuel rail assembly to replace the breather box and some other things in there, and absent mindedly didn't label which injector wire goes to which injector. I realized the mistake when I put it back together. Two of the wires are longer and two are shorter, 1 or 4 and 2 or 3 respectively, but I don't see how to tell which is which. Is there a way to?

I know I could just start the car and see how it runs, however I just put in a brand new VX cam as well. I want to break it in correctly, which means bringing the engine to ~3000RPM and keeping it in that range for a while. If my injector wires are all mixed up that'll be difficult.

So, is there a way to trigger each individual injector to tell which wire is which? Some test mode I'm not aware of? Or even some way to trace the wires and tell? The car is a 91, LH2.4 car.

Thanks for the help with my bone-headed mistake!

The "they all fire at once" comment almost came out of my mouth the other day when you asked, but then I doubted myself because it still sounds stupid to me. It sounds wrong.

We can both feel ignorant together.

Well, now we know I guess...

Hi,

The Bosch LH2.4 injectors use batch injection design (compared to sequential injections in nowadays cars). It doesn't matter which injector wire goes to where.

I've been using VX cam for many years now. Bought from IPD. During installation I used Permatex engine assembly lube (also from IPD) at the cam lobes. Looking back you could use any lube with high zinc content such as the olde blue can STP oil treatment.

Just be sure you could rev the engine up to that rpm. Mine which comes with ZF transmission could result in friction disc failure just by doing that, unless the engine has been off for more than half-hour and no gear was selected before revving. For AW transmission I think it is safe.

Regards,
Amarin.

Huh, John Sargent just said the same thing in the comment above. I've been working on these cars for years and years and I had no idea this was the case. I feel a bit dumb, actually, even dumber than when I thought I screwed up up forgetting to label the injector wires!

I've lubed the cam lobes with some Isky cam assembly lube I had left over from a SB Ford I built a while back, so I should be set, hopefully, as far as break in goes.

All four injectors open and close simultaneously. It doesn't matter which connector is plugged into which injector.
--
john

Wait, really? How can that be? Isn't every cylinder necessarily on a different stroke at any given point in time in these engines? Shouldn't each injector only fire during the compression stroke?

EDIT: Amarin said the same thing as you in the post below. I had no idea this was the case!

I understand your question, but the injectors are all wired in common in the engine wiring harness.
--
john

I edited my earlier comment above. Amarin said the same thing. I've been working on these cars for years and I had no idea!

Thanks for the help!

"I've been working on these cars for years and I had no idea!"
It surprised me too.

When I was rewiring my sister's 89-245, I discovered that. Seems to be a foolish design. The manifold is designed for sequential injection yet Bosch put in batch injection control. I think it is dumb to be spraying fuel onto a closed intake port.

But being a carb guy myself, I think it is also dumb to be spraying fuel into an open port without vaporizing it first (it is the vapor that burns, not the liquid). Anyhow, I left my sister's setup as it was.
--
1980 245 Canadian B21A with SU carb, M46 trans, 3:31 dif, in Brampton, Ont.

Hi,

The choice for either batch or sequential injections seems to start from emission requirements. With stricter requirements the sequential design seems to fit very well but with added complexity. As for top power output there is much similarity between them as the injectors fire almost continuously.

As I'm not in the engine design business the link below might explain:
http://www.enginebasics.com/EFI%20Tuning/Batch%20vs%20Sequential.html

Regards,
Amarin.