Injector questions

[steve_d]

Hi

Started my 3.5 EFI which has been stood for some time and one of the injectors has most likely died.

I plan to fit MegaSquirt to it at some time so these two issues prompt some questions I hope someone could answer.

1. Will my existing injector type (believed to be ERC3620) be suitable for use with MS?

If they are not suitable then I will not waste money replacing the dead one and go straight over to MS and the required injector type.

If they are suitable I will find a replacement (FF lives just down the road from me, nudge, nudge) which will get me on the road until MS is installed then I may justify buying a new set.

2. The current injectors are driven through a resistor pack, will this still be required for MS?

3. The 3.5 engine is not the finest example so may not last long when I start playing with the Dakar so would the existing injectors have any scope for a larger engine if I found a 3.9, 4.0, 4.6?

Many thanks in advance

Steve

RRC 1987 3.5 EFI now becoming a Dakar.

[FridgeFreezer]

Steve,

The only issue with your injectors is the resistor pack, as standard they can be unreliable, although I never had a problem, and they can be safely stuffed full of sealant to prevent issues in future - it's the connector that usually causes problems.

If you can be bothered, swapping to 3.9 green-band injectors is nicer as they don't need the resistor pack, are clamped by the fuel rail rather than having little hose tails, and were used all the way to 4.6 as standard, they're what I'm running on the 4.6 in fact B)

MS can drive anything injector-wise, either your current ones with the resistor pack or the 3.9's without.

You can drive your current ones without the resistor pack using PWM current limiting but frankly it's a bit of a faff and can create interference.

[steve_d]

So it could be a resistor pack problem rather than the injector dead. Will have to try swapping leads and see if I can move the fault to No. 1 cylinder as it's No.3 that's playing up and I don't want to take the plenum off unless I have to.

If I go to 3.9 injectors do I need a new inlet manifold as well as a new fuel rail?

Anyone got a 3.9 injector set and fuel rail for sale?

Steve

[FridgeFreezer]

To prove the wiring you can swap the plug on the injector with the one next to it. if it's been sat for ages the injector may have seized, in which case you may be able to unstick it by tapping it with a hammer (a small hammer, not a Land Rover Tool #1).

Why would you need to remove the plenum for a faulty injector?

Sticking 3.9 injectors in you need the injectors & fuel rail, that's all.

[istruggle2gate11]

Ive been running my MS for a good while now with flapper injectors.

I sent the injectors off to be cleaned a couple of weeks ago, all the injectors had different flow rates!!! One was down by 34%.

They were cleaned and refurbed (new filters etc) flow and flow patterns checked all for £130 inc.

Believe it or not, they now all flow 191cc / min within 1.5% of each other and the difference is very very noticeable, much smoother tickover and midrange along with a free reving engine.

Dont worry about running the injectors on a 3.9 or even bigger they will work absolutely fine.

Personally I dont see any gain in changing over to green injectors, its a lot of work just to lose the resistor pack (wiring / fuel rail etc) and has Fridge mentioned, the resistor pack is reasonably bomb proof, mines been immeresed in water plenty of times and keeps on working.

And before its mentioned that £130 was spent on cleaning flapper injectors - green injectors will need cleaning too! Most injectors / manifolds available on the second hand market will be at least 10 or 15 years old and ready for a service.

Also, both types are still available new.