928newb

So I tried to install 24lb injectors from a Mustang Cobra in the 928 and the car would not start...

The injectors were cleaned in an ultrasonic bath, flushed, and new seals and tips installed.

When I pulled them, the tips were wet with fuel.

Installed the original injectors, and the car starts again...

Is the 19lb to 24lb upgrade a simple swap or does it need anything else to make it work?

Any insight is much appreciated....

Speedtoys

Umm...was your ECU told they were 24lb injectors?

davek9

"Is the 19lb to 24lb upgrade a simple swap or does it need anything else to make it work?"

Is this on an 86/ 86.5?

What are you trying to accomplish?

Thanks
Dave

928newb

Umm...no. Forgive me my ignorance, but I obviously still have a lot to learn..how do I do that?

928newb

Yes it was on a 1986.5

From what I have read on here, it is supposed to facilitate a smoother acceleration.

76FJ55

The 85-86.5 cars had 24# injectors from the factory. it should have been a simple swap with nothing else necessary. I am running the Ford Racing 4 hole injectors in mine with no issues. I also have S300 chips and 87 FPR, but these should not be necessary just to run the Ford Injectors.

928newb

Hmm the ones that were in the car look just like these:

http://www.ebay.com/itm/Porsche-928-...0d1804&vxp=mtr

I have tried to swap them with these:

http://www.ebay.com/itm/REBUILT-24lb...bc8ce6&vxp=mtr

Speedtoys

Today, I learned something.

Thanks!

davek9

Exactly, and that's why I was asking the OP

Avar928

Like 76 said, the S3s which is the US 85-86.5 MY have 24lb injectors as stock. The S4s which is 87+ (and up I believe) are all 19lb injectors.

The injectors you're trying to put in probably are bad or are not compatible. The direct swap in Ford injectors are the M-9593-A302 - http://www.summitracing.com/parts/fms-m-9593-a302 These should be plug and play. I'm actually just swapping mine in. I have the fuel rails with injectors installed sitting on my table.

The AA302s are the more recent Ford injectors that can be swapped but these need to be modified to fit. They are much slimmer in design compared to the fat body A302s, which unfortunately are discontinued. I got my set on eBay, brand new, for a little over $150 which is a steal.

There's a set on eBay right now for over $200 http://www.ebay.com/itm/Ford-Racing-...item20dc333ec4

76FJ55

I would expect those to work. I am running the design 3 injectors.
similar to these but desgn 2s should be fine too.

KenRudd

I just installed these:
Bosch 0280150947 Ford Racing 24lb/hr Fuel Injectors
See this post:
https://rennlist.com/forums/10949456-post60.html
I based this choice on Stan's post here:
https://rennlist.com/forums/10014125-post3.html
I replaced the Pintle caps ( and o-rings and spacers) with kits from Roger based on his suggestion. The replacement Pintle covers were longer that the ones that come on the injectors, but the top clip area and the electrical plug were an exact fit.
Car is running well, but no track time yet.

Avar928

He may have gotten some bad ones then. Is there any way to test them ex vivo the car (i.e. outside on a bench or something)?

jcorenman

That's the Bosch part# for the Ford Motorsports M9593-A302, referenced above. Nice injectors, and work well.

Injectors are not all created equal. Possible issues are high versus low impedance (our ECU's need high impedance), lower o-rings that don't fit (resulting in large air leaks and lean mixtures), and opening-times (aka latency, dead-time) that can vary a lot with different part#'s-- to the point where the engine won't happily start or idle.

mark kibort

you need to talk to the ECU?

I installed the 30lb injectors on the stock S4 system to better deal with the greater displacement going to a stroker. But, as i suspected it was a little too much fuel based on the restrictive intake of the stock S4. would love to try 24lb injectors, as they seem to be where i need to be based on expected HP and fuel air mixture goals. (right now, i have to be near 44psi to make it all run 12:1, before, at 320-330rwhp, i was 12.6:1 and running 70psi with a 19lb injector)