I notice that most of the posts I see on the Ford 5.0 injectors relate to the 24# ones. I ordered & received the 22# ones from fiveomotorsports. I haven`t installed these yet. I figured they were comparable to the stock injectors in my `87. Are they?


Ken


PS--- they have pink tops :bb

 

Well he claims their flow and electrical characteristics are closely matched to that of our stock ones.
I have been using the same ones for 4 months.

 

Thanks

 

When you install....

....your new injectors and you want a bit more and a smooth idle and the broad powerband only a flow-matched set of injectors will give you, email SunCarb, www.suncarb.com

They will take your old injectors, remanufacture them to any size you want (or substitute ones from their stock) flow-match them and send them back with all the seals necessary for installation for $200 plus return shipping. Factory injectors aren't matched and Ford injectors in Chev is non sequitur, IMO.

FWIW,
BIG JIM

 

They are good injectors, made by Bosch. Prolly at least as many in C4's as replacements than the crappy OE Rochesters!

 

Yeah: I read somewhere on this forum that GM shops around for their OE injectors for different applications, so I don`t feel bad using Ford injectors if they work ok.

Ken

 

OK, I got a question to go with this. Just what size are stock 87 fuel injectors? I've heard everything from 18 to 22 pound. So, what's the answer? And if I go with these 22 pound Ford injectors will I need to do anything to my Hypertech chip? Don't mean to hijack, just want some info on this as well. Thanks.

 

22lbs
Need not mess with anything else

 

Thanks Agent 86, appreciate the info. Looks like I'll have to give them FoMoCo injectors a try, even if they are pink. I hope the car doesn't suffer any kind of transplant rejection.

 

Besides the engine dont know whats its name is on the valve covers!

 

I've had the fivemotorsports injectors in my92 for about 2 months now. These are the 22lb Bosche ones they say match flow/electrical specs. They run fine. Just passed emissions test with really low numbers for a V8. So it appears I'm running clean.

One thing though, my gas mielage in town and highway dropped a noticeable amount. I was averaging about 19.5 mpg before. Now I'm averaging about 17mpg. Not sure what happened. Car responds well and starts right away hot or cold. Idle smoother too. Not really happy about that drop.

Any ideas why the car would run fine but drop mileage like that?

Graham

 

Maybe it's that heavy foot!

 

Yeah when I autox the car but I don't care about the mileage then

Day to day driving on the highway though the mileage loss kinda sucks...

 

Yes, FordMotorSports rates their injector flow at a lower fuel pressure than GM. The FMS 22# injectors will flow more fuel than the GM 22# injectors at the stock pressure. Your ECM will compensate for this very easily in closed loop, but at cold idle and WOT (open loop) you will always be a bit rich. Over time the ECM "learns" about the richer mixture and saves compensation values in the BLM (Block Learn Multiplier). Even so, the ECM is always acting on "recent history" feedback from the O2 sensor, so a slight decrease in mpg is to be expected. After a while the ECM will have the BLM cell values dialed in and you should gain most of your mpg back.

 

Thanks Mike. That's good info. If I went to an adjustable fuel pressure regulator and lowered the pressure then I could get the proper match? Like maybe 36-38lbs instead of 40lbs? I was told the factory setup would deal with it but it doesn't seem to be learning too quickly...

Graham

 

Yes, an AFPR would help some. I did exactly that to my 88 after installing 24# injectors. I have a scan tool so I can do measured tests and watch the Integrator and BLM valueschange with each pressure tweak. My FP guage hose connection point failed on me so I had to stop before finding the perfect pressure value, but I've got that fixed and intend to continue testing to see what the ideal pressure is.

The factory setup (ECM & O2 feedback) will deal with the larger injectors in most situations, but open loop will always be a bit rich. One thing to remember, a lot of "factory" settings may not be the current "factory" setting on your car. The ECM can only compensate if the feedback it gets is accurate. Over time the stock pressure regulator can become less accurate with the O2 sensor definately doing the same. When I installed the new 24# injectors I also concurrently installed a new Bosh O2 sensor. I then passed CA's most stringent smog tests even before I did any fuel pressure adjustments.

See Hib Halverson'e review of the Denso O2 sensor at the Corvette Action Center web site in which he says the stock O2 sensors in his ZR-1 started showing their age at much less than the normally accepted mileage.
Hib's O2 article

If you have a stock setup and have only added 24# injectors, I'd check the current fuel pressure and using an AFPR tweak the pressure down by 8%~12%. Another alternative is to have one of the CF chip burners burn a chip for you using the stock bin file for your car and just replacing the injector constant with a value equivilent to a 24 (Ford pressure) or 26 lb/hr rate at GM pressure.

 

OK. That sounds reasonable. I guess I forgot to mention that I have an Ed Wright Fastchip installed. So it is already modifying things. Maybe I should pull it out and see how the car runs with the factory chip for a while. I'm pretty happy with Ed's chip so I haven't touched it since I installed it.

Like you though I passed emissions with flying colors. NC is not as stringent as CA. But my numbers were very low and well under the NC minimum.

I'm still on my original O2 sensors with 110K miles.

Graham