Louie928

No, I don't exactly. Jim Corenman mentioned this when he changed to the Ford 4 hole disk type injectors on his GT. He was carefully sharktuning and realized the idle and low speed mixture was richer than with the pintle injectors. He reduced the dead time a bit and the previously tuned map was now ok with the new injectors. I've read that the disk injectors open faster too, but no specifics. It seems that the dead time, or latency, is a difficult to find parameter. You might email Jim and ask him.

worf928

Thanks Louie. You guessed correctly that it was a Shark Tuning question

Louie928

Jim may have used around 0.75ms rather than the more normal 0.85 - 0.9ms

IcemanG17

I also agree with this.....sharky did run better overall with the 4 pintle injectors..BUT my low rpm smog HC #'s went up substantially.....not enough to fail, but enough that I made sure the cats were extra hot when I would go in for a test.......

Speedtoys

Reviving an old thread with this question...


Wouldnt the ECU figure out the new injectors, and trim to them properly then reducing these bad HC numbers?

AO

Nope. Ecu thinks it has 19# injectors installed. Fuel map tells it to give it a certain pulse width. Nothing to tell it otherwise. O2 sensor might be able to compensate a bit, but nor designed to work that way.

Speedtoys

Ya..this puts me on the fence...get stockers, or get Fords...

Louie928

If you move away from the stock injectors, I'd suggest Sharktuning especially where you need to be concerned with passing smog test.

Hilton

I'd go with either:

19# Ford 4-hole injectors (disc style) - they're the same flowrate as stock, so pulse width is fine for stock ecu chips. They're cheap enough that it makes getting your 20 year old stock ones cleaned pointless.

24# injectors and a sharktune to adjust fuel maps - if you intend to do any simple power modifications in future (cams, exhaust/headers), then you'll want the larger potential fuelling.

danglerb

Since our injectors all get the same pulse width, deviation from a perfectly matched set will leave some cylinders rich and some lean. I think the O2 sensor then "tunes" from either the leanest or the richest, so all the deviation will be in one direction. Long way of saying, regardless of what you go with, get a flow matched set might be a really good idea.

Larry Velk

I put in the higher pressure regulator in our '86.0 along with Ford 4-pintle from Roger. I made up a 'Porken' LED and ran it. Leaned the MAF a bit improving the LED flash somewhat - runs fine. It did seem to need leaning from the base spec. I realize '87 and up guys can't do this, but it did seem the higher pressure regulator required a slight leaning in the '86 system. The 4-pintle gave an improved seat-of-the-pants performance off idle. This is noticed as the clutch is engaged during normal driving.

worf928

If the "new injectors" are 19# injectors then the short answer is: yes, if everything else is working as it should.

If they are not 19# injectors then the answer is no.

Tom. M

I've been running 24's in my GT ever since I had the rear turbo on there. The LH adapts to these and the car runs fine when it's receiving O2 info. Fuel economy hasn't changed significantly unless it goes to the preset maps (preset pulse widths) and then it'll be rich (even more rich than stock) since it assumes it's a 19 lb injector in there.

But as I said, they run fine day to day. Only real issue with my GT is the fuel economy gauge shows super fuel economy (fuel economy is figured out based on pulse width and the brain calculates a shorter pulse width when the O2 is in the loop).

Either you are running WOT maps for some reason..or the O2 is out of the loop (maybe not warmed up enough???)...