Injectors for a 4.0 HO Engine

After much searching, it appears like I should NOT use the 19# ford injectors
in my 1991 HO engine - I "Think" I need to stick with 21# injectors.

Stop me if I'm wrong. . .

I'm running a Banks header, and cat-back exhaust, and will be adding a bored TB and cold air intake.

Looking for an alternative to my Jeep dealer at 52.45 each

Only option I have found is ACCEL ACC-150121 (found that on Dyno's page) but I can't find them referenced for a Jeep anywhere else.

Internet price on these is about 35.90ea.

Anyone running these?

All the Injectors you'll ever want, and at a pretty good price, too - http://fiveomotorsport.com/Injector_SetsJEEP.asp

that's where I got mine. Great service too. Check out his ebay store, you can usually get a better deal from him there. either way, they're super cheap..

Yucca-Man said:

All the Injectors you'll ever want, and at a pretty good price, too - http://fiveomotorsport.com/Injector_SetsJEEP.asp

Click to expand...

Sorry, should have included:

Five-o is where I got the 19lb injectors for my 87, great service no complaints (I actually had my other browser window open to their site when I asked the question). But the HO engine came OEM with 21lb injectors, they don't offer 21lb injectors. . .

Are you trying to say that "even with a lightly modified engine the 4.0HO can compensate correctly and only needs 19lb injectors (same as the Renix). . ."

3XJFamily said:

Are you trying to say that "even with a lightly modified engine the 4.0HO can compensate correctly and only needs 19lb injectors (same as the Renix). . ."

Click to expand...

No way. The stock 21.0lb injectors on the '91-'95 4.0 will handle a free-flow intake, TB spacer, performance exhaust, high-flow cat, and header. Once you then add a bored TB, the engine runs lean and starts to ping under moderate load so by then you need to think about adding 24lb injectors.
If you go beyond the external bolt-ons by porting the head and adding a performance cam, the 24lb injectors become a necessity.

Dr. Dyno said:

No way. The stock 21.0lb injectors on the '91-'95 4.0 will handle a free-flow intake, TB spacer, performance exhaust, high-flow cat, and header. Once you then add a bored TB, the engine runs lean and starts to ping under moderate load so by then you need to think about adding 24lb injectors.
If you go beyond the external bolt-ons by porting the head and adding a performance cam, the 24lb injectors become a necessity.

Click to expand...

Thanks Dr. Dyno. Five-o references 19lb injectors for the 87 - 90 non-HO and the 91 - 95 4.0, but OEM in those years was 21lb. Is it your opinion that 19lb would be marginal at best on a stock 91 - 95 4.0, and unworkable on a slightly modified engine?

After reading your mod diary, 24lb injectors will likely be too rich for the few exhaust mods I currently have so. . . 21lb seemed to be the answer, and unfortunately Five-o does not have 21lb injectors. . . Do the ACCEL ACC-150121 injectors just plug right in like OEM ones?

3XJFamily said:

Thanks Dr. Dyno. Five-o references 19lb injectors for the 87 - 90 non-HO and the 91 - 95 4.0, but OEM in those years was 21lb. Is it your opinion that 19lb would be marginal at best on a stock 91 - 95 4.0, and unworkable on a slightly modified engine?

After reading your mod diary, 24lb injectors will likely be too rich for the few exhaust mods I currently have so. . . 21lb seemed to be the answer, and unfortunately Five-o does not have 21lb injectors. . . Do the ACCEL ACC-150121 injectors just plug right in like OEM ones?

Click to expand...

Yes they do. That's what I've got on mine. I've got a stroker so I will be switching to 24 lbers soon. The Accels that I have are the 150121s that your asking about. I bought them new and only have about 8,000 miles on them. If your interested in buying them send me a pm.

K