Fuel Injectors

i.chevrette

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Is anyone running and willing to share their opinion and experience running the Bosch 4 hole upgrade. I have a single bad injector i am thinking It would be a good time to swap out. I had to remove all to test.
2000 TJ 4.0
134,000
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Yes. I have a single bad injector and pulled the rest out to test as well.

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I ran them on my 4.0, complete waste of money and nothing more than a placebo effect (for those who claim to feel a difference).

There's no way you're going to feel a performance increase from swapping to these 4 hole fuel injectors. Sure, maybe if we were talking about a turbocharged engine and you were swapping to some higher flow fuel injectors, but not on our 4.0 engines.

This is another one of those internet myths that people never let die.

However, if you need to replace bad fuel injectors, then I see no harm in it. Just don't waste money on replacing them unless your fuel injectors are already bad (which is pretty darn rare).
 
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I replaced mine with the Bosch 4 hole a couple weeks ago.

My thoughts:

1. I'm happy with the replacement
- I feel this is important. Some changes can result in either happiness, regret or no difference.
(ie: I bought Steelhorse chrome hoodlocks in the late '90's...and I regret doing that.)
(I should note I've ran the stock hoodlatches since)


2. Did it improve my mpg?
- yes*

* my answer has 2 caveats
2a. I think there was a very subtle leak in one of my fuel injectors, possibly just the o-ring. I had previously thought I had fuel pressure loss due to a bad anti-drain valve in my fuel pump, but upon taking out the injectors and inspecting closer, I think I had a bad fuel injector.
(meaning the fact that ANY new fuel injector/o-ring would improve my mpg, and it's not necessarily due to the 4ports)

2b. I don't accurately keep track of my mpg, so I'm just using an educated guess. I know where to expect my gas guage to be when I drive out to the cottage, and I've been seeing a visible difference. I'm also going an extra day or so between gas fillups.

3. Did it improve the performance?
- If we are talking any improved acceleration, I'd say I did not notice any changes.

- But it significantly improved my startup speed. This could either be attributed to not having any fuel pressure loss...as well as possibly the better atomization of the 4 ports. Psychologically, this fast starting makes me feel the engine is "healthier", if that makes any sense. Since I did not perform an A/B test with brand new 1port injectors vs brand new 4port injectors, it's difficult to answer if the improved startup speed is purely due to the injectors being new/clean or if the 4ports actually helped or not.

4. Anything else?
- It sounds a bit better. Seriously. It's a very minor change that you probably only notice after driving the same vehicle for 20yrs though. It's definitely not in the same league as the sound change with a different muffler.

- I'm glad I changed them. If anything, I feel better knowing that I now know how to change fuel injectors. Perhaps a bit of extra pride for a non-mechanic like me. I also like have "new" fuel injectors in as my TJ is technically over 20 years old now...and everything deteriorates over time. I also had an issue with 1 injectors (or o-ring) that has been fixed. Maybe I'm just happy that it actually started up the 1st time after I changed them.

5. Do I recommend them to others?
- uhmm...I'd give the suggestion of replacing the original 1port injectors with the 4port injectors IF/WHEN you need to replace one. Meaning, if you are buying a new fuel injector, I'd personally lean towards buying the 4port instead of another 1 port.

If you are expecting any "noticeable" improvement to your perfectly good 1port injectors, I think you are risking being disappointed.

The reality is, it's entirely possible I could have "fixed" my injector issue with a $2 o-ring replacement instead of replacing all the fuel injectors.
But I bought:
- peace of mind (new injectors all around)
- knowledge (how to replace injectors)
- experience/pride (I replaced them myself)
- scalability (maybe there is a turbo and a CPU reprogramming in my future, lol, ahem...)
- a performance upgrade that I'm going to say...probably works better than stickers.
 
In my younger years most of my money went to chasing women. Now it goes to a TJ. I swapped the stock injectors for the 4 hole jobs. I did notice it runs a bit smoother. No hp gains and I don't know if it improved mileage but I now have new injectors and learned a thing or two.
 
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Any suggestions on what fuel injectors i should use for a 1999 jeep wrangler sahara 4.0
OE. The computer constantly adjusts the length of time an injector is left open to spray fuel and shuts it off when it has the right air-fuel mixture. Installing "high performance" injectors that can spray more fuel just means they'll have their spray time reduced so as to insure the engine is getting the correct air/fuel ratio. It's real hard to be the quality of OEM. It's not hard to beat the quality of most aftermarket injectors, especially store brands.
 
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