When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Hi folks,
I'm looking to replace the fuel injectors on my 96 LT4. Based on the few searches I've done so far, it looks like I'll need 28 lb/hr fuel injectors for the LT4 (whereas the LT1 takes 24 lb/hr).
The problem is, I can't seem to find any 28 lb/hr injectors out there. All I find are 24, 26, and 30 lb/hr parts.
So my question is:
1. Where can I find the 28 lb/hr injectors.
2. Is it safe to go with either the 24 lb/hr or 30 lb/hr options instead?
Even if you found 28 lb injectors from a different manufacturer, you're still likely to need re-tuning due to the different voltage offsets.
Couple of options...
1.) If you commit to the fact you're going to retune, I'd go with 30 lb, and specifically Bosch 0280-155-759 because they have published data on the voltage offsets. The cross reference to Ford Motorsport, and Ford published the data. I run these exact injectors and they work beautifully.
2,) Call Southbay and see what they may have that doesn't require any retuning. Some of the L98 guys swap in Delphi's which evidently match the factory, but I'm not sure if they make 28 lb versions.
Even if you found 28 lb injectors from a different manufacturer, you're still likely to need re-tuning due to the different voltage offsets.
Couple of options...
1.) If you commit to the fact you're going to retune, I'd go with 30 lb, and specifically Bosch 0280-155-759 because they have published data on the voltage offsets. The cross reference to Ford Motorsport, and Ford published the data. I run these exact injectors and they work beautifully.
2,) Call Southbay and see what they may have that doesn't require any retuning. Some of the L98 guys swap in Delphi's which evidently match the factory, but I'm not sure if they make 28 lb versions.
I'm definitely not looking for any tuning. Running fully stock setup.
IT seems to be hit and miss with Bosch-III's for some reason. Some people see no difference...other people encounter running issues and need the re-tuning.
Reviews posted by certain people need to be analyzed very carefully. Reading thousands of posts here and many other boards, you realize that most comments don't offer any empirical data. Many are based on perception of performance or lack thereof, and others are regurgitated information from other people. Such information is repeated over and over with no real testing whatsoever.
Few people offer real data to back up claims.
I replaced my injectors because the "consensus" is that the Multec injectors are garbage and need to be yanked immediately. After switching, I noticed ZERO difference in idle quality, power, driveability, etc. Of course, I have no empirical data before and after. 😉
Ric
EDIT: As far as people having issues... Again, is there proof of anything one way or the other? I made a left turn from a standing still. I heard a clunk and within seconds P0300 popped up. They had absolutely nothing to do with each other. My point: Pure coincidence can be perceived as a new part causing problems. 😉😉
Last edited by rremesal; Jan 22, 2024 at 10:39 AM.
Are you saying I need to retune? What offset are you referring to?
Thanks
It's a reporting by the ECM on how it's adjusting fuel delivery (over the long term) based on what the O2 sensor is reporting.
A BLM of 128 indicates everything is running perfectly and the ECM is seeing what the design engineers told it to expect.
The ECM is always making minor adjustments to fueling every millisecond based on the O2 sensor. Over short periods of time, like a few seconds, the O2 sensor may trend rich or lean. When that happens, there's another "short term" fueling trend indicator called the Integrator (or INT for short). If the fueling trends rich (i.e, O2 sensor detecting a prolonged rich condition), the INT will start to drop below 128, indicating the ECM is having to trim the fuel leaner to compensate. If the fueling trends lean, INT will increase above 128, indicating the ECM is trimming richer to compensate. Once the O2 detects things returning to normal, the INT will return to 128. Mind you this is a slow motion description of what's occurring over seconds and milliseconds on a continual basis.
However, let's say some malfunction occurred, such as a bad spark plug or something like that (and it occurred on the side of the engine where the O2 sensor is). What will happen is that the INT will start to change. But it never recovers because the spark plug fouls. For example let's say the INT is dropping... the ECM starts "chasing it" trying to get it to recover, but it can't. INT continues to drop. At this point, the BLM starts to drop as well... from the 128 ideal, it starts falling to 120, then 116, the 110, etc. The ECM is now recording a "long term" fueling correction because of the fouled plug. Ultimately the INT can only go as low as 108 (or as high as 160 on the lean end). At that point, if the BLM hits those extremes as well, then the ECM is out of adjustment range.
The injector offsets are a characteristic of the inejctors. Injectors will flow differently at different voltages. Since many different cars will be operating at different voltages while running (typically varying between 12.5 and 14.5V, the ECM needs to know how the injector behaves at each voltage possibility, that way it knows what pulsewidth to command. The ECM has to know about the injectors so it knows how to command them on and off to get the right amount of fuel delivered.
Often times, different injectors have different offsets, so there's a table for this in the ECM where you plug in the numbers for a given injector.
LT4 Fuel Injectors
