1993C4LT1

I've had them in my car about, two weeks. My average MPG went down after installing these. Did anyone else get this, or just me? Yes, I bought them from FIC. Not trying to put the product down, or anything.

gerardvg

Hi

Same here, reset the trip computer and see how she goes over the next few weeks. My milage came back to "almost" normal after a while.

I have seen posts talking about injector swaps needing re-tuning work with the new injectors.

Did you have the battery disconnected?
I usually take my vette for a good hour or two on the highway to get the mpg down, then the trip computer will be more accurate and back to normal. When running around town continually the average mpg will be poor, you need some mixed highway and town driving for the average to be in the middle not one end or the other.

1993C4LT1

Thanks for the reply. Yes, I did have the battery disconnected. I'll reset the trip and see what happens. Will take it on the freeway as well. Did you have to get your car tuned?

Silver96ce

I have had them on mine for about 2 1/2 years now. Though I didn't pay much attention to the mileage average through the trip computer, I didn't see any real reduction. It seemed about the same. I would do as gerardvg recommends. I have a feeling it'll be about the same as it was before.

Joe C

- same here. I've installed several sets (90,90,96), and really didn't notice any decrease in mileage. you really can't go by the on-board computer readouts, but you need to use detailed, old school math when calculating gas mileage.

WW7

When I installed my new motor a few years ago the guy tuning my car made this comment....He said "Quote"..(Well if you already bought the Bosch 3 injectors I can tune around them, but it would have been easier with a different injector..."Unquote".....This tuner "that most on this forum know" said that the Bosch 3s had a different curve that had to be adjusted for...He told me that it's a good thing I was having a tune done at the same time as installing these injectors, because without a tune the car could run lean at certain rpms....I personally don't know much about tuning or injectors , but this guy was one of this forums most used tuners, so I didn't doubt his word. ......WW

1993C4LT1

I'll look into that, thanks.

WW7

The best way to check if the car is running within the air/fuel range the ecm can handle, (or adjust for), is to hook it up to a scanner while driving and record data, then view the results of where the BLMs are running...BLMs of 128 are considered normal, higher numbers are lean, lower numbers ar rich..... I use Datamaster to record my engines data, then play it back later to check for any anomalies..I believe anytime a major engine part ( or parts) are replaced that can affect your air/fuel ratio, that the car should be hooked up to a scanner and checked for changes that could damage the engine....WW

eutu1984

With my old oem injectors my mpg computer used to read up around 30 mpg, I was actually getting 21 to 22 mpg, with the Bosch III it reads about 22 to 23 mpg which is what I am actually getting with the Bosch III's.

1993C4LT1

Did any of you need to get the car tuned when these were installed? They are 24lb, like the original multechs I took out. Did a search on the forum, some say they got a tune, others say no tune was needed. I also noticed longer starting times when engine is cold.

Silver96ce

Didn't need a tune after they were installed - car actually ran better. I had a low rpm miss which went away. And my start time also got shorter.

1993C4LT1

Well, I guess I just have bad luck. My idle is smoother waiting at stoplights.

WW7

Here are a couple instances of people having trouble with Bosch 3s running lean, it doesn't happen all the time , but if your one of the unlucky ones you could cause serious engine damage if it's not corrected...As you can see from the posts below , the only way to know for sure that your BLMs are correct is to have a scan done while your car is running..I hear alot of guys saying they installed the injectors and their car is running fine, most times you will never know the car is running lean, until a scan is done......It's your car , all I can do is warn you....WW



MrWillys
CF Senior Member
I was sent a set of Bosch yellow 280-155-700 back in 2012 from a friend who wanted to purchase multiple sets from FIC. Upon install at 48 psi I datalogged the vehicle and observed very high blm readings up in the 150's, and some cells hitting the max of 160. I modified my flowrate down to 19.8 that brought my blm counts back in line closer to 128.

Others here have said theirs run fine without this lean condition. I'm not trying to bash anyone, but rather make a point that one should always observe blm counts after making such a change. Get a cable, or an OBD1 scanner and confirm. If you get a set that runs lean it will stumble at tip in. Even if the ecm makes up for part, or all it is not proper operation.
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samsonb
CF Senior Member
I first went with Bosch III 22#, and I ran super lean. 160+ BLM's. Never could figure it out. Ended up putting in Bosch III 24#, and my BLM's were dead on.

Only way to know is run a scan before, then pick a set and run a scan after.

toptechx6

Which Bosch III injectors did you buy, first link are generic 24#, second link are specially tuned to address the issue you are complaining about and are specific to 93's only.

http://fuelinjectorconnection.com/sh...p?productid=76


http://fuelinjectorconnection.com/sh...?productid=202

Don't take my word for it, call Jon and he will explain.

1993C4LT1

I bought the ones from the second link.



WW7, I will get my car scanned.

toptechx6

In that case I would call Jon back and ask him to exchange the injectors or refund your money.