Just got them in from fiveomotorsports.com, they came quick (less than 2 days)! I don't know anything about installing these. Does anybody have a DIY guide for installing fuel injectors on a 1990 vette for dummies cuz when it comes to cars, this I am! Thanks cooters!

 

Are you replacing injectors with same size or bigger. If bigger and your motor is basicly stock, then you don't realy need them. Probebly just end up scruing things up and making the engine run supper rich.

 

Very true! My 89 ran like crap after changing from stock 22 to 24 lbs/hr. Both were Bosch injectors. That's even with a MAF sensor equipped car, usually better than MAP cars at taking changes and engine/intake/fuel system modification.

 

CooterCatchinVette, don't let the previous comments throw you. If you have 22# injectors then you have stock flow rate injectors and are just fine. If you have 24# injectors for your 90 L98 you will be good too. The ECM will take a day or two to 'learn' that the 24# units are causing you to run about 10% rich and will easily adjust for the difference. That is what the Long Term Fuel Trim and Block Learn Multipliers (BLMs) are for.

Do a search and you should find a couple of very comprehensive threads in the last few months concerning how to do the injector swap. I know I contributed to an excellent thread on this subject relatively recently. It would behoove you to go to the Helms website www.helminc.com and order a GM Factory Shop Manual (FSM) for your 90 (about $100) or try eBay for a discount price on a used one. The FSM covers everything you need to know for this adventure in Vette maintenance.

k0rv3tt389, Having replaced the injectors in my 88 and my brothers 89, I do not know any reason for the problems you experienced in doing the same with your 89. I can say that MANY other L98 owners on this Forum have swapped in 24# units in place of the original 22# units and had no problems once the ECM had a few miles to make the adjustments. Perhaps your O2 sensor was going bad? This would cause the ECM to incorrectly gauge the change and cause a problem as you describe.

CooterCatchinVette, you might consider a new O2 sensor at the same time as the injector swap if your current O2 sensor has more than 25k miles on it. They should last at least 50k, but they do sometimes get 'lazy' or react slower than they should according to spec after as little as 25k miles..

 

I replaced my injectors with five O's 22lb injectors and I have a great running car with a little less mileage than I should be getting. The mileage on the dash does calculate right anymore either. I must have a stupid computer.

 

I have no idea why this was happening in my car, but I also hear the ECM can only compensate for so much. While those injectors were in my car and the computer untuned, my BLMs were steady at 108, aka the richest correction mode. The computer was doing everything it could to correct but that still wasn't enough. I was running so rich that sometimes I'd almost stall if I had it close to WOT. Plus gas mileage was 9 mpg in the city. I haven't checked my O2 sensor. Right after I got my mail order chip from Alvin, the car just ran 100% better than before. Hopefully when I change my O2 sensor to a different one soon for headers, I won't run bad or lean. But as the scanner says, it looks like the O2 sensor is ok because it is giving a signal between the normal operation ranges.

 

I'm pretty sure that the Five-O 22# injectors are Ford Motorsport (FMS) injectors. FMS rates the flow at 39psi. GM stock units are rated at 43psi. The 10% difference in pressure rating is why the mileage is slightly less. The ECM is adjusting fuel flow based upon the O2 sensor feedback, but it is still computing fuel usage based upon the pre-programmed values for the stock units.

 

Search for threads started by me. There is one (intuitively named) where I describe my experience with these, and a super quick how-to. It was easy, and I didn't have to change anything else - including the FPR. Good luck,

-Alex

 

Can't find it.

 

http://forums.corvetteforum.com/show....php?t=1164176