I measured the injectors when I got home from work last Friday (hot). A few days before, I measured 6 of the 8 @ 16 ohms and 2 @ 12 ohms. When they were hot, I remeasured the drivers bank (which had the 12 ohm injectors in it.

One drops to 10 ohms when hot, while the good ones appear to rise to 17. The other one stayed at 12 ohms.

The sumbeach is idling rough (like a fouled plug). If I shut if off and restart, it smooths out until it goes closed loop again. My assumption is the computer sees the lean condition from the O2 sensor (which is located on the drivers-side manifold). It puts more gas in which makes it run rough -- especially with unbalanced injectors.

Anyone agree/disagree before I tear da dang thing apart?

 

When mine were bad they were measuring 2-3 ohm so 10-12 ohm doesn't sound to bad to me. My new ones measured 13 ohm but imagine that varies between manufactures.

 

I always look for differences between injectors (assuming they are all the same). The fact that they are changing value would seem to indicate a problem. I'd replace them all (though it's not necessary).

 

A good injector should measure at a higher resistance when hot. Sounds like you have 2 going bad.

 

Maybe yours went south faster and/or you didn't notice them as quickly if you have an automatic.

With a stick, I notice it because the DMF knocks when the idle gets rough. Automatic owners wouldn't have this extra clue.

 

Oh yeah. What brand of replacements does everyone recommend and why?

Is there any reason to upgrade their capacity? If there's any HP increase by putting bigger injectors and a MR/SR in it, I might consider it. If I have to replace the heads/cam to suck in the extra air/fuel, that probably won't happen in the near future.....

gp

 

Gregg: Here is a suggestion for injectors for your L98 engine:

Multec Replacement Injectors - Installed the new injectors today. Nice smooth install took about 1 1/2 hours. The new injectors made a big difference both in starting, idle and general performance (nice little bite off the line and smooth acceleration). These FMS injects are a Denso (I'm told one of the most reliable, more so than Bosch (opinion of my son and colleagues, certified master techs for Toyota and Honda (I forgave him for not being a gm guy!). The nice thing is these injectors were tested/rated at 22.5 lbs @43PSI. The installation was purely plug and play, no AFPR, no ECM retune, just a nice injector for a bone stock L98. The only noticeable thing is the ford injectors are louder, if that's negative it's the only I have to say. For those of you that would like a quality replacement injector for a stock L98, the FMS number is F55E-A2D/E. I purchased a reconditioned set of 8 (flow matched) with a 1 yr warranty for $199.92 + $10.00 shipping. The business is www.injectors4u.com. The owner is Howard Haack (989-644-2695) from the great American motoring state of Michigan. I would highly recommend this vendor both in service, honesty and some of the best technical resources in the injector business. Web link to above info:
http://forums.corvetteforum.com/show...post1560357682

I do not recommend you use higher rated injectors unless you are prepated to change the ECM programming.

Hope this is helpful to you

 

It sounds like its time to work on the fuel injectors. I have heard nothing but positive feedback from www.Cruzinperformance.com They will rebuild YOUR injectors at a reasonable price, with a quick turn around time. Without going into much detail I would also stick with #22 injectors.

 

Actually I have a 6 speed manual. I noticed the problem when a major Chevy dealer in the Denver pressure cleaned them and then 3 days later my main Cat went out. They said the bad injector caused the Cat to burn out. Whatever. They wanted $750 to replace one injector. I started doing some research and checked the rest of the injectors at that point.

I changed all 8 with stock replacements from Car Quest for $360. Like someone else recommended, I would change all 8 since once you remove the fuel rails they are sitting right infront of you.

Good Luck.

 

Bob L (I really like that name!!!) indicated that Rich at Cruzin Performance could service and clean you Multec injectors. From personal experience, Rich will not touch the Multec injectors as they cannot be serviced. Here are his comments to me in an email:

The problem you currently have is that from 1989 through 1991 on the L98 engines GM installed Multec injectors. These injectors have one of the highest failure rates of any injector ever installed. It's not a matter of "if" they are going to fail, it's simply a matter of "when" they will fail. That is why some of your injectors look differently than the others. Some of them have obviously already failed and were replaced. Because of their design they cannot be repaired so the only solution is to replace them.


Hope you get the Vette fixed and running well.

 

I too purcahsed from www.injectors4u.com. Flow matched set (Denso's), $212 to my door. Car is running great. Good Luck.

Enjoy the ride!

 

When injectors show a lower ohm reading hot or cold it means that they are "shorted out" to a degree. When this happens the # of wraps of wire around the pintle are having a kind of a reduced effect. The "shorted" condition results in a smaller magnetic field being generated inside the injector thus the injector is not being allowed to open/fully open and creating your "lean" condition.

If you hook an "O" scope up to the problematic injectors you will see it - if a problem if it exists.Here is an excellent website that shows examples of these types of failure:
http://www.automotivetestsolutions.c...rWaveforms.htm

My injectors went bad and I put in the Bosh yellow tops from http://fiveomotorsports.com installed in my '89 (8 new injectors for $333.00 delivered). To be realistic it took me about 3 & 1/2 hours to swap mine out and get the car running again (I've been turning wrenches on this car for years).

 

accel injectors

 

I wasn't aware that Rich at www.Cruzinperformance.com wouldn't work on the Multec injectors. You learn something new every day!!!!

 

I sent injectors4u an email 2 days ago with no reply. I hate that!

I like the looks and ad copy for the accel and am wondering if they really are redesigned and a good product (from summit racing).

Because I think Bosch O2 sensors are iffy and because they didn't even carry/show the correct model for my '97 Jeep, I think I'll avoid them. (Fyi: I went to all the major autoparts stores and found the one listed for my jeep had the wrong config!). I had to buy another brand (to avoid dealer pricing) and it was hard to track down.

gp