Hi all. 1985 l98. I'm doing intake manifold gaskets. I'm changing all the fuel rail/injector orings. My injectors look like they have seen better days. I assume they need to be replaced. Good place for replacements? Stock motor.

 

If you're not looking to get into the ECM for recalibration, then I'd avoid Bosch-III style injectors. They seem to be hit or miss in terms of how they run w/o re-tuning for them.

What I have heard is that Delphi injectors seem to run the best w/o touching the ECM, though I also hear they're a little pricier than the Bosch-III's.

Probably give Southbay fuel injectors a call about it.

 

I used the REAL Bosch III's (NOT the cheap Chinese knockoff garbage) in both my bone stock '87 and current '86 without issues. I checked the BLM on both after replacement and I was right around 128 on both cars, so no ECM reprogramming was necessary, Guess I was one of the lucky ones, eh?

Would recommend either Southbay or Fuel Injector Connection for replacements.

 

been running bosch3's in my 85 for better than 15 years now. ABSOLUTELY NO ISSUES, and no, so called ECM recalibration. matter of fact, 6-sets of bosch 3's over the years (L98's and LT-1's) and as far as i'm concerned, bosch3's (from FIC) is the only way to fly.

 

different Bosch-IIIs have different voltage offsets. I think Depending on how far off they are from factory Multecs will determine how it runs. If the user isn't taking data he may not notice the fuel trims adjusting to compensate and if the trimming isn't severe he probably won't notice the difference from the driver seat.

But I can say that I've had to retune at least 6 cars where the owner had running issues after changing to Bosch--III.. Two I did in person with friends cars (bone stock) where the injector change resulted in the BLM fuel trim shooting up to 150... then simply putting in the correct offsets got the BLM back to 128.

Then my own car had a similar issue. I had bought some used Bosch-IIIs where the p/n was scrapped off the injectors (this was before I learned about offsets). I couldn't for the life of me get the fueling dialed in. After I found out about voltage offsets I bought a set that had the official Ford datasheet available online and put those on and then put the correct offsets into the calibration. BOOM.... problem was solved (it was so strikingly apparent that I knew it was solved as soon as I heard the car start up and idle...even before I got on the road and started taking data).

Then 3 other cars from members on the thrdgen.org site... all with similar stories.

That's why I say it's hit or miss.

 

i'm guessing you know more about this than i do. time for me to move on. have a good one.

 

85s didnt come with multecs

 

Ok....

Well whatever manufacturer it was.... that doesn't change my synopsis though.

It's Bosch-III vs whatever injectors the car came with originally (GM's original programming in the calibration reflects the original equipment).

What I'm saying is that certain items on the engine have calibration parameters that go along with it. If you change the equipment, you may need to change the calibration.

Another example is the ignition control module... the spark latency table in the calibration needs to be matched to the module, otherwise you could be getting a different spark timing than what the ECM is commanding.

 

I had the same experience and could never get the off idle stumble fixed. Gave up and put my old injectors back in. These new injectors are sitting in a box in my garage now :-( Nobody could help me with correct offsets, which I think was the problem. Mind sharing the correct offsets so I could try them again someday?

 

What is the p/n of the injectors you have?

 

Sorry, lost sight of this. Part number is 0280155752. They are the Bosch injectors that fuel injector connection sells.