Red1990VT

Just picked up a set of NEW Delphi FJ10024 injectors for my 1990 L98. Got home and compared to the ones that came in the car from Bolling Green. The Delphi units are at least an eighth of an inch shorter than the ones from the factory.

Will this matter? Anyone here used the Delphi FJ10024s to replace the original injectors?

Despite the expense, I decided my Corvette should have the best and OEM-est fuel injectors possible. I'm sure there are many fine aftermarket units, but I like using what the factory used when the car was new whenever possible. Especially for something like fuel metering.

So, should I install these, or try to find replacements that are the exact length or nearly exact length of the originals?

WVZR-1

Despite the DELPHI tag being generally "assumed" to be GM/OE that just ain't so. OEM-est doesn't necessarily "fit" the description. I'd be inclined to use a product that MOST have been quite happy with and NOT be the "TESTER" for the product you chose. What warranty do these come with? Not knowing what you paid BUT you mention despite price was it a good choice? Your wallet and your decision!

If these weren't a LOCAL purchase and they were returnable I'd maybe consider that. A LOCAL purchase with a reasonable warranty maybe there's reason to rethink my comments.

Where did you buy?

Red1990VT

I purchased these from a local and respected Corvette shop where I live. The owner has a large stock of new old stock he buys up as it becomes available.

I appreciate your thoughts, but what I'm really trying to determine is whether the Delphi units being at least 1/8 inch shorter than the originals is good, bad or neutral. One possibility is that moving the tips up in the manifold may keep the tips cleaner. But that's a guess. Also, these have four tiny holes, while the originals have three larger holes. Given the flow rates, the holes may not matter, and the four very tiny (visually) holes may atomize the fuel better.

But the main reason for this thread...does the Delphi units being about 1/8" shorter than the originals matter? If I go to the trouble of putting all 8 in the fuel rail and bolting that down, will the injectors go far enough into the manifold to work and avoid leaks? I am 'assuming' it is yes, but never like to assume. Best case is if someone who has bought and installed FJ10024 Delphi's in an L98 could share their experience...

aklim

A google on the image makes me think it is the Multec injector. If so, you couldn't give me a set even if you installed it for free on my cars. I'd shoot the guy who tries.

aklim

I wish people would stop having the idea that anything factory is the best. If it is for NCRS reasons, sure. Other than that, factory is just the cheapest priced item they can get away with for the most part.

Red1990VT

Thanks for your thoughts.

As an engineer, I have a pretty good idea of what went into the TPI system design, and just how critical it is to get fuel injectors that have all the same characteristics as the OEMs. Sure, there are lots of pretty good alternatives. But, the system was designed from the ground up for the Delphis, and I know they will work properly in the car. No question. They are what the engineers designed the rest of the system to use and function properly with, across all operating ranges.

And, having gotten 25 years and nearly 100000 miles out of the original injectors, these new not refurbished and not aftermarket injectors are likely to last many years and many miles. I just wondered if the shorter length might matter, but also guess that the engineers felt pulling the tips up a bit might be better.

The system would not hold pressure with the injectors installed, and pinching the supply line corrects that. So now I am off dealing with possibly replacing the fuel pump and maybe pulsator (or replacing it with submersible hose).

Thanks again for your replies. Once the car is back together, and hopefully running well, I will post a follow up.

Red1990VT

Oh, and yes I realize the regulator could be at fault (or even one or more of the new injectors), but pinching the return line does not hold pressure, while pinching the supply line does, suggesting the fuel pump or pulsator is the culprit...

aklim

With all due respect, I don't believe the engine was designed around the injectors nor do I believe GM gave us the best that there possibly could be. Believing that would be like asking Madoff for ethical trading advice. I mean, how bad do you have to be to go so far that Obama can fire and hire your new CEO as part of a bailout? Ford used the regular coolant that they had for the 7.3 diesel when the designers, International, prefered a more robust coolant that didn't need additives. AFAIK, my motor is pretty dumb. As long as it gets a fine spray of the correct amount of fuel, it runs.

Don't know. It could be a new design altogether.

Pump Install Kit and Pump Kit

Red1990VT

Agreed, I doubt anyone at GM started with the injectors and designed an engine around them. But, devices like fuel injectors have a series of characteristic operating curves, and the L98 is set up to run with those. Or, perhaps and more likely, the injectors were chosen or designed to meet the operating needs of the L98 across temperature, RPM, load, and whatever. I'd expect there are a family of curves somewhere for the injectors. If other injectors reasonably meet those, they'll work reasonably well. But there is no question the Delphi units meet the need, and for the existing ECM firmware load (no 'tuning' necessary).

Almost every alternative to the Delphi injectors are 'refurbished' or 'rebuilt'. Or if new ridiculously expensive. Stating the obvious, injectors comprise a precision solenoid and extremely precise flows and tolerances that operate in an environmentally severe environment electrically and mechanically millions of times in its useful life. And cannot really be rebuilt. Someone can clean it, maybe replace a filter and o rings. But it is still in the end an old, used injector. I would not put something like that in my car.

Which leads back to either the OEM units or even more expensive aftermarket units.

I've gotten nearly 100,000 miles and 25 years out of the OEM injectors. And all of them still Ohm out ok even hot. So I figured the factory installed units are simply at the end of their mechanical life, and rather than clean them and wonder, given the complexity involved in accessing them on the L98, why not replace them with the same new models. I realize not everyone will agree with that, and that's ok.

No intent to be controversial here, and I definitely see some strong opinions on Multec and Delphi injectors. My only concern in creating this thread was that the replacements are a bit shorter than the originals. Again, I'm guessing this is to get the tips up a bit, and keep them cleaner. Just wonder what others have experienced if using the Delphis to replace the originals.

Thanks, and for the pump information too. I see they replace the pulsator with a hose, which is looking more and more to be a good idea.

WVZR-1

Your choice of the Delphi isn't the choice of "most" that post here regularly. I'd think you need to take YOUR PARTICULAR QUESTION to Delphi .. period.

I won't question the choice and certainly they should be assumed to be a quality product. OE quality? Who knows!!

You mention it seems "engineering credentials" so it would seem you'd know to GO TO THE SOURCE!!

You bought them from someone you say is "trusted/local" well then you go maybe to him for either documented information OR MAYBE "a shoulder shrug" ....

Red 91

I put injectors from fic in my 91 several years ago, they were shorter yhen the oem and also did not use the retension clips. I think you could look up injector installs on the net or call jon at fic he seems to be very helpful on injector issues and I think he may be the sort of guy to help even without a sale. good luck!

Galaxie500XL

vette196

call FIC....I looked up those Delphi injectors....$55 - $75 EACH...I got a set of 30lb rebuilt injectors from FIC for under $200....

mickey5

I bought a set of Delphi's for my '90 L98 from Jon 5 years ago on his recommendation and lifetime warranty to the original buyer. Car continues to run well with no problems.

The only problem with the Multec original injectors was they failed from E10 fuel. The alcohol attacked the wet windings thus the resistance change when checking for a failed unit. My Multecs lasted 22 years and 44K miles.

aklim

I think the issue is not that it lasts 22 years. It can last forever if you never use the car, IOW, fuel doesn't get through it. Assuming the stations aren't lying and do have pure gas, what would you do? Forever run to those few stations? You can but it is a PITA. Unless you have to keep it OEM, I'd just buy the newer Bosch injectors so I can go anywhere I want

mickey5

Are the Bosch injectors better than the Delphi's? I'd hate to have to pull them out some day as they took me forever (sic) to install. LOL

aklim

If you have the Delphi ones that are ethanol resistant life is good. It's only the old multec that are bad. You probably have the good ones unless they are from the boneyard.

PatternDayTrader

First - Ive never done what you are doing so I cant speak from actual experience. Next, I think I would do something so that the injector tip or nozzle (or whatever you want to call it) sits in the exact same place as the old injectors.
Regardless of some of the bs passed around as fact, it is obvious any injector that will atomize fuel better, and in a more precise way, is better !
Knowing this, there is zero downside and only upside by using them. So I hope you make it work and come back and tell us what you think once its done. I myself have though quite a lot about the injectors in my lt1 car, and I suspect that if I make a modern design version work, more power and better drivability will be the inevitable result.

Red 91

Make damn sure the injectors can't travel down out of the fuel rail, or you will burn it down. Good Luck!

aklim

I forgot. Does the fuel rail in an L98 adjust up or down? If not, can Jon make some adapter for it? I think I remember him saying that he did for some other ones?