BigWhiteGTP

Ive replaced just about every sensor on this thing, the motor is good, the
transmission was just rebuilt with the stock TC and has Transgo parts in it. City I can get around 17 or so. But I still can't seem to get over 20mpg highway with cruise on at 75mph. The injectors are 20 year old originals and Ive wanted to replace them for awhile.

They ohm fine, but I bet they are old and people are amazed at the difference idle quality is. Will new ones help me get better mpg as well?

sofakingdom

iTrader: (1)

Possible, but hard to predict. If their spray pattern is poor, or some are clogged differently from others, then putting a set where all are equal might help.

I'd suggest NOT going back with the originals. Try the "Ford" (Bosch) light-blue top units. You can pick em up used all day long on ebay for less than $100 a set, as an example like these http://cgi.ebay.com/ebaymotors/Ford-...item2a0cd3f2af You have to be careful how you put them in, and make sure you use the little clippy things on top to hold them in the fuel rail. You may even have to grind down the place where your rails bolt to just a little bit, to let them go further down into the hole.

RS-Chevy-SS

I know mine have terrible spray pattern. They dont look like a cone at all

jtsk

iTrader: (3)

I would also give Southbay Fuel Injectors a look too. They have great prices and excellent customer service.

TheDarkMinister

Maybe using a good fuel system cleaner can help.. also have you checked out your filter?

ASE doc

17 in town isn't bad. However, at 20 years old, your injectors have lived a long life and could use a rest. I would replace them if there is any doubt at all. Of course replace the fuel filter along with them just to protect the new nozzles. Also, a new O2 sensor wouldn't be a bad idea. for maximum efficiency.

TheDarkMinister

1983Chimaera

http://users.erols.com/srweiss/tableifc.htm
This table helped me immensely when I was looking for larger injectors for my E85 conversion project. I scored some 36.25 lb/hr Bonneville injectors, and found others in places I would never have thought to look. I now have tons of injectors from 14 lb/hr, 18 lb/hr, 19 lb/hr, 22 lb/hr, 24 lb/hr, 28 lb/hr, up thru the 36 lb/hr ones (all free when they fit in your pocket at the junkyard).

ASE doc

Using junk yard injectors sorta sends blueprinting a matched set out the window. Buy quality, new injectors. They really are flow matched to prevent a lean cylinder.

BigWhiteGTP

Well another reason to suspect them being bad or not flowing well at least is track times in the last 4 weeks. All in 14.8-15.1 range. That is fine if the variables weren't changed. But tonight was a different story. All of these would be considered improvements: drag radials, 400ft DA, temps in the high 40's, the best I got was a 14.89@91mph. Previous best was 14.80@94.6.

I know these cars run rich from the factory, but even if they ohm fine, the spray pattern has got to be like a stream. And with the IAT readins such low temps and telling the injectors to dump in more fuel, the engine is basically bogging because of the cold weather.

And Im sorry, 20mpg isn't good w/ CC set at 75mph on flat roads with windows up and no AC. I get 20mpg on the highway with AC on, CC set at 75mph, 200lbs of an extra person and luggage up the hills on Yuma and into hilly southern california. That is more understandable. It just goes to show that variables don't play a part in my suspecting of the injectors going south.

And yes, Southbay is where Im going to get them from. No junkyards or used for me.

ninetyone

iTrader: (2)

You can use the Ford 24lb/hr, but i had to lower my fuel pressure to get the car to not run so rich. I lowered my fuel pressure 3 lbs and the car ran better and smoother, and got better mileage.

1983Chimaera

Actually you can have any injector blueprinted, Fuel Injection Specialties in San Antonio will completely disassemble, clean, reassemble, and flow test your injectors for cheaper than buying a new set, and their service is guaranteed to have them like if not better than new. They charge around $20 per injector, which is far cheaper than buying a new set, especially where larger flow injectors are concerned. They also specialize in a lot of DIY EFI solutions and can build custom harnesses. Keep in mind the list price for the 36.25 lb/hr Bosch injectors I found in the yard is $101.99 EACH.

1983Chimaera

http://www.fuelinjection.com/

BigWhiteGTP

Southbay sells a set of brand new 22s for $160 or so.

ASE doc

The one thing an injector service cannot guarantee is that the coil isn't close to failure. If it ohms tests well, it gets reused. On our TPIs, coil failure is the probably the most common.

1983Chimaera

Fuel Injection Specialties both replaces the internals if needed AND guarantees their work. I've taken injectors there before and not only do you get a injector that is practically new for a fraction of the cost, unlike a new bought injector you get all the data from it as well such as spray pattern graphs, head flow rates, and current draw from both before and after cleaning and rebuilding.

Note - Coil life on most Bosch injectors is 1.5 million miles. Factory TPI units use Delphi injectors, which even GM has stopped using in favor of Bosch.

Bosch 36.25 lb/hr @ 43.5 psi - part #0-280-155-811, GM part # 24508208

Ultimately if you want to spend more money on brand new injectors with no flow data, then do so. If you want to spend significantly less and have complete data and the same warranty (typically one year) as the brand new ones, then go the used / rebuilt route.

southbay08

I have one important question,,,exactly what internals are they replacing, and how do they do it? How do they re-assemble them if they take the injectors apart???? If they can do such a thing, it is a new one on me.
We do sell the 22's for $165 but tgo members get 10% off. If you purchase through our website just put in promo code TG11 or if you call us just mention that you are tgo members.

southbay08

Well, that's kinda not true. When we flow our injectors we run them at various duty cycles, and we run them from 600 rpm up to 10,000rpm, 2.5ms - 12ms and during this time we bump up a little on the pressure. If the coils are starting to fail the injectors shut down during this flow process although the resistance checks out fine. Nine times out of 10 it is related to the coil.They will also flow without a problem so unless you perform these additional tests,, you will not know if there is an issue with the coil.

www.southbayfuelinjectors.com
516-492-6504

1983Chimaera

All I can say is we've used them before with excellent results, and their information is posted on their website if you have any questions for them.

southbay08

I am not saying that they are a "bad" company, but i am not clear as to how they replace internals, take them apart and put them back together again.

1983Chimaera

And I'm saying call and ask them. I don't work for them, I've only had work done thru them. I'm just pointing out that rebuilt injectors are an option, especially for a budget build.