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Injectors for 86 TPI?

vettebuff

Member
Joined
Dec 19, 2004
Messages
18
Location
Skåne, Sweden
Corvette
1986 coupe white/silver
The enginee is rebuilt some thousand miles ago (at 140k miles) but the injectors were left alone. I do not get the same punch I THINK I remember from the days the car was 50k miles. And definitely not the fuel milage. I now also encounter slow reving down, the car (automatic) kind of drives by itself at speeds around 30mph. However, once stopped the rev goes down to 600-700 after some short time. But letting go of the pedal while driving does not slow it down as it used to. My thoughts go to the injectors.

What injectors should I get for a stock 86 TPI? What I understand 22lbs are the originals, but would 24 work (seem the aftermarkets are 24 and are much cheaper). Pros and cons would be appreciated. I am all ears!
/P-H
 

vetteboy86

Well-known member
Joined
May 26, 2003
Messages
2,760
Location
IN
Corvette
1986 Black "Indy 500 Pace car replica"
Welcome to CAC, most of your corvette needs can be answered here. There could be a few things that would contribute to your problem. There is an ohm test you can perform to find out if your injectors are good, but I dont think this will tell you if they are leaking, and the spray pattern is a whole other story. I would investigate the throttle cable, throttle body, throttle position sensor, or the idle air control valve also. Sometimes all it takes is a good cleaning. And yes 22 lb/hr are the specs of stock injectors.
 

Edmond

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Joined
Aug 1, 2001
Messages
5,218
Location
Louisiana
Corvette
2003 Z06
Many have gone with the Ford "pink top" injectors. They are a less expensive alternate to the OEM (Bosch, I believe) and Accel injectors. I think you can pick up a set for about $220 or so on eBay. If you change, make sure you change all 8 of them. Don't just change a few, you're going to end up doing the rest later anyway.
 

Hrtbeat1

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Joined
Nov 24, 2002
Messages
923
Location
MS Gulf Coast
Corvette
'90 coupe (gone) '96 CE LT4 Z51
The 24's should work fine for you. There is such a range that the injectors work at depending on the fuel pressure you could even go bigger but turn down the fuel pressure and get the same results.

I would check the IAC, EGR, and throttle position sensor. Any could need a cleaning or just a bit of adjustment.

FYI the stock injectors are made by Rochester, the Ford "pink tops" and Accel injectors are made by Bosch.

:pat
 

vettebuff

Member
Joined
Dec 19, 2004
Messages
18
Location
Skåne, Sweden
Corvette
1986 coupe white/silver
Thanks for the replies. The IAC, EGR are replaced. The cables checked and throttle body etc cleaned. The TPS is adjusted according to the books and checking the range against a volt meter it seem to work fine. This is where I start think about the injectors.
So you say 24's would work? Coudn't there be any problem NOT going for the original 22's? At WOT, what happends then for example?
 

Hrtbeat1

Well-known member
Joined
Nov 24, 2002
Messages
923
Location
MS Gulf Coast
Corvette
'90 coupe (gone) '96 CE LT4 Z51
You may run a bit rich @ WOT with the larger injectors. If you have a adjustable fuel pressure regulator you could back off the pressure to lean it back out.

:pat
 

Edmond

Well-known member
Joined
Aug 1, 2001
Messages
5,218
Location
Louisiana
Corvette
2003 Z06
like Hrtbeat1 said, I don't think there's enough of a variance in the 22 and 24 injectors to make a real big difference.

How do the spark plugs look?
 

vettebuff

Member
Joined
Dec 19, 2004
Messages
18
Location
Skåne, Sweden
Corvette
1986 coupe white/silver
Have not checked the plugs lately. And now the car is put away for the winter (not at my house) so it has to wait.
Why is it that it seem easier to find 24's (to a good deal) than 22's? Or isn't is?
 

Edmond

Well-known member
Joined
Aug 1, 2001
Messages
5,218
Location
Louisiana
Corvette
2003 Z06
The plugs can give you a pretty good idea if the injectors are leaking.

I think a lot of the 24 lbs. injectors are taken off of crate motors after dyno testing and tuning was done. Maybe they took the 24's off and went to bigger ones as the need came up?
 

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