24lb per hr. ford blue tops in my 90, will it work fine?

JeffP1167

JeffP1167

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Yucaipa, CA.
I understand for got the 24lb per hr from fuel pressure being set at like 36 psi. With an adjustable regulator cap on my TPI if I back my pressure to around 35psi, will my ecm be fine with the change or are 22lb per hr GM injectors my best choice?

Right now it has 19lb per hr. Bosch injectors in it with pressure set at around 48psi and it actually seems to run pretty nice. Or am I fine with whats in the car now? I only installed these 19# injectors since they were new and I knew I had to flush my fuel system & I already had them. This 90 vette is completely stock and no mods to engine are ever planned.

I'm not interested in rebuilt injectors at all. Don't really care about rave reviews people have made about them, when it comes down to it they are still at a unknown mileage and used. I would rather have brand new even if it costs me 350 bucks.
 
They should be fine, but you may be on the slightly rich side if everything is stock. I would think Ford orange top 19lb @ 48lb that you are running would be the better option. Why are you wanting to change?

I have been running the orange tops on my TPI engine and have been very happy with them. I have never bought any new injectors. I just buy truck intakes withinjector at swapmeets for $15.
 
Fuelie74 said:
They should be fine, but you may be on the slightly rich side if everything is stock. I would think Ford orange top 19lb @ 48lb that you are running would be the better option. Why are you wanting to change?

I have been running the orange tops on my TPI engine and have been very happy with them. I have never bought any new injectors. I just buy truck intakes withinjector at swapmeets for $15.
Click to expand...

I'm not using ford "orange" top injectors. I have Lucas/delphi bosch style 19lb per hr injectors in the car. I basically used them because I bought them new and they were just sitting on my shelf is all. They are basically black with like a blue ring on them would have to look at the number on them though. I figured these would be a better choice then the mix & match set that was on the car when I bought it and perfect to flush the old fuel out of the car & make sure it would run without damaging "correct" injectors for the car.

I'm fairly certain only clean gas is going through the system now and this is a California car so need the car burning clean so don't need higher lb per hour injectors then it really needs.

Also are these ford injectors a direct fit for my TPI and do I use GM o-rings or ford?

these were originally bought for a 305 TPI engine.
 
Ok this is where it gets confusing. Ford runs and rates there injectors at a lower pressure than GM. It was something like 37 vs 45, but don't hold me to those exact numbers. More pressure is more flow and a grater lb per hour rating.

GM used 19lb injectors for 305 and 22 lb injector for 350. That means that currently you don't have big enough injectors.

Ford used 19lb (orange top) injectors in there 302's. Now remeber the pressure differance.

When you run the 19lb (orange top) injector at the higher GM pressure it will be close to 22lb per hour. Now please don't take this the wrong way I am not saying that they are a perfect match, but they are very close.

The Ford injectors are a bolt in and use the same GM O-Rings.
 
thought the 90 vette ran at 43.5 psi so by upping my pressure 5 lbs that would put my 19's at about 21 lbs per hr correct? The ecm can also correct by a variance of + or - 2 lbs per hour correct? I've never ran the car on the street so I am unsure how it will react to being under a load. However it also seems to idle smoothly and rev up freely and doesn't hesitate a bit.
 
The computer can adjust on closed loop, but not open loop. So WOT will be effected by size.

Your current injectors are probably fine. I was just trying to point out that while blue tops would probably work fine orange tops might be a better option for you.
 
JeffP1167 said:
I understand for got the 24lb per hr from fuel pressure being set at like 36 psi. With an adjustable regulator cap on my TPI if I back my pressure to around 35psi, will my ecm be fine with the change or are 22lb per hr GM injectors my best choice?

Right now it has 19lb per hr. Bosch injectors in it with pressure set at around 48psi and it actually seems to run pretty nice. Or am I fine with whats in the car now? I only installed these 19# injectors since they were new and I knew I had to flush my fuel system & I already had them. This 90 vette is completely stock and no mods to engine are ever planned.

I'm not interested in rebuilt injectors at all. Don't really care about rave reviews people have made about them, when it comes down to it they are still at a unknown mileage and used. I would rather have brand new even if it costs me 350 bucks.
Click to expand...

OK, first thing is that is a 22LB injector stock. Put in a 22LB injector and put the FP at 43.5 where it belongs.

There is really no difference between new and rebuilt, just using the core, but that is a personal preference. We give lifetime warranty on all our rebuilts.

Next, there is no such thing as a GM injector. The stock ones are made by Multec and they are terrible.

Go with new Bosch, they make the best injector for that application.
 
JeffP1167 said:
Fuelie74 said:
They should be fine, but you may be on the slightly rich side if everything is stock. I would think Ford orange top 19lb @ 48lb that you are running would be the better option. Why are you wanting to change?

I have been running the orange tops on my TPI engine and have been very happy with them. I have never bought any new injectors. I just buy truck intakes withinjector at swapmeets for $15.
Click to expand...

I'm not using ford "orange" top injectors. I have Lucas/delphi bosch style 19lb per hr injectors in the car.
Click to expand...

Which are they? Those are 3 different injectors, one is pintle, the other is disc.

I basically used them because I bought them new and they were just sitting on my shelf is all. They are basically black with like a blue ring on them would have to look at the number on them though. I figured these would be a better choice then the mix & match set that was on the car when I bought it and perfect to flush the old fuel out of the car & make sure it would run without damaging "correct" injectors for the car.
Click to expand...
How long were they sitting? Injectors have a shelf life if not used and can fail if sitting too long. The insides get sticky. If not sitting too long, should be fine.
I'm fairly certain only clean gas is going through the system now and this is a California car so need the car burning clean so don't need higher lb per hour injectors then it really needs.
Click to expand...

The ECU manages the AFR, not the injectors. it will self regulate no matter what sized injectors you have.

The problem comes at both sides of the spectrum. TOO BIG and it won't idle right. Too small and you will run lean at WOT.

Everything else would not be noticable. The 22s have overhead built in to keep the duty cycle where it's supposed to be.

Also are these ford injectors a direct fit for my TPI and do I use GM o-rings or ford?

these were originally bought for a 305 TPI engine.
Click to expand...

GM o-rings. .552 is the size.
 
Fuelie74 said:
Ok this is where it gets confusing. Ford runs and rates there injectors at a lower pressure than GM. It was something like 37 vs 45, but don't hold me to those exact numbers. More pressure is more flow and a grater lb per hour rating.

GM used 19lb injectors for 305 and 22 lb injector for 350. That means that currently you don't have big enough injectors.

Ford used 19lb (orange top) injectors in there 302's. Now remeber the pressure differance.

When you run the 19lb (orange top) injector at the higher GM pressure it will be close to 22lb per hour. Now please don't take this the wrong way I am not saying that they are a perfect match, but they are very close.

The Ford injectors are a bolt in and use the same GM O-Rings.
Click to expand...

Ford rates the injectors at 39.7 GM are 43.5. Like I said prior, you will see a difference at idle and at WOT.
 
They are all marked D1570ba ... I believe them to be the disc design. They were sittling for a pretty long time, however this is the first time they have ever had fuel through them. They all ohm'ed out at the 16ohm range and when disconnecting one injector at a time from the harness you can tell the difference on how the motor is running, so I am certain they are all working.

I've seen new multecs for sale at like 25-30 an injector. I know everyone really hates them but my best friend has a 90 that until last year they were working fine. He had about 135K miles on his car so his seemed to last quite awhile.

I have had probably 20 gallons of gas through the car so far, so I am fairly certain all the old gas is gone out of the system. When I changed the fuel pump last week it's sock was caked with some tan colored looking crap however the tank appeared pretty clean. This weekend I'm going to change the fuel filter then it should be ready for new injectors.
 
Hey Jeff

I cleaned out my mailbox, I see you tried to PM, try again.

Thanks.
 
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