5.7 Intake and Fuel Injection

[pwdcougar]

Thanks to the info I've gotten on this board and a few youtube videos I'm tackling the intake and fuel injection on my 97 Silverado.

One question (actually I have a dozen but I'll start with this one)

The inside runners of the intake look awful oily and dirty. The truck has always run well and has 125000 miles. Does this look normal?


I plan on replacing the original cap, rotor, wires and heater hoses. I'll use the hose barb as a restrictor instead of the more expensive original clip in style heater hose.

Thanks!


Paul

[Tom]

Yes that looks normal.

[pwdcougar]

Thanks for the reply Tom. I really thought there was something seriously wrong with the engine after looking at the crud in the intake runners.

Paul

[speedygonzales]

Two things you must have if you can afford the injectors.
http://www.summitracing.com/parts/smp-fj504/overview/

And these metal intake gaskets
http://www.summitracing.com/parts/fel-ms98000t

Do not use any other gaskets.

[BigBlocksRule]

^ amen to both, especially the gaskets.

Nobody carries the metal intake gaskets separately which is annoying.
At any rate, you get a valve cover and dizzy gasket along with the gasket for the top half of the clamshell.

DON'T USE THE PLASTIC GASKETS - THEY'RE NO BETTER THAN GM'S ORIGINALS!

[pwdcougar]

Picked up these parts a few months ago. It took 2 hours to clean the intake! What a mess.

Thanks guys.

Paul

[54 jimmy]

you will love the power and better gas millage with that new injector. did mine a few months ago. what a difference. fyi change the oil pressure sender behind the intake while it is easy to get at. just don't buy a cheap sender made that mistake and had to change it with everything in the way. pain in the ass plus you need a special socket to change with the intake in the way.

[1997z71]

Originally Posted by 54 jimmy

you will love the power and better gas millage with that new injector. did mine a few months ago. what a difference. fyi change the oil pressure sender behind the intake while it is easy to get at. just don't buy a cheap sender made that mistake and had to change it with everything in the way. pain in the ass plus you need a special socket to change with the intake in the way.

How much of an increase in power and mileage can we expect from this upgrade? My 97 only has 53,000 on it and runs as good as it did new.

[pwdcougar]

Figures. I got your suggestion to replace the oil pressure sensor after re installing the intake. I'm not really looking for a power increase or better fuel economy. The intake gaskets have been leaking for years!

Paul

[54 jimmy]

1997z71 my truck has 180,000 miles on it a now runs like new with the new upgraded injection spider. on you truck with 53000 miles it probably won't make a difference. my intake runners were so carboned up the whole intake was black. plus my poppet were leaking on my injectors. fuel milage was crap. I get 17 around town and like 22 on the hiway depending on how much I get into it. I have 3.73 gears and 255 70 17 tires.

[54 jimmy]

pwdcougar figures you would get it after lol just hope it doesn't crap out I changed mine just because.

[pwdcougar]

Originally Posted by 54 jimmy

pwdcougar figures you would get it after lol just hope it doesn't crap out I changed mine just because.

\


Well so far so good. Buttoned everything up and road tested. Power is way better. Had a misfire code on initial start up. Guess it didn't like the spark plug wires in the wrong spot. The cheapo scan tool has run all but one of the tests so there is still a yellow light not green. Cleaning up the garage and drinking a beer. I'll finish road testing tomorrow! I'll definitely keep an eye on the oil sensor.

Again thanks for all the help everyone.

Paul

[speedygonzales]

Got one more task left even though you may not have a SES. Cam sensor retard. For years I thought all was perfect after having pulled the distributor a couple of times. Then I scanned it for retard and found I was off by 16°. Not a task for the average $200 scanner though.

[pwdcougar]

Thanks Speedy. I'll check it once I find the right scanner.

Paul

[speedygonzales]

I have a Solus and from what I've seen, all the Snap-on ones can do it. Just take it somewhere to get it straight till you have time to find one.

[1997z71]

Originally Posted by 54 jimmy

1997z71 my truck has 180,000 miles on it a now runs like new with the new upgraded injection spider. on you truck with 53000 miles it probably won't make a difference. my intake runners were so carboned up the whole intake was black. plus my poppet were leaking on my injectors. fuel milage was crap. I get 17 around town and like 22 on the hiway depending on how much I get into it. I have 3.73 gears and 255 70 17 tires.

I also have the 5.7 and 3.73 gear. Best I ever saw was 16.4 mpg @ an easy 65 mph on the highway on flat roads. Have checked it a few times to verify it. I average 14 and I don't accelerate or brake hard.

[pwdcougar]

Originally Posted by speedygonzales

Got one more task left even though you may not have a SES. Cam sensor retard. For years I thought all was perfect after having pulled the distributor a couple of times. Then I scanned it for retard and found I was off by 16°. Not a task for the average $200 scanner though.

Speedy, took my truck to a local shop. The guy said if there was no check engine light then I'm fine. My cheapo scanner is still giving me a yellow light. All the tests have run but the OH Oxygen Sensor Heater Monitor.

I've only put 20 or 30 miles on the truck.

Paul

[pwdcougar]

And now the cooling system doesn't stay pressurized for more than 20 minutes and you can smell coolant. No visible leaks and no coolant in the oil.

Paul

[speedygonzales]

Originally Posted by pwdcougar

The guy said if there was no check engine light then I'm fine.

Unfortunately he is wrong.

The spec is +- 2 degrees. When I checked mine it was - 16 degrees with never a check engine light. Now does putting it back to zero change anything? Not sure.

If you removed the distributor and put it back, there is no way you got with +- 2 of target.

It takes no time at all to scan it. If you go back to the same guy, tell him to scan it if he has the capability. If it is within +- 2 degrees away from 0 and he wants to be paid, I'll pay him. I know good and well it will not be there.

Originally Posted by pwdcougar

And now the cooling system doesn't stay pressurized for more than 20 minutes and you can smell coolant. No visible leaks and no coolant in the oil.

Paul

Not sure what you are actually saying about pressurizing. Are you saying there is a smell after 20 minutes of running? Or are you saying it is loosing pressure?

In any case, you should use a coolant system pressure tester. If you don't have one, you can borrow them from auto parts stores. Check under the passenger foot well rug to see if it's wet.

[BigBlocksRule]

How the hell was it running at 16 degrees off?
I've stabbed two and both were within spec when I had 'em scanned. Maybe I'm just lucky. Getting 14mpg in town and about 17 on the road, better than when new, so I'm leaving mine alone.

[pwdcougar]

Originally Posted by speedygonzales

Not sure what you are actually saying about pressurizing. Are you saying there is a smell after 20 minutes of running? Or are you saying it is loosing pressure?

In any case, you should use a coolant system pressure tester. If you don't have one, you can borrow them from auto parts stores. Check under the passenger foot well rug to see if it's wet.

Speedy, the cooling system pressurizes after running for a while but does not stay pressurized for very long and you can smell coolant when you walk by the front of the truck. The carpet is dry under the heater core. And there are no visible leaks. When it stops raining I'll re check all the hose connections and try the pressure tester.

Last thing, how long does it take for the truck to run all the scan tests? The OH test has not run yet after two days of driving around.

Paul

[speedygonzales]

How do you know it's not staying pressurized? Wouldn't one reason it's not staying pressurized is the cap itself?

Every drive cycle the PCM checks all values. Certain conditions must be met for some of the tests to run.

As for the cam retard, the moment it's started up, the check would fail. However the conditions for failure are unknown. The spec is +-2 but the PCM will not fail when it's even as much as -30°. I drove around for years with it at -16°. Once I moved it to +1, it through a code. So I settled on -1. No problem. Currently I am at -3 and I'm not going to mess with it. It's close enough for me.

So you can see that the spec and the DTC have different parameters.

[Tom]

Originally Posted by BigBlocksRule

How the hell was it running at 16 degrees off?

Pretty easy actually.

[pwdcougar]

Pressure tested the cooling system and it held 15 pounds of pressure for 3 hours. Looks like the cap is bad. I'll replace it and keep driving it and see how things go.

Thanks

Paul

[Already Gone]

Originally Posted by speedygonzales

Two things you must have if you can afford the injectors.
http://www.summitracing.com/parts/smp-fj504/overview/

And these metal intake gaskets
http://www.summitracing.com/parts/fel-ms98000t

Do not use any other gaskets.

Do you think these parts make 1999 5.7 Vortec Cop Tahoe ( 255 factory hp) with 97,000 miles run any better and have more power? The Tahoe runs great right now.