Injector swap

[malignd1]

Okay, so today i'm going to attempt to swap out the injectors on the 90'Blazer because after a 3rd emissions fail, post tps swap, rotor and cap and wires change and o2 sensor change; I finally got frustrated enough to take her to a shop and have her tested. $240 and an hour later the tech calls me to tell me the motor has a dead miss so they wanna do a compression test;agreed; 2hours and another $240 later I get a call and told that the test was inconclusive but that the miss was fixed by putting in some regular ol' spark plugs. (Unlike the set that I had paid $100 for 8of em' which I mistakenly had thought would be better. Turns out they only make new engines run better. Ufortunately I was still charged almost $8 a piece for the set put in by the shop.) Then the tech said the injectors are dumping far too much fuel into engine and he would be happy to replace them for me......for $650!!!!!No thank you, I'll attempt it myself. I now have 2new injectors purchased from Napa in hand.
So, I guess m question would be: what is the best way to alleviate the pressure in the lines to accomplish my task. I'm also going to put a new in line fuel filter in. Any info is appreciated.

 

[BoondocK5]

Uhm, Stock TPI engine? any mods at all? Hotter cam? anything?

injector replacement is easy enough, just time consuming. make sure the area round the hole for the injector is clean so no debris falls in to it. make sure to lube the O-rings with something I always use a little tiny squirt of silicone spray on each one.

As far as depleting the pressure in the system, just push the schrader valve in at the pressure gauge port and let it run out, cover your eyes!
Should be an easy repair. just time consuming.

 

[malignd1]

no mods. standard tbi. just 2 injectors on top

 

[BoondocK5]

no mods. standard tbi. just 2 injectors on top

Cake! ten minutes!

 

[4X4HIGH]

1) Remove air cleaner

2) Remove 8 screws holding injector top cover

3) Grasp injector between the electrical connector pins and pull upward

4) Make sure that the thin spacer is left inside the injector pod then reinstall new injectors making sure to put a small amount of grease/lube on the O-ring to keep it from tearing and making install easier. (Be careful as the injectors only go in ONE WAY and one is opposite of the other, there is a small pin the sits into a slot in the injector pod housing).

5) Reinstall injector cover and 8 screws

 

[Fordum]

Bet the plugs were either Platinum or one of the multipoint type.

Most likely Platinum.

I see that time and again. NEVER put Platinum in an older engine. If it did not come with them, they won't work.

Back when they were being pushed on TV, I got a small reputation as being almost psychic.

A friend would tell me that he had done a tune up and now had a miss. Would I look at it for him?

I would say I didn't have to look at it. Just take the Platinum plugs out and put in regular ones and it would run fine.

Of course, I did not hit 100%, but my batting average was more than high enough for people to think I was some kind of genius......

 

[4xcrazy]

Running Platinums, AC Delco "professional series" in mine, work great, no problems..

i only run either a stock replacement, or like these platinums with the exposed tip, i have ran those crappy Bosch platinums in the past and burned them out in 3 months of driving. I won't spend the money on those multi-point/tipped sales pitched things either.

To relieve the pressure, you're gonne have to crack a line, also open the gas cap as well, for some reason this has always helped when i messed with my TBI unit or even for changing out fuel filters.

Those TBI injectors only go in one way too, there should be alittle pin you will see on the injector, it sits in the injector pod one way.

 

[4X4HIGH]

Running Platinums, AC Delco "professional series" in mine, work great, no problems..

To relieve the pressure, you're gonne have to crack a line, also open the gas cap as well, for some reason this has always helped when i messed with my TBI unit or even for changing out fuel filters.

Those TBI injectors only go in one way too, there should be alittle pin you will see on the injector, it sits in the injector pod one way.

TBI DOES NOT retain pressure once the engine is shut off.

I also mentioned the injectors only fitting one way. I've seen people screw up and break injector pods or damage injectors from getting them in wrong.

 

[4xcrazy]

TBI DOES NOT retain pressure once the engine is shut off.

I also mentioned the injectors only fitting one way. I've seen people screw up and break injector pods or damage injectors from getting them in wrong.

uh huh,,, come work on mine.

 

[4xcrazy]

I guess i should agree that TBI does not retain the pressure when turned off,,, maybe FULL pressure, but there is always pressure from the tank and the reason i mentioned opening the cap to relieve any of this pressure. Not as much as the pump puts out, but enough to cause fuel to come out when any part of the line is opened.