I'm replacing VC gaskets on 3.4L, should I do FI's at same time or leave well enough alone

I've been combing Timmy's video's and other sticky's on replacing valve cover gaskets on 3.4L v6 but I see that the tear-down process is similar to getting into the fuel injectors. Should I consider doing both at the same time or am I just being stupid? '98 SR5 V6 4WD with 160k.
I'm doing my own wrenching and my time is valuable, so I tend to fix/replace things while they're in front of me. I'll probably keep this truck for another 5+ years. Maybe longer.

Has anybody done both VC's and FI's at same time vs on two separate occasions? If I do only FI's in the future it would probably be faster than dealing with the VC's because I don't have to clean up VC gasket surfaces, etc. Looks like I would have to buy a couple of new plenum gaskets at that time and some crush washers for the fuel sys. Am I trying to fix something that ain't broken by doing the FI's now when I'm into the VC's? I currently don't have any particular issues with how it runs and I'm simply replacing vc gaskets to fix persistent oil leaks.

 

Good question, I have NOT done VC but did end up sending my FIs out for service since I was having a misfire I couldn't pinpoint. I have 190,000 miles on my '03 and the test showed one of the injectors was almost totally clogged despite fact the the truck ran fine (minus the sudden misfire that turned out to be bad plug wire). While I didn't feel a noticeable difference in engine performance or fuel mileage, I have the piece of mind that they are cleaned and will last a while longer. As you said your keeping the truck for a while, it makes sense to do the FI service and isn't technically difficult job.

Some say you can reuse the plenum gaskets but I got new ones to be safe. There are a few write ups here I can try to find and send to you plus the company that serviced by injectors if you want.

 

I did them both at the same time, a month ago. It was my first time doing either project and it went smooth. I felt fuel injectors were the easier half of the project. It's just three fuel rail banjo bolts holding them in, which is a lot easier than the 16 bolts holding the valve covers in, plus cleaning and resealing all the moons and replacing tube seals.

Definitely doable in a single day, even if you're taking it slow and writing notes.

 

"If it ain't broke, ...."

 

if it was me I would get a scan tool and look at the fuel trims before starting. follow my thinking, if the short and long term trims are +- 5% dont worry about it, if they are +- 10% I would consider it, but before that, I would do a propane enrichment check. Very simple to do. Propane torch with a hose. Dont light the propane. You are using it to artifically enrich the area around where the injectors go into the lower intake. watch the trims and see if they start to go negative, it they do, the injector o-rings are hard, cracked or both or there is a slight lower intake leak.

 

Thanks for the great suggestion! I have the propane and I'll see if my hose can reach the injector locations. I don't own a scan tool but have been considering it for a few years. I'll probably go with OBD Bluetooth device and android app. I was leaning towards not doing the injectors at the same time as the valve cover gaskets just because I want to take some time to clean up VC's, but doing the tests you suggested will help to confirm whether I should go that route.

 

I have done both at different times. Aside from the common task of taking the intake plenum off, they are really independent jobs. I think you could do it either way if you have a full day available. But I would plan for 2 in case you really need to clean up the valve covers, and...
When I did the FI’s (replaced with matched reman set from Motor West, same guys in Timmah’s video), I pulled the intake manifold and replaced both knock sensors and knock sensor harness (both are available pretty affordable for OEM on eBay right now).This requires you get 2 new intake manifold gaskets as well. Good time to drain and replace your coolant too.

Other items I should have had on hand when I did this, had to re-do later:
-fuel pressure gauge and banjo fitting + adapter to check fuel pressure regulator and pump performance
-the 2 pre-formed Hoses that feed the IAC on the throttle body (had to get OEM)
-small wire harness that connects main harness to coolant temp sensor
-new upper/lower radiator hoses (since I was draining everything anyways)
-new spring loaded hose clamps (OEM is a decent price )for the IAC hoses, mine were non-spring style and couldn’t seal
-check all your other hoses around the intake, PCV, etc and have on hand, many will crack as you remove them

 

Thanks for the shopping list. Very helpful. It's challenging to figure out what other parts to order when I haven't pulled everything part to see what makes sense to do while I'm in there. I'm going to test the injectors per Glamisman post and if they check out ok then I'll do the injectors and other parts at a different time. If I'm going to pull the intake and drain the coolant then I might expand that project to include new radiator, thermostat, etc, and perhaps a timing belt and water pump too... and that's a whole different project.

 

I wouldn't, if it ain't broke dont fix it.