#6 injector replacement question (1 Viewer)

[Death Star]

Is there any way to replace the #6 injector without removing the upper intake? Any helpful tips?

 

[george_tlc]

No idea, maybe someone else has done it. There's a bunch of stuff needed to get the fuel rail off AND more importantly re-seated properly on the o-rings of the injectors that removing the upper intake seems to be a really good idea and pretty easy to do with a bunch of extensions etc.

Changing all the vacuum lines on the bottom of the upper intake is a good idea while you have it off and you may as well replace the #1 bypass hose etc while you're in there Clean the intake runners as well while it's off. i.e. a good time to commune with that area of the 80 and do a bunch of PM that will save you having to do it in near future on a ~20yr vehicle.

All you need are vacuum hoses, the #1 bypass hose and the metal gaskets for the intake (get the one for the throttle body to intake too).

cheers,
george.

 

[BILT4ME]

And pull all the injectors and send to Witchhunter for rebuild/balancing and reinstall for smooooooth operation. Also replace the fuel filter while you're in there.(and maybe relocate it.)

 

[george_tlc]

^2 agreed... Good time for all the PM that you can do while 'in there'. I assume you've seen my #6 injector write up?

Just slot the fuel filter - makes it easy to remove/replace next time.

cheers,
george.

 

[Death Star]

So it sounds like I might as well pull it and replace the PHH and manifold heater line, fuel filter, etc. I was hoping to make this a quickie. I have a misfire on cylinder 6. Replace everything but the injector. Kinda tough working 7 days a week.

 

[george_tlc]

Yep, do the job right or you'll be back in there sooner than later. I presume it's a solid misfire versus intermittent?

You can pop off the connector (carefully so you don't break the plastic tabs etc) and ohm out the injector, should be around 10 ohms (check with the FSM for exact numbers).

cheers,
george.

 

[sbman]

You can separate the upper intake and lift it off in 30 minutes, believe it or not. In brief:

• Do not remove the EGR valve, just remove the nuts and pull its mounting studs
• Pull electrical and vacuum lines off
• Pull the upper coolant line up near the distributor. No need to drain radiator, only a little coolant comes out
• Leave the throttle body in place and all cables attached
• Remove most of the nuts/bolts standing above the engine compartment
• Remove the remainder with the help of a friend and 20 or 30" of extensions with a flex head socket laying under the truck
• Once it's loose, pull the side towards fender up slightly and edge it out. You can 'flex' the EGR valve a bit
• Once you have it completely loose, just carefully rotate it over and balance it on top of the motor

That's how I did it, and it saved a lot of time. Much easier than trying to fiddle with it in place, and really not difficult to pull, there is only the rear most bolt that is a PITA, but you can get it. Before you pull lines and electrical/etc.. make sure it's actually attached to the upper, not much is.

 

[Death Star]

It's pretty consistent. It only threw a code for it once. P0306. After checking the wiring harness by the EGR (it's good), I cleared the codes. Now I get P0135, consistently. Idles rough, it has a bad skip, loss of power. The #6 plug is MUCH worse than the other 5.

 

[george_tlc]

If it is misfiring you should be getting a p030x code since the ECU will detect a timing issue when an injector should fire and doesn't.

P0135 is O2 - but the ECU may find something unhappy if the fueling is messed up.

I would pop off the injector connector and ohm the injector. Mine was open circuit when I had a consistent misfire and p0136 being reported.

cheers,
george.

 

[Death Star]

#6 plug

The other 5

 

[BILT4ME]

Does #6 smell like fuel or feel like oil?

Either way, it's not firing properly. It's also possible that #6 injector is hanging open. Does it start hard when warm?

 

[Death Star]

Always starts fine. Here's my logic for thinking its a bad injector.
Disclosure: I DO have an exhaust leak at the Y pipe. It's been there for a while. I replace the rear cat and muffler pipe and downstream O2 earlier this summer.

Out of the blue, I started to get a rough idle. Then a pretty bad skip on the highway. I threw codes P0300, P0306 and P0135. I replaced the upstream O2. Pulled the EFI fuses to clear the codes. No change in how it runs. The skip is worse but it's only throwing P0135.

I originally thought it to be a head gasket, but no steam, no chocolate milk shake oil, and I did the blue liquid exhaust gas in the coolant test.

I figure the only thing it could be at this point is an injector because only cylinder 6 is being affected.

 

[sbman]

I'm sure you've already done it, but that spark plug looks pretty badly oiled on the outside, like your spark plug tube is leaking. Possibly the plug has gone bad? Even if it sparks when out of the cylinder, it does not mean it is firing under compression.

 

[Death Star]

I just did the valve cover gasket and spark plug tube grommets. I stuffed a rag down the hole today and it came back relatively clean.

 

[BILT4ME]

I didn't see where you mention it, but what about the wiring harness by the EGR? Some of the folks have had an issue that it cooked the wiring, then after something like doing the tube seals, the movement of the harness finally breaks the coatings and they start intermittently shorting out. That will also give the P0306 code...

Check your harness.

 

[baldilocks]

So it sounds like I might as well pull it and replace the PHH and manifold heater line, fuel filter, etc. I was hoping to make this a quickie. I have a misfire on cylinder 6. Replace everything but the injector. Kinda tough working 7 days a week.

At this point you are over half way to head gasket while your in there!

 

[Death Star]

I already checked the harness at both ends an re-wrapped it with heat shielding tape.

God, don't say that about the head gasket!

 

[george_tlc]

ohm out the #6 injector! At least determine if there's an obvious electrical fault in it first. How long has it been misfiring? I love how the 'extra' details come out as the thread evolves

cheers,
george.

 

[Death Star]

Actually the details have been in other threads over the last week as I've been trying to diagnose it. I'm checking the injector now.

 

[george_tlc]

Yes, but how do WE know what is in the other threads if you don't link all the pertinent data together... I'm not sitting on the edge of my seat following each of your threads

13 ohms is the nominal resistance #6 should have. Measure say #5 as well - just to make sure your meter is of reasonable quality.

cheers,
george.