Fuel Rail Removal (Page 1/2)
Brent7088 SEP 22, 11:18 PM
I'm having a tough time getting the fuel rail off my '86 V6 so I can clean my fuel injectors.

I removed the upper intake plenum, the 3 fuel lines, all 6 injector harnesses, the 2 rail mounting bolts and it still doesn't seem to budge much. I shake it back and forth and it does give, but still seems like something is still tying it down.

Any suggestions? Could the injectors themselves be stopping it?
Fie Ro SEP 23, 06:21 AM
the front/rear injectors sit in a 90 degrees angle in the fuelrail which in itself makes it harder to remove. The O-ring at the injectors bottom is what seals them in the plenum, these may be stuck. I would try to squirt WD40 in the injector holes in the plenum to loosen up these O-rings. There are retainer clips just under the fuelrail that secure the injectors to the rail, if you can reach them and remove 1 bank of 3 of them it might be also easier to get the injectors out. Replace the O-rings with new ones when reinstalling.
Hope this helps.
fierofool SEP 23, 09:55 AM
If it's that solidly stuck, you might consider replacing the fuel line O-rings while they're disconnected. I had a problem finding them for a Fiero so I searched for a 93-95 Firebird and Camaro 3.4 and found them. The 3.4 fuel rail is almost identical to the Fiero fuel rail. That's a hidden area and you definitely don't want a fuel leak under there.

This is from Rock Auto for a 94 Camaro 3.4 V6, but O'Rielly and other auto parts stores carry Standard motor products.
https://www.rockauto.com/en...863&pt=6264&jsn=1393
Brent7088 SEP 23, 10:59 PM
Thank you for the replies... I swquirted WD-40 on all of them and did finally get the whole thing to slip out.

On another note - I plan to clean them out using the 9v battery method with Gumout. Do the terminals on those injectors have polarity, or would it not matter which is connected to positive and negative?
sanderson231 SEP 24, 11:57 AM
For $18 each Mr. Injector in Idaho will replace inlet screens, ultrasonically clean and flow test from 0-100%. You might be able to clean them yourself but with professionally cleaning a good result is assured.

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formerly known as sanderson
1984 Quad 4
1886 SE 2.8L
1988 4.9L Cadillac
1988 3800 Supercharged

Brent7088 SEP 24, 01:10 PM

quote
Originally posted by sanderson231:

For $18 each Mr. Injector in Idaho will replace inlet screens, ultrasonically clean and flow test from 0-100%. You might be able to clean them yourself but with professionally cleaning a good result is assured.




I'm not sure mine would require a whole lot of cleaning since the car only has under 49K on the odometer, but can't say for sure. I was just gonna attempt it myself for what it's worth to see what kind of stream I get. From what I understand from a YT video, the terminals may not have polarity for connecting to a battery. I was going to use pure Gumout, but may dilute it with gas.
sanderson231 SEP 24, 04:03 PM
I built my own test stand so I can measure flow rate and get visual on spray pattern. There is no plus width modulation so the injectors are commanded to be at 100% capacity. I use a 12V battery to power the injectors on the test stand. That said I have sent several sets of injectors off to Mr. Injector to get professionally cleaned. What kills injectors is not using them. If the car sits for along period of time time without Stabil or similar product in the gas that's a problem. I pulled a set of 8 out of the junk yard and none of them flowed. Same with fuel pumps. If a car sits for a couple of years there's a good chance the fuel pump will gum up.

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formerly known as sanderson
1984 Quad 4
1886 SE 2.8L
1988 4.9L Cadillac
1988 3800 Supercharged

Brent7088 SEP 25, 05:52 PM
Sanderson - thank you for the input.

Just for the heck of it, I went and added a few splashes of Gumout to some gas and injected some of it into the first injector that I pulled (using a 9V ). It was coming out as a single straight stream, which made me think it was clogged since all vids I ever saw on Youtube showed cleaner coming out as a cone-shaped mist.

After doing a search however, I found that many MPFI injectors do indeed spray a straight stream, so I'm going to assume they really didn't need all that much cleaning to begin with. I'll do the rest of them just for safe measure.
sanderson231 SEP 25, 06:39 PM

quote
Originally posted by Brent7088:

Just for the heck of it, I went and added a few splashes of Gumout to some gas and injected some of it into the first injector that I pulled (using a 9V ). It was coming out as a single straight stream, which made me think it was clogged since all vids I ever saw on Youtube showed cleaner coming out as a cone-shaped mist



Typically it is a shallow cone. What pressure do you have at the injector? That will make a difference. Also make sure the inlet screen in the injector is not partially clogged.

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formerly known as sanderson
1984 Quad 4
1886 SE 2.8L
1988 4.9L Cadillac
1988 3800 Supercharged

Brent7088 SEP 25, 08:32 PM
I'm not real sure what the pressure would be - I'm just using a syringe plunger so it's not much. I'd imagine a lot more pressure would create more of a conical shape. Is it required to remove something else to see the screen in an injector?

Another thing I can't figure out is in some videos I see people backflushing their injectors. It would seem to me they would need to have polarity, and everywhere I read shows injectors don't have +/- connections.