Remove 5th Injector

grimlock

Veteran Member
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Mar 14, 2003
Location
Vancouver, BC Canada
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'96 Passat Sedan, Black
I plugged my fifth injector hose a long time ago. I want to remove the solenoid & etc, to keep my engine compartment more "clean" looking....

I read one or two posts in the past stating to use a 10 or 15 ohm resistor w/ 10W rating. If need be I could parallel a couple 30ohm resistors for even more power headroom... I have access to various "large" power resistors, but why such a high power rating?

If I removed the solenoid without putting in the resistor will the CEL come on?

My engine had the recall done quite awhile ago, my ECU ends in GQ.

Richard
 

GoFaster

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Jun 16, 1999
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Brampton, Ontario, Canada
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2006 Jetta TDI
The resistor needs to be able to withstand 12 volts continuous applied voltage. Roughly that's about 1 amp of current. That's 12 watts of power dissipation ... It's actually OK with 10 watts, because the power isn't actually continuously applied, but it's definitely a significant duty cycle.

However, if you have the "GQ" ECU, it is probably irrelevant, because that ECU doesn't use the supplementary injector. Try unplugging the solenoid to see what happens. I betcha nothing happens, in which case ... you are good to go.
 

grimlock

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'96 Passat Sedan, Black
The resistor needs to be able to withstand 12 volts continuous applied voltage. Roughly that's about 1 amp of current. That's 12 watts of power dissipation ... It's actually OK with 10 watts, because the power isn't actually continuously applied, but it's definitely a significant duty cycle.

However, if you have the "GQ" ECU, it is probably irrelevant, because that ECU doesn't use the supplementary injector. Try unplugging the solenoid to see what happens. I betcha nothing happens, in which case ... you are good to go.
The math doesn't quite make sense to me... but I trust your judgement. I'll unplug it and see what happens.

1.0A means the solenoid must appear as 1ohm load with 12V... That's a lot of current for a somewhat thin wire, IIRC. (maybe 16gauge wire?) However if the cycle isn't continuous, it should be ok.

Or did you mean: 12V / 10ohm ~ 1.2A, then Pdiss ~ 1.2A * 12V = 14.4W? If this is the case, and I did need the resistors I'll take two 30ohms in parallel, to give me that much more power dissipation across the two resistors...

regardless I not out for a pissing match on the math, just want what works to remove the useless part...

thanks for your help!

Richard
 

RIP TDI

Top Post Dawg
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'15 GSW SE 6MT...... '01 Golf GLS 5MT.... '96 Passat Variant....
However, if you have the "GQ" ECU, it is probably irrelevant, because that ECU doesn't use the supplementary injector. Try unplugging the solenoid to see what happens. I betcha nothing happens, in which case ... you are good to go.
A GQ ECU does require the resistor.
 

Lug_Nut

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Sterling, Massachusetts. USA
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idi: 1988 Bolens DGT1700H, the other oil burner: 1967 Saab Sonett II two stroke
Only the BK ECU (black plastic case) has a circuit monitoring the voltage drop across the 5th injector solenoid coil. The GQ totally ignores the solenoid. You can pull and plug the now obsoleted fifth injector without fear of MIL.
 

GoFaster

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Jun 16, 1999
Location
Brampton, Ontario, Canada
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2006 Jetta TDI
Re the math: I will no longer round off the numbers that I did before. Remember, I = V / R and power = V x A (basic Ohm's law stuff).

14 volts, 10 ohms. Current is 14 / 10 = 1.4 amps. Previously I had rounded this to 1 amp. It's duty-cycled, so it may actually be closer to 1 amp. Regardless ...

Power = voltage x current = 14 volts x 1.4 amps = 19.6 watts. Remember, again, it's duty-cycled. Strictly speaking, if this were not the case, a 10 watt power resistor would NOT be enough to withstand normal operating voltage, which is 14 volts not 12.

Comprendez?
 

Lug_Nut

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idi: 1988 Bolens DGT1700H, the other oil burner: 1967 Saab Sonett II two stroke
And my BQ ECU continues to operate a 10 watt resistor instead of an injector coil after three (maybe four?) years. I've had the same resistor and plug in my past two cars. I've also run for days on end with a dash illumination indicator lamp instead of the ceramic resistor because it was of an adequate resistance. The lamp is most definitely NOT 20 watt output lamp.
 

grimlock

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Mar 14, 2003
Location
Vancouver, BC Canada
TDI
'96 Passat Sedan, Black
My ECU (GQ) complains when I just disconnect the fifth injector....

I put in two 33R 11W resistors in parallel. Overkill, but why not.

For the mathematicians, assuming 14.4V, then each resistor is getting ~436mA, and is dissipating ~6.28W. But as Brian has pointed out, the fifth injector is duty cycled so the resistors shouldn't even get hot....

Just gotta rip the guts & plumbing of the fifth injector, not enough time today....

thanks for your guys' help.

Richard
 

redmondjp

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Jul 1, 2004
Location
Redmond, WA
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'96 Passat Sedan
In the process of my TB change, I decided to yank the 5th injector and it's associated plumbing as well--it makes it easier to get my arm in there to work on things.

I took a hacksaw and cut the protrusion off of the air box which holds the injector. I cut and blocked the fuel line near the "T" at the filter. To block the exhaust, I found a ball bearing which fits inside the fitting nut that was originally on the end of the line (had to cut end of hose off to get the fittting off--I could also have pinched the end of the fitting instead of using the ball bearing).

Mine was already blocked, but it's much nicer with the useless stuff completely removed.
 

grimlock

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Mar 14, 2003
Location
Vancouver, BC Canada
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'96 Passat Sedan, Black
hmmm, I was thinking about properly "plugging" the exhaust end of injector. I'll probably just pinch it off. (oh great I can see the puns/quote from that last statement now...)

I'm using the protrusion of the airbox to hold up my resistors at the moment. I heatshrinked the hell out of them, to keep them waterproof. Guess I should hack it off, to allow easy access for emptying the fuel filter of water. I'll have to find somewhere else to zap down the resistors.

Did you find any "seapage" of diesel coming off the plugged tee?

thanks for the ideas.

Richard
 

redmondjp

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Jul 1, 2004
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Redmond, WA
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'96 Passat Sedan
Did you find any "seapage" of diesel coming off the plugged tee?
Well, since I haven't started the car since I did this, no!


I used a 1/2" long piece of steel rod (1/4" dia?) and a hose clamp to block off the hose--I left about 2" of the rubber hose sticking out from the tee.
 

latitude500

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Jul 12, 2004
Location
Austin Tx, USA
TDI
Jetta 1998 Green
I'm a little lost on the idea of a Fifth Injector. Does my 98 jetta with the AHU motor have this. Is this something I need to remove. What does this item do. I've been reading up on some posts about it, but I'm still lost.
 

grimlock

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Mar 14, 2003
Location
Vancouver, BC Canada
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'96 Passat Sedan, Black
latitude, you don't have it....

Only 96 Passat had/has the 5th injector.

IIRC, according to the TDIFaq it was used to "help" in emissions by spraying diesel on the catalyst -- but it actually just caused a huge amount of smoke on acceleration after warm-up.

But that's what you get for having the first NA TDI. (mind you, us '96 Passat owners don't have EGR coolers, one less item to remove for intake cleaning
)

Richard
 

MattBissell

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Jan 13, 2005
Location
Gilroy, California
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2012 Golf DSG 4D Shark Blue
Okay I want to remove the 5th injector to make more room for my CAT filter. I guess I'll unplug the solenoid and see if I get a CEL I have the updated silver metal ECU. If I do get a CEL can someone explain to a forester, without electronics know how, what to do with the resistors? Do I just go to any electronics store and ask them for a 12v 10watt resistor, could someone make me a plug and play set up for a fee? Pictures of this would be great as well. Thanks for any help.

Matt B.
 

Lug_Nut

TDIClub Enthusiast, Pre-Forum Veteran Member
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Jun 20, 1998
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Sterling, Massachusetts. USA
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idi: 1988 Bolens DGT1700H, the other oil burner: 1967 Saab Sonett II two stroke
Matt, The ECU accepts a voltage drop associated with resistances of 8 to 12 ohms as valid. Resistances above or below will generate fault codes of "open" or "short to ground". Rad10 $hack has wide selections of resistors for DIY projects. Choose a 10 okm resistance value with a 10 watt current capacity. I think this size comes in a two pack.
Locate the plug connector. Cut the wires about three inches down on the cat side of the plug. You can then bring that half of the plug indoors for surgery. Connect one end of the resistor to one lead in the wire pair, the other end to the other lead. Insulate everything (electrical tape doesn't last long exposed to the elements and is not recommended) to prevent shorting. Plug in.
 

MattBissell

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Gilroy, California
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2012 Golf DSG 4D Shark Blue
Thanks Lug Nut. You can see my knowledge not even speaking in ohms, but I am familiar that resistance is measured in ohms. I am assuming that by the term connecting you would suggest soldering the connections and then sealing with shrink tubing?

Matt
 

Lug_Nut

TDIClub Enthusiast, Pre-Forum Veteran Member
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Jun 20, 1998
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Sterling, Massachusetts. USA
TDI
idi: 1988 Bolens DGT1700H, the other oil burner: 1967 Saab Sonett II two stroke
At ease, Solder!

Don't forget to put on the shrink tube, if that's what you choose to use, before making the wire to resistor connection. Cut one of the plug wires shorter than the other. Fold one resistor lead back along side the resistor. This will produce a smaller package of resistor and splices. Slide a larger diameter shrink tube over the entire assembly.
Soldering is preferred if you have confidence in your soldering skills.
If you have doubts, then a squeeze on butt splice is better than a mediocre solder joint.
 

MattBissell

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Jan 13, 2005
Location
Gilroy, California
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2012 Golf DSG 4D Shark Blue
Well I did the resistor thing this weekend and it worked no CEL. Now I am wondering if anyone knows the size of the fitting and the thread pitch where the braided line enters the exhaust pipe. I would like to buy a cap of the same size instead of just pinching off the hose.

Matt B.
 

Lug_Nut

TDIClub Enthusiast, Pre-Forum Veteran Member
Joined
Jun 20, 1998
Location
Sterling, Massachusetts. USA
TDI
idi: 1988 Bolens DGT1700H, the other oil burner: 1967 Saab Sonett II two stroke
Capping the hose is a bit of overkill.
I have a vasectomy, I don't need to be castrated, too.
 

RIP TDI

Top Post Dawg
Joined
Feb 16, 2000
Location
Santa Barbara, CA
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'15 GSW SE 6MT...... '01 Golf GLS 5MT.... '96 Passat Variant....
Use the original compression nut from the supply line. The fitting on the cat has a spherical compression-type profile and a ball bearing of appropriate diameter (don't remember the size), captured by the compression nut, does the job beautifully.
 

MattBissell

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Jan 13, 2005
Location
Gilroy, California
TDI
2012 Golf DSG 4D Shark Blue
Chris,

So I unscrew the braided hose and remove the nut, purchase the appropriate size bearing, put the bearing on the hole and re-install the original nut?

Matt
 

lupin..the..3rd

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Feb 7, 2004
Location
USA
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Passat B4 1996
Here's what I put together:



It's a 10 Watt 10 Ohm resistor from Rat Shack. I reused the original connector and cut the wires, soldered them onto the resistor, and covered the solder joints with heat shrink tubing. I then took a large heat-shrink tube and covered the entire thing (after taking this photo) effectively sealing it from the elements. Works like a champ.

I removed the diesel solenoid thing and cut the rubber fuel hoses, leaving about an inch of hose at either end. I then inserted a bolt into the end of the hose and used a small hose clamp to tighten it into place, effectively sealing it shut.

Big thanks to Lug_Nut for the detailed instructions!

No fuel leaks and no CEL. Works like a champ!
 
Last edited:

jollyGreenGiant

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Feb 3, 2003
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MA
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03 Golf TDI GLS ( my 5th TDI ), 03 Eurovan GLS - VR6 :(
Lug_Nut said:
Only the BK ECU (black plastic case) has a circuit monitoring the voltage drop across the 5th injector solenoid coil. The GQ totally ignores the solenoid. You can pull and plug the now obsoleted fifth injector without fear of MIL.
My GQ may or may not set the CEL for not having a connected 5th injector pump ( I don't have a cluster with a CEL currently ), but I can say that it does in fact log a DTC for "Washer Metering Pump" or something to that effect.
 

Mrg-images

Member
Joined
Jun 2, 2015
Location
Port Charlotte, fl
TDI
1996 Passat TDI
Help

Does anyone have pictures to show the downpipe plug plugged so I can get a better idea? I need to invest in a new exhaust system. My downpipe broke at the turbo and it's interesting cause no exhaust is going through the system you would think an engine light would come on? 5th injector is plugged under the hood. It's still connected to the downpipe.
 

ToddA1

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Aug 3, 2011
Location
NJ 08002
TDI
'96 B4V, '97 B4 (sold), '97 Jetta (scrapped)
I welded some sheet metal to a nut, making a cap, and threaded it on. IIRC, the bung is M14x1.5.

-Todd
 

TommyB4v

Member
Joined
May 26, 2015
Location
Mount Vernon WA
TDI
1996 B4V
EGR/5th Injector repl

'96 w/silver computer sets EGR wiring code when EGR unplugged. Thanks to forum I put in 15 ohm 10watt ceramic resistor which works fine for the last week. Prior 2 watt overheated and burned open.
Max voltage during charge abt 14.5volts; 15 ohms gives slightly less than 1A at 100% duty cycle. I may still need a 25w 15 ohm long-term, we'll see. But Check Engine light is off again for now!
5th injector no problem with 2w resistor. Maybe my computer never activates the injector. Never had smoke. But it lights chk engine if there isn't a resistor.
 
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