Author Topic: Injection Systems  (Read 6784 times)

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Offline 1.8t

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Injection Systems
« on: February 12, 2006, 07:16:30 pm »
Whats the deal with the mk2 fuel injection systems?

What are they called? Whats the advantages of each one?

Whats the one you want? What determines which one you get?

 :D Alot of questions i know, basically which one is the most reliable/cheep to maintain.

Nick
Dudlee the 86 318i
Past.. 95 328i M Coupe, 97 Pug 306, 97 Vento

Offline NasTnaS

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Re: Injection Systems
« Reply #1 on: February 12, 2006, 09:13:09 pm »
i hate air leaks....
...Nigel Aston
1971 Porsche 911T - Burgundy - Weekend Warrior
2006 Audi RS4 Avant - Daytona Grey - Daily Driver

Offline rambo_005

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Re: Injection Systems
« Reply #2 on: February 12, 2006, 09:31:51 pm »
From my knowledge (correct me if I'm wrong and you're right!):

K-Jet (16V & 8V pre '88) or Digifant II (8V '88 upward)

K-Jet is mechanical, and Digifant is computerised.

I have Digifant and I like it. Only ever had one problem, that was the Idle Stabilising Valve (ISV).

It is not easy to confuse K-Jet with Digifant, the engine compartment in each looks quite different...
NZ: 1988 Mk2 Golf VR6 3 door manual
UK: 2008 Mk5 Golf R32 3 door manual

Offline 1.8t

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Re: Injection Systems
« Reply #3 on: February 12, 2006, 10:08:07 pm »
From my knowledge (correct me if I'm wrong and you're right!):

K-Jet (16V & 8V pre '88) or Digifant II (8V '88 upward)

K-Jet is mechanical, and Digifant is computerised.

I have Digifant and I like it. Only ever had one problem, that was the Idle Stabilising Valve (ISV).

It is not easy to confuse K-Jet with Digifant, the engine compartment in each looks quite different...

So K-jet is the older style more mechanical type system?  I asume over time this would be more reliable, less things to go wrong?
Dudlee the 86 318i
Past.. 95 328i M Coupe, 97 Pug 306, 97 Vento

Offline rambo_005

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Re: Injection Systems
« Reply #4 on: February 12, 2006, 10:10:34 pm »
Not so sure on that one, someone like Jem would be the one to ask.

I do know that K-Jet is prone to air leaks, (as NasTnaS pointed out) which causes a few problems...
NZ: 1988 Mk2 Golf VR6 3 door manual
UK: 2008 Mk5 Golf R32 3 door manual

Offline NasTnaS

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Re: Injection Systems
« Reply #5 on: February 12, 2006, 10:12:03 pm »
mines done 350 000kms, has air leaks to show, but once it heats up, it goes... and goes well!
...Nigel Aston
1971 Porsche 911T - Burgundy - Weekend Warrior
2006 Audi RS4 Avant - Daytona Grey - Daily Driver

veedubtom

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Re: Injection Systems
« Reply #6 on: February 12, 2006, 10:13:19 pm »
Kjet good, unless it leaks air
« Last Edit: February 13, 2006, 09:21:33 am by EVL 28K »

Offline rambo_005

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Re: Injection Systems
« Reply #7 on: February 12, 2006, 10:20:35 pm »
My Digi Mk2 has done 182,000km, been in the family since about 110. Have only maintained it and swapped the ISV for a spare we had.

My Brothers old Digi Mk2 had done 145,000km and in his ownership the gearbox went, the fuel pump died and the distributor needed replacing otherwise it was good!
NZ: 1988 Mk2 Golf VR6 3 door manual
UK: 2008 Mk5 Golf R32 3 door manual

shay

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Re: Injection Systems
« Reply #8 on: February 13, 2006, 07:30:59 am »
I have a digifart in my mk2 Gti.

I havent had too many problems with the injection system, aprt from the broken dipstick causing an air leak and having to clean out the ISV periodically ( why I don't just buy a new one as that would be easier).




Neil_Corrado

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Re: Injection Systems
« Reply #9 on: February 13, 2006, 08:22:34 am »
Kjet good, unless it leaks

Unless it leaks what?

GolfGeek

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Re: Injection Systems
« Reply #10 on: February 13, 2006, 08:38:33 am »
I have a digifant mk2. Due to its aggressive ignition map, the Digifant 1.8L has a torque hole at just off idle. This causes the infamous Digifant hesitation. I recently upgraded the ECU and this hesitation is now gone and it gave it a bit more grunt. Yes, vacuum leaks are a problem. I changed my rubber intake boot to an aluminum 3"pipe. I also replaced all the vacuum lines. It is also a good Idea to give the ISV and throttle body a good clean.

Check out this site. It has some good info on Digifant 2.
http://www.members.tripod.com/~fuelie/intro.htm


hitmanGTI

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Re: Injection Systems
« Reply #11 on: February 13, 2006, 08:38:47 am »

Offline rambo_005

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Re: Injection Systems
« Reply #12 on: February 13, 2006, 02:36:51 pm »
GolfGeek, what exactly did you do to your ECU?
Cheers
NZ: 1988 Mk2 Golf VR6 3 door manual
UK: 2008 Mk5 Golf R32 3 door manual

GolfGeek

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Re: Injection Systems
« Reply #13 on: February 13, 2006, 06:28:12 pm »
GolfGeek, what exactly did you do to your ECU?
Cheers
I upgraded one of the chips. It only takes about 20 mins to install. I bought it on ebay for US$43 including shipping. This guy is pretty good I got the chip in a week.

Link below:
http://cgi.ebay.com/ebaymotors/VW-Performance-Chip-Volkswagen-Digifant-2_W0QQitemZ8037963065QQcategoryZ33597QQrdZ1QQcmdZViewItem




The Admiral

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Re: Injection Systems
« Reply #14 on: February 13, 2006, 10:48:22 pm »
Digi was available on the 8V GTI from around 1989 (UK). VW then replaced Digifant with Simos fully sequential injection for the later MK3 8V's (engine code ADY)... but would you believe it, for the ABF super whizzy late 16V MK3, they went for... yup, Digifant. It think Digi is a variant of the Bosch system.

Digifant is fully electronic (i.e., it has a microcontroller), whereas K-Jet is mechanical.

I'm not sure why people assume that things with computers in them are less reliable than purely mechanical items. It's normally the ancillary devices that fail, and again normally due to mechanical wear, or dirt ingress (eg, ISV!!).

I'm a geek.


shay

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Re: Injection Systems
« Reply #15 on: February 14, 2006, 08:19:57 am »
The electrical systems in the Golfs seem pretty reliable, well in mine anyway.

I honestly thought one day the ECU would have definetly been fried, when jump-starting another car I asked them to attach the leads to their battery thinking that hey were reasonably mechanically minded and would attach them to the proper terminals. I turned the key to their car and nothing happened, tried again and nothing. I get out and check things. There was a stink of plastic. What had happened was, they had attached them leads the wrong way around and they were slowly self destructing. Got a broom handle and whacked the leads off and slwly prpared myself for the idea of replacing the ECU at the least. No such luck, the ECU was fine, along with all the rest of the electrics.

I have seen Japanese cars that seem to crap themselves if you go within 1 ft of putting the leads on the wrong terminals

GolfGeek

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Re: Injection Systems
« Reply #16 on: February 14, 2006, 08:37:49 am »
That is because Germans know what they are doing. And they build robust systems out of industrial standard electronics. Do yourself a favour and open up the ECU box and have a nosy. Well designed! ;D

The Admiral

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Re: Injection Systems
« Reply #17 on: February 14, 2006, 09:05:04 am »
That is because Germans know what they are doing. And they build robust systems out of industrial standard electronics. Do yourself a favour and open up the ECU box and have a nosy. Well designed! ;D
indeed! Read my post about GPS navigators built in NZ vs those made in China...

orggti

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Re: Injection Systems
« Reply #18 on: February 14, 2006, 09:34:25 am »
Im sure you could fry your ecu on a golf, I think its sparking they dont like so much.
K-jet is good but its old now and not that fuel efficient.

Thanks for pointing out the broken dip stick tube as a air leak i hadnt thought of that.

Offline rambo_005

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Re: Injection Systems
« Reply #19 on: February 14, 2006, 02:31:51 pm »
I think Digifant is a VW version of Bosch L-Jetronic ??
NZ: 1988 Mk2 Golf VR6 3 door manual
UK: 2008 Mk5 Golf R32 3 door manual