I have a 2.0 GA in my 72 with the proper ECU and harness.Do I need the 270 ohm resistor on my head temp wire?It runs a little chuncky on low end but has lots of rev and power on top.Will the resistor help with smoothing out the whole range of power.
Why do some systems have it and others do not?

The answer is - well maybe?

It depends upon which year GA & EFI you have in your 72.

The 73 MY 2.0's were a little different than the later ones, & did require the resistor & a -017 CHT -which are now NLA!! There is also a spacer for the -017 CHT which the Factory put out as a later add-on service bulletin IIRC, which I think you can get a repro one from Brad Mayeur's 914/VW shop in Peoria IL (see member vendors section or Google for his phone #, since he doesn't have a web-business at all).

The 74 MY GAs use the -012 CHT with no resistor, but may benefit from the spacer.

You can read up more at the link below, but you really need to first find out what GA & EFI set-up you've got in there.

http://members.rennlist.com/pbanders/index.html

.... scroll down to the d-jet tech articles & start reading on "your" system.

There is also a trick apparently of running the power lead to the MPS underneath of the #3 injection tube, in order to avoid electrical interference from the coil & distributor above that spot in the engine. PM John/avidfanjpl on here for more on that one.

Being 35-40 years old, the D-jet EFI can have things go wrong, but once you got them set up right & everything in good working order, they're pretty reliable & bullet-proof - especially considering they're early examples of groundbreaking "black box" electirc FI systems which we have on many makes & models today!


OH - and .......

For a question like this you must post complete info on your setup with part numbers.

If it is there then whomever put it there thought the engine needed a little richness in your fuel delivery across all bands not just idle.. You can take it off by unplugging it and see hows it runs without it.. It is a good item to have around in case you ever need to richen your fuel mixture/.. Some one put it there for a reason, ..

It is a factory stock part on 1973 2.0


very nice link below with djet parts and descriptions what thhey do with what set ups ect..

http://members.rennlist.com/pbanders/DJetParts.htm

so if its running lean this will richen it up?could a lean condition be causing the low end chunckyness and bad idel?

you need to find out if yoru engine needs the resistor or not, it depends on which FI systemn you have. the were different for different years, the resistor is supposed to work with the stock 1973 FI system, not the 1974 system. the two systems had different brains, MPS , head temp sendor, distributor, etc... and maybe some other things. you need to read up on which brain MPS temp sendor etc... that you have and make sure that they are all matched together. you need to locate the part numbers on these units to be sure. Anders website has the part numbers for all these components. so see what you got, then we can tell if the resistor is supposed to be there or not.

you also got to make sure all the componensts are working right and calibraitions is ok. putting an extra resistor on to help some probelm may not be the right thing unless your sure all the other stuff is right. remeber the added resistor richens the mixture across a hole range of conditions, that might not be right for you

time for a complete inventory of what you have, seeing as the 1972 car did not come with the 2.0 liter motor, you shoudl take some time and confirm what you got is all for the same engien.


good luck

I'll be back

Could be many things....
for a 73 2.0L setup the parts are: (these are the ending numbers of the part numbers)
037 ECU
037 MPS unmolested end plug
017 CHT w/ 270 ohm ballast

The typically during warming up idles crappy..

The CHT is for warmup and it out of the loop after the engine warms up say, 10 minutes.
It your problem when the engine is fully warmed up?

I do not understand chunkiness.. here the link to idle troubleshooting same links.. read up on it..

The cht has a value warmed up,it is not out of the loop. Idle crappy is not by desighn or typical of a good runing engine.. Though you may be right on the avg. condition of 914's it is not how they are supposed to be..

the 270 ohm resistor adds resistance which in turn adds to the richeness, taking it off would lean it out across the whole spectrum, there is also an idle control knob on the ecu that leans and richens the fual mixture just at idle though I do not know if you have one on your ecu.. you have not provided aany info other than GA in your engine code and that you have a 270 ohmn resistor.. would help to know your mps part# the ecu part# and the year of your engine and weather it is stock ect..

AND the 73 (only) used the inline resister to MAKE the 73' 1.7 ecu work the first year of 2.0... bandade...

get ecu, m.p.s., cht, numbers and check for compatability

I checked Ander's site and I have the correct ECU for the 73 GA motor it does have the control knob on top.Tonite I will look at the rest of the #'s to check for compatabilty of all systems.For some reason the mecanic put the resistor on the car.I took it off and the top end revs and power went up however then my low end and idle got a littel ruff.Should I leave the resistor off and adjust the ECU in hopes it will clear up the idle?if so witch way do I turn the knob?

leave it on if you have as stated the correct ecu for a 73 2.0 it needs the 270 ohm resistor.. the 037 ecu works with that resistor, they are made for each other, also I never recomend taking parts off your car you do not know what they are yet..
plus i doubt whomever put it on did soi unwittingly.. if your having an issue post it so you can heare some options// ,

i'm no expert here but i'm thinking you need to confirm the mps and cht compatability. could be the mechanic just patched the core issue.

I checked the #'s on the ecu mps and cht they all match according to Ander's info.He states to use the resistor and explains how to use the knob on the ecu.
I guess its put the resistor back on and try adjusting the ecu to help the idle and low end.then it will be to make sure the mps is correctly working.
Any more ideas out there?

My car, a really early 73 2.0L (GA000336) never had the resistor. I put one in, but removed it. I am still experimenting with the tuning, but when I had it in, it ran really rich.

My mechanic removed it then timed and tuned the engine. It runs pretty damn well and I am getting 26 to the gallon.

However, after the CHTS 017, they went to an 012 CHTS and had the resistor in place, but not necessarily with the E version of the ECU, which was only for part of 1973 and possibly 1974. I have 2 matching E version ECU's.

It is nothing short of witchcraft and wizardry to figure it all out, but my car runs.

Later this summer, when I finish the exhaust system and some restoration, I will reinstall a recently acquired working 017 CHTS and have the 270 ohm resistor standing by. Mine is not working within ohm specs on the Anders site.

Maybe even this weekend I will get around to it. I have more parts for my FI than a lot of people, including 2 almost complete FI systems correct for the early 73 motor.

But not all the parts. Just a lot of them. I am definitely one of a couple of hoarders here. I want this car to run when I am 103 and have to be lowered into it from above.

John

I am catching the same passion for this endevor.I will prevail and have a great performing car.Thanks everybody for the help.

you said earlier the top end power was negitively effected w/ the resister, i would think the resister should help, not hurt the top end power (richer mix thru out). i think the ecu knob effects only the idle (please correct me if i'm wrong). if thats acurate why did the high rpm power drop off w/ resister?

have you ohmed out the cht? is it the correct #? has the m.p.s. been adjusted/messed with? does a leaking m.p.s. have a tendency to either richen or lean out the engine? (question to d-jet smarties)

When an MPS goes bad, nothing works. They are either working or ruptured. Small leaks can develop, but they immediately affect all modes of operation. The car may not even start. Should flood out if the MPS diaphragm ruptures.

The CHTS is also critical, and a broken one will prevent starting at all times.

The AAV could be bad and it would mess up idle until the car is warmed up, but it will be hell getting there, and the idle will be at 2500.

Any exhaust leak will push idle up and ruin acceleration, and make it run rich.

You should be able to be no more than 3 clicks off of click 11 on the idle adjustment on the ECU. There are 21 total clicks, 11 being the dead middle. I am 3 clicks counterclockwise to lean, but then again, I have an out of spec 017 CHTS that gets replaced this week with a 1200 ohm at 70 degrees ambient working CHTS for a 73 2.0L.

You have to go one by one through things like dwell at 50, .017 point gap, dizzy timing (27BTDC at 3500 rpm), all intact vacuum hoses, no ignition wires near MPS, a working AAV, decel valve working and hosed correctly. No split elbows into the throttle body, a correctly set TPS, plugs at .026 and all grounds working.

And then the right FPR setting at 30PSIG.

Each item contributes to rich/lean and acceleration. Especially no plug wires near the MPS. The coil in the MPS is sensitive to plug wires too close. I was a victim of each of the above, and the MPS one was a shocker to see the difference when I moved the 3 plug wire under the intake pipes away from the MPS.

Good luck!

John

wow, good pointers!

Thanks! These are things I almost have tatooed in my brain at this point 16 months after getting my 6th 2.0L in 35 years.

They are just plain hard to come by nowadays, and everyone thinks theirs is worth 25K.

Not yet, anyway.

All the tips were painful to learn. Maybe I can save some people some trouble?

I love the 2.0L, but even that love is not unconditional.

I have lots of pain to prove it. Especially my right lower back.

John

with a blown MPS you can still start and run the car but it will be running really rich as the core is pushed against the WOT stop.
with a shorted out MPS nothing works
with a dead CHT the car won't start as its too rich, smell the raw gas coming out of the tailpipe.