okay, so my car is up and running. i've put about 300 kms on it, trying
to rack up some mileage to get through the break in. it runs like a top,
idles fine, everything seems in order. the only problem i've encountered
so far is pinging under load.
break down -
car runs hotter than it used to, but before i was using a 16v rad. now i
have a 8v rad with overflow built in. running pink coolant with a bottle of
water wetter and low temp switch/thermostat. before it used to always be
a 1/4 and maybe 1/2 when in traffic. now it's consistently at 1/2, sometimes
a nug over. have two derale 10" pusher fans on the inside of the rad that
management is TT digi 1 16v chip. i spoke with colin at TT, gave him the break
down of my setup and he's like no problem. injectors are beefier than stock, 36 lb/h
if i recall correctly. i have an aeromotive FPR dialed in at 45psi.
internals are JE 11.5:1 83.5mm pistons. there was cruddy 4 year old gas in the
tank (although, really low) so i put in some fresh 91. after putting like 150 kms on
the motor, i put a couple 15 dollars shots of 94. (tank leaks so can't fill it up)
i'm still not really hammering it because i'm still in break in, but i can feel
under load that it's going to ping. checked the marks top and bottom for the belt,
everything is all good. adjusted the timing a whole bunch of times. 6d BTDC, 3d BTDC,
not really any difference i can see. i haven't really tried the car when it's cold, since
the engine is so fresh its always running a bit before i drive it, still checking everything.
now, i have an adjustable cam gear, if i retard the cam timing a bit would that
work to calm down the ping a bit? i was reading the bentley and in the notes it says to
not install the knock sensor with a washer, and i checked, there's a washer on it.
i know it's torqued right and it's under cyl #1.
what else should i be checking? is it possible it's running lean that's why it's
I had the same issues with my Digi setup. After checking my wiring, fan switch, thermostat, bigger FPR and another chip from TT it ended up being a bad knock sensor. The sensor was reading open on my meter. A new knock sensor really helped my pinging. I ended up setting my timing to the TDC center mark and it runs great with no pinging. I've ran both the 8v and 16v radiators and had the same results.
84 GTI 8v
90 GLI 16v
well, what is the actual temp rating of the thermostat, and with that CR, there will be addition heat generated. And if you can "feel under load that it's going to ping", why bother with the knock sensor?
A fresh motor is going to generate more than normal heat until it is completely broken in, I wouldn't worry too much about it unless it is overheating. A good stock radiator will be more than able to handle cooling needs, but to help it, do you have an external oil cooler, that will aid in cooling and help the oil do it's job better.
And the best way to tell if it's running lean is to throw a WB on it and see what it is doing.
thanks for chiming in boys.
i have an external oil cooler on it, and it seems to run pretty cool, oil wise.
i don't know what the exact water temp is, but i have a infa-red thermometer,
so i'll check that out tonight and see where we're at. shouldn't it not really
ping even if the knock sensor was disconnected?
i extended the wiring harness so i could hide everything, i really hope the wiring
for the sensor is good. because the knock sensor im using has less than 10k kms
on it and it was one of the ones from my motronic setup.
i checked the belt orientation last night and it looks pretty spot on. but, this head
has been decked twice at least, so im wondering that maybe it's not exactly where
it should be. im wondering if i should try it a tooth foward or back (or play with my
adjustable cam gear) to see if that would help.
Do you know the actual CR? You say the head has been decked twice and you have 11.5:1 pistons in it ... that to me means you have a higher CR than what you think. And 11.5:1 is already pushing things a bit for pump gas.
It might change the dynamic CR some, but I doubt enough to matter. And a compression test won't give you much help, you can ballpark the CR from that, but that could be a big ballpark.
You need to have the head cc'd and input that and all the other parameters into the CR calc to get a definite number.
should i look at replacing the 16v knock sensor i have now with a
corrado G60 one? i'm looking at the worldpac parts catalogue here at
work and it shows that a G60 connector is green, the one im rocking
now is black? i also noticed in the bentley that the digi knock sensor
torque specs are lower than 16v ones.
i gotta check my oil filter/cooler housing as it has started leaking, so
since i'll be down there fiddling around, i might as well replace it i guess?
it's $50 for a fresh knock sensor.
i'll take the old one out, remove the washer, put the new one on, do a
re-torque and try that out. do i require a special bolt? im using now a
standard VW 6 point allen key style bolt.
Not sure if the sensor will make a diff, but you might try removing the washer. I know TT sold an alum spacer for them that "dulled" the sensor's sensitivity some, so, the washer might be doing that.
we're removed and rewired (so the colors are not OE, nice )
the new knock sensor came in, so i'll have to get busy and see if that will do anything.
going to take out the spark plugs too, check them, and quadruple check the
the only thing that's throwing me off is the high engine temp that im getting,
i've seen/read a few things that would lead me to think the belt is off a notch.
plus that kent cam gear i have has a notch AND a dot on it. the dot is at TDC
lined up with the notch on the valve cover... there's no way i could of screwed that up
right? would of been a mega disaster no?
Dont bother getting the green knock sensor, it wont make a difference. Before I got the green knock sensor I ran a blue knock sensor and a black knock sensor and the new one made no difference. All the knock sensors I mentioned all check good and had the same resistance value as the new green sensor.
84 GTI 8v
90 GLI 16v
While on the knock sensor issue. Just make sure the terminals are the same. If there gold plated, you have to match knock sensor with same connector. Also check your resistance from the connector to the ECM on the knock sensor harness. Should be 1.5 ohms or less, any higher value will give incorrect reading to the ECM. Have you try higher octane than 91? What your co pot set at? 400-500 ohms range is ideal. Also a weak fuel pump can make it run lean too.
that giving me. i haven't had time to play around with this, but i'll hopefully
tackle it before the weekend. i have been putting 94 in it for the past couple
of fill ups. i did adjust the COpot to 450ohms, so that should be alright. the
fuel pump seems to be working fine, the fuel pressure is steady and it was
working fine the last season (2007) i was driving it.
im wondering if the torque spec is off. on top of me putting a washer on the
bolt for the knock sensor (bentley specifically says NOT to), i think i may have
torqued it to 16v spec and not digi 1 spec.
it leaks if i put more than $20 in it (although that was in 2007, so now it's probably likeI just noticed you can't fill up the tank! I'm assuming the tank is rusty, if knock sensor wiring test out good, I think problem is fuel issue. Rust is not good fuel system. When last time fuel filter replaced? What the condition of fuel pump(s)?
$40 - going to be changing the fuel tank very soon though) i've never had bad fuel problems
before, but again, anything is possible with this car.
the fuel filter is brand new (300kms). more or less EVERYTHING on the engine is
brand new, the fuel pump is still the OE one but working strong. ive almost changed
everything on this car but the fuel pump, ha!
pic of said nightmare...
so i swapped out the knock sensor with the new one. the part number
on the old one compared to the new one was one number different in
the last three digits. new bolt, no washer, torqued to 15 ft/pds.
started the car up, let it idle for like 2 minutes and then took it for a rip.
no pinging! kept trying and trying, feeling good! then the temp raises about
halfway (still too hot i find) and then all of a sudden, pinging again!
it started to rain, so i brought it back home and stashed it in the garage.
so i guess the next thing would be is to kick back the belt a notch, maybe
the timing is too advanced?
i ordered the thermostat from screwed up and gave me the wrong one.
maybe i should just take it out all together? it's not like this car is ever
gonna go out in the winter.
i assume the CTS works because when i unplug it to check/adjust the timing,
the idle drops and it runs all screwey.
Working, yes, accurate, maybe. With digi, I don't know if there is anyway to know what temp the ecu is being told. Do you have a wideband on the car to tell you what the AFR's are when cold and when at operating temp? Since the CTS has a large input into what the ecu does with fuel, and that you are on a fixed tune with the chip, a wideband will be the only way to know what the ecu is doing.
Sorry to hear your still having problems! I don't want to sound like an a-hole but I advised earlier that a new knock sensor would not fix your problem. One thing I forgot to mention that helped my pinging along with setting my timing at TDC was I am running a 80* thermostat and 82* fan switch. I relayed the power to the fan and I'm using the hi-speed to cool the radiator. Fan comes on sooner and is a little louder but cools alot faster. Like I mentioned before all these things helped my pinging but did not totally fix it. I will occasionally get some light pinging when I'm cruising, low speed, low rpms, tall gear and I decide to mash the throttle, it's not perfect but that scenario is not something I normally do.
I dont think running a colder thermostat(71*) is gonna fix your pinging. If it does happen to fix or calm down the pinging your car will never see a normal operating temperature and will run rich. I too spoke with Colin about this same pinging and possibly running a colder thermostat and he suggested against it.
On a more technical note! After I got a handle on my pinging I decided to give Moates Burn2 and Tunerpro a shot. After doing a ton of reading in tuning and experimenting with different files it somewhat started making sense. One thing that really hepled was all the resources available for Megasquirt. After studying the TT files that I have I noticed that they run alot of timing at low end. From what I understand alot of timing at low end can generate alot of heat causing pinging at the top end no matter how much you pull the timing. This kind of jives with the higher than normal temps you and I have been experiencing. I had higher than normal temps with both radiators! I can keep rambling on about this but I'll stop for now. If you have any specific questions let me know.
Last edited by rcortez13; 05-04-2012 at 01:18 AM.
84 GTI 8v
90 GLI 16v
How is the fuel mixture? I assume since it's chipped & you have the CO Pot set to 450 ohms. that it's ok.
If check timing with a light and and tap the block with a wrench can you see the ecu retarding timing? I know on a stock 16v if you tap on the block with somehting you will see it retard timing.
tonight i'm going to put some work in.
going to install the new thermostat, even if it might not solve my problem,
i would still want the car to run cooler. the fans are wired straight to constant
power and when they click on they're both running full blast. im going to make
sure that the terminals at the thermoswitch are in the right position too. i'm
running a 3 prong switch with a one speed fan, so gotta make sure they come on
at the low temp, not the high.
got the new coolant temp thermostat (the correct part number confirmed)
going beef up the coolant mix and add some more water wetter.
then im going try and retard the timing a bit using my adjustable cam gear
or backing it up a tooth.
if none of that works, i'm gonna blow my brains out.
i'll make sure to test the knock sensor by tapping the block to make sure
that it's working. but i dunno, maybe once it reaches a certain temperature
the coolant temp sensor sends incorrect signals to the ECU, hence causing
it to ping.
fuel pressure could be dropped down a hair. 3 bar is 43 psi not 45 like you have it set. Small issue but that 2psi can make a difference. I had the TT aluminum bushing on my knock sensor too and the minute I took it off it got rid of the pinging. I still get it but mine is on the low end under full load, like when I let out the clutch to fast at a stop. Timing it crucial. Digi does all the work and everything should be set to TDC. Don't advance it or retard it even a hair. Also, stick with the blue CTS. It's working just fine if you unplug it and the idle drops like you described.
There's a reason the stock motronic CIS had two sensors. I honestly don't think Digi 1 is set up to handle the high compressions for the 16v N/A. Not that I regret it, mine definitely has more power now it just has different mannerisms than it did before.
Last edited by GTItus; 05-04-2012 at 07:06 PM.
so i had an 80 degree thermostat in there before, now that's been
replaced with a 71 degree. i redid the mix, a little more watery than
before with the water wetter and now it runs better/cooler. the needle
is hanging around right under the light, what it was doing before.
i replaced the CTS, that didn't do anything though. but i did retard my
cam gear like 3 degrees and i'd say about 80% of the pinging went
away. it hear it VERY minorly while hammering 2nd gear, but banging
through the rest of them, couldn't hear anything.
i was even rolling with the window down next to barriers to make sure i
could hear it and i still couldn't hear anything! i'm at a total of around 400kms
on the motor so far, still want to put some more mileage on it before i start
really hammering it, but this is some progress!
okay, scratch that. hahahahah
i didn't reset the timing after i adjusted the cam pulley, so i was
running timing a 0-1 degrees. it's fine there, won't ping, but the
car also has got no balls.
this might be a ridiculous question, but when i loosen the adjustment
nuts on the pulley, is it clockwise advance, counter clockwise retard?
the little arrow at the 0 looks like it moves forward when i back the belt
up and vice versa. like opposite style. i'm running a kent pulley.
i've only played with the belt timing 4-5 degrees. can i go more?
another thing that im thinking is that maybe the dots on cams are misaligned in
the head? drove it again to work today, no pinging until it heats up.
no difference with the spark plugs.
i called colin at TT and explained him the situation. he seemed
like he's encountered this before and told me to send back the
chip so he can dial down the timing advance. he says he doesn't
do it while it's cold because its running more rich, so a re-tune
should solve the problem.