so i got my new motor in as you guys are aware, and i got my busted plug out... as you are aware. and now i got my megasquirt operating correctly. but now im learning to tune and its tough. i keep getting pinging on any load thats more than maybe like 30% throttle. i know this is very bad. i am trying to fix it but the only way to see if it worked is to try to press the gas more... then it pings and i quickly let off. these are all part throttle obviously and with no boost but how much of this can my brand new 80 mile motor handle? it scares me.

 

IIRC pinging that comes from more than about 1/3rd throttle is probably from having timing that's too advanced. Although that might just be intake backfiring I'm thinking of, since if your car is really "pinging," the engine probably would have already gone out. Intake backfiring on the other hand (which is less of a "hitting something metal with a hammer really hard" and more of a "rapraprapraprap."

Although that's with the stock ECU, and NA...

 

it sounds like the hood is squeaking. is the best i can describe. its a wierd sound but its definately the engine and i thought that was pinging i was hearing.

 

What is your setup? Injector size? Fuel pump? Turbo or NA? Can you post your MSQ file? Are you using a wideband or narrowband or just guessing?

We need more information.

 

start with less timing, not more. out of boost you would have to be running some rediculous timing numbers to get audible pre-ignition, something in the range of 50*BTDC or maybe less if there is no timing split.

maybe what you are hearing isn't pre-ignition from the engine but could be more from a faulty accessory bearing or slipping belt.

 

He has megasquirt with a map that I had working in my s5 turbo motor. He has s4 n/a rotors. The tuning of the ignition timing is frustrating because my car ran just fine, but backing off the ignition timing under load didn't seem to make much of a difference when I did it. I was thinking it could be a faulty crank angle sensor, but I don't know how feasable that is considering it runs great otherwise. But I made a new map that has about 7 degrees less timing under vacuum and tapers down nice under boost. I stepped up his split from 0 under vacuum to a quick 8-15* as soon as it hits any kind of positive pressure. I thought my modified map wasn't that agressive when I made it for his car, but obviously something was very wrong. Now the new map starts at about 31-32* under vacuum and tapers down with about the same curve as my map, just about 5-7* lower in most ranges.

I am hoping this new map works because this is scary how audible this ping is. Yes, this is my first time tuning high compression turbo, so it will be a little trial and error. Hopefully not to the extent of a blown motor.

dpf22

 

stupid question but you did test the accuracy of the advance with the megasquirt correct? if the megasquirt is misinterpretting the CAS signal then your advance curves may not reflect what the actual timing of the engine is.

 

im running 550 primaries 690? gsl-se secondaries turbo 2 fuel pump, turbo 4 port motor with s4 na rotors. we are using the stock narrowband o2 sensor but that wont last for long. im investing in a wideband sensor next week. i cant post my msq but i think dpf22 can if he wanted to.

turbo is stokc but my exhaust is all kinds of free flowing. tubular header and 80mm tubo back manderel exhaust

 

yeah, well, its not the computer because it runs like a champ in my car. makes power, and doesn't ping. I have the same wiring scheme except for we ran new cas wiring on stevensimon's car because of interference from the body harness because it runs all the way across everything else on the opposite side of the car.

Trust me the computer is fine, but I am guessing either my wiring is backwards somewhere, or there is something with my map, or there is something wrong with the cas. the computer is fine though.

dpf22

 

i would start by checking the timing and advance on the megasquirt figures vs what the pulley tells you.

 

I am starting to wonder if the trailing plug outputs being backwards could cause this situation myself.


dpf22

 

Can you post your MSQ file?

Trailing tires backwards will certainly cause this issue.

 

Ok here is the msq. Derek YOU STILL HAVEN'T TRIED SWITCHING THE TRAILING WIRES LIKE I TOLD YOU?????
Noone listens to the short spanish guy sheesh