Pinging under load need help

[ja_racing]

I have a 90 comanche renix 4.9 stroker low compression pistons 64mm tb 24lbs injectors 50psi fpr 2001 intake manifold borla headers stock cam shaft 

 

ive been battling pinging for a while now got the rem not that long ago hoping i would figure out why.

it pings when its in 3rd 4th cruising anywhere from 35mph and want to speed up 

rems showing high knock and ign timing in the 40s doesn’t seem to drop

i have all the stock sensors hooked up

also ive tried 91 oct and still does it

if i full throttle it ign timing is in the low 20s and no pinging at wot

 

ive been wanting to try and do the high altitude mod but backwards to retard a bit but I'm not sure if the ecu is just gonna correct it

 

any help greatly appreciated 

[89 MJ]

Sounds like your knock sensor might be failing. This is exactly what it’s supposed to prevent. 

[ja_racing]

4 minutes ago, 89 MJ said:

Sounds like your knock sensor might be failing. This is exactly what it’s supposed to prevent. 

Something i didn’t state it was cut on my harness and don't remember how i connected it idk if its backwards if it will do its job or not

[Ωhm]

2 hours ago, ja_racing said:

 

ive been wanting to try and do the high altitude mod but backwards to retard a bit but I'm not sure if the ecu is just gonna correct it

 

Shifting the CPS either CW or CCW only fools the ECU to thinks a cylinder is at TDC when it is not. Shifting will also shift, for each cylinder, when KNOCK looks for ping and when the INJ fires. The ECU seems to be able to handle CPS ADVANCE, not sure on CPS RETARD.

 

 

2 hours ago, ja_racing said:

Something i didn’t state it was cut on my harness and don't remember how i connected it idk if its backwards if it will do its job or not

 

I'd pin it out, back to the ECU just to make sure.

[ja_racing]

5 minutes ago, Ωhm said:

 

Shifting the CPS either CW or CCW only fools the ECU to thinks a cylinder is at TDC when it is not. Shifting will also shift, for each cylinder, when KNOCK looks for ping and when the INJ fires. The ECU seems to be able to handle CPS ADVANCE, not sure on CPS RETARD.

 

 

 

I'd pin it out, back to the ECU just to make sure.

I'm going to hold of on messing with cps rn
I'm going to check the knock plug to ecu for continuity and found a page hopefully its accurate in how the wires go following how its pictured and get a new better knock sensor i have a autozone in it rn 

[Ωhm]

Drawing matches the stuff I/we have.

 

_mj1988electricalmanual_1.pdf

[ja_racing]

Ok cool ima buy a oem knock from a member and make sure its connected correctly and go from there 

[ja_racing]

4 hours ago, Ωhm said:

Drawing matches the stuff I/we have.

 

_mj1988electricalmanual_1.pdf

Just checked it and i have the wire continuity on the knock sensor connected opposite than what the diagram says I'm going to correct that see if that does anything 

[Tex06]

Any update on this? 

[ghetdjc320]

Do you happen to know what your quench distance is? Low comp strokers have had these issues before. Has the cam timing been adjusted at all? And when you say stock cam, is it an oe renix cam? What’s your actual stroker recipe/combo? 

[ja_racing]

Still pinging ign timing at 47 and showing knock but not retarding the timing 

 

 

[ja_racing]

11 hours ago, ghetdjc320 said:

Do you happen to know what your quench distance is? Low comp strokers have had these issues before. Has the cam timing been adjusted at all? And when you say stock cam, is it an oe renix cam? What’s your actual stroker recipe/combo? 

I do not off the top of my head

and cam is a stock ho cam from a 91-95

And by cam timing adjusted what do you mean by that exactly

my stroke is 3.895 rod 6.125 bore is 4”

[ghetdjc320]

24 minutes ago, ja_racing said:

I do not off the top of my head

and cam is a stock ho cam from a 91-95

And by cam timing adjusted what do you mean by that exactly

my stroke is 3.895 rod 6.125 bore is 4”

Did you degree in the camshaft using an adjustable timing set? 

[ja_racing]

15 minutes ago, ghetdjc320 said:

Did you degree in the camshaft using an adjustable timing set? 

No

[Ωhm]

When pinging occurs is ECU in OPEN LOOP (OP) or CLOSED LOOP (CL)?

[ja_racing]

14 minutes ago, Ωhm said:

When pinging occurs is ECU in OPEN LOOP (OP) or CLOSED LOOP (CL)?

Not sure ill check that later

[ja_racing]

I feel 47 is to much timing tho I'm kinda lost at this point

[Ωhm]

Not sure here but KNOCK might only come into play here during WOT when ECU is in OP.

[ja_racing]

1 minute ago, Ωhm said:

Not sure here but KNOCK might only come into play here during WOT when ECU is in OP.

I can do wot and no knock and timing lower in the range of 26-30

[Ωhm]

Looks like ECU is in OL only.

 

Correction: OPEN LOOP = OL, not OP

[ja_racing]

1 hour ago, Ωhm said:

Looks like ECU is in OL only.

 

Correction: OPEN LOOP = OL, not OP

Ill check this later ill drive it

i also have the Bosch 12009 o2 sensor and going to swap it with the ntk soon 

[ghetdjc320]

9 minutes ago, ja_racing said:

Ill check this later ill drive it

i also have the Bosch 12009 o2 sensor and going to swap it with the ntk soon 

Has it always has this pinging issue since it was built or is this a new issue? 

[ja_racing]

3 minutes ago, ghetdjc320 said:

Has it always has this pinging issue since it was built or is this a new issue? 

Its a pretty new issue i use to have a big cam and race it 

then i made it my daily took motor out refreshed it and put a stock cam and no ping then it started and thats when i started connecting all the sensors i had unplugged like o2 knock distributor sync and even bought the rem from nick that has helped alot with finding problems that i was unaware of

 

i feel like some days it won’t do it till its at 200-210 temp and the hottest point of the day for me which is like 110-115 degrees

and some days does it since i get in it and start it

[ghetdjc320]

9 minutes ago, ja_racing said:

Its a pretty new issue i use to have a big cam and race it 

then i made it my daily took motor out refreshed it and put a stock cam and no ping then it started and thats when i started connecting all the sensors i had unplugged like o2 knock distributor sync and even bought the rem from nick that has helped alot with finding problems that i was unaware of

 

i feel like some days it won’t do it till its at 200-210 temp and the hottest point of the day for me which is like 110-115 degrees

and some days does it since i get in it and start it

Interesting, one more question: have you always ran it on the same Renix system? And is it the 89-90 or the earlier ECU?

[ja_racing]

1 minute ago, ghetdjc320 said:

Interesting, one more question: have you always ran it on the same Renix system? And is it the 89-90 or the earlier ECU?

Yes always renix

its a 90 harness and 428 ecu

i just took off msd box and coil and went to oem stuff i had