pingging ques. to C-4/5 specialist.

[Da Hawaiian Punch]

Aloha once again! Yes you guessed it... its Double Clutch with what seems to be a never ending saga of Questions to C-4/5 specailist!! Heres this weeks question.... why does my car (C-4 91 L-98) ping like as if the timing was off or as if it has a case of bad gas?....kinda Like I do evey so often. Only when the air conditioner is on and the temperture on the motor is up slightly, about what it would be if the air con. was off, and with a stock thermostat, about mid range on the temp gauge, on the, in car display dash. I do have a 165 thermo. inside, along with the Ed wright race chip. I also have done all the usual common mods every body does to there vette. The timming is set at 6 deg. Should I back the timming off even more? I only use the good stuff when I put gas in the car (Shell, Cheveron, Union 76.) In that order of choices. Mahalo again!!

 

[evolution]

Sounds like a combination of all things. First off, only run High Test fuel if you are running with a chip in your shoulder (Shell and Chevron, nothing else 'cept maybe airplane fuel ). I am also not sure that if you tweak the timing manually that it will actually do anything since the timing and whatnot is governed by the chip. Do you have a lo-temp fan switch installed? Do you run Water Wetter? Are your valves in good adjustment? Are your sparky plugs in good shape?


Valve clak is usually either:

-High Temps and Lo Octane
-High Temps and Bad Gas (just plain bad)
-High Temps and Waaaay to advanced timing
-Way advanced timing and bad gas/lo octane
-Plain f'd up valve adjustment

BTW 6 degree timing advancement does not sound like ..... well... I think your chip is making the car run more advanced than that, It seems to me anyways. I think mine is at like 12 and that is with a Hypertech stage II. I had a van that ran at like 18 degs and it ran like a bat outta hell (the SMOG ref looked at me like "Ummm yeaahh. You aint gonna pass")


I dont know honestly why a bat would fly out of hell any faster than another flying animal. They must be pretty pressed to get out of there that quickly.

/end lame insight;

 

[evolution]

Ahhh! Almost forgot!!!!

The damn knock sensor! Make sure yours is in good shape!

 

[LarryBible]

Yes, there's one flimsy wire going to the knock sensor. It could be knocked off or otherwise disconnected. It just shouldn't ping if the knock sensor is okay and connnected. It, on the '88 at least, is located in the right side center of the block, just above the pan rail.

Have a great day,

 

[Da Hawaiian Punch]

Mahalo Guys!!! Lots of info! I get right on those things you both suggesed, I'll get back with you on the results!

 

[c4ever]

Don't forget the ESC module(not the sensor).Located on the passenger side, facing side of car, near firewall, if memory serves me right. The sensor harness plugs into it. That was the culprit on my 85. It's an easy diagnostic to test the entire circuit. Well worth it, rather than buying what you don't need.
Just my .02

Carlo

 

[evolution]

Hey LarryBible....

Is that quote from Doc Sarvis?

 

[c4c5specialist]

HI there,
Before anything further is questioned, please consider the following.
Is your EGR valve working?????
Your diagnostic for the ESC system is alot more sensitive than that of the EGR.
If your EGR is not working, due to a bad solenoid, broken vacuum line, or a bad valve itself, you would get so much knock, that your ESC could NOT control it by timing retard.
Honestly, I would go here first.
YoursinCorvette, c4c5

 

[blactopballr]

getting over L-98 pinging

when i purchased my86 L-98 i found that it was sluggish due to the ignition base timming being retarded, set at 2 degrees btdc!
after i moved the timing up to specs 6degrees btdc i noticed pinging that that was intermittent mostly noticeable on half throttle or more, with 93 octane amocco premium!i figured it was my egr due to(code 32 egr solinoid) but egr wasnt in the picture. i next replaced the knock sensor while on the lift having new
mufflers installed. after reading several wiring schematics
i found that the csr has an est module that controls the spark advance and uses the knock sensor to detect audible pinging.
the system works to ways. 1st check to see if the spark advance
deativates when disconecting the timing by-pass connector
between the power brake booster and the drivers valve cover close to the fire wall( single wire make/femaleinterlocking plug)
if so then the esc module is working. 2nd the esc module senses
pinging through the knock sensor. theesc module located
on the passenger side where the hood closesandmeets the passenger fender (its a square box with a 5 wire pluged into the bottom) disconnect the negative batt terminal 1st. then find the brown wire the esc module harness plug and splice a piece of 14 gauge wire about 16 in long in to the brn wire about (2inches below he harness plug . .insulate it well with elec tape. leaving all harness wires intact reconnect the harness,strip the free end of
the jumper wire about two inches. i backed off one of the large
bolts at the passenger hood latch facing the module and wrapped the jumper wire around for a stromger ground retightening the bolt. end of pinging.(the brown wire is the esc module ground) the module will ignore the knocksensors signal
when the ground is weak and will not retard the timing when the engine is pinging/detenating! Goodluck ! Now someone please give me some feedback on a good chip for my 86' L-98 alluminum head 4+3! torn between hypertech stage 2 and A.D.S stage 2
i have 160 stat , K&N Filter accel super coil & 8.8 spark wires
ac delco rapid fire plugs, hooker aerochamber mufflers with
the dynomax/walke rear y-pipe with balance tube. 97K miles

 

[Da Hawaiian Punch]

HI there,
Before anything further is questioned, please consider the following.
Is your EGR valve working?????
Your diagnostic for the ESC system is alot more sensitive than that of the EGR.
If your EGR is not working, due to a bad solenoid, broken vacuum line, or a bad valve itself, you would get so much knock, that your ESC could NOT control it by timing retard.
Honestly, I would go here first.
YoursinCorvette, c4c5

Ahhhh!! I for got to mention to you that the Ed wright chip has the egr deletted. Sorry!