digital

I have the older style Whipple Supercharger that used the "piggy-back" Whipple computer. I removed the Whipple electronics and now have a Nelson tune.

I have just had both knock sensors professionally replaced.

I am still throwing the code "Knock sensor low voltage".

Is there anywhere that you know of where the Whipple computer spliced into any wire that could affect the knock sensor wire voltage?

Any help is greatly appreciated.

Thanks,

Digital

dewmanshu

iTrader: (4)

I know nothing about the whipple and the old piggy back. But here is the schematic for the knock sensors. I highly doubt th epiggy system tapped into them...nevermind, I don't know. I know a guy that had a hummer with the whipple and piggy back pcm...he eventually got a divorce and let her have the hummer. It ran like ****. Codes constantly. She was hatin life. Truck would barely run.

This diagram is for the 2000 chevy silverado 5.3.

digital

dewmanshu,

Thanks for the reply, that really helps....

350SS

iTrader: (36)

Low voltage referrs to the ground. The knock sensor grounds to the engine block so if they used a sealer that doesn't conduct electricity it could cause a problem... something to check.

digital

Hey 350SS,

Thanks for the reply, I'm still trying to figure this thing out.

Do you know where I can find the ground wires on the block for the knock sensors?

I appreciate the help.

thunder550

iTrader: (70)

The body of the knock sensor grounds to the block - there are no ground wires specifically for the sensors. That's why he was saying that a non-conductive sealer might be causing the problems - if there is not good metal-to-metal contact between the sensor and the block, it could cause issues. There are several ground straps that connect the engine to the chassis, but I doubt that those could be the problem.

Take an ohmmeter and touch one contact to the engine block (valley cover, if you can) and one to the pin on the knock sensor connector behind the intake manifold. Each knock sensor should read somewhere around 100K ohms. If it is too high or too low you know there is a problem.

I got water down in my knock sensor holes and it corroded one of them. I did the ohmmeter test, front sensor came back at 65K ohms and the rear was at 98K or something. Replaced the front one and all was fixed.

dewmanshu

iTrader: (4)

yeh good point guys..."professionally replaced"? Did they put wrap or sealer on the threads? Ask them.

digital

I talked to the mechanic, no sealer on the threads...he did put the (forgot the name) grease that conducts...

Any how, I guess the next step is to hook up the ohm meter and figure this thing out...thanks for the help..