Bought a 98 Z28...

**ChevyZ76** · 04-30-2014, 12:47 PM

While driving home the check engine light came on. I got 2 codes both for knock sensors bank one and bank two intermittent. I saw the write up to remove the manifold looked pretty simple. My question is are the both the same sensor? And how does this effect performance and gas mileage? And any advice? Thanks guys

***SMWS6TA*** · 04-30-2014, 01:43 PM

Yes both are the same. However you need to ask for the 99< KS and wire harness. The reason why is because the GM discontinue the >98 KS. Some parts places still have em. The 99< is to be a better sensor.

Some guys have tuned them out and have zero issues.

How it effects gas mileage - when the ecm detects knock it retards the fuel effecting performance.

**ChevyZ76** · 04-30-2014, 02:43 PM

Are the delphi ones good, or should I just go to the dealer and ask for the 99 sensors and connector? Does it make the car seem sluggish or under powered? I got 17.33 mpg coming on the highway with cruise control on. I though for sure it should be higher. I had an 88 IROC had a few things done to it and it makes this car feel like a turtle at times. Everything was fine when we turned the light out. But as soon as it cmd back on I feel a difference.

**pajeff02** · 04-30-2014, 06:14 PM

The knock sensors triggering will cause the PCM to pull timing. Once you get it all apart, be sure to check over the wiring harness for corrosion and wear.

**ChevyZ76** · 05-01-2014, 02:54 AM

What do I do if I do find his corrosion?

***SMWS6TA*** · 05-01-2014, 06:58 AM

I got mine from gmpartsdirect.com when I ordered mine.

99<
Wire harness, Part # 12601822 $ 34.67
Knock Sensors, Part # 12589867 (Need 2) $ 49.95 ea

There is also a $15.00 shipping/handling fee.

**pajeff02** · 05-01-2014, 05:33 PM

Originally Posted by ChevyZ76

What do I do if I do find his corrosion?

If you can acceptably remove the corrosion do it and then give the connections a dab of dielectric grease to protect them. If the harness is in bad shape, then replace it to avoid future issues.

**ChevyZ76** · 05-02-2014, 05:47 AM

Found some BWD Sensors at the local Advanced just going to replace the connector with one from the dealer. Looked at a write up. Didn't look to be to big of a job. Just the back screws for the intake seem like they will be the worst. Thanks everybody for al your help.

***SMWS6TA*** · 05-02-2014, 08:44 AM

I also ran a bead of rtv around the KS "plug" and the valley cover plate to seal the KS from getting moisture. Also recommend using some masking tape to hold wire harness in place or you will be going back again to replace it if it gets caught between the intake and heads wrong. BE CAREFUL with the OPSU. It is in a crappy spot and is very brittle and will break if you tap it wrong. The parts places sell a $10 socket to remove it, well worth it.

**ChevyZ76** · 05-05-2014, 04:07 PM

Thanks guys...I'll be doing this on thursday

**ChevyZ76** · 05-07-2014, 05:38 AM

Quick question. Does the intake need a separate gasket when I out it back on?

***SMWS6TA*** · 05-07-2014, 08:28 AM

As long as they (8 of them) are still in good working condition you can reuse them. If they are compressed and are too firm (like when rubber that's been expose to heat for too long) then you may want to replace.