1G possible bad knock sensor?

[spocks90talon]

ok ive had this problim before about 3 weeks ago, but it suddenly went away after about a day, the car ran fine the next couple weeks then yesterday it started again but is much worse. whats happaning is while im driving the car normal it runs like shit, it will hesitate and shudder very bad every 5 or 6 seconds its just like the cars cutting for like 1 second then it just runs normal again, it feels like when your car fuel cuts but its when im not even boosting, in fact it DOESNT do it when i do boost! also somtimes when it hesitates the car feels like it just doesnt spray fuel when i hit the gas, like i can lay the gas down and my boost gauge will go up to zero and the exhaust gets deeper but the rpms dont go up, the car doesnt acclerate. but if i clutch into neutral and shift it back into gear it will be fine again for a few seconds. ive checked a few things but nothings helped. i checked the fuel pump it was good, i checked my wires,plugs, coil all tested good, when i unpluged my maf the check engine light comes on and the car stalls when i shift to neutral coming to a stop but it still hesitates like before so i dont thinks its that. a freind suggested it may be a bad knock sensor, so reached down the backside of the block felt what i think is it(never had to mess with the knock sensor before so im not sure) and it had a brownish blackish ooz coming out the sides and back of it, i called my freind and he said the means its bad. i need to know if this is for sure a bad knock sensor because i dont want to buy a part i dont need because my moneys kinda tight right now and this cars taken enough of my money the last 2 months . thanks guys

 

[andymoraitis]

The ooze coming out of the knock sensor is a dead giveaway that it's toast and the symptoms you're having all point to phantom knock. While the sensor needs replacement, you should run a logger in the car so that you could hav seen physical knock counts and known that something was wrong. While you're replacing the knock sensor, it would be a great idea to also replace your O2 sensor if you're not sure when it was last replaced.

Keep in mind that knock sensor torque is 17 lb/ft and that overtightening the new one will also give you false knock readings and kill performance from timing being pulled.

Good luck,

Andy

 

[spocks90talon]

i dont have the money for a logger right now but do you think if i replace the knock sensor and oxygen sensor the car will run like it used to? where can i get these items cheap, any shops you suggest?

 

[andymoraitis]

We have an FAQ thread for vendors who sell OEM parts:

http://www.dsmtuners.com/forums/showthread.php?t=238788

O2 sensors are best ordered from:

http://www.sparkplugs.com

Yes it should run better, but without a logger you won't be able to tell how it's running in detail.

 

[spocks90talon]

i found new knock and o2 sensors for a decent price, i ordered them today but it will be about a week till they get here. do you think driving the car for only 2 or 3 miles a day(just to work and back) would hurt the motor? i have no other way to work but if it would hurt the motor ill just walk it instead. and as for dataloggers, i know i need one but like i said my moneys tight these days, my buddy has a 91 turbo laser and he suggested just getting a safc 2, he said thats all he's ever used and he's never had any problims with it and its cheaper than most other dataloggers/tuning devices. what do you guys think? i know you have to have a eprom ecu to use dsmlink and i dont have one, nor do i plan on getting one since i just had to drop $200 bucks on getting my ecu rebuilt last month. do you have to have a eprom to use any other dataloggers?

well i can scratch that idea, i can even drive the car now. it starts and runs but cant drive, as soon as i give it gas it hesitates and bogs down. im hope changing those sensors fixes it, anybody have a cheap safc 2 by the way?

 

[ROOKIE1]

You need a logger with or before you use the safc . The safc will change fuel settings etc... , the logger is used along with the safc to see what and why you are changing things . The logger is just a diagnostic tool . Used to see what is happening to the engine . Your friend may not notice problems now , but at some point he will more than likely have some huge issues.

http://cgi.ebay.com/ebaymotors/1G-D...oryZ6763QQssPageNameZWDVWQQrdZ1QQcmdZViewItem . This now or more problems later . Is your profile updated ?

 

[spocks90talon]

ok so my knock sensor went completly bad, my car would start and idle but as soon as i gave it gas it would hesitate and not go above 2k rpms, i let it sit a few days while i ordered the new knock sensor. well i got up today and was bored so i put my new dejon type s bov on and decided to take the negative off the battery to re-flash the ecu, when i hooked every thing and started the car, it ran fine! i drove it around the block and it ran fine most the time but after about 15 mins it started to feel like the ecu was pulling the timing(knock) so i parked it at home, it wasnt hesitating like last time at all though im replacing the knock sensor any way when it comes in tommrow but why would simply re flashing the ecu stop the horrible hesitation?

on another side note how should you run your vaccumm lines for a MBC? i just hooked up mine and want to make sure i did them right.

 

[THE REAL DEAL]

I found a temporary fix when my knock sensor was bad and the black gunk was melting out of the back. I put a few layers of electrical tape over the back and believe it or not, it actually helped. Of course, I've replaced the sensor but that's just a temporary fix while you're waiting to get a new one.

 

[Gromit]

ok so my knock sensor went completly bad, my car would start and idle but as soon as i gave it gas it would hesitate and not go above 2k rpms, i let it sit a few days while i ordered the new knock sensor. well i got up today and was bored so i put my new dejon type s bov on and decided to take the negative off the battery to re-flash the ecu, when i hooked every thing and started the car, it ran fine! i drove it around the block and it ran fine most the time but after about 15 mins it started to feel like the ecu was pulling the timing(knock) so i parked it at home, it wasnt hesitating like last time at all though im replacing the knock sensor any way when it comes in tommrow but why would simply re flashing the ecu stop the horrible hesitation?

on another side note how should you run your vaccumm lines for a MBC? i just hooked up mine and want to make sure i did them right.

Disconnecting the battery reset the ECU back its starting point, so to speak. Everything it has "learned" while you have been driving has been reset, so things like fuel trims are all set back to 100%. When you 1st started the car it used all those standard settings & ran OK. As you saw, driving it for awhile allowed the ECU to "learn" what was really going on in your engine & it adjusted the trims & such accordingly. It takes awhile of driving for the ECU to re-learn everything, expecially in a 1G. This is exactly why you really need to have a logger - so you can see what the heck is going on in your engine & how the ECU is adjusting things.