is my knock sensor out?

[koolade9]

when I'm just cruisin on the highway, around 70-80mph, I'm just under boost, like -5 to 0 vac. When it goes just into boost (slowly accelerating), it bucks a little and my egt shoots to 1600+, and i have to keep it at 70 just to keep it around 1450-1500, any faster and its at 1600. but, when I goto open loop on the o2, it'll run like it should, at wot, it'll stay at 1600 or just below. the car is basically stock, only actual mods are the type s, and mbc...

if the knock sensor was out would that cause this? or am I getting some type of phantom knock? please help me out here!! It sucks doing 65 on a chicago interstate...

 

[koolade9]

any ideas?

 

[Keehnel1414]

I am fairly new to dsms but if your bov is vented into the atmosphere it will cause the car to run very wierd. I am not sure how to explain it. Maybe someone else can do better. Just trying to help for now.

 

[pneumo]

Under partial boost with the throttle partway open the BOV will open slightly. Don't vent to atmosphere.

 

[koolade9]

bov isn't vented to the atmosphere.

this is a timing related problem...

what would pull the timing while just cruising, but not retard timing at wot??

 

[Groomz]

Timing retard can be contributed to several things. What you may be experiencing is phantom knock, which is basically what is referred to when the knock sensor picks up lifter tick or other noises as knock and pulls timing. When knock is detected on 2G DSMs, timing is pulled and the boost control solenoid ( BCS ) is activated. You have a 99 DSM, so I would assume that your knock sensor is still intact ( unlike mine ). Replacing the lifters with 3rd generation ones eliminates lifter tick, and some sort of boost controller would bypass the BCS and eliminate the ECU control over boost. 2G DSMs are well known for being very sensitive to timing and pull it often and sometimes randomly. Start with a boost controller and then replace the lifters. There is plenty of info on this site ( too much to list ), but a quick search should yield some good information. A DSMlink ( www.dsmlink.com ) would allow you to define the knock threshold for the sensor, but you would still have to alleviate the ticking lifters and BCS anyway.

The timing is reduced at WOT ( because of the presence of boost pressure ), so timing is always pulled back at WOT. Timing being pulled at cruise sounds 100% like what I described above. Good luck!

 

[koolade9]

awesome, thanks alot. I've been looking into it as much as i can and I think you're right on the money, I've got some lifter tick I'm trying to elieviate as well. I just ordered a new 2g knock sensor, I'm trying to hold off on replacing the lifters untill I can pick up a built head. If i were to pick up the new lifters, when i pick up a built head, can they be transplanted into the new head? or with they be too worn in or "set" into the old head to be re-used?

 

[Groomz]

Originally posted by koolade9
awesome, thanks alot. I've been looking into it as much as i can and I think you're right on the money, I've got some lifter tick I'm trying to elieviate as well. I just ordered a new 2g knock sensor, I'm trying to hold off on replacing the lifters untill I can pick up a built head. If i were to pick up the new lifters, when i pick up a built head, can they be transplanted into the new head? or with they be too worn in or "set" into the old head to be re-used?

The lifters do not "wear" in the conventional sense, so you can use them on any head at any mileage. I am going to do the same thing, which is to buy new lifters for my stock 4G63 and then transplant them to a built head when I purchase one. Once a lifter pumps up, it does not move, it only allows the rocker arm a pivot point to act against. The pumping action allows them to adjust out any lash in the valvetrain, which helps on high mileage vehicles where valvetrain components stretch and wear down.

http://www.slowboyracing.com/Engine rebuild/Lifters/lifters.html

The picture on that site shows the huge difference versus the 3G lifters and stock ones. The lifters will work for any 4G63 head, any year.