ok i have searched over this forum many times to try to cure my surging problem. I now have the upper and lower off the car, and looked at the gasket that went from the lower intake to the heads and it appears that it may have been blown.... I noticed my oil level increasing just slightly, and my coolant level decreasing just a tiny bit... After i disassembled the lower to take it to the machine shop tommorow, i noticed that the act sensor was completly coverd in crap. I dont just mean a little carbon either.... This thing is nasty!!! Could this sensor be the cause of my surging?????
can a dirty act sensor cause surging??
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HO93LX302
Founding Member
VERY unlikely that it's bad - it's a thermistor which is either good or bad - no in between. Just clean it up for a liottle faster response to air temp changes.
At 50°F it should read ABOUT 58k ohms and at 68°F it should read ABOUT 37k ohms. If you want to see it respond, put the ohmeter on the sensor and run cold and then warn water over the sensor.
At 50°F it should read ABOUT 58k ohms and at 68°F it should read ABOUT 37k ohms. If you want to see it respond, put the ohmeter on the sensor and run cold and then warn water over the sensor.
ok well i guess it could have just been a vacum leak somewhere. from all i hear about your porting, it only seems logical that you've taken a few intakes off of cars before tmoss, an im about to put my top end back together so i have another question for you which would be do i need to put rtv sealant on my gaskets for my lower intake to the heads by the water jackets???? there fel pro gaskets if that helps at all.....
HO93LX302
Founding Member
Is your EGR valve new?? The EGR valve could be stuck open causing the surge at idle.. I've had many customer cars at work that had surging problems due to EGR valves being stuck open.. Tap it with a small hammer and see if it changes the idle at all, if it does theres your problem..
HO93LX302
Founding Member
You wanna put the RTV in the corners of the gaskets, right were the head meets the block.. I usually put some first on bare metal (all 4 corners) then put the gaskets down and put a little more in the corners again over the gaskets.. You don't need that much but at least it won't leak there
well see thats the thing.... i just checked all my vacum lines, and the ones that go into the car from the little vacum "switch" (i think its what its called) the lines on the backside of that were all broken!!!! i just unhooked em, since the only one that wasnt capped off before was the one for the egr vavle.... would the valve still function at all with this unhooked??? also i dont have any smog stuff if that helps at all....
If the intake has some corrosion pits around the water holes, then yes skin the corrosion pits with a thin layer of RTV to fill the pits just before installing the gaskets. I use gasket tack on the intake to hold the gaskets in place while setting the lower. Yeah, check the EGR valve - if you have a hand held vacuum pump check that the valve opens and closes and you can clean the seat of any crud that might keep it from closing.
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