EpicQuest Posted March 2, 2008 Report Share Posted March 2, 2008 Ive searched a bit and changed a few things but im still experiencing the same problems. whenever i try to go above 4500 rpm my engine wont push much further, the power just drops off. it doesnt do this unless im in gear and driving, when in neutral i can redline the car but it'll sputter a little bit. Also when I rev the motor, then let off the gas abruptly, the car almost dies then bounces up and down and settles at iits 1000prm idle. ive done some things for the car:had the injectors cleanedhas newer spark plugsnew vacuum advance distributorthe tps was reset bought a optima red top batteryreplaced the alternator new O2 sensornew cat I took the car to a shop to get the ecu codes and the O2 sensor and tps came up. theyve both been addressed and im still seeing the same problem. The shop says it could be my ecu but id like to get some more advise before i buy one. Link to comment Share on other sites More sharing options...
Wolf87Conquest Posted March 2, 2008 Report Share Posted March 2, 2008 At that rpm, it's getting close to the engine's torque limit.I'm assuming it's a warm engine...run issues on warm engines is the CTS most commonly.Check/ verify the ISC and TPS are working correctly. Proper voltage signals, clean and tight connections. I believe there's a FAQ here that has the procedure and proper voltage requirements.Could also be a weak coil..test it...primary should be 1.25 ohms, secondary 11.0 ohms. Test it both warm and cold.The ECU sends the ground to the injectors, so verify a good ground on the ECU case. Coil case and ignitor box case also need a good ground.It may be a good idea to go thru the entire ignition system. Verify good parts, clean and tight connections. The only part that can test good and still be failing is the pick up...it looks burnt...replace it.High rpm fall off is remotely possible exhaust resriction. Link to comment Share on other sites More sharing options...
UlrichWolf Posted March 2, 2008 Report Share Posted March 2, 2008 You should check the timing chain. It sounds to me like it may have jumped a tooth. Have you checked the ignition timing? Tim Link to comment Share on other sites More sharing options...
Indiana Posted March 2, 2008 Report Share Posted March 2, 2008 you can only check the code for O2 with the engine running and warmed up otherwise you will get it every time and the tps isn't going to limit your rpms, its something else like those used plugs are fouled or like mentioned you timing is off what plugs are they and what gap you have them at, if they are black and look crusty they either need media blasted to be able to use them or throw them away and get new ones NGK bpr7es gap about 35-38 then check them once in a while and don't forget to use antisieze lubricant on the threads if you have mechanical valve train maybe its out of adjustment or you have clogged exhaust Link to comment Share on other sites More sharing options...
Alcyone Posted March 2, 2008 Report Share Posted March 2, 2008 Also when I rev the motor, then let off the gas abruptly, the car almost dies then bounces up and down and settles at iits 1000prm idle. that sounds like a vacuum leak to me. Link to comment Share on other sites More sharing options...
EpicQuest Posted March 3, 2008 Author Report Share Posted March 3, 2008 i was thinking vacuum leak as well but the previous owner says he changed all of the vacuum lines and none look too worn but i guess i better try that as well.i will go grab some plugs today and gap them to spec. the people i took the car to didnt have the car running when they got the codes so they may have wasted the $20 i spent on a new sensor i now have like three... Link to comment Share on other sites More sharing options...
EpicQuest Posted March 3, 2008 Author Report Share Posted March 3, 2008 i'll have the timing checked if the plugs dont solve my problem. I really appreciate the responses btw. Link to comment Share on other sites More sharing options...
Fanta Posted March 3, 2008 Report Share Posted March 3, 2008 It might not mean bad hoses. It might just mean something isn't hooked up correctly. Also. Never. EVER. Rev up to redline, especially in neutral. The way our engines are designed is that you do that and the oil pickup starts to suck up air, you starve your engine and bearings of oil and KABOOM! Take it to heart. Live by it. I always try to never go over 4500/5000 Link to comment Share on other sites More sharing options...
emagdnim Posted March 3, 2008 Report Share Posted March 3, 2008 It's because you have a 12a. :wink: Link to comment Share on other sites More sharing options...
EpicQuest Posted March 3, 2008 Author Report Share Posted March 3, 2008 ok i pulled one of the plugs... it is gapped to .042 Link to comment Share on other sites More sharing options...
EpicQuest Posted March 3, 2008 Author Report Share Posted March 3, 2008 one of the plugs in the car are different. three are ngk bpr5ey and one is ngk bpr7es. would this present a problem? i gapped them all to .032, will come back with results in 10min... Link to comment Share on other sites More sharing options...
Wolf87Conquest Posted March 4, 2008 Report Share Posted March 4, 2008 All the plugs should be the same plug...different plugs, different heat ranges.I run mine gapped at 0.35 without a problem. Link to comment Share on other sites More sharing options...
EpicQuest Posted March 4, 2008 Author Report Share Posted March 4, 2008 ok i put on a *DM downpipe i have and the idle bouncing stopped while the car was cold but resumed when it warmed up and the high rpm sputtering continues... the car does feel stronger though. had to order the bpr7 plugs, will have them in 2 days. Link to comment Share on other sites More sharing options...
G54Bstore Posted March 4, 2008 Report Share Posted March 4, 2008 suprised no one has mentioned valve float.may have weak valve springs .valves may not be closeing fast enuff at that high of rpm. Link to comment Share on other sites More sharing options...
Shelby Posted March 4, 2008 Report Share Posted March 4, 2008 no one sugest'd he check his fuel system pressure under road conditions the engine will only make power as long as the fuel system maintains proper fuel system pressures,,as soon as the pressure drops at all,thats the limit of the engines power makeing abilitys maintaining a set pressure means the pump and or system is capiable of delivering that much and more fuel but any losss in pressure means there is not enought fuel flow volume to maintain said pressure so the engine stops makeing power beyond that point ,,aprox the same result as the exh system not being able to flow enought exh gases to increase engine rpms beyond a certain rpmremember the engine is a very good air pump but the turbo isn't , you restrict it and it'l just stop working but don't try to over simplecate this several things can be wrong at one time Link to comment Share on other sites More sharing options...
EpicQuest Posted March 4, 2008 Author Report Share Posted March 4, 2008 how do I address those two problems? Link to comment Share on other sites More sharing options...
Caliber308 Posted March 5, 2008 Report Share Posted March 5, 2008 4500 to 5000 rpms is about what you should expect from a stock engine. A word of warning: Dont rev your car to redline in neutral!!!!!!!!!!!!!!!!!!!! CALIBER 308 Link to comment Share on other sites More sharing options...
Caliber308 Posted March 5, 2008 Report Share Posted March 5, 2008 You should check the timing chain. It sounds to me like it may have jumped a tooth. Tim Like when he redlined it in neutral :wink: :wink: :wink: CALIBER 308 Link to comment Share on other sites More sharing options...
Caliber308 Posted March 5, 2008 Report Share Posted March 5, 2008 one of the plugs in the car are different. three are ngk bpr5ey and one is ngk bpr7es. would this present a problem? i gapped them all to .032, will come back with results in 10min... Stock plugs are: NGK BPR-6ES-11 Set gap between: .039 and .043 in. If your going to run 7s, set gap between .035 and .039 in. CALIBER 308 Link to comment Share on other sites More sharing options...
Recommended Posts