car is breaking up at 3500rpm June 29, 2009, 10:44:04 PM When i drive my car and if i go over 3500 and in boost it breaks up, and it runs like **** after 3500rpm. Anybody know what it can be? thanks86 tc. 5 speed. no cat, cone filter. Quote Selected
car is breaking up at 3500rpm Reply #1 – June 30, 2009, 12:20:55 AM Are you running copper plugs? Platinum plugs suck in boosted engines. Quote Selected
car is breaking up at 3500rpm Reply #2 – June 30, 2009, 08:26:43 AM im running platinums. i have no leaks any where or cracked hoses. i think it may be the bad gas in the tank. the car sat for 10 years, Quote Selected
car is breaking up at 3500rpm Reply #3 – June 30, 2009, 09:27:09 AM I would start with the gas then. Go fill it up with Premium. Is it missing under boost? Quote Selected
car is breaking up at 3500rpm Reply #4 – June 30, 2009, 09:49:15 AM Usually that is a symptom of low fuel pressure. My 85 sat for 7 years and it had extremely low fuel pressure due to a cracked hose inside the fuel tank (from the pump to the mounting plate). It's like a one-dollar fix, but it takes a long time to install.I'd check the pressure with a gage if I were you. If it's low, suspect that hose. It's a common problem on these cars when they are left to sit.CoogarXR Quote Selected
car is breaking up at 3500rpm Reply #5 – June 30, 2009, 11:03:44 AM Im not sure about a T/C-never kept the 4cyl long enough to remember. I know on my Tyhoon if gut the cat the motor overboosts becausethe stock wastegate can't handle it. Quote Selected
car is breaking up at 3500rpm Reply #6 – June 30, 2009, 01:13:42 PM I doubt it'd make it to 3500 RPMs if the hose in the tank was ruptured, but testing fuel pressure under boost is what should be checked... Bettin it's the pump, no matter, you'll get to pull the tank one way or the other... Quote Selected
car is breaking up at 3500rpm Reply #7 – June 30, 2009, 04:13:40 PM I replaced the hose in my tank and it was good for a while and then developed a small leak around the connection where it was not tight enough. Mine was kinda doing the same thing. Leaning out under boost. Mine was earlier though. I could barely make 3000. had good pressure for idle but then when the regulator opened up the pressure dropped way off. You really need to get a gage on it. Quote Selected
car is breaking up at 3500rpm Reply #8 – June 30, 2009, 08:11:41 PM Well, it must be the gas. Anyways, the motor has a knock to it, it sounds like the rocker arm fell off but its going back to the guy i bought it from and hes gunna fix it. I had the car on the road for 1 day and get a knock, wtf? So its going back to his shop to get fixed. Ill be on vacation so my dad is gunna take care of it while im gone and when i come back i should be fixed and ready to go. Today it spiked to like 15psi at like 3500rpm, and i wasnt even at full throttle. Quote Selected
car is breaking up at 3500rpm Reply #9 – June 30, 2009, 09:43:22 PM Take it back eh??? That's a interesting concept...When I buy em at auction they are mine, if it falls to pieces on the way home so be it...Bought a Datsun once that the transmission sounded like it was missing about half the teeth in the transmission... Was almost afraid to drive that one, but found it was the pocket bearing and was quiet once in 4th gear... Still I swapped the transmission... Had to put spider gears in the rear end of a Chevy Malibu to be able to drive that one... Another Malibu would blow out the water quicker than you pour it in, had to be dragged home(put a engine in that one and drove it six years sold it and got the money I had in it back)... Did a timing belt and water pump on a Escort, another job in the auction parking lot...Other than a couple parts TCs I drove all those home... One did have to have a alternator(locked up), but they're easy to swap... Quote Selected
car is breaking up at 3500rpm Reply #10 – June 30, 2009, 09:59:44 PM Well, i bought the car form a good friend of my dads who owns a mechanic shop, so we are taking it back and they are gunna fix it and at least give me half off on fixing it or just make me buy the parts and labor for free. Quote Selected
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