Guest jjohart Posted September 3, 2004 Share Posted September 3, 2004 Hi, my 83 280ZXT, with I/C, Greddy boost control, open element air intake/filter, pop off valve and DSM blow off valve is extremely hard starting when cold (i.e not driven 2+ hours). My lackluster mechanic hasn't really taken responsibility for the fact that this started after he replaced the fuel injectors with used ones, which were actually stuck to the point of not working until he soaked them in fuel system cleaner, after which they worked, but this cold starting condition set in a day or two later. He described it as a lean condition, when the car may turn over in 2 -5 seconds of crank time, but then is lumpy and unresponsive to throttle inputs, may even stall out, but then usually recovers, and driveability is fine thereafter! His "advice" is to add an adjustable fuel pressure regulator and A/F gauge. I fail to see how that would address the fact that this is a "cold start" issue, and I think he's failing to look at engine component pieces like the cold start valve, those injectors (would an ultrasonic cleaning help?). I don't want to go adding needless devices that may not fix the problem. Can anyone tell me what I should tell a mechanic to look for, as I am thinking of turning to another garage. Thanks John Quote Link to comment Share on other sites More sharing options...
Guest 2slo4u Posted September 3, 2004 Share Posted September 3, 2004 Mine (81zxturbo) does the same thing when cold. It only takes two cranks, sometimes three to get it to start when cold, and idles poorly for a few seconds, then clears up and runs ok. I have brand new turbo injectors, not used and my fuel system has been thoroughly cleaned. It seems like a lean condition on mine also. There isn't a cold start injector stock on the L-6 turbo cars, though so I think the ecu has to compensate when the engine is cold. Maybe check your temperature sensors on the engine for clean connections and correct resistance when cold. If not, you might have an air leak as I think I do. Please let me know if you figure it out, it may be the same problem I'm having. 81zxturbo 95slobaru Quote Link to comment Share on other sites More sharing options...
slownrusty Posted September 4, 2004 Share Posted September 4, 2004 I am with both of you on this. My ZXT is not the happiest camper starting cold, I mean after sitting and the engine is death cold. Needs two cranks and some feathering of the throttle and usually I have to sit with my foot on the accel. pedal for a minute or so with the rpms at about 1200rpms and then as the engine gets warm it settles down and is ready to pounce. I am running a host of upgrades, IC being one of them. Yasin Quote Link to comment Share on other sites More sharing options...
Guest 2slo4u Posted September 5, 2004 Share Posted September 5, 2004 I'm not running an I/C like you guys, so I guess if the problem is common, the I/C tubing could be ruled out. Tomorrow, I'm going to check evey sensor for cold resistance and I'm also disconnecting the fuel temp. sensor I added. I used a new coolant temp. sensor for this because I could not get the sensor that came on the 300zx fuel pressure regulator seperately. I'll let y'all know if I find anything after checking all temperature sensors. (If it doesn't rain) Brian 81zxturbo 95slobaru Quote Link to comment Share on other sites More sharing options...
Guest 2slo4u Posted September 5, 2004 Share Posted September 5, 2004 Well, I checked the chts resistance and it was aok, at the sensor and at the ecu, exactly same resistance. I am going to put my fuel pressure gauge on today and drive it a few days checking the pressure at startup. I'm also wondering if there could be AIR in the fuel line. If this was possible, it would explain the rough running for a few seconds until the air got pushed out. Maybe I'll also change my fuel inlet hose to the pump. I'm also putting a clear glass fuel filter on the return line to see if air is moving through it while running. Maybe after the engine is shut down and cools, the contraction of the fuel is sucking air around the fuel regulator or through the injector pintles. I've always wondered about this happening on the zx fuel rail. Brian 81zxturbo 95slobaru Quote Link to comment Share on other sites More sharing options...
cygnusx1 Posted September 28, 2004 Share Posted September 28, 2004 My 83 ZXT motor used to fire up INSTANTLY from any temperature. Since I installed the I/C, the TO4B, and the 60mm TB it takes two or three cranks and stumbles a bit before actually finding happy idle. I have no idea why it changed after those installs. Yes, sensors, switches, fastidle, signals, and wires, are all working as they were before. Maybe the extra volume of air between the AFM and the pistons, by adding the IC, causes a delayed AFM response at low rpm (cranking) speeds. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.