Guest 73Turbo240z Posted December 16, 2005 Share Posted December 16, 2005 alright, figure while i'm down doing this bloody headgasket i can talk shop about another thing both ted and i have been noticing, on a cold start, the cars will relatively speaking, fire right off... however, go park and shut down @ the local mini-mart, come back out, and your in for a crank fest to try and get it to come back to life, sometimes holding the pedal down all the way in flood clear mode will do the trick, othertimes it will not... i've gone in and messed w/ crank pulsewidths that are referenced off temperature, figured leaning out the pulsewidth a little bit would help with warm start scenario's, but so far nothing conclusive. this is on a 25v2 megatune setup btw, for what it's worth... anyone else got an answer to this one? i figured alot of us would be dealing with it, could become a real hassle if you shut your car down in the lanes waiting to get to the staging box, and suddenly couldn't start the car... Quote Link to comment Share on other sites More sharing options...
proxlamus© Posted December 16, 2005 Share Posted December 16, 2005 I get it ALL the time.. Cold starts = needs about 3 or 4 starts runs too rich HOT starts = ughh.. runs very very rich and idles very rough untill I start driving under load after 2,000 RPM ... THICKER oil has helped, but I need to mess with megaSquirt. Quote Link to comment Share on other sites More sharing options...
mobythevan Posted December 16, 2005 Share Posted December 16, 2005 This should be fixable using the 024s9 or newer code because after start enrichment looks at coolant temp to determine percentage of enrichment. On older versions like 021u for example the after start enrichment always happens, regardless of coolant temp. You should not have this issue if you use 024s9 or newer and lower your ASE as coolant temp rises. Let me know what you guys figure out since I just spout theoretical fixes and don't have a car to try it out on. Quote Link to comment Share on other sites More sharing options...
PeterZ Posted December 16, 2005 Share Posted December 16, 2005 Any chance you have a leaking injector bleeding off fuel pressure when the car sits? (That includes the cold start injector) I haven't seen a MS set-up but a pressure gauge could determine a fuel pressure loss pretty easily Quote Link to comment Share on other sites More sharing options...
Cruez Posted December 16, 2005 Share Posted December 16, 2005 I had that problem after my mods and the stock FI, without the cold start installed. I have since changed to a Haltech unit which has yet to be programmed. Since I can adjust to allow no more fuel when the car is warm, I believe this will solve the problem. Quote Link to comment Share on other sites More sharing options...
jkube Posted December 16, 2005 Share Posted December 16, 2005 One other thing to look at. I occasionally have a problem with MS on the 240z N/A car on startup, where MS is energizing the injectors fully on startup and flooding the engine. I suspect either I may have a short through the FETS to the casing, and the body or there is fault in the TPS (dont ask why I think that the TPS is a fault, its just a hunch). My suspicion is that one of the mylar insulators for the FET drivers is cracked. I have plenty of heat sink paste on it, but I noticed that one of them had been bent over and cracked I watch the injector LED to see if its fullly on when I start the car. I just engage the ignition key and watch the LED If its fully lit, I disconnect the switched 12 volt. and hit the starter a bit. After that I reconnect the 12 volt switched power and all is well for a few days. Quote Link to comment Share on other sites More sharing options...
Thumper Posted December 16, 2005 Share Posted December 16, 2005 Well the afterstart enrichment is set to 0, the warmup wizard is set to 0 and the cranking pulsewidths are at the smallest they will go 1.5 Any smaller and the car doesn't start at all because the injectos aren't opening. Also this happens even if the you turn off the car for only 3 seconds. Turn off wait a second turn on. But if you give it full throttle right off the bat it starts perfectly after the 2 second wait time. Only thing I can think of that may be causing this is we have our fuel pressure base 47psi, 40 with vacuum, this is so we can get alittle more power out of them before we have to upgrade. Also is there a problem with lowering the wait time to 1.5 seconds or even 1 second so it will start that just faster. Nothing big about it just annoying sometimes. Quote Link to comment Share on other sites More sharing options...
jkube Posted December 16, 2005 Share Posted December 16, 2005 How about the pulsewidths at -40 and at 170 F. You should be able to affect the fuel amount with these numbers. Try lowering the number for the 170f setting. As reference I have the following on the NA car at -40 - 9.0 at 170 - 4.0 For the turbo car at -40 - 8.0 at 170 - 3.0 Both cars start well both hot and cold Quote Link to comment Share on other sites More sharing options...
Thumper Posted December 16, 2005 Share Posted December 16, 2005 Well the afterstart enrichment is set to 0, the warmup wizard is set to 0 and the cranking pulsewidths are at the smallest they will go 1.5 Any smaller and the car doesn't start at all because the injectos aren't opening. at 170f they at at 1.5 m/s Quote Link to comment Share on other sites More sharing options...
mobythevan Posted December 17, 2005 Share Posted December 17, 2005 My car never had that problem. I did retain the AAR so it would get more air for cold starts. But it would always start up warm, be a bit rich but idle fine. hmmmm Quote Link to comment Share on other sites More sharing options...
jkube Posted December 17, 2005 Share Posted December 17, 2005 Thumper, With 1.5 at 170f and all the other settings at 0 I'm surprized the car would even start. What can you tell us about the TPS. Is there any possibilty that the throttle is being activated when starting? I know that if I even touch my throttle during startup the car will flood. Quote Link to comment Share on other sites More sharing options...
Thumper Posted December 17, 2005 Share Posted December 17, 2005 Nope at idle the throttle is not being touched. The tps read out on screen says 0% plus megasquirt I believe learns the position of your tps so it automatically adjusts as long as its in the same position everytime it closes. Also we are running 440cc injectors at 47psi fuel pressure. The car idles best around 1.8-1.9 pulsewidths. So 1.5 during startup seems reasonable. Also both of us have tested our injectors for leaks. They both hold pressure for a couple hrs after the car shuts down so no problem there. Quote Link to comment Share on other sites More sharing options...
jkube Posted December 17, 2005 Share Posted December 17, 2005 Do you have the EGO still activated? I have mine set to activate at 6000RPM. It seemed that MS became more stabile during tuning for me when it wasnt affecting the fuel. In fact I still have it set that way and both cars start well all the time. Give this a try Quote Link to comment Share on other sites More sharing options...
Thumper Posted December 17, 2005 Share Posted December 17, 2005 Do you have the EGO still activated? I have mine set to activate at 6000RPM. It seemed that MS became more stabile during tuning for me when it wasnt affecting the fuel. In fact I still have it set that way and both cars start well all the time. Give this a try Nope ego is set to active only above 6500rpms so this isn't it. Thanks Quote Link to comment Share on other sites More sharing options...
mobythevan Posted December 17, 2005 Share Posted December 17, 2005 What about the priming pulse that occurs once after ms powers up? Quote Link to comment Share on other sites More sharing options...
proxlamus© Posted December 28, 2005 Share Posted December 28, 2005 ohh man.. Thumper I don't know how your car could even start.. I tried changing the Priming pulse to 1.5 and the -40* F at 1.5 and it would NOT START.... i changed the settings while the car was running... so i was driving down the street and then i stalled it.. and I was stuck.. and no laptop.. so I push started it and ran at 500RPM for about 1/2 mile uphill.. that was NOT fun.. argg Anyway.. this is what I am running now.. I'll let ya guys know how it works out Priming Pulse = 2.0 Pulsewidth at -40* F = 12.0 Pulsewidth at 170* F = 4.0 Quote Link to comment Share on other sites More sharing options...
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