From: James at Pelican Parts [james@pelicanparts.com] Sent: Sunday, May 23, 1999 9:59 PM To: lesterah@pacbell.net Subject: Re: Engine surge I did find the air temp sensor you are talking about. Not much information though. All I know at the moment is both the wires go to the brain (not much help). What I'm thinking is that this sensor works in conduction with some other part of the system, but I haven't been able to figure it out yet. Unless somebody pops up with the answer, I'll need a schematic for the brain. I know they exist, but I don't know were. Have you tried to artificially stimulate it? james "GEORGE L. LESTER" wrote: > I have totally retuned the engine sense that time, actually the engine that was rebuilt > was replaced with the last factory engine available in the USA according the Porsche > dealer in Sacramento. ( very long story why it was replaced ) The computer has a mixture > control on it and that has been set entirely through its range, the timing is at 27 > degrees ar 3500 rpm, oh yes it is a temperature sensor, not pressure. George > > James at Pelican Parts wrote: > > > Your right, this is a difficult one. I still can't find a reference to an air temp > > sensor, but I don't have any books at hand. You are sure this is not air pressure > > sensor? What I was just thinking: if the guy who rebuilt the engine tuned it to run > > without the device, that could cause a problem when the device is hood up. Have you > > tried to tune (mixture/timing) the car with the device hooked up. It sounds like you > > have eliminated most of the hardware questions. I'm going to look into this further > > and should be better informed next week. Keep in touch. > > > > james > > > > "GEORGE L. LESTER" wrote: > > > > > The MPC system has an electrical plug on top of the air intake right next to the > > > throttle valve, it is supposed to detect air temp and adjust fuel mixture > > > according for best engine performance, I disconnect ( unplug its two pin plug ) > > > and the engine runs good ( and as I said it passed a smog check with the plug > > > disconnected ) so the mixture must be OK however it's not the way Porsche > > > designed it. I have tried another manifold pressure sensor, also tried a > > > different cylinder head sensor, the idle speed air bypass valve opens and closes > > > after approximately 5 minutes after the engine is started ( like it should ) > > > basically the engine runs just fine with the temp sensor disconnected, but it's > > > just not right HA , oh yes I have even changed the computer and it was the same. > > > This all started as I remember when I had the engine rebuilt by Auto Sport > > > Technology in Sacramento ( Dwight Mitchell ) he is known as a expert on Porsche > > > performance in the club here, anyway when I got it back the sensor was > > > disconnected and taped up, I asked why and was told the engine performs better > > > that way. Over the years I have learned allot about the 914 2.0 and its systems > > > however this has me stumped. I have had this car sense 1983. George Home phone > > > ,916-645-8169 > > > > > > James at Pelican Parts wrote: > > > > > > > Hi George, > > > > I don't have a 2.0 914, and my 1.8 is completely different. Its been a while > > > > since I've even owned a D-jet car. My 911 does the same thing when the > > > > mixture or timing is set incorrectly. I'm also not sure what you mean by > > > > inlet air temp meter; perhaps Aux. air regulator, or air pressure meter? > > > > When you say you disconnected it: do you mean the hose or the electrical > > > > plug? A bad aux. air meter can cause such a problem when cold; but if it > > > > happens all the time I might suspect a leaking injector, or cold start > > > > valve. > > > > > > > > Please get back to me as I am very interested in this problem. > > > > > > > > good luck > > > > > > > > james > > > > > > > > Wayne at Pelican Parts wrote: > > > > > > > > > Hi there. I'm going to forward your email to James in tech support, who > > > > > might have some input on your problem. > > > > > > > > > > Thanks, > > > > > > > > > > Wayne at Pelican Parts > > > > > > > > > > -----Original Message----- > > > > > From: lesterah@pacbell.net [mailto:lesterah@pacbell.net] > > > > > Sent: Saturday, May 22, 1999 12:07 PM > > > > > To: pelicanparts@csi.com > > > > > Subject: Engine surge > > > > > > > > > > Im a member of the Sacramento Valley Region Porsche Club. I really > > > > > appreciate your web sight it's very helpful. I have a 73 914 2.0 in > > > > > excellent condition it has everything that was put on the 73 and I mean > > > > > everything including the dealer add on a/c. The problem I have is that > > > > > when the inlet air temp sensor is connected the engine surges ever so > > > > > slowly or dies at idle, with it disconnected it idles perfectly and > > > > > drives perfectly, I have checked the numbers on all the different > > > > > controls an they are for the 2.0 MPC system, Im really stumped, the > > > > > valves are adjusted right on the compression is good fuel pressure is > > > > > with in spec. throttle switch is adjusted in/a/w your article ,all hoses > > > > > are new, and I can find no air leaks. When the last smog check was done > > > > > it passed ( They could see the disconnected sensor ) Now It's exempt > > > > > from smog due to it's year, Can you help????? > > > > > Thanks George