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Annoying, but not aggrivating (yet)
I've noticed that after starting my car and letting her warm up for a few minutes, she initially stumbles upon accellerating from a standstill. After driving for any more than a couple of minutes, the problem goes away... until she sits without being driven for over an hour or more.
Thoughts?
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Current Stable: Black 07 Porsche 987 Cayman S: Long-Tube Headers; FabSpeed Exhaust; VividRacing ECU Tune; IPD Plenum; 997GT3 Throttle Body. Blue 1983 Porsche 928S. 1985.5 Porsche 944 Rat Rod. 2011 Acura MDX. 2008 Mazda 3. Gone But Not Forgotten:Garnet Red 86 Porsche 951("The Purple Pig"). Alpine White 83 Porsche 944 ("Alpine Wolf"). Guards Red 84 Porsche 944. |
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07-29-2003, 07:01 AM
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Fuel. Pressure, dampner, filter, pump, cat hair.
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Hugh - So Cal 83 944 Driver Person NOT a 'real' Porsche -- Its Better!!!! When was the last time you changed your timing and balance belts and/or cam chain and tensioner? New Users please add your car's year and model to your signature line! Never break more than you fix! |
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07-29-2003, 07:07 AM
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Join Date: Jan 2003
Location: Louisville, KY
Posts: 633
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mine always used to do that, never felt like paying to figure it out or fix it.
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'84 944na -- Sold '84 944na -- Sold '85 944na, -- Sold |
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07-29-2003, 07:15 AM
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Join Date: Dec 2002
Location: St. Petersburg, Florida
Posts: 1,990
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during the rebuild my ENGINE TEMP SENSOR at the front of the block, just under #1 injector, literally crumbled off in my hands. The wiring harness connection was fine but the plastic connection on the actual part was destroyed from the inside out.
I think it is responsible for the dme knowing if the engine is warmed up yet and it adjusted the mix accordingly. It is very easy to get at and $28(napa) to replace.
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83 944 white w/Boxster wheels Planned mods- custom leather interior, 968 antenna, soundsystem, 968 style rockers, clear sidemarkers
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07-29-2003, 07:25 AM
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Join Date: Dec 2002
Location: St. Petersburg, Florida
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BTW(i can't believe I now don't even flinch at paying $30 for a part half the size of my little finger!!!)
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83 944 white w/Boxster wheels Planned mods- custom leather interior, 968 antenna, soundsystem, 968 style rockers, clear sidemarkers
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07-29-2003, 07:27 AM
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Writer/Teacher
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SoCal - in trying to sort out an apparent accelleration problem (part of me still thinks it's my worn clutch affecting my accelleration), I replaced the fuel filter, cleaned the air filter, replaced the spark plugs, tested the throttle switch with an ohmeter, tightened the throttle cable, and cleaned out the inside of the throttle body... I know it sounds like a lot to do without knowing what's really wrong, but I felt it needed to be done.
Someone suggested to me that the problem could be either the AFM sensor (which i still need to test) or the DME... if it is the DME, will getting Wilk's Power Prom solve the problem? (i was going to buy the Power Prom anyhow) TCMdocs - how do i know if my Engine Temp Sensor is faulty?
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Current Stable: Black 07 Porsche 987 Cayman S: Long-Tube Headers; FabSpeed Exhaust; VividRacing ECU Tune; IPD Plenum; 997GT3 Throttle Body. Blue 1983 Porsche 928S. 1985.5 Porsche 944 Rat Rod. 2011 Acura MDX. 2008 Mazda 3. Gone But Not Forgotten:Garnet Red 86 Porsche 951("The Purple Pig"). Alpine White 83 Porsche 944 ("Alpine Wolf"). Guards Red 84 Porsche 944. |
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07-29-2003, 08:15 AM
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Registered
Join Date: Mar 2003
Location: Redmond WA Can anyone help me with my snorkle mod?
Posts: 245
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_ If the problem did not go away and only happened at low RPM, I would guess that it was the injectors, but I don't really know.
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'77 924 - Metallic Blue - enlarged TB/ intake '99 Specialized HardRock - Blue/Silver - Jett C Shocks - Cat Eye Velo computer If it ain't broken, drive it until something is. Have you spent quality time with your Engine Gnome lately? Defend Your Joy |
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07-29-2003, 08:49 AM
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why do you think it is the injectors?
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Current Stable: Black 07 Porsche 987 Cayman S: Long-Tube Headers; FabSpeed Exhaust; VividRacing ECU Tune; IPD Plenum; 997GT3 Throttle Body. Blue 1983 Porsche 928S. 1985.5 Porsche 944 Rat Rod. 2011 Acura MDX. 2008 Mazda 3. Gone But Not Forgotten:Garnet Red 86 Porsche 951("The Purple Pig"). Alpine White 83 Porsche 944 ("Alpine Wolf"). Guards Red 84 Porsche 944. |
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07-29-2003, 10:01 AM
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vott does ziss do?
Join Date: May 2003
Location: Seattle
Posts: 6,676
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it could be more than just the injector(s). start with the fuel system in geneeral and then go to the F/I system-electronics.
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07-29-2003, 10:29 AM
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what is that supposed to mean?
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Current Stable: Black 07 Porsche 987 Cayman S: Long-Tube Headers; FabSpeed Exhaust; VividRacing ECU Tune; IPD Plenum; 997GT3 Throttle Body. Blue 1983 Porsche 928S. 1985.5 Porsche 944 Rat Rod. 2011 Acura MDX. 2008 Mazda 3. Gone But Not Forgotten:Garnet Red 86 Porsche 951("The Purple Pig"). Alpine White 83 Porsche 944 ("Alpine Wolf"). Guards Red 84 Porsche 944. |
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07-29-2003, 10:50 AM
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vott does ziss do?
Join Date: May 2003
Location: Seattle
Posts: 6,676
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check the fuel system in general, i.e. filter, fuel pump, lines, injectors etc. this will show whether you're getting proper fuel pressure. then move on to the rest of the fuel injection system IOW the electronics side, and check the throttle switch and air flow meter. also be sure to check for intake air vacuum leaks
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07-29-2003, 11:08 AM
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Writer/Teacher
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1) how do i check the pressure, or that i need a new fuel pump or lines?
2) filter was just replaced a month ago 3) already checked the throttle switch
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Current Stable: Black 07 Porsche 987 Cayman S: Long-Tube Headers; FabSpeed Exhaust; VividRacing ECU Tune; IPD Plenum; 997GT3 Throttle Body. Blue 1983 Porsche 928S. 1985.5 Porsche 944 Rat Rod. 2011 Acura MDX. 2008 Mazda 3. Gone But Not Forgotten:Garnet Red 86 Porsche 951("The Purple Pig"). Alpine White 83 Porsche 944 ("Alpine Wolf"). Guards Red 84 Porsche 944. |
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07-29-2003, 11:10 AM
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vott does ziss do?
Join Date: May 2003
Location: Seattle
Posts: 6,676
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1) unfortunately I don't have the official shop manuals but you can check the fuel pump by removing the plug from the end of the fuel rail and connecting a fuel pressure gauge. Before you do that, you can 'drain' the fuel system by pulling the fuel pump fuse and letting the engine run until it quits. That way you won't get fuel all over.
Once you have the fuel pressure gauge in place, you can then test the system by running the fuel pump (withouth the engine running) by jumping two terminals in the air flow sensor connector plug. Unfortunately, since I don't have the manual, I can't tell you which terminals to jump and what pressures you're looking for. At least this gives you a basic idea of how it's done. I'm going to see if I can come up with the specs but hopefully some of the other listers can help sooner. AFJuvat and SoCal, you guys listening? 
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07-29-2003, 11:26 AM
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Location: St. Petersburg, Florida
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To check the engine temp sensor I am sure you just check for ohms/no ohms both cold and in hot water. It only has two prongs on the plug, cold is usually in the closed position. This looks very similar to the thermo-fan switch only alot smaller and hooks to the dme.
The condition of mine was so poor that it couldn't even be tested(prongs ?rusted? off). It was significant enough that my next project will be to go through every sensor that the dme uses, pull the plug, clean it up, and plug back in. Age/heat is unkind to plastic and rubber.
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83 944 white w/Boxster wheels Planned mods- custom leather interior, 968 antenna, soundsystem, 968 style rockers, clear sidemarkers
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07-29-2003, 11:37 AM
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vott does ziss do?
Join Date: May 2003
Location: Seattle
Posts: 6,676
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step two of the process would be to check the fuel system under idle. This is where I need to get the numbers for what pressures you're looking for. The first part is to check the pressure while the engine is running at idle. The second part is to disconnect the vaccum line to the intake manifold while the engine is till idling and then closingoff the vaccum hose. These two steps will give you the readings you need to see if the fuel system is performing properly. Now if I just had those numbers.
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07-29-2003, 11:37 AM
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vott does ziss do?
Join Date: May 2003
Location: Seattle
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Quote:
Ditto on that, my car has about 146k on it but still runs really well. However, I do wonder how much better it would run if I did the same.
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07-29-2003, 11:39 AM
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Location: St. Petersburg, Florida
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Ya know, I haven't even said it because CJf is an oldster around here but.
HEY CJ, with the work you were doing to clean up the afm etc. did you accidentally pull loose a vacuum hose? Didn't think so.... Just thought I would check.
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83 944 white w/Boxster wheels Planned mods- custom leather interior, 968 antenna, soundsystem, 968 style rockers, clear sidemarkers
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07-29-2003, 11:48 AM
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Isn't the TPS often implicated in this type of problem, cold start, TPS isn't working... stumbles?
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Jake 1983 Euro 944 (Mine) 2000 BMW 323i (Hers) 1997 Sentra (unclaimed!) |
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07-29-2003, 12:11 PM
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vott does ziss do?
Join Date: May 2003
Location: Seattle
Posts: 6,676
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Quote:
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07-29-2003, 12:14 PM
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83 944 DME Testing Plan -- about 20 pages -- also included in the factory manuals. Gives all of the resistances and stuff. Also a XY cause and effect cart.
__________________
Hugh - So Cal 83 944 Driver Person NOT a 'real' Porsche -- Its Better!!!! When was the last time you changed your timing and balance belts and/or cam chain and tensioner? New Users please add your car's year and model to your signature line! Never break more than you fix! |
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07-29-2003, 02:55 PM
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2007 Porsche Cayman S
The Viridian Falcon
SOLD! -- The Purple Pig
SOLD! -- Mighty Mouse
SOLD!! -- Alpine Wolf
1983 Porsche 944 2.5 liter
1983 Porsche 944NA 2.5
