| Porsche Technical Discussions Porsche related technical discussions and questions go here. |
![]() |
|
|
Thread Tools | Display Modes |
|
|
|
#1
|
||||
|
||||
|
Dorki's,
Such a great weekend at Summit, but a new issue has come up with the car and i'm looking for a little advice on how to do some diagnostics. Problem: The car has decided it doesn't like starting up immediately like it used to a couple weeks ago. Now about 75% of the time I have to crank it for a good 5-8 seconds before it will start up. I believe the long start is more tyical when the car is hot, but haven't been able to prove this point. Another piece of information is that the 'check engine' light comes on briefly, but then goes out. I don't have a Hammer, so can't pull any codes, but when I try the gas pedal method there are no codes flashed back. Once the car starts it runs smoothly and as expected. David Riley (thanks!) suggested I check the ignition coils and/or control units, but instead of just replacing them I would like to know how to test them. I have not dealt with these before and am a complete novice (but willing to learn), so any help is greatly appreciated and welcome at an elementary instructional level. Thanks all, -Skip
__________________
Skip '91 964 #54 '97 993 C4S |
|
#2
|
||||
|
||||
|
skip: If you're not aware of its existence, Rennlist has an excellent 964 forum that's proved helpful to me on many occasions. Sounds to me like you might have a fuel-delivery problem. A very common problem on 964s is a failed or failing DME fuel relay (best advice from many 964 owners is always to carry a spare DME fuel relay since they fail often). If you have the extra one, you might try popping that in to see if it cures the problem.
__________________
Richard Curtis Fairfax Station, Va. '93 911 C2 |
|
#3
|
||||
|
||||
|
Quote:
__________________
Kyriakos E. Stylianos Baglama inspired 1982 SC Targa - (Currently Wallowing for GothingNC) |
|
#4
|
||||
|
||||
|
Richard - thanks I've been on Rennlist for a long time and have posted over there too, but like to gather information from as many sources as possible.
I already replaced the DME Relay (should have listed that in the OP) and nothing changed. Charlie - not sure about a fuel accumulator or similar. Should I consider installing a new fuel filter? I'm not sure how long it has been since it was replaced. How do I test the ignition coils?
__________________
Skip '91 964 #54 '97 993 C4S |
|
#5
|
||||
|
||||
|
Quote:
Might want to explain the other symptoms too. Didn’t you say after cranking for a couple of second if yo pressed on the accelerator it would start.
__________________
David I hope to arrive to my death, late, in love, and a little drunk! Just because I don't care doesn't mean I don't understand... Homer Simpson "That's what's keeping me out of F1.... Too much mental maturity...." N0tt0n Some cause happiness wherever they go; others whenever they go. CHAOS, PANIC, AND DISORDER my work here is done... Live without pretending, Love without depending, Listen without defending, Speak without offending |
|
#6
|
||||
|
||||
|
David - on your recommendation I tested without touching the accelerator and it was, as you thought it might be, coincidential. It will startup without hitting the gas after the 5-7 second mark.
I'll try to look through my service records to see when the fuel filter was last changed, but I'm not sure. It doesn't look old as I look at it, but that doesn't mean anything. So where to start and how can I check if the coils/ignition controls have issues? Thanks all - I will have some time tonight to look at it. -Skip -Skip
__________________
Skip '91 964 #54 '97 993 C4S |
|
#7
|
||||
|
||||
|
Test for spark with an inductive timing light on the coil to dizzy wire. See if the timing light blinks during crank but no start portion of the starting cycle. If it does you might want to look at fuel. Sounds like the fuel pressure is dropping off.
|
|
#8
|
||||
|
||||
|
I thought you might be interested in reading this web page:
http://forums.rennlist.com/rennforum...ferrerid=24812 From, Paddy
__________________
95 993 16 GTI 02 BMW Spec E46 #27 01 Boxster 86 944- AER/Chump #33 20 F250 Tremor |
|
#9
|
|||
|
|||
|
Skip,
Any update on the hard starting problem with your 964? I have a similar problem with my '93 C2. As a matter of fact, its sitting in the middle of the garage and won't start! (Just changed the brake pads.) Wife's car is outside in the hurricane waiting to come inside for safety! Rick
__________________
Rick G. Black '93 964 C2 #421 Running on, running on empty, Running on, running blind, Running on, running into the sun, But I'm running behind
- Jackson Browne, 1977 |
|
#10
|
||||
|
||||
|
No update...sorry. I'm taking it to ASG on Wednesday this week as I haven't had any time to do anything.
Sorry.
__________________
Skip '91 964 #54 '97 993 C4S |
![]() |
|
|