Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5

first cold start symptom
#1

Conducted a search, nothing quite the same as this issue turned up



Spoke to flash at length, and he provided a list of possible culprits which will be tested



So the reason for this post is simply to find out if anyone here has experienced the same symptom and if so, what was ( were ) the cause (s ) and solution to the problem



After the car sits for at least 6-8 hrs, at the first turn of the key ( it cranks fine ) it struggles to start , "stumbles", it really never catches on enough to actually idle, and then stalls completely in about 2 seconds.. pushing the gas pedal during this does not make a difference, or keeping the pedal down a little, or half way before cranking does not make a difference



However, after the car shuts off, I pause no more than 1 or 2 seconds and turn the key again, the car starts immediately and idles perfectly ( no idle hunting at all, it's smooth as can be ) and runs / responds for the rest of the time without a single problem. Or I can pause for 5 seconds, or for a minute, or for hours after that first intital stall, it still starts and runs as if the problem was never there



So, again it's consistently only during that very first attempt that the problem manisfests itself, and consistently starts right away and runs perfectly a second or two later



Has anyone here experienced this issue ?



p.s. yes, I replaced the DME relay to see what might happen ( i have two brand new spares, tried both ) - no change
Partial Post: Please Login or Register to read the full post.
Reply
#2

I'm curious:



1. Do you have any blink test codes?

2. Would it stumble the first time you attempt to start it if you turned the ignition to "ON" for 5-10 seconds, *then* tried to start the car? ('cuz I wonder if your <acronym title='mass air flow'>MAF</acronym> wire isn't getting the current it needs to heat up quickly enough.)
Partial Post: Please Login or Register to read the full post.
Reply
#3

I presume Flash has suggested changing the check valve after the fuel filter/pump?
Partial Post: Please Login or Register to read the full post.
Reply
#4

so as to eliminate repetition of things i have already told him to check:



key on delay has been checked - no change



vacuum lines are being checked. old hoses. possibly a secondary system leak (i.e. AOS)



spark plug torque is being checked. i put in new plugs. the seals were shot, and the old plugs and plug threads were very wet. the new plugs may have backed off.



throttle plate position is being checked. it might be stuck open too far, and not closing fully until some air from the first start gets in there and settles it.



yes, i suspected the check valve and/or filter, for a minute. however, i don't think that is the problem, as it starts right up after the first failure. if it were the valve or a fuel supply issue, there would be a delay of a few seconds before it started.



the other thing that is suspect is the high tension lead. his spark plug wires are shot. the high tension lead fell apart in my hand, leaving part of a connector stuck in the distributor cap. i had to make up a new wire to get him home, as everybody was 2 days out on a correct replacement part. wires and cap are being changed.



MAF was cleaned thoroughly before he left.

Durametric showed no codes when he left.



this problem popped up only after he had been home for a couple of days. all was fine up until then.
Partial Post: Please Login or Register to read the full post.

94 Midnight Metallic Blue Cab Porsche 968 w/deviating cashmere/black interior and WAY too many mods to list - thanks to eric for creating www.968forums.com



"It isn't nearly as expensive to do it right as it is to do it wrong."
Reply
#5

.
Partial Post: Please Login or Register to read the full post.
Reply
#6

[quote name='tamathumper' timestamp='1384298184' post='152121']

I'm curious:



1. Do you have any blink test codes?

2. Would it stumble the first time you attempt to start it if you turned the ignition to "ON" for 5-10 seconds, *then* tried to start the car? ('cuz I wonder if your <acronym title='mass air flow'>MAF</acronym> wire isn't getting the current it needs to heat up quickly enough.)

[/quote]



1. No ( blink test ) fault codes

2. Tried that ( Bob already covered the key delay ) but yeah, no change

3. And as noted in Bob's post there is an entire laundry list to test, most of which I will hand over to my mechanic



So my intent was only to determine if someone here had this exact issue happen to their car, rather than a supplemental " possible causes " search . Of course the hope is for a : " - yes, that's precisely what mine did, and as soon as I cleaned and reconnected the thingamajiggy, it never had a probelm since....and I also gained an extra 25 hp " reply.. <img src="/forum/images/smilies/968/laugh.png" class="smilie" alt="" />
Partial Post: Please Login or Register to read the full post.
Reply
#7

Update : just for the heck of it, I switched one more dme relay and at flash's suggestion, re-seated the coil wire plugs, once again. ( when the symptoms first started I unplugged and re-plugged the wire but it did not make a difference at the time..) . The car started on the first crank this morning. Now I wish I would have done just one of those things, at a time ! <img src="/forum/images/smilies/968/whine.gif" class="smilie" alt="" /> But the bet is on the makeshift coil wire, so as soon as the broken part insidethe distributor cap's neck is removed, and the OE wire goes in there, I'll switch back to the old DME relay and if the symptom does not repeat I'll know for sure. And if it does, I'll do the DME switch again to test that possibility.
Partial Post: Please Login or Register to read the full post.
Reply
#8

yup - i had to build that wire, as i had already given away my spare to somebody else. that's why i said to change it as soon as you got home. it's no surprise to me that it would be the cause of the problem. it isn't a perfect fit. i had to mess with it quite a bit to get it to seat and stay there. very possible it just isn't making good contact.



we'll know soon enough.
Partial Post: Please Login or Register to read the full post.

94 Midnight Metallic Blue Cab Porsche 968 w/deviating cashmere/black interior and WAY too many mods to list - thanks to eric for creating www.968forums.com



"It isn't nearly as expensive to do it right as it is to do it wrong."
Reply
#9

Interesting. My car is doing pretty much the same thing. When starting it to first time of the day, it doesn't catch. But on the second attempt, without touching the gas, it start perfectly, and idles smoothly at the correct rpm. I doubt it's the DME relay, because I tested it by applying 12V to the connectors that energize the coil, and then confirmed the switch activates (it makes a loud, reassuring click). I'll take a good look at my coil wire, and maybe just go ahead and replace it. But what is it about a faulty coil wire that could cause such a consistent starts-on-the-second-try symptom?
Partial Post: Please Login or Register to read the full post.
Reply
#10

the high tension lead sees current all the time the engine is running. the spark plug wires only get it as the rotor passes by. hence, the high tension lead burns out much faster. also, spark plug wires are very fragile. it takes very little to mess up the inside. since they fail from the inside, and you cannot tell with any form of inspection, they are recommended to be changed every other spark plug change.



in dan's case, his came apart in my hand, leaving the contact stuck in the cap. i had to build a wire with a standard sleeve type connector, rather than the pin type that we normally have. this did not make contact like the OEM. it worked, but was only a temporary measure. i would have replaced it correctly, if we had access to a new part. he had to make the drive home though, and there was no time to get the correct part.
Partial Post: Please Login or Register to read the full post.

94 Midnight Metallic Blue Cab Porsche 968 w/deviating cashmere/black interior and WAY too many mods to list - thanks to eric for creating www.968forums.com



"It isn't nearly as expensive to do it right as it is to do it wrong."
Reply
#11

But any idea why a faulty high tension lead would manifest as this particular symptom?
Partial Post: Please Login or Register to read the full post.
Reply
#12

something at one of the connectors i'm sure.
Partial Post: Please Login or Register to read the full post.

94 Midnight Metallic Blue Cab Porsche 968 w/deviating cashmere/black interior and WAY too many mods to list - thanks to eric for creating www.968forums.com



"It isn't nearly as expensive to do it right as it is to do it wrong."
Reply
#13

switched DMEs back this morning and the car started right way, so it was definitely the coil wire connectors' contact that caused the problem. so nice when you realize it's the cheap and simple fix , as opposed to the PITA one.. <img src="/forum/images/smilies/968/smile.png" class="smilie" alt="" />
Partial Post: Please Login or Register to read the full post.
Reply
#14

yeah - like i said at the beginning, i didn't like that wire, but had no options. things like this are hard to diagnose, because you can't see any cause of symptoms
Partial Post: Please Login or Register to read the full post.

94 Midnight Metallic Blue Cab Porsche 968 w/deviating cashmere/black interior and WAY too many mods to list - thanks to eric for creating www.968forums.com



"It isn't nearly as expensive to do it right as it is to do it wrong."
Reply


Possibly Related Threads…
Thread / Author Replies Views Last Post
Last Post by Waylander
08-29-2023, 04:24 PM
Last Post by edm
06-27-2020, 08:42 AM
Last Post by ds968
11-25-2017, 08:17 PM
Last Post by MLB
09-18-2017, 11:55 AM

Forum Jump:


Users browsing this thread: 1 Guest(s)