New owner
06-26-2014, 05:21 PM
#1
Racer
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New owner
Hi all, I'm new to the 930 club purchased a dage converted 88 targa today.
I have a c2 which I am way more familiar with but am keen to learn about the 930 variant.
I'm looking forward to getting it out however on the drive back home it seems to be suffering with misfire and back fire issues. My question is where to start.
Cheers
Dave
I have a c2 which I am way more familiar with but am keen to learn about the 930 variant.
I'm looking forward to getting it out however on the drive back home it seems to be suffering with misfire and back fire issues. My question is where to start.
Cheers
Dave
06-26-2014, 10:23 PM
#2
Rennlist Member
Welcome to the forum. Nice looking turbo targa. 
It would help if you post a photo of your engine compartment and provide a list of anything not stock on your car, drivetrain wise. In other words, we don't need to know about the Club Sport wheel, the Momo shift ****, or the fuzzy dice hanging from your rear-view mirror.
Also, please provide as much detail [what, where, when, how] about your current issue, as possible.
It would help if you post a photo of your engine compartment and provide a list of anything not stock on your car, drivetrain wise. In other words, we don't need to know about the Club Sport wheel, the Momo shift ****, or the fuzzy dice hanging from your rear-view mirror.
Also, please provide as much detail [what, where, when, how] about your current issue, as possible.
06-27-2014, 05:32 PM
#5
Racer
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Hi guys,
Thanks for the advice, the engine is bone stock and in good clean order at least from appearance. I had the leads dizzy and rotar off today checked them all and are all a ok. Obviously I can't see if a lead is leaking and causing a misfire but they are all passing current. The coil is doing its job and as well.
I've ordered new plugs and leads just to eliminate this possibility but I'm definitely missing a cylinder although all the plugs on inspection look the same and appear to be firing.
The misfire is most noticeable under acceleration and back firing on the over run which leads me to believe it has to be a timing issue ie a leaky lead.
What else could it be?
Cheers
Dave
Thanks for the advice, the engine is bone stock and in good clean order at least from appearance. I had the leads dizzy and rotar off today checked them all and are all a ok. Obviously I can't see if a lead is leaking and causing a misfire but they are all passing current. The coil is doing its job and as well.
I've ordered new plugs and leads just to eliminate this possibility but I'm definitely missing a cylinder although all the plugs on inspection look the same and appear to be firing.
The misfire is most noticeable under acceleration and back firing on the over run which leads me to believe it has to be a timing issue ie a leaky lead.
What else could it be?
Cheers
Dave
06-27-2014, 06:29 PM
#6
Burning Brakes
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Could be a simple air leak. If you're not yet familiar with CIS injection - and particularly turbocharged CIS - it can pose some interesting symptoms if parts of the system are worn. I would hate to see you throwing serious coin into her when you may just have a vacuum leak (hoses, turbo and intercooler O'rings are the first place to look).
I would agree with everyone: Tuneup first, check timing, check system and control fuel pressures as a matter of course (you'll need the special gauge setup for that) and if everything looks to be set and adjusted correctly and the new wires and plugs don't resolve your issue, start looking for vacuum leaks.
Just curious: How does she perform on full boost....or will she even reach it without stuttering, etc?
I would agree with everyone: Tuneup first, check timing, check system and control fuel pressures as a matter of course (you'll need the special gauge setup for that) and if everything looks to be set and adjusted correctly and the new wires and plugs don't resolve your issue, start looking for vacuum leaks.
Just curious: How does she perform on full boost....or will she even reach it without stuttering, etc?
06-27-2014, 07:48 PM
#7
Rennlist Member
1. gurgle, gurgle, pop, pop, gurgle, or
2. gurgle, POP, gurgle, gurgle, POP
Have you driven a Porsche air-cooled CIS car before? The gurgle/pop on the over run is a normal by-product of CIS.
Does you car miss and "back fire" only under load, or will it misbehave if you jazz it sitting in the driveway? Any chance you could put up a sound bite of your perceived issues?
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06-29-2014, 05:18 PM
#8
Racer
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Could be a simple air leak. If you're not yet familiar with CIS injection - and particularly turbocharged CIS - it can pose some interesting symptoms if parts of the system are worn. I would hate to see you throwing serious coin into her when you may just have a vacuum leak (hoses, turbo and intercooler O'rings are the first place to look).
I would agree with everyone: Tuneup first, check timing, check system and control fuel pressures as a matter of course (you'll need the special gauge setup for that) and if everything looks to be set and adjusted correctly and the new wires and plugs don't resolve your issue, start looking for vacuum leaks.
Just curious: How does she perform on full boost....or will she even reach it without stuttering, etc?
I would agree with everyone: Tuneup first, check timing, check system and control fuel pressures as a matter of course (you'll need the special gauge setup for that) and if everything looks to be set and adjusted correctly and the new wires and plugs don't resolve your issue, start looking for vacuum leaks.
Just curious: How does she perform on full boost....or will she even reach it without stuttering, etc?
Next stop is the timing as it idles lumpy and is definitely missing or misfiring throughout the rev range.
On other 911 I've had the timing is controlled by the ecu . On this I think you have to set it on the dizzy.
Is there a link for timing on here.?
06-30-2014, 10:26 AM
#11
Racer
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Right so I take drive out to Bournemouth today cars got the same issues. But only now decides to die into a round about and then will not start! Lots of waving hands in the sausage motion and beeping at Chichester round about while I push the car off the road. With my wife in the passenger seat.
Anyway attempt to trundle home but car won't start antil it drops in temp below a quater.
As approaches just over a quater temp engine dies again and lots of popping and shuddering. Ie lean fueling before hand.
Have to wait until it cools down before I attempt to limo home but finally make it just as it cuts out again at the magic temperature. Just over a quater.
Gotta be fueling problem and have done some research maybe a warm up regulator. But that by all accounts looks spanking new!
Anyway attempt to trundle home but car won't start antil it drops in temp below a quater.
As approaches just over a quater temp engine dies again and lots of popping and shuddering. Ie lean fueling before hand.
Have to wait until it cools down before I attempt to limo home but finally make it just as it cuts out again at the magic temperature. Just over a quater.
Gotta be fueling problem and have done some research maybe a warm up regulator. But that by all accounts looks spanking new!
07-02-2014, 03:57 PM
#13
Racer
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More digging today. Still same issue. Did a compression test on all the cylinders dry. And engine cold all showed 7 bar pressure except for no. 3 ..... 5.8 bar hmmmm. Anyways new leads and plugs installed problem is the same as before. Wtf.
