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Discussion summary
YOUR RESEARCHplease help, can't figure out misfire.
Leading reported evidence
Disconnect fluids, hoses, wires, etc
Performed · outcome unconfirmed
No successful repair reported for this finding.
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Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context
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Discussions that performed work without a confirmed outcome
1
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Performed · outcome unconfirmed · Original poster
today i drained and disconnected all the fluids, hoses, wires, etc...
Leading evidence: 'Disconnect fluids, hoses, wires, etc' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, the most frequently mentioned possible cause is 'found' (1 discussions; 0 report identifying it and 1 suggest it). The most frequently discussed action is 'Check grounds and make sure everything is' (1 discussions). For that action, 0 discussions report a resolution and 0 report an unsuccessful attempt. No action has an explicit, attributable resolution report under the current rules. These are forum reports and suggestions, not a confirmed diagnosis.
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Discussions that performed work without a confirmed outcome
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Performed · outcome unconfirmed
Had a similar problem after I replaced my coolant tank.
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Discussions that suspect a cause
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Suspected cause
The problem was found to be the drain tube from the coolant tank was placed right over cylinder 6 and when it would drip onto the coil pack it would misfire and the CEL would come on.
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Suggestion
Check your grounds and make sure everything is clean and well connected.
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found
No successful repair reported for this finding.
0
Identified cause
1
Suspected cause
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Reported fixes
Read evidence and context
Discussions that suspect a cause
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Suspected cause
The problem was found to be the drain tube from the coolant tank was placed right over cylinder 6 and when it would drip onto the coil pack it would misfire and the CEL would come on.
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44 eligible posts · 0 unverified posts · 1 discussions match the subject in their title or opening post.
Rennlist: 1 discussions
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the car was running fine until one morning i started it and it was making a terrible noise. my CEL indicated a misfire in cylinder #6. I replaced the spark plug and ingnition coil and the light is gone and there are no codes.
But the symptoms are still there: car has a very loud rattling from inside the engine, no power, shudders and shakes.
Ideas?
Intermediate shaft, bearing, and timing chain. I really don't know if this is it, and I don't want to alarm you, but you should think about not running the engine until a mechanic looks at it just in in case. If you search IMS on this forum, you will not sleep tonight. So, don't.
Maybe the muffler baffle came loose, you have a broken cat, or something like that, but best to be safe.
Good Luck!
And I just remembered, a couple of folks in this 996 forum had an engine rattling noise that mysteriously disappeared. It was about a month ago, so if you use the advanced search with the word "engine," you should find it.
Just don't read any topics on oil, none of us know squat about that.
thanks for the posts man. what is strange is that i drove it at night and it was great. parked it overnight. and in the morning i get that terrible noise and the misfire. never had an oil pressure or overheating issue. how could this happen?
Had a similar problem after I replaced my coolant tank. The problem was found to be the drain tube from the coolant tank was placed right over cylinder 6 and when it would drip onto the coil pack it would misfire and the CEL would come on. Re-routed the drain tube and haven't had a problem since.
Good luck.
Hate to say this...but it sound so typical of an intermediate shaft failure. They just seem to go for no reason....the car may be idling and run great one minute then rattle like a coffee can full of rocks the next. That noise won't go away if it's IMS failure. It's a catastrophic failure that requires an engine rebuild. I sincerely hope not...but ......
no, bought it at a porsche salvage yard 80 miles from my house. seller says it's just been rebuilt with a warranty. i haven't picked it up yet, he wants my core first. i hope to get the old motor out by wenesday and the new one in by the end of the week.
no warranty. engine was nearly $6k. doing the labor myself.
i figure i'll change the tranny fluid while i'm at it, does anyone know what exact fluid i need to buy for a tiptronic?
OT: also curious about a good place to buy the updated rear lights, dealer wants almost 800 bucks.
Yuck - sorry to hear that. Same thing happened to mine - sat in the garage over the X-mas holiday, and 4 days later I got the same thing you did, followed by lots of smoke. I knew immediately.
Better get some sort of warranty with that motor!
Best of luck.
Did you verify that it is rebuilt? I had someone say it was rebuilt then asked for the eng ser # that will tell you if it was done from Porsche, turns out it was not and he said really! For couple more grand you can get it rebuilt from Porsche with 2 year warrenty. If you already paid them then I hope your Karma is good.
hah, thanks mother, my karma is awesome and i haven't shed any serious money yet. what is suspicious is that the dealer says no one can rebuild these except the factory, but the guy i am buying the new one from says he rebuilds them.
PLUS, today, my tech said it doesn't sound that serious because the car drives and doesn't even idle rough. so i am putting the replacement engine on hold and i am gonna pop open my left valve cover and see whats up. we both have a feeling that the bracket holding the valve (spring) broke or got loose. i have my fingers crossed.
also, i will check out sunset porsche later on this week, (thanks).
p.s. no offense to 996 fanatics but these '99 3.4 engines are pieces of ****. i have owned dozens of different makes and models and this is the first well maintained car to take a dump this serious on me at 70k miles. like i said in previous posts, i miss the freakin 993s but it's too bad they look so outdated.... (IMHO)
It seems that compression and leak down tests would be done before removing the valve cover, which isn't exactly a simple process because the cams must be supported before the cover can come off.
That's them as far as I know. I called a few weeks ago and the engines where around $8200 exchange. Let us know what they quoted you maybe we can do group buy.
yeah, i got the same price. the one i am buying is about $7k with a 6 month warranty. they are giving me back $1500 for my core so net cost is $5500.
today i drained and disconnected all the fluids, hoses, wires, etc... tomorrow i hope to drop the drivetrain...
Yes...Sunset is in Oregon....a great guy to deal with for the Porsche stuff is Jeff Clark....he puts it together and if he can save you some money he will speak up and offer a suggestion. I buy almost all my parts from them. You can contact him directly at
[email removed]
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Maybe I missed it, but did you determine what was actually wrong with the engine? It sounds like you had a misfire and then decided you need a new engine. Was there some diagnosis between those points that led you to this conclusion? If not, I'm with Doug. Perform a leakdown test and try to get some answers before you shell out for a reman engine.
Hope it works for ya that's the main thing, but is the engine been rebuilt by them with receipts or did they just say that? Einmalig in cal has the same offer but in my opinion they just did not make me feel rosey like they just wanted to get rid of the engine with a sales pitch. Sounds like you are making good progress.
whew! new engine is in. minor setbacks like different wire harnesses and intakes set me back about a day. anyways the car won't crank. two ideas: first, something with the alarm, and second, starter isn't working.
i'm exhausted so i plan to test the starter tomorrow, but do these cars have any special tricks to the alarms? i closed everthing and locked the door with the key. then unlocked, opened the door, and turned the ignition. getting full power, just no crank.
Wow, I have no clue how to help I just wanted to let you know that what you did was impressive as hell.
When I was a kid my friend's Supra engine imploded. He ordered a new engine and we spent 14 hours ripping out the old one and installing the new block. Car wouldn't turn over.. next day we check and the timing belt was off... a quick adjustment and it fired right up.
Good luck dude!
okay, so now i have tested the starter. very wierd results:
works when out of the car, doesn't work when in the car.
it's getting power but doesn't move or make a noise. when i remove it and give it power it works. now i'm stumped... ideas???
Check your grounds and make sure everything is clean and well connected. I had the same problem on another car and it turned out that I just didn't tighten down the connection at the battery. Felt like a real dummy that day... Especially when you remove and replace an engine it's likely you missed a ground...
thanks for the compliments guys! i'm gonna start hunting down these cars with fried engines, i would love to get my hands on a 6spd for cheap.
i just noticed that since i bought this car in january, i've only put on 300 miles... just not a big fan of the tiptronics i guess...
Why was there issues with the wiring harness and intake? Was it the drive by wire or did you do something other than a direct swap?
By the way congrats on the DIY!
two reasons. wiring harnesses are different on tips and manuals. the motor they gave me came out of a manual and i have a tip. the intakes are different because porsche modified the 3.4 at some point. i had an early 3.4 and the engine i got was a later 3.4
good lookin out mother, i actually just bought a 6spd cabrio today with a ****ty motor. talk about putting your money where your mouth is, right? (see previous posts, lol) anyways, i hope to get it running by monday....
it's white, navy top, navy int (almost black), stick, clear corners all around, 80k miles on the clock, and pretty cherry aside from some front bumper scuffs.
gonna pop in a zero mile reman motor and new sachs clutch kit this week. hopefully it all turns out well and i can finally dump my tiptronic (ugh!)
Sounds like good find with great timing and you are right your Karma is working. I am looking for a rebuilt engine for mine right now, if you could please PM me when you hammer out a price, maybe I can use this as leverage with my dealer on getting best price so far $8200 is lowest I have seen. Have fun.
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