It may be time... sigh. A question on pricing a 99 996 Cab roller...
06-01-2018, 09:11 PM
#31
Rennlist Member
He did not replace the injectors, but did send them to have them flow checked for balance and spray pattern.. But the "TUNE' that he paid dearly for, may have caused the over-fueling condition on full throttle where the codes would not necessarily set. He did drive very aggressively, hitting above 165mph quite a few times...( on appropriate surface ofcourse). I did suggest installing a wideband 02 to monitor the A/F and to double check the "tune", but he was tapped out after the build, and clutch upgrade and suspension/tires ect....besides, having no software my self to change the tune, I would be of no help...
He put his trust in the dyno operator who sent the dyno info/ A/F data info to FVD tuner to have them adjust the tune...and still was over-fueling I guess..
He put his trust in the dyno operator who sent the dyno info/ A/F data info to FVD tuner to have them adjust the tune...and still was over-fueling I guess..
06-01-2018, 09:19 PM
#32
Rennlist Member
I'm a little confused here. Is the oil consumption a result of damaged cylinders from cylinder wash? Or, will it actually cause oil consumption from oil dilution due to overfueling? Or is this cause and result, with a small window to resolve the issue before the damage occurs?
If the bores are not properly cleaned or rings are damaged during installation (by not using a tapered sleeve ring compressor), either of these errors will result in the same symptoms which can lead to damage to the bores as well.
We send over tons of technical information to try to limit mistakes and have added more info in the last year, but if engine building was easy, everyone would be doing it.
The newest thing, other than injectors failing left and right, are that tons of intake and PCV components are plastic (aos vent tube and oil fill come to mind), any one of which can crack, causing a vacuum leak, which then leads the engine to running over-rich. Worse yet, it takes a really big leak to throw a CEL.
06-02-2018, 12:45 AM
#33
Former Vendor
I had to read all of that twice. Thanks a ton for the insights.
In thinking about it (and I’ll have to doublecheck later) I believe the injectors may have been cleaned and not replaced. That said, on what was a massive bill at the time, the difference between new injectors and cleaning the old couldn’t possibly have been more than a relative rounding difference ($100 or two, max?), so it doesn’t make a whole lot of sense not to have replaced them at the time. And I surely wasn’t asking about smaller costs as it went along. So very odd.
In thinking about it (and I’ll have to doublecheck later) I believe the injectors may have been cleaned and not replaced. That said, on what was a massive bill at the time, the difference between new injectors and cleaning the old couldn’t possibly have been more than a relative rounding difference ($100 or two, max?), so it doesn’t make a whole lot of sense not to have replaced them at the time. And I surely wasn’t asking about smaller costs as it went along. So very odd.
But... Guess how many of those engines died from a failing cylinder, then the new engine has issues on the same exact cylinder later? You guessed it. We have put this puzzle together a lot, 12 times in 2016 alone.
Your engine might be able to be saved... Its hard to say, but we’d like to try it.
06-02-2018, 12:56 PM
#34
Rennlist Member
Excellent. Thanks for the input Charles and FSI. BTW, my AOS tube was cracked from bank 2. No CEL, I only located it looking for the oil leak that it created. I couldn't find a single other post related to this corrugated tube cracking. Surely they're getting old enough to start failing. Mine was so brittle it cracked 20 times when I flexed it after removal. I think I'll smoke test my vac system soon for a piece of mind.
06-02-2018, 12:59 PM
#35
Rennlist Member
It's to the point I'm thinking of adding smoke testing when we do any pre-qual for an IMS job. We already bore scope to check for cylinder scoring and check fuel trims, but I'm pretty sure every car we have gotten in has had a cracked aos vent and oil fill tube.
The next thing will be wiring issues. We're seeing 99 and earlier harnesses getting brittle and failing. Soy based wire sheathing is designed to decompose.
The next thing will be wiring issues. We're seeing 99 and earlier harnesses getting brittle and failing. Soy based wire sheathing is designed to decompose.
06-02-2018, 01:40 PM
#36
Rennlist Member
I keep saying this, all rubber and plastic parts in these cars need to be changed sooner rather then later!
06-02-2018, 02:01 PM
#37
Former Vendor
Forums don’t hold all the secrets.. Just because a post can’t be found, doesn’t mean a problem doesn’t exist. We put together classes filled with content, and strive for this to all be original content “silver bullets”.
We’ve been instructing in these classes to change these AOS vent conduits since then.. Today most every one of these has been compromised... As soon as it is touched by human hands to do some other work on the engine, it will fail, if it hadn’t already.
When this tube leaks, the cracks can be small enough to leak air, but not oil.. The only way to diagnose this is with a manometer test, with simultaneous data collected from fuel trim values. A smoke test works in some cases, but oil located at a crack can seal that crack with the engine not running, and having no vacuum during the smoke test.
Wereplace these conduits with all of our builds, and have for over a decade. Sometimes you buy more than an engine, if you buy it from the right place.
We’ve been instructing in these classes to change these AOS vent conduits since then.. Today most every one of these has been compromised... As soon as it is touched by human hands to do some other work on the engine, it will fail, if it hadn’t already.
When this tube leaks, the cracks can be small enough to leak air, but not oil.. The only way to diagnose this is with a manometer test, with simultaneous data collected from fuel trim values. A smoke test works in some cases, but oil located at a crack can seal that crack with the engine not running, and having no vacuum during the smoke test.
Wereplace these conduits with all of our builds, and have for over a decade. Sometimes you buy more than an engine, if you buy it from the right place.
06-02-2018, 04:10 PM
#38
So much valuable info in this thread. Thanks to FSI and Charles for the insight. You may have saved an engine or two.
From what I'm gathering, a manometer reading and fuel trims would tell the story if you knew what to look for. Or maybe treat your injectors like wear items? 10 year life?
From what I'm gathering, a manometer reading and fuel trims would tell the story if you knew what to look for. Or maybe treat your injectors like wear items? 10 year life?
06-02-2018, 06:13 PM
#39
Rennlist Member
I agree^^
Wear life is a great question!
Wear life is a great question!
06-02-2018, 06:44 PM
#40
While I was reading this thread and appreciate all the knowledge sharing. I checked pelican and Bosch injector is 40 bucks while Porsche brand is 300... are they same or different?
06-02-2018, 06:46 PM
#41
Rennlist Member
That's a tough question. For years we thought it was sufficient to send the injectors out for testing and cleaning. After seeing injectors fail just into their service life after being tested, new injectors may be required, but they got pricey as of late too. Causes quite the dilemma when shops are rebuilding engines and they cut corners to meet the customers expectations for price for the job so as to not loose the job. There is a reason why Jake charges so much for his engines.
Probably the best thing to do is use Top Tier fuels with regular servicing with a product like Driven Injector Defender which has additives to prevent corrosion from ethanol, to lessen the likelihood that an injector fails. I use it every other tank of fuel. Cheap insurance.
Checking fuel trim values regularly as part of maintenance is probably not a bad idea to ensure the car isn't trying to enrich or lean out the mix, indicating there may be an issue somewhere that hasn't yet caused a CEL.
Probably the best thing to do is use Top Tier fuels with regular servicing with a product like Driven Injector Defender which has additives to prevent corrosion from ethanol, to lessen the likelihood that an injector fails. I use it every other tank of fuel. Cheap insurance.
Checking fuel trim values regularly as part of maintenance is probably not a bad idea to ensure the car isn't trying to enrich or lean out the mix, indicating there may be an issue somewhere that hasn't yet caused a CEL.
06-02-2018, 06:48 PM
#42
Rennlist Member
As long as the aftermarket injector is a genuine Bosch purchased from a reputable vendor, I'm fine with aftermarket. Don't go with off brands. But sometimes, Genuine is all that is available. We just had to get a set at the whopping $1800 for one customer.
06-02-2018, 08:13 PM
#43
Rennlist Member
Prices for injectors are all over the place..
Last edited by Porschetech3; 06-02-2018 at 08:31 PM.