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 10 Severe lack of power (for 15 minutes after start) (Read 7444 times)
Dave W
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Re: Severe lack of power (for 15 minutes after start)
Reply #15 - Jan 8th, 2019 at 5:36pm
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One common vacuum leak that is very difficult to see or detect is the bottom of the first rib of the J-boot.  At idle, the crack may be sealed but any engine movement will open it up.
  

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Re: Severe lack of power (for 15 minutes after start)
Reply #16 - Jan 8th, 2019 at 9:41pm
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I looked for that with the j boot removed, definitely no cracks.

I have been burning tons of oil for years.  Could the catalytic converter be clogged with oil residue?  Maybe that’s why it clears up when I drive it on the highway.
  
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Dave W
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Re: Severe lack of power (for 15 minutes after start)
Reply #17 - Jan 8th, 2019 at 10:58pm
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that's easy enough to test.  loud but easy.  just disconnect the pipe and run it.

I have heard of people "washing" their cats to try to get the oil out of them.  I don't know how successful that is if you don't also address the oil issue.
  

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Re: Severe lack of power (for 15 minutes after start)
Reply #18 - Jan 9th, 2019 at 8:59pm
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I'm certainly not an expert on this topic, but after going through my throttle body recently and the TPS, seems like that could be a possibility.  The butterfly on my throttle body was NOT opening and closing smoothly especially the first little bit of movement.  The TPS has wiggle room to adjust and the throttle body itself has two places to adjust the butterfly/air mixture..... just a thought.  Seems like the issues end-up being something pretty simple once they're discovered and corrected.  Good luck.  KB
  

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Re: Severe lack of power (for 15 minutes after start)
Reply #19 - May 24th, 2019 at 9:22pm
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So I sent it in about a month ago.  They flow tested the exhaust, catalytic converter isn't clogged.  They checked all the sensors were reading correctly, and cleaned the grounds.  The throttle body opens smoothly.  They suggested I send the ECU back, Specialized ECU bench tested it, and said it was good. I think that covers every idea I've had so far.

My garage is good they specialize in European cars.  They said the next thing to do is check the entire wiring loom and sensor cables for corrosion and possible shorts.  It's a big job they have to take off the intake manifold, but I did repair some cracked wires behind the speed/ref sensor last year so there could be more.

It's so weird because when I repaired those wires it ran great for like 3 months and then the problem reappeared in the exact same way.
  
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Dave W
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Re: Severe lack of power (for 15 minutes after start)
Reply #20 - May 28th, 2019 at 5:48pm
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You could try putting in new orings for the AOS.  That might be the oil issue.  Leaky seals there will cause oil in the throttle body as well as a vacuum leak.
  

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OhioTom
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Re: Severe lack of power (for 15 minutes after start)
Reply #21 - May 29th, 2019 at 8:20pm
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So, when you play and touch things, it works for a while, then falls back into poor running eventually.

That really sounds like a bad connnection somwhere.
you touch or wiggle it and it's good for a while.
Given time, it corrodes and degrades giving bad readings.

Things that can be affected by poor connections:
Temp sensor(s).
TPS (throttle position switch)
AFM


I would install a fuel pressure gage (even if only temporary) to ensure fuel pressure is correct under all driving conditions.

After that, I would do as your mechanic recommended and inspect every connnection for the: TPS, AFM, and temp sensors.
These are all low voltage, analog sensors that can be thrown off calibration by a failing connections.
  

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Re: Severe lack of power (for 15 minutes after start)
Reply #22 - May 29th, 2019 at 8:22pm
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You could also try this:
Play with the wires to the temp sensor, then drive it. See if it changes how it runs.
Do the same for each sensor I have listed above.... one at a time to see if it affects how the car runs.
If you suddenly fix the problem by wiggling something, you can find it real fast like.

  

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Re: Severe lack of power (for 15 minutes after start)
Reply #23 - May 30th, 2019 at 4:16pm
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I have been burning tons of oil for years.

Lots of good suggestions mentioned already. I have to say that I would be really concerned if the car is burning lots of oil for years!

That's a major problem Angry
  

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Re: Severe lack of power (for 15 minutes after start)
Reply #24 - Oct 30th, 2019 at 4:01am
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After reading all the good ideas and testing along with repair and fundamental reports from idle to power reviews you have loose wiring or unstable plugs at the connectors.

Like you mentioned the G5 DME relay electrics box and the DME under warranty. The experience indicates not necessarily distributor but possible terminal 85b and 87 at relay which is the voltage regulator to the DME.

That would break or destroy the firing sequence for the injectors based on the transistor pulse and the coil would disrupt the spark. Have you thought about voltage regulator change out in the alternator? and the DME relay you mentioned might be a solution . If not then the plugs at the wiring harness for engine and the DME male and female plugs matching and inspection?

It just so happens temperature extremes in differential compromise semiconductor transistors . Therefore the initial post describing the sitting in the snow ( adding ice) includingla lake effect wind traveling in close proximity to metal conduction might have caused failure of transistor substrates in the DME and the P-N junctions in other semi conductor materials.

Most outright failures are centered on throttle body AFM. The next leading probability is ECU or DME for intermittent failures based on CMOS components.

Statistical papers land on failure not intermittently determinations that is customarily why replacement of DME and G5 relay lead the compromised 944 intermittent failures. That prognosis lands squarely on MTTF mean time to failure and FIT failure in time. That is why they are so easily replaced and have market value.

However it is the failure of the transistors that have the 114 year testing prediction from Bell Labs and the electronic industry.

Long 2 years experts inside and out the normal repair cycle. Congrats on being a good listener to you dyno folks. The 3rd thing might be lifting of ribbon trace due to temperature.

Supportive is Temperature operating life file attached. The lower temp limits is based on ionization or electro volt energy combination. Without knowing the PN junction and without verifiable chip testing it is impossible to predict failure rates. The idea is in stringent testing and highly intrumented hot wire  anemometer temperatures signal arrays is the only way to resolve failure rates it is based on space program travel only.
MIL-STD-883E. Real to public 1996 and MIL-HDBK-217
« Last Edit: Nov 1st, 2019 at 1:25pm by anchor »  

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