Tip In Stumbling problems - Porsche Forum - Porsche Enthusiast Forums


Porsche 944 The Porsche 944 and 944 Turbo was a huge success for Porsche throughout the 1980s.

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Old 03-05-2005, 09:45 PM
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Default Tip In Stumbling problems

First post, hope I can get some quality info. I just pruchased a bone stock 80k 86 951. Purchased all new vac lines and conversion kit from lindsey. I installed boost and a/f ratio guage as well as new 3" exhaust and wastegate. After installing my autoauthority stage II chips, I noticed that under full throttle situations the car falls on its face. I haven't been able to figure it out yet any ideas? Is it the chips? Thanks in advance.
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Old 03-07-2005, 03:24 PM
 
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Default RE: Tip In Stumbling problems

Can you give us a better description of what "falls flat on its face" means? Does the car just not feel as powerful as you think it should, or does the boost cut out all together?

As far as your chips go, Authothority chips are known to run rich, and they have to have the banjo bolt restrictor to function properly. They make two versions of the chips, one for a stock car and one with the Autothority MAF, so make sure you have the right ones. Regardless of which Autothority chips you have, there are MUCH better chips available from Vitesse that will smoke your chips, make a lot more torque and hp and make the car run smoother.

Give us more info, and we'll get you sorted out!

Regards,
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Old 03-07-2005, 05:28 PM
ZOD ZOD is offline
 
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Default RE: Tip In Stumbling problems

It is hard to tell what your problem is from your post. Maybe the turbo is fine but the engine is running lean. try unplugging the O2 sensor and see if the car runs better. I had a similar problem and a new O2 sensor fixed it. There is a dial inside the DME that advances and retards the timing a little as well as makes the mix a little bit more lean or rich. You might need to poke out a little metal tab to get to it without opening up the DME box. It can be adjusted with a small screwdriver.

position 1 | stock mix | stock timing
position 2 | +3% | stock timing
position 3 | +6% | stock timing
position 4 | -3% | stock timing
position 5 | +3% | -3 degrees
position 6 | +6% | -3 degrees
position 7 | -3% | -3 degrees

Can you give a more detailed description of the problem?
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Old 03-07-2005, 05:37 PM
 
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Default RE: Tip In Stumbling problems

If you are going to adjust the FQS switch on the DME, do yourself a favor and make a triangle shape tipped tool to use to adjust it. Its very easy to make a tool for it by either grinding or filing either a small metal screwdriver or a wood or plastic golf tee, and it keeps you from screwing the thing up. I have seen a few too many DME's with FQS switches that were screwed up by folks jamming whatever they had onhand in it to turn the thing...

The Autothority chips don't require a FQS switch adjustment, so I doubt thats the problem. The FQS switch was originally used to compensate for gas quality in various regions around the world (and not regions within the US, any stock US car should have its FQS set at the "0" position).

Regards,
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Old 03-07-2005, 07:18 PM
ZOD ZOD is offline
 
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Default RE: Tip In Stumbling problems

By all means, never jam anything into your DME. I have a set of very small screwdrivers one of which fits into the rotary switch. Static protection is also a good idea if your going to open up the DME.
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Old 03-12-2005, 11:11 PM
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Default RE: Tip In Stumbling problems

Thanks for your replies. The car actually seems like it cuts fuel completely. A/F guage goes completely dark. I'm going to replace a cracked connector hose on the cool side of the ic and install a fuel pressure guage this week. I don't really want to but i may go back to stock chips to see if this helps. Any other ideas?
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Old 03-13-2005, 10:57 AM
 
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Default RE: Tip In Stumbling problems

Change that intercooler hose first, a vacuum leak under boost could describ what you are experiencing. Keep up posted.

Regards,
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