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Ran the 89 951 on a Dyno this evening. This is after the head gasket was replaced while I was away in the sand box. The set up is as follows;

K27/6, Autothority MAF, Guru 18 PSI chips, FQS in the stock setting, Adjustable FPR (set to 36PSI), Inline pro MBC (one run at 14 psi and a second at 16 psi) plumbed up to a Tial 38mm wastegate running in single port mode, (cycling valve deleted), gutted cat, Lindsey hard pipe, 993 BOV. Lindsey vacum lines run everywhere I can find a vacum line. Autometer Boost gauge.

Something is causing it to run way rich. It was doing this same thing with the Autothority chips as well so I believe it is not a chip issue, and something else is causing this.

Run 1 at 14 PSI 255.83 HP, 257.57 TQ, AFR drops to less than 10 to 1 by 2700 RPM.

Run 2 at 16 PSI 266.31 HP, 269.99 TQ, AFR drops to less than 10 to 1 by 2800 RPM.

Suggestions on where to start looking?

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hally

Are your chips AFM chips or custom built for your authority MAF setup?
Rich == not enough air (leak after metering) or too much fuel (FPR problems?)

black944 turbo

Leak after metering would cause lean wouldn't it? Because it would be sucking more air than it thinks. I know when my J-boot was torn it ran realy lean. Check for vacum leaks and as stated FPR.

hally

fair point could go either way depending on vacuum / boost leak scenario
leak under boost -> richer, leak under vacuum -> leaner.

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Chips are for the K27 / Autothority MAF set up.

So if it is a boost leak that would mean that the MAF is metering X amount of air, and that it is somehow not getting all of X amount of air to the intake? HUMMMMM The boost gauge shows that the system is holding the boost that is being prduced. Also the boost is steady.

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sweanders

Could it be that you will get closer to target with higher boost? It looks this way from the 14 and 16 psi runs. Maybe you could do a 15, 17 and 18 psi run as well and see the trend?

Ski

FQS set to zero you mean? If the trend continues and you don't want to buy a piggyback, you might email John at Vitesse Racing about his DME chipboard, I think he has a program on file for your very mods, with great hp/torque and A/F results.

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Sweanders The Dyno guy and I discused the idea of simply adding more boost but the second run mimicked the first so the conclusion was reached that something is wrong causing the HUGE fuel dump.

Ski FQS is set to zero or all the way counter clockwise. A piggy back is the next step and I am leaning in the direction of the MAFTERBURNER / UEGO from Lindsey. However, I still believe something is wrong. I am going to try the carberator cleaner sparyed on various componets in an attempt to find this leak if it is a leak

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fast951

Which injectors are you running?

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The injectors are the stock injectors as far as I know. It would not surprise me if the PO put something else in and did not tell me. How would one tell by simply looking at them?

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fast951

All injectors have a brand name and part # on them. You might be able to read this info while the injectors are on the car, but you may need to remove the rail.

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I could not see a brand name on these but they are green in color and the following numbers are clearly visible.

845
0280150803

Are these stock or something else?

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by the way is it typical of the K-27/6 to have the HP and TQ curves so close together?

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Ok it does not seem to be any kind of a leak while the sytem is in vacum which leads creedance to the leak under boost theroy. Any ideas on how to hunt for something like that?

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sweanders

A good place to be when diagnosing boost leaks is at the dyno. You will most likely get a "whoosh" sound where there is a boost leak. On most cars I've seen with a boost leak it has been at the right side intercooler pipe connection. Often it holds boost until 12 psi or so and leaks over that.

fast951

Could it be that the chip is mapped incorrectly and there is nothing wrong with the car? Put the chip that came with the MAF, comapre the results.