Rich mix = chip to fix?
#1
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I have been fixing up my 83' 944.
Testing it out with a friend who is a "ricer" performance mechanic, he told me that I was running with a rich mix. His diagnostic came form the following symptom: When I had the car on idle for a while and then reved it up, a cloud of black smoke came out. Also my oil tends to be jet black.
He recomended to chip the car, even though he knows this will do little to the car's HP.
My questions are:
1) Is there some other way to fix the mix problem?
2) Is there a chip mod for 83' 944 since they do not use a chip but use a DME system?
3) Could it me some other problem?
Testing it out with a friend who is a "ricer" performance mechanic, he told me that I was running with a rich mix. His diagnostic came form the following symptom: When I had the car on idle for a while and then reved it up, a cloud of black smoke came out. Also my oil tends to be jet black.
He recomended to chip the car, even though he knows this will do little to the car's HP.
My questions are:
1) Is there some other way to fix the mix problem?
2) Is there a chip mod for 83' 944 since they do not use a chip but use a DME system?
3) Could it me some other problem?
#2
Three Wheelin'
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If you need to adjust your air to fuel ratio then you can find help at the bottom of this page http://www.connact.com/~kgross/FAQ/944faq12.html
"There is a provision on the Motronic cars (944 and 911) to make small adjustments to the fuel mixture (injection pulsewidth) and the ignition timing in order to compensate for the quality of fuel available in your particular country or region.
There is an board-mounted eight-position rotary switch accessed through the little hole in the back side of the DME box. These adjustments can be made without opening the cover of the DME box"
But I suggest you seek a qualified opinion before adjusting.
"There is a provision on the Motronic cars (944 and 911) to make small adjustments to the fuel mixture (injection pulsewidth) and the ignition timing in order to compensate for the quality of fuel available in your particular country or region.
There is an board-mounted eight-position rotary switch accessed through the little hole in the back side of the DME box. These adjustments can be made without opening the cover of the DME box"
But I suggest you seek a qualified opinion before adjusting.
#3
Race Director
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I doubt the +3.1 or +6.3% adjustments available on the FQS is enough to send the fuel necessary for a black sooty exhaust. Most likely, it's an AFM-calibrationn issue or FPR/dampener problem. I've found quite a few AFMs that have been tinkered/adjusted/messed-with by previous-owners who changed the spring-preload to increase fuel in the mistaken assumption that more fuel equals more power! HAH! Anyone been around tuning long enough to remember the saying from the '60s???
Also DO NOT use the FQS table on the 944-FAQ, it's for a 911 and you'll end up with adjustments that will DESTROY YOUR ENGINE!!!. Instead, use the FQS-table on my 951 RacerX website or FR Wilk's site; they are the correct ones for the early & late 944NAs.
Also DO NOT use the FQS table on the 944-FAQ, it's for a 911 and you'll end up with adjustments that will DESTROY YOUR ENGINE!!!. Instead, use the FQS-table on my 951 RacerX website or FR Wilk's site; they are the correct ones for the early & late 944NAs.
#4
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IIRC, chipping an '83 requires de-soldering the chip and soldering in a new one. Not something to do on a whim. And if the problem is a failing FPR, it may not even fix the problem.
You need to check the fuel pressure. If its high, replace the FPR. Costs about $50 and takes about an hour. Its a good time to reseal the fuel injectors, too. Or just replace the FPR without a test. its a realtively cheap repair. Other signs of a failed FPR are stumble on acceleration and poor idle. Eventually, you won't be able to start the car if it fails completely. And you'll have so much gas in the oil that you will have to change the oil.
Good luck.
You need to check the fuel pressure. If its high, replace the FPR. Costs about $50 and takes about an hour. Its a good time to reseal the fuel injectors, too. Or just replace the FPR without a test. its a realtively cheap repair. Other signs of a failed FPR are stumble on acceleration and poor idle. Eventually, you won't be able to start the car if it fails completely. And you'll have so much gas in the oil that you will have to change the oil.
Good luck.
#7
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I'll second the FPR. My 83 was leaving a little soot under the bumper and replacing the FPR (Bosch 0.280.160.293) did away with that.
Along with replacing the O2 sensor (cheap $25 Bosch 11027 single wire on these cars), the spark plugs with Bosch coppers, and the fuel filter, my fuel economy has also improved considerably.
On the FRWilk site that Danno mentioned, is an explanation of the "detuned" stock chip that the factory fitted on U.S. spec cars with lower compression engines. Since the early DME requires soldering to change out the chip, FRWilk had a deal going for a while where you'd send him the DME and he'd do it for around $150.
Several people in the E-Mail lists did this, and were quite pleased (including Scott H. (Sh944), but the fuel economy worsens somewhat. Not sure how much a chip can make up for lower compression pistons, etc. so I would pass on messing with the chip at all and go for the classic "tune up" items (see above) first. YMMV.
Along with replacing the O2 sensor (cheap $25 Bosch 11027 single wire on these cars), the spark plugs with Bosch coppers, and the fuel filter, my fuel economy has also improved considerably.
On the FRWilk site that Danno mentioned, is an explanation of the "detuned" stock chip that the factory fitted on U.S. spec cars with lower compression engines. Since the early DME requires soldering to change out the chip, FRWilk had a deal going for a while where you'd send him the DME and he'd do it for around $150.
Several people in the E-Mail lists did this, and were quite pleased (including Scott H. (Sh944), but the fuel economy worsens somewhat. Not sure how much a chip can make up for lower compression pistons, etc. so I would pass on messing with the chip at all and go for the classic "tune up" items (see above) first. YMMV.
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#8
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If your "ricer mechanic" doesnt know that the DME has a chip WTF is he doing messing with the car. As others have said it requires resolder on the early cars. Sounds more likely that there is a mechanical problem however.
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