More D-Jet stuff
I have been having an intermittent Gremlin that has been driving me nuts, a "sputter" or "miss" under acceleration at 1500-2000 RPM's ever since I rebuilt the AAV and sealed the air leaks with new hoses, I am waiting on The PerTronix ignition, but...sometimes it seemed to run perfectly, even after warming up, then when I "hit it" hard I heard/felt it dramatically, and getting on the freeway taking it up to 70 i would feel it, but very subtle, driving around twon < 45MPH and driving it easy the problem doesn't "manifest"
I noticed it seemed to drive better when I had the air cleaner off and once I put the air filter on and forgot to hook up Temp Sensor 1, and the "improvement" seemed to carry over
Today I ran some tests, same temp, same route, "hit it HARD" on the same freeway onramp, and with Temp Sensor 1 connected, I got sputter, without it runs like a dream
Temperature Sensor I
Temperature Sensor I is an ambient air temperature sensor.As the ambient air temperature decreases,the density of the air increases.As a result,the ECU must inject more fuel on a cold day than on a warm day.
Temperature Sensor I is a temperature sensitive resistor known as negative temperature coefficient thermistor (NTC). This sensor has a resistance of between 400 and 500 ohms at 50 degrees F. At 100 degrees F.,the resistance is between 150 to 200 ohms.
Temperature Sensor I actually has little effect on the operation on most D Jetronic equipped vehicles.This is because most of these cars have tens of thousands of miles on the engine and are running very rich due to this wear.The troubleshooting consequence of this is that disconnecting the air temperature sensor during the diagnostic procedure may have little effect on the way the engine runs,and in some cases it may actually improve the way it runs.
I am interested in what this means, am I running too rich? too lean? lacking fuel pressure? I am lacking a CO2 meter and a Fuel Pressure sensor, I am going to have to knuckle under and start getting these and better tools, but off the top of their head, anyone have any ideas about why this should be so? it was probably 65F when I ran "the tests" I will also try at a -HOT- ambient temp day, but somewhere in this is the reason this car has never liked hot days
The ECU screw was/is adjusted about 2/3rds to the "rich" side, there are too many variables to try to set this right now, as in I don't...until I get the other parts functioning perfectly I will be unable to really test this with any real accuracy, when I set it right in the middle (towards "lean") I don't know if the sputter was caused by this or this gremlin
it's something pretty subtle, because under "these" conditions it runs like a dream, but under "those" conditions it loses power and "misses" from 1500-2000 Rpm's, subtly when cruising, dramatically when punching it, I just don't know exactly the difference between "these" and "those" conditions, the running great bit seems to be early, as in on the way to the parts store, on the way home, ie when it gets "hotter" it seems to get worse, I've driven at night, runs great, seems to run very well, better in cooler conditions regardless of the engine coolant temp
I just can't seem to make the mental leap to figure out if I am running rich or lean, probably rich but then why the change? does it get too rich? why does disconnecting the temp sensor make it run better? why does it seem to run worse on warmer days and after being driven harder, what is it about "hot" that changes the mixture that causes the sputtering
initially my suspects were the trigger points and the dist points, but as time passes I am not so sure, I will know more after I install pertronix I guess but I hate throwing parts at it when the truth is I have more important things to be doing with my money, like my disposable income has some pretty important old debts to pay from a bankruptcy a few years ago
Build a man a fire and he will be warm for a night, set a man on fire and he will be warm for the rest of his life
Last edited by The Proctologist; 08-09-2011 at 11:52 AM.