3800SC SERIES 3 QUESTION (Page 1/4)
Lou6t4gto JAN 05, 01:21 PM
on a 2005 series 3 3800SC, WHAT is it that "controls" the "INITIAL" amount of "extra FUEL" supplied to "Start the engine" ? (a 2.8 has a cold start switch and inj supplying More fuel for a quick start) I know that was done away with), but WHAT is the "Operation" that "took over" that job on the newer engines?? *HOW does it work* ? Please explain. If I "understand" exactly WHAT is "supposed to happen", I can probably fix the problem. Thank you
Dennis LaGrua JAN 05, 06:48 PM
In the start cycle the PCM lengthens the pulse width of the signals to the injectors. That provides the engine with more fuel to start. The inputs from other sensor values all influence open and closed loop operation.
Lou6t4gto JAN 05, 11:39 PM
can't figure WHY I'm getting No fuel to "initially start", Runs fine After it's started. doesn't matter hot or cold, (either way needs a shot of quick start to get going.)
Dennis LaGrua JAN 06, 04:23 PM

quote
Originally posted by Lou6t4gto:

can't figure WHY I'm getting No fuel to "initially start", Runs fine After it's started. doesn't matter hot or cold, (either way needs a shot of quick start to get going.)



If the injectors were getting no fuel then how did the engine start? I guess your assuming that only the starting fluid provided the juice. That's very unlikely. What reading is the IAT sensor putting out?

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" THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite.
"THE COLUSSUS"
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H
" ON THE LOOSE WITHOUT THE JUICE "

Lou6t4gto JAN 06, 06:33 PM
that is something else ! whoever built this harness left NO pigtail plug for a Idle Air temp sensor !!!
Lou6t4gto JAN 06, 06:37 PM
this harness DOES Have 2 plugs that Look like the "Coolant TEMP Plug" , a 3 wire plug). the IAT plug on the "others" looks like a" 3 in a row" plug. "owner "thought" the Second Plug was for the AC inline "Pressure switch", but it won't fit that either.
olejoedad JAN 06, 08:20 PM
There is no sensor called 'Idle Air Temp'.

The 'Inlet Air Temp' is part of the MAF - if it is a 5 wire plug.
If it is a 3 wire MAF like stock 3800 SC series 2, then the Inlet Air Temp sensor is two wire and located in the ducting between the air cleaner and the MAF.
olejoedad JAN 06, 08:24 PM
The three wire plug may be for the Throttle Position Sensor.
Lou6t4gto JAN 06, 10:31 PM
ok so it IS a 5 wire MAF plug, ( 2 wires with 5 volts, none with 12), so no iat sensor. the tps is connected and working.
olejoedad JAN 07, 12:06 AM
You need 12v on one wire of the MAF sensor, as I stated in the other thread you started about this same problem.