RX-7 cold start problems
01-09-15, 03:01 PM
#1
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RX-7 cold start problems
First here is the car and all mods done to it:
1987 GXL
RB catback exhaust and headers
Hollowed out cat (bad idea because s4s need back pressure i know)
I did buy a presilencer to fix the back pressure problem but I am away from the car until the 25th
NGK plugs and wires
K&N filter
Coilovers (not like they could be the problem haha)
Rebuilt and flow tested injectors
Whenever its below 40F my car takes forever to start and sometimes it wont at all. It turns over afterburns and shoots flames once and awhile but wont start. Then if it does start you have to keep on the throttle for a few minutes or it will stall (im guessing its the TPS?). Im just confused on why it wont start, not really the idle at this point though. I have done a fuel pressure and volume test and they both where below spec. Do you think a good way to go is upgraded fuel pump? Also thinking about a FD alternator because my battery dies trying to start it, maybe when it runs the alternator will give it a better charge? What do you guys think?
1987 GXL
RB catback exhaust and headers
Hollowed out cat (bad idea because s4s need back pressure i know)
I did buy a presilencer to fix the back pressure problem but I am away from the car until the 25th
NGK plugs and wires
K&N filter
Coilovers (not like they could be the problem haha)
Rebuilt and flow tested injectors
Whenever its below 40F my car takes forever to start and sometimes it wont at all. It turns over afterburns and shoots flames once and awhile but wont start. Then if it does start you have to keep on the throttle for a few minutes or it will stall (im guessing its the TPS?). Im just confused on why it wont start, not really the idle at this point though. I have done a fuel pressure and volume test and they both where below spec. Do you think a good way to go is upgraded fuel pump? Also thinking about a FD alternator because my battery dies trying to start it, maybe when it runs the alternator will give it a better charge? What do you guys think?
01-10-15, 10:53 AM
#4
A Walbro would be for a turbo so it will be overkill for you NA engine thus an OEM replacement would suffice.
Your starting problem could be a function of a problematic water thermosensor. Pin 2I (Green/White wire) needs to read 2 to 3 volts w/key to on on a cold engine. The voltage eventually drops to .5 volts w/a fully warmed engine. The sensor helps the ECU gauge how much fuel is to be used when starting and running a cold engine as well as an engine which is warmer to begin with. Pin 3B (Black/Blue wire) also needs to read about 8 to 10 volts or so w/key to start. This pin tells the ECU that the engine is starting and the ECU then selects which fuel map to select from. W/o the proper signal at this pin the ECU will believe the engine is rather warm and use less fuel in an attempt to start the car as opposed to more fuel to help start a cold engine (cold engines require more fuel to start as compared to a warm engine).
Your starting problem could be a function of a problematic water thermosensor. Pin 2I (Green/White wire) needs to read 2 to 3 volts w/key to on on a cold engine. The voltage eventually drops to .5 volts w/a fully warmed engine. The sensor helps the ECU gauge how much fuel is to be used when starting and running a cold engine as well as an engine which is warmer to begin with. Pin 3B (Black/Blue wire) also needs to read about 8 to 10 volts or so w/key to start. This pin tells the ECU that the engine is starting and the ECU then selects which fuel map to select from. W/o the proper signal at this pin the ECU will believe the engine is rather warm and use less fuel in an attempt to start the car as opposed to more fuel to help start a cold engine (cold engines require more fuel to start as compared to a warm engine).
01-10-15, 11:40 AM
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A Walbro would be for a turbo so it will be overkill for you NA engine thus an OEM replacement would suffice. Your starting problem could be a function of a problematic water thermosensor. Pin 2I (Green/White wire) needs to read 2 to 3 volts w/key to on on a cold engine. The voltage eventually drops to .5 volts w/a fully warmed engine. The sensor helps the ECU gauge how much fuel is to be used when starting and running a cold engine as well as an engine which is warmer to begin with. Pin 3B (Black/Blue wire) also needs to read about 8 to 10 volts or so w/key to start. This pin tells the ECU that the engine is starting and the ECU then selects which fuel map to select from. W/o the proper signal at this pin the ECU will believe the engine is rather warm and use less fuel in an attempt to start the car as opposed to more fuel to help start a cold engine (cold engines require more fuel to start as compared to a warm engine).
01-10-15, 11:53 AM
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One last question. Since I can find a spec on LPH for the stock fuel pump, how much should I run? I see fuel pumps that put out alot of different numbers.
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