5sfe 5th injector?

David · 10-31-2009, 04:49 PM

So my dad was working on his MR2 and he's been fixing a lot of things, because ever since he got the head fixed, a whole lot of other things started going wrong and it's been running pretty rough. But it's started improving a lot. Just the other day he told me there was a 5th fuel injector that goes to the intake manifold. It doesn't have any power at idle, and he thinks it's bad, but first he wants to know when exactly it's supposed to kick in. More specifically, at what RPM range is it supposed to work? Any help is appreciated.

David · 10-31-2009, 04:51 PM

By the way it's an autotragic if it makes a difference.

mr2_mk1.5 · 10-31-2009, 08:22 PM

the 5th injector that you are refering two is the cold start injector, if you look at the fuel rail there is a bolt with a banjo fitting there, trace the hose up and there is the cold start injector. the positive side of the injector is run through the coolant time switch and only applies power when the engine is below I think 80 degrees C. the ground is fed through the ecm and its only purpose is to feed a shot of fuel if the engine is cold when its cranking. To test the injector simply unbolt it from the intake and place it in a cantainer leaving the fuel line connected then jump the B+ and FP terminals in the test connecter and see if its leaking. The permissible leak rate is no more then 3 drops per minute. There is no need to check everything else if it starts fine but if it doesn't check the time switch(2 wire connecter on the water return neck I believe the connector is black) just check for resistence when its cold and no resistence when its warm, also check the resistence of the cold start injector it should be 2-3ohms

David · 11-01-2009, 12:41 PM

Thanks sooo much.

Sh0ty · 11-03-2009, 11:11 PM

Fun fact: Some JDM Toyota engines lack a cold start injector, such as a 3VZ-FE

10-31-2009, 04:49 PM	#1 (permalink)
David Banned Join Date: Jun 2007 Location: Tampa, Fl Posts: 2,621 Thanks: 120 Thanked 55 Times in 54 Posts My Google Map iTrader Rating: (4/100% )	5sfe 5th injector? So my dad was working on his MR2 and he's been fixing a lot of things, because ever since he got the head fixed, a whole lot of other things started going wrong and it's been running pretty rough. But it's started improving a lot. Just the other day he told me there was a 5th fuel injector that goes to the intake manifold. It doesn't have any power at idle, and he thinks it's bad, but first he wants to know when exactly it's supposed to kick in. More specifically, at what RPM range is it supposed to work? Any help is appreciated.

Thread Tools
Show Printable Version Email this Page
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode

10-31-2009, 04:51 PM	#2 (permalink)
David Banned Join Date: Jun 2007 Location: Tampa, Fl Posts: 2,621 Thanks: 120 Thanked 55 Times in 54 Posts My Google Map iTrader Rating: (4/100% )	By the way it's an autotragic if it makes a difference.

10-31-2009, 08:22 PM	#3 (permalink)
mr2_mk1.5 Cage Fighter Join Date: May 2009 Location: Regina, Saskatchewan Canada Posts: 165 Thanks: 0 Thanked 10 Times in 9 Posts iTrader Rating: (1/100% )	the 5th injector that you are refering two is the cold start injector, if you look at the fuel rail there is a bolt with a banjo fitting there, trace the hose up and there is the cold start injector. the positive side of the injector is run through the coolant time switch and only applies power when the engine is below I think 80 degrees C. the ground is fed through the ecm and its only purpose is to feed a shot of fuel if the engine is cold when its cranking. To test the injector simply unbolt it from the intake and place it in a cantainer leaving the fuel line connected then jump the B+ and FP terminals in the test connecter and see if its leaking. The permissible leak rate is no more then 3 drops per minute. There is no need to check everything else if it starts fine but if it doesn't check the time switch(2 wire connecter on the water return neck I believe the connector is black) just check for resistence when its cold and no resistence when its warm, also check the resistence of the cold start injector it should be 2-3ohms

11-01-2009, 12:41 PM	#4 (permalink)
David Banned Join Date: Jun 2007 Location: Tampa, Fl Posts: 2,621 Thanks: 120 Thanked 55 Times in 54 Posts My Google Map iTrader Rating: (4/100% )	Thanks sooo much.

11-03-2009, 11:11 PM	#5 (permalink)
Sh0ty Armchair Racer Join Date: Aug 2008 Location: Novi, MI Posts: 1,273 Thanks: 22 Thanked 57 Times in 54 Posts My Google Map iTrader Rating: (3/100% )	Fun fact: Some JDM Toyota engines lack a cold start injector, such as a 3VZ-FE