Ωhm Posted May 4, 2020 Share Posted May 4, 2020 On 5/4/2020 at 11:03 PM, eaglescout526 said: I wonder what T3 shows at the ECU connector? Expand When ECU wants fuel pump relay ON, T3 will switch to ground. Internal to the ECU. Link to comment Share on other sites More sharing options...
eaglescout526 Posted May 5, 2020 Share Posted May 5, 2020 Ok that eliminates the fusible link being blown. Could pin 86 be tested on the FP relay during crank to see if the ignition switch is sending voltage to energize the relay? Thanks Ohm! Link to comment Share on other sites More sharing options...
SoCalManche Posted May 5, 2020 Author Share Posted May 5, 2020 On 5/5/2020 at 12:01 AM, eaglescout526 said: Ok that eliminates the fusible link being blown. Could pin 86 be tested on the FP relay during crank to see if the ignition switch is sending voltage to energize the relay? Thanks Ohm! Expand I'm assuming that question was for Ohm, lol. Link to comment Share on other sites More sharing options...
Ωhm Posted May 5, 2020 Share Posted May 5, 2020 Fuel pump relay block (86) is HOT with KEY ON or engine CRANKING. Link to comment Share on other sites More sharing options...
Ωhm Posted May 5, 2020 Share Posted May 5, 2020 Remove FP relay. Check FP relay block (86) for battery voltage with KEY ON. Same circuit as D1-2. Link to comment Share on other sites More sharing options...
eaglescout526 Posted May 5, 2020 Share Posted May 5, 2020 On 5/5/2020 at 12:10 AM, SoCalManche said: I'm assuming that question was for Ohm, lol. Expand Both of ya but mostly you. But lets do see what our voltage looks like where Ohm said. Link to comment Share on other sites More sharing options...
SoCalManche Posted May 5, 2020 Author Share Posted May 5, 2020 On 5/5/2020 at 12:17 AM, eaglescout526 said: Both of ya but mostly you. But lets do see what our voltage looks like where Ohm said. Expand On 5/5/2020 at 12:14 AM, Ωhm said: Remove FP relay. Check FP relay block (86) for battery voltage with KEY ON. Same circuit as D1-2. Expand D1_2 and FPR Pin 86 are not battery voltage. They are ~12.05V. Link to comment Share on other sites More sharing options...
eaglescout526 Posted May 5, 2020 Share Posted May 5, 2020 So both are getting power to them? So then it should be energizing the relay for the fuel pump. Link to comment Share on other sites More sharing options...
SoCalManche Posted May 5, 2020 Author Share Posted May 5, 2020 On 5/5/2020 at 12:21 AM, eaglescout526 said: So both are getting power to them? So then it should be energizing the relay for the fuel pump. Expand Unicorn. This is why I try to stay away from electrical. Ha Yes, I have power to both. I also do not understand why this is an issue still. Link to comment Share on other sites More sharing options...
Ωhm Posted May 5, 2020 Share Posted May 5, 2020 On 5/5/2020 at 12:18 AM, SoCalManche said: D1_2 and FPR Pin 86 are not battery voltage. They are ~12.05V. Expand That's close enough. Need to take two (2) voltage drops. Connect DVOM as follows: Battery terminal plus (+) and D1_2. CRANK engine and take reading. Battery terminal plus (+) and D1_6. CRANK engine and take reading. Both readings should show 0vdc. Link to comment Share on other sites More sharing options...
SoCalManche Posted May 5, 2020 Author Share Posted May 5, 2020 On 5/5/2020 at 12:34 AM, Ωhm said: That's close enough. Need to take two (2) voltage drops. Connect DVOM as follows: Battery terminal plus (+) and D1_2. CRANK engine and take reading. Battery terminal plus (+) and D1_6. CRANK engine and take reading. Both readings should show 0vdc. Expand D1_2 + Batt Pos = ~0.4V during crank. D1_6 + Batt Pos = ~9V during crank. Edit: With Fuel Pump Relay installed. Link to comment Share on other sites More sharing options...
Ωhm Posted May 5, 2020 Share Posted May 5, 2020 On 5/5/2020 at 12:46 AM, SoCalManche said: D1_6 + Batt Pos = ~9V during crank. Expand Try this voltage drop again. This time remove FP relay and install jumper wire (30-87). Link to comment Share on other sites More sharing options...
SoCalManche Posted May 5, 2020 Author Share Posted May 5, 2020 On 5/5/2020 at 12:50 AM, Ωhm said: Try this voltage drop again. This time remove FP relay and install jumper wire. Expand With jumper wire installed: D1_2 + Batt Pos = ~0.3V. That was the initial readout, but it continued to descend as I continued to crank. D1_6 + Batt Pos = 0.231V. This voltage was maintained regardless of crank or not. Link to comment Share on other sites More sharing options...
Ωhm Posted May 5, 2020 Share Posted May 5, 2020 Pass on both VD test. Good readings. Link to comment Share on other sites More sharing options...
SoCalManche Posted May 5, 2020 Author Share Posted May 5, 2020 On 5/5/2020 at 12:59 AM, Ωhm said: Pass on both VD test. Good readings. Expand Well I suppose that is good and bad. Glad it's a good readout, but continues confusion to the underlying problem. Link to comment Share on other sites More sharing options...
SoCalManche Posted May 5, 2020 Author Share Posted May 5, 2020 On 5/5/2020 at 12:21 AM, eaglescout526 said: So both are getting power to them? So then it should be energizing the relay for the fuel pump. Expand Also, here is the fuel pressure test kit I rented. I wouldn't recommend getting it since it's $150 for one piece to fit, but here it is, haha. Link to comment Share on other sites More sharing options...
eaglescout526 Posted May 5, 2020 Share Posted May 5, 2020 On 5/5/2020 at 1:24 AM, SoCalManche said: Also, here is the fuel pressure test kit I rented. I wouldn't recommend getting it since it's $150 for one piece to fit, but here it is, haha. Expand All I needed was something to go off of. Thanks. So with the relay installed do you see pressure on the fuel rail? Link to comment Share on other sites More sharing options...
SoCalManche Posted May 5, 2020 Author Share Posted May 5, 2020 On 5/5/2020 at 1:26 AM, eaglescout526 said: All I needed was something to go off of. Thanks. So with the relay installed do you see pressure on the fuel rail? Expand No pressure at TBI with fuel relay in circuit, key ON. I also swapped a different relay in to verify, and no fuel pressure, both times. I also just picked up a noid light set to verify pulse on the injector harness, and it does light up when i switch key to ON, as well as crank. Link to comment Share on other sites More sharing options...
eaglescout526 Posted May 5, 2020 Share Posted May 5, 2020 WTF! Its like everything checks out. So I wonder what voltage is getting to T6(if any goes there) at the ECU connector, perhaps a voltage signal is not going to the relay to energize it. Link to comment Share on other sites More sharing options...
SoCalManche Posted May 5, 2020 Author Share Posted May 5, 2020 On 5/5/2020 at 1:52 AM, eaglescout526 said: WTF! Its like everything checks out. So I wonder what voltage is getting to T6(if any goes there) at the ECU connector, perhaps a voltage signal is not going to the relay to energize it. Expand I need to just take out a loan to do a 4BT swap, lol. Link to comment Share on other sites More sharing options...
Ωhm Posted May 5, 2020 Share Posted May 5, 2020 On 5/4/2020 at 11:57 PM, Ωhm said: When ECU wants fuel pump relay ON, T3 will switch to ground. Internal to the ECU. Expand My mistake, NOT T3, but T6. T3 would have IGN SW voltage on it. On 5/5/2020 at 1:52 AM, eaglescout526 said: So I wonder what voltage is getting to T6(if any goes there) at the ECU connector, perhaps a voltage signal is not going to the relay to energize it. Expand Link to comment Share on other sites More sharing options...
SoCalManche Posted May 5, 2020 Author Share Posted May 5, 2020 On 5/5/2020 at 2:08 AM, Ωhm said: My mistake, NOT T3, but T6. T3 would have IGN SW voltage on it. Expand Should I check this? Link to comment Share on other sites More sharing options...
SoCalManche Posted May 5, 2020 Author Share Posted May 5, 2020 Also, would a bad injector in itself cause this issue to happen? I'm not looking to drop $100+ on an injector, but I don't know how to check to see if it works or not. I only know that the harness is working. Link to comment Share on other sites More sharing options...
Ωhm Posted May 5, 2020 Share Posted May 5, 2020 Its would be a quick test. Disconnect ECU connector. Check for voltage on T3 with KEY ON. Link to comment Share on other sites More sharing options...
SoCalManche Posted May 5, 2020 Author Share Posted May 5, 2020 On 5/5/2020 at 2:13 AM, Ωhm said: Its would be a quick test. Disconnect ECU connector. Check for voltage on T3 with KEY ON. Expand Where do I ground? Link to comment Share on other sites More sharing options...
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