Intermittent Starting (1 Viewer)
- Thread starter Therealtotodile
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- Thread starter
- #22
I appreciate the nod, but my starter works great. The truck just wont turn over(crank, crank, crank), but the battery and starter are very strong.
- Thread starter
- #23
So I ended up finding a 1996 FSM and followed some steps. Here is what I found:
Car was forever cranking in the driveway Yesterday. Couldn't get it to start for the last 24 hours.
I first replaced the fuel pump resistor because it was reading 1.1 ohms(should be 0.7 per FSM). Grabbed one from a junkyard that tested good, no dice there.
Swapped fusible links, and then follow the FSM to test the FPRelay and CORelay which I now have two of. They all(2 of each) work, per the continuity and jumper tests.
Swapped out both old and new relays just in case, nothing there either. It did turn over once, and died after about 20 seconds, felt like it wasn't getting gas.
I have also confirmed the pump works, per FSM. Tested it with battery voltage and it spun. Continuity was also there.
Also took a deep look at the fusebox. Per my last post, the pump fuse slot was fried. I pulled the wires and wired in one of the fuse holder wire things and put a new 15A in there. I also looked deep at the EFI wiring, looks good. Also swapped in a new EFI fuse, but I have had the CEL this entire time, so I don't think its my issue.
I have also gotten significantly better with an ohm meter, and realized that having tiny alligator clips will make my life much much easier.
@jonheld hoping you could point me in a new direction. I attempted to test the ECM ports per the FSM, but like I said it was 1996 and it looks slightly different. I'm not sure I jumped the right ports, and couldn't get any voltages. I also took a deep look at the harness. I think that part of the diagnostic may help me figure out what part of my harness may be of issue.
There was another post I can't recall, where someone mentioned a wire that controls some of the FP or B+ logic that comes off the fuse box. There is one wire, right kind of behind the alternator, that comes of the main fuse box harness and goes right next to the fuel rail. That connector is pretty ****ed up. There is also some weird wiring s*** from the PO in the kick panel where the COR lives. Not sure if my issue might be there. I followed the rest of the harness from ECM to firewall to EGR area and the fuse box and FPR/resistor live. Wiring looks pretty solid.
THANKS
EDIT: @jonheld you mentioned the AFM at the beginning of the thread. I'm going to run the FSM test, see if it is the correct resistance.
Car was forever cranking in the driveway Yesterday. Couldn't get it to start for the last 24 hours.
I first replaced the fuel pump resistor because it was reading 1.1 ohms(should be 0.7 per FSM). Grabbed one from a junkyard that tested good, no dice there.
Swapped fusible links, and then follow the FSM to test the FPRelay and CORelay which I now have two of. They all(2 of each) work, per the continuity and jumper tests.
Swapped out both old and new relays just in case, nothing there either. It did turn over once, and died after about 20 seconds, felt like it wasn't getting gas.
I have also confirmed the pump works, per FSM. Tested it with battery voltage and it spun. Continuity was also there.
Also took a deep look at the fusebox. Per my last post, the pump fuse slot was fried. I pulled the wires and wired in one of the fuse holder wire things and put a new 15A in there. I also looked deep at the EFI wiring, looks good. Also swapped in a new EFI fuse, but I have had the CEL this entire time, so I don't think its my issue.
I have also gotten significantly better with an ohm meter, and realized that having tiny alligator clips will make my life much much easier.
@jonheld hoping you could point me in a new direction. I attempted to test the ECM ports per the FSM, but like I said it was 1996 and it looks slightly different. I'm not sure I jumped the right ports, and couldn't get any voltages. I also took a deep look at the harness. I think that part of the diagnostic may help me figure out what part of my harness may be of issue.
There was another post I can't recall, where someone mentioned a wire that controls some of the FP or B+ logic that comes off the fuse box. There is one wire, right kind of behind the alternator, that comes of the main fuse box harness and goes right next to the fuel rail. That connector is pretty ****ed up. There is also some weird wiring s*** from the PO in the kick panel where the COR lives. Not sure if my issue might be there. I followed the rest of the harness from ECM to firewall to EGR area and the fuse box and FPR/resistor live. Wiring looks pretty solid.
THANKS
EDIT: @jonheld you mentioned the AFM at the beginning of the thread. I'm going to run the FSM test, see if it is the correct resistance.
Last edited:
- Thread starter
- #24
One more update... Checked the AFM per FSM.
First test, got open and then 0.2-0.3 ohms(fingers pushing on the flap to open it). FSM says should read open, and then 0. Not sure if 0.3 ohms is effectively zero or not.
Would appreciate someone's input there.
Second test, got 262 ohms, and went up to 500 ohms. Good there.
Seems like the AFM is good? Flap doesn't feel sticky or anything either.
First test, got open and then 0.2-0.3 ohms(fingers pushing on the flap to open it). FSM says should read open, and then 0. Not sure if 0.3 ohms is effectively zero or not.
Would appreciate someone's input there.
Second test, got 262 ohms, and went up to 500 ohms. Good there.
Seems like the AFM is good? Flap doesn't feel sticky or anything either.
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For a typical multimeter, it will read a few tenths of an ohm even if you just touch the leads together - you're measuring the resistance of the leads etc...
So, yeah, 0.3 ohms on your meter is as good as 0 ohm.
cheers,
george.
So, yeah, 0.3 ohms on your meter is as good as 0 ohm.
cheers,
george.
So to clarify your current problem, you have no voltage at the fuel pump while cranking?
- Thread starter
- #27
@thabruiser so I would be really appreciative, if you could share what pin(s) should be checking and what I am checking for, certain voltage, etc.
I couldn't find anything in the FSM about checking that plug, and I agree, I think that's a good place to check to understand my issue.
I would like to know something along the lines of -- is there too little power, no power, or its up to spec and I have a logic issue in the circuit rather than a ground/short or something. The only thing I have tried, is testing for continuity between the ground pin and red pin(not cranking but key turned) which I do have. Ill have my girlfriend crank while I watch the ohmeter.
Thanks
If you have a1993 OBD1 vehicle, why are you referring to a1996 OBD2 manual? This is not going to help you.
In the resources section you will find a 1994 FSM and EWD that will be a direct match to your truck.
- Thread starter
- #29
@jonheld thank you for pointing that out. Grabbed the 1994 FSM.
My update:
Thought about things for a while, and then decided to retest my pump. With my girlfriend cranking, no power to pump. Doesn't spin. Jumped it after that through the sender plug, and the pump spins. Finally I can confirm that it is for sure a wiring/logic issue.
I then pulled out the multimeter, and read 5.9-6.1V at the ground and power from the male plug that goes to the sender while my girlfriend cranked. Now I know there is power to the plug, but it is 6V, not 11V or 12V. Could this be my issue?
As a reminder, a got a new FPrelay and CORelay. Both are installed and tested to be working per FSM. Also replaced the out of spec resistor with a working one. I have checked all the wiring as much as I am savvy. Replaced the fuel pump fuse with an inline holder because it was so melted. Also replaced a connector that goes from the fusible links to behind the alternator and down parallel to the fuel rail because it was fraying. Ive also checked the plug that is below to the left hand passengers door, it goes from the tank up through a port into the chassis and continues to the drivers kick panel. Looks good there.
update: Just checked some other voltages while cranking. At the pump fuse, I am getting 11.2V. At the FPR, I am getting the same 5.9V as the connector to the fuel pump sender.... At every pin combination for the COR, 11.2V as well.
If anyone knows what wires would be of concern, between the COR and FPR, or if there's another place to test, I would appreciate suggestions.
Thanks all,
Chris
My update:
Thought about things for a while, and then decided to retest my pump. With my girlfriend cranking, no power to pump. Doesn't spin. Jumped it after that through the sender plug, and the pump spins. Finally I can confirm that it is for sure a wiring/logic issue.
I then pulled out the multimeter, and read 5.9-6.1V at the ground and power from the male plug that goes to the sender while my girlfriend cranked. Now I know there is power to the plug, but it is 6V, not 11V or 12V. Could this be my issue?
As a reminder, a got a new FPrelay and CORelay. Both are installed and tested to be working per FSM. Also replaced the out of spec resistor with a working one. I have checked all the wiring as much as I am savvy. Replaced the fuel pump fuse with an inline holder because it was so melted. Also replaced a connector that goes from the fusible links to behind the alternator and down parallel to the fuel rail because it was fraying. Ive also checked the plug that is below to the left hand passengers door, it goes from the tank up through a port into the chassis and continues to the drivers kick panel. Looks good there.
update: Just checked some other voltages while cranking. At the pump fuse, I am getting 11.2V. At the FPR, I am getting the same 5.9V as the connector to the fuel pump sender.... At every pin combination for the COR, 11.2V as well.
If anyone knows what wires would be of concern, between the COR and FPR, or if there's another place to test, I would appreciate suggestions.
Thanks all,
Chris
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Check the condition of connector BO1 for the fuel pump. It lives under the body directly under the C pillar and is exposed to the elements.
- Thread starter
- #31
Hi all, just wanted to wrap this thread up. So after snooping around more, I couldn't find any bad wires. Ended up wiring a second relay, around the FPR. All is now good. Something in my harness is grounding, and instead of breaking all the other wires in the harness to find it, just wiring around it did the trick.
Thanks for all the help!
Chris
Thanks for all the help!
Chris
Glad you figured it out!
