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chachi
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 Posted: Mon May 21, 2018 10:52 pm Post subject: no start, no injectors |
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2.3, auto, I was trying to decode running problems in this thread when the van stopped starting at all. It had always been hard to start in the cold, with much stomping of the gas and consternation, but it is now perfectly warm out. After a long string of other checks and replacements, I finally pulled the injectors on the driver's side and cranked the starter, as per Bentley, and nothing, just a slight bit of gas out of one injector. Fuel rail shows 32 and pump runs when it should. I measured continuity between the injector plugs and pin 12 on the ECU plug and on each plug I get 6 ohm for the red/white wire and .6 ohm for the white wire, which makes me think the wiring is at least mostly ok since I got something on each wire and they're consistent. I have not tried a known good ECU yet, but I'm wondering if there is something I can further try before I borrow one.
Thanks for your all your help! I feel super close...
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MarkWard
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| Posted: Tue May 22, 2018 4:08 am Post subject: Re: no start, no injectors |
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Do you have spark? The ECU needs the rpm signal from the negative side of the coil to fire the injectors. A noid light across an injector harness connector will tell you if the ECU is trying to work the injector.
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chachi
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| Posted: Tue May 22, 2018 7:41 am Post subject: Re: no start, no injectors |
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yes, I do have spark. replaced the coil with new and got a nice hot spark, and I just did a noid test and it does fail that. which is new, because I noid tested maybe a month ago and got the light.
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chachi
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| Posted: Tue May 22, 2018 9:51 am Post subject: Re: no start, no injectors |
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i also should say that I pulled the dash wire mentioned in this thread and it didn't start. also built crazyvwvanman's wiring loom test tool and it didn't start.
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MarkWard
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| Posted: Tue May 22, 2018 10:08 am Post subject: Re: no start, no injectors |
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With the fuel pump relay energized you should have 12 + volts at one terminal in the injector plug. Check that first. Then the injectors are sprayed by a ground supplied directly from the ECU via pin 12 on the ECU plug. I would ohm the ground wire on each injector to make sure you have continuity at the ECU plug connector. If the ground path is good, then the ECU is not able to supply a ground and you will need to figure out why. There is a short brown ground wire next to the ECU box that can fail. I would look there first.
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chachi
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| Posted: Tue May 22, 2018 11:30 am Post subject: Re: no start, no injectors |
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| MarkWard wrote: |
| With the fuel pump relay energized you should have 12 + volts at one terminal in the injector plug. |
so the relay energizes when the starter is engaged? could i effect the same change with that test wiring tool?
| MarkWard wrote: |
| Then the injectors are sprayed by a ground supplied directly from the ECU via pin 12 on the ECU plug. I would ohm the ground wire on each injector to make sure you have continuity at the ECU plug connector. If the ground path is good, then the ECU is not able to supply a ground and you will need to figure out why. There is a short brown ground wire next to the ECU box that can fail. I would look there first. |
that wire checks ok, and i’m assuming that since i measured just a little resistance on the white wires between the plugs and pin 12 those grounds all check out.
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chachi
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| Posted: Tue May 22, 2018 1:51 pm Post subject: Re: no start, no injectors |
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| chachi wrote: |
| MarkWard wrote: |
| With the fuel pump relay energized you should have 12 + volts at one terminal in the injector plug. |
so the relay energizes when the starter is engaged? could i effect the same change with that test wiring tool?
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dumb question. so if the noid doesn’t flash, and grounds are good, no 12v.
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MarkWard
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| Posted: Wed May 23, 2018 7:55 am Post subject: Re: no start, no injectors |
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Yes, that would be a good guess. I am not familiar with your jumper wire, but if the pump is running looking at the diagram, the injectors should have voltage.
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jberger
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| Posted: Wed May 23, 2018 10:07 am Post subject: Re: no start, no injectors |
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| chachi wrote: |
| chachi wrote: |
| MarkWard wrote: |
| With the fuel pump relay energized you should have 12 + volts at one terminal in the injector plug. |
so the relay energizes when the starter is engaged? could i effect the same change with that test wiring tool?
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dumb question. so if the noid doesn’t flash, and grounds are good, no 12v. |
So continuity through the harness checks out, 12v at the injector with key on? The ground through the ECU to fire the injector is momentary and rapid, hence the noid test, so you can see it flashing. If you have 12v and no noid operation, and all protraining tests check out then the ECU is bad. |
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chachi
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| Posted: Wed May 23, 2018 8:02 pm Post subject: Re: no start, no injectors |
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| jberger wrote: |
| So continuity through the harness checks out, 12v at the injector with key on? The ground through the ECU to fire the injector is momentary and rapid, hence the noid test, so you can see it flashing. If you have 12v and no noid operation, and all protraining tests check out then the ECU is bad. |
checked with a known good ecu last night and no start so it’s gotta be one of the wires. i do not get 12v at the injector with the key on, with either pin in reference to ground or bridging the injector pins. if either one of these is the correct test for 12v it seems to be my problem. if i’m understanding you guys correctly the injector is powered with the system and fires when the ecu opens the ground on pin 12. i was able to check ground continuity with pin 12 but what is the other side, where does it get 12v from?
thanks so much folks. soo soo close.
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jberger
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| Posted: Wed May 23, 2018 8:14 pm Post subject: Re: no start, no injectors |
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| chachi wrote: |
| jberger wrote: |
| So continuity through the harness checks out, 12v at the injector with key on? The ground through the ECU to fire the injector is momentary and rapid, hence the noid test, so you can see it flashing. If you have 12v and no noid operation, and all protraining tests check out then the ECU is bad. |
checked with a known good ecu last night and no start so it’s gotta be one of the wires. i do not get 12v at the injector with the key on, with either pin in reference to ground or bridging the injector pins. if either one of these is the correct test for 12v it seems to be my problem. if i’m understanding you guys correctly the injector is powered with the system and fires when the ecu opens the ground on pin 12. i was able to check ground continuity with pin 12 but what is the other side, where does it get 12v from?
thanks so much folks. soo soo close. |
The power relays above the coil... check them out... |
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MarkWard
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| Posted: Thu May 24, 2018 4:03 am Post subject: Re: no start, no injectors |
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I only glanced at the wiring diagram, but I am pretty sure the injectors only have power when the fuel pump is running. You would only have 12 v with key in run position momentarily. I could be wrong.
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chachi
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| Posted: Thu May 24, 2018 8:16 am Post subject: Re: no start, no injectors |
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yeah, with key on i get no power at the fuel pump relay on the bottom tab, but i do get it at the bottom tab on the other relay. i get voltage on the top pins of both relays without the key on. when i switched the relays it was the same.
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jberger
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| Posted: Thu May 24, 2018 8:18 am Post subject: Re: no start, no injectors |
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| chachi wrote: |
| yeah, with key on i get no power at the fuel pump relay on the bottom tab, but i do get it at the bottom tab on the other relay. i get voltage on the top pins of both relays without the key on. |
You do have the digifant protraining manual right? Follow the test procedures for the fuel injectors. |
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MarkWard
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| Posted: Thu May 24, 2018 11:14 am Post subject: Re: no start, no injectors |
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I would jump the fuel pump relay to see if you can get the pump to run and power to the injectors. Connect terminal 30 and 87 with relay unplugged.
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chachi
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| Posted: Thu May 24, 2018 2:47 pm Post subject: Re: no start, no injectors |
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yeah, i first tried the wiring test tool mentioned above and then simply jumpered the pins in the relay box and i can hear the pump run and i get my noid light back but...it still doesn’t start. and the injectors...according to the digifant manual you should get 87 cc’s, there’s no way i’m getting that much.
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