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gyman98 Samba Member
Joined: May 14, 2021 Posts: 16 Location: Sask
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Posted: Fri May 14, 2021 9:28 pm Post subject: Re: Official Fuel injection questions thread |
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busdaddy wrote: |
Welcome!
Are you saying the fuel pressure reads zero?, it couldn't have run like that before. To test the pump and it's circuit depress the flap in the air flow meter through the air cleaner end while the key is on, you should hear a click from under the ECU in the luggage compartment and a whirring from up front. The injectors will show power on both terminals unless you unplug all 4, it's a batch fire system and the resistance of the coils will give you false results if any others are connected.
I'd start with the simple things first since I'm assuming it was running OK until the engine came out for the clutch job. Where did you reconnect the two white wires with ring terminals near the top of the alternator?, is the single white wire connected to the #1 terminal on the coil? (same terminal as the points), is the AFM plugged in?, is the sensor on #4 cylinder's rocker box connected to it's single wire?, were either of the fuel lines clamped to allow them to be disconnected and not leak?, are the clamps off now? |
I don’t know what I have for fuel pressure exactly, doesn’t seem high and seemed no different with the fuel pump hot wired. Now that I know the pump only runs while cranking and engine running it could have been working before.
Yes it ran before, I drove it into the shop. I think there was 2 pairs of white wires that went to a screw on the generator case? They went back there. Yes the white wire is connected on the right side along with the lead to the points. Sorry not sure what the AFM is but I’ve triple checked everything and compared all to pictures I took before taking anything apart. Sensor on #4 is connected, I hope to the right spot, pictures I had didn’t show that but there was only one wire there to connect too. I just used plugs in the line and reconnected. I have gas flow at both sides of the fuel rail when I pull the lines off |
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busdaddy Samba Member
Joined: February 12, 2004 Posts: 51003 Location: Surrey B.C. Canada, but thinking of Ukraine
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Posted: Sat May 15, 2021 8:43 am Post subject: Re: Official Fuel injection questions thread |
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AFM = Air Flow Meter, it's the device between the air cleaner and the S boot connected to the throttle body (TB). Any chance that S boot got ripped during installation?, they get brittle with age and a vacuum leak of any kind effects how it runs, a big enough leak and it won't even cough in some cases. _________________ Rust NEVER sleeps and stock never goes out of style.
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gyman98 Samba Member
Joined: May 14, 2021 Posts: 16 Location: Sask
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Posted: Sat May 15, 2021 9:05 am Post subject: Re: Official Fuel injection questions thread |
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busdaddy wrote: |
AFM = Air Flow Meter, it's the device between the air cleaner and the S boot connected to the throttle body (TB). Any chance that S boot got ripped during installation?, they get brittle with age and a vacuum leak of any kind effects how it runs, a big enough leak and it won't even cough in some cases. |
Thank you I did check those too and didn’t see anything but will check again. I’m sure it’s something simple I did but just can’t find it |
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gyman98 Samba Member
Joined: May 14, 2021 Posts: 16 Location: Sask
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Posted: Sat May 15, 2021 9:14 am Post subject: Re: Official Fuel injection questions thread |
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busdaddy wrote: |
AFM = Air Flow Meter, it's the device between the air cleaner and the S boot connected to the throttle body (TB). Any chance that S boot got ripped during installation?, they get brittle with age and a vacuum leak of any kind effects how it runs, a big enough leak and it won't even cough in some cases. |
I stuck my finger in and manually opened the afm and with the key on the fuel pump runs so that should fix that. I’m going to pull off the right side rocker box and make sure I have it timed to #1 compression stroke and not exhaust stroke |
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busdaddy Samba Member
Joined: February 12, 2004 Posts: 51003 Location: Surrey B.C. Canada, but thinking of Ukraine
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Posted: Sat May 15, 2021 9:22 am Post subject: Re: Official Fuel injection questions thread |
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Good plan, although they usually backfire now and then if you've timed it to #3's TDC, better if you remove the LH rocker cover and watch #3's rockers as you roll back and forth a few degrees each side of where you suspect #1 TDC should be, 3's rockers should both be moving. _________________ Rust NEVER sleeps and stock never goes out of style.
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gyman98 Samba Member
Joined: May 14, 2021 Posts: 16 Location: Sask
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Posted: Sat May 15, 2021 9:43 am Post subject: Re: Official Fuel injection questions thread |
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It’s timed correctly, I have spark, slightly held open the afm to run the pump for a bit and still won’t even try and fire. Anything else you can think of? |
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busdaddy Samba Member
Joined: February 12, 2004 Posts: 51003 Location: Surrey B.C. Canada, but thinking of Ukraine
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Posted: Sat May 15, 2021 9:48 am Post subject: Re: Official Fuel injection questions thread |
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Is the single small brown wire connected to the negative post on the battery?
Aside from that I keep circling back to the #1 wire on the coil, it has to be on the terminal the points use to get the signal to fire the injectors.
Edit, you can try a spoonfull of gas down the throttle body to see if it at least coughs, that will eliminate a few things. _________________ Rust NEVER sleeps and stock never goes out of style.
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gyman98 Samba Member
Joined: May 14, 2021 Posts: 16 Location: Sask
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Posted: Sat May 15, 2021 10:09 am Post subject: Re: Official Fuel injection questions thread |
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busdaddy wrote: |
Is the single small brown wire connected to the negative post on the battery?
Aside from that I keep circling back to the #1 wire on the coil, it has to be on the terminal the points use to get the signal to fire the injectors.
Edit, you can try a spoonfull of gas down the throttle body to see if it at least coughs, that will eliminate a few things. |
The brown wire is on the negative post. I cut the end off the wire on #1 coil terminal and put a new end on. No change. It will run on spray but quit right away |
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busdaddy Samba Member
Joined: February 12, 2004 Posts: 51003 Location: Surrey B.C. Canada, but thinking of Ukraine
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Posted: Sat May 15, 2021 10:28 am Post subject: Re: Official Fuel injection questions thread |
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OK, two more things to try.....
With the key on pull that #1 wire off the coil and touch it to ground momentarily, do it repeatedly and listen for injector clicks in synch with your grounding. If that checks out unplug the temp sensor wire to the head by #4 cylinder (TS2) , leave it disconnected and see if it tries to fire. _________________ Rust NEVER sleeps and stock never goes out of style.
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gyman98 Samba Member
Joined: May 14, 2021 Posts: 16 Location: Sask
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Posted: Sat May 15, 2021 10:35 am Post subject: Re: Official Fuel injection questions thread |
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busdaddy wrote: |
OK, two more things to try.....
With the key on pull that #1 wire off the coil and touch it to ground momentarily, do it repeatedly and listen for injector clicks in synch with your grounding. If that checks out unplug the temp sensor wire to the head by #4 cylinder (TS2) , leave it disconnected and see if it tries to fire. |
No clicks from the injectors when I touch that wire to ground |
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busdaddy Samba Member
Joined: February 12, 2004 Posts: 51003 Location: Surrey B.C. Canada, but thinking of Ukraine
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Posted: Sat May 15, 2021 10:42 am Post subject: Re: Official Fuel injection questions thread |
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Hmmm...., yet you say there's power at the injector plugs....
Next place to look is the double relay (DR) and it's nearby connectors up in the luggage area, maybe something got yanked and dislodged? Also have a close look at the resistor block on the inside of the RH fender well, all wires attached and plug OK?, careful, it's easy to break the wires off the ends of those ceramic cigarretes in it.
Also confirm all the wires got reattached to the battery terminal on the starter solenoid, one of them powers the FI system. _________________ Rust NEVER sleeps and stock never goes out of style.
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gyman98 Samba Member
Joined: May 14, 2021 Posts: 16 Location: Sask
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Posted: Sat May 15, 2021 10:57 am Post subject: Re: Official Fuel injection questions thread |
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Yes power to both sides of the injector plugs and can hear them clicking when it’s cranking over through the stethoscope. DR looks ok, unplugged and replugged it again
The ceramic resistor looks rough but everything is plugged in on it. I didn’t have the starter solenoid off but there’s two wires on the trigger side only one heavy cable on the battery side. Cleaned those up |
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VW_Jimbo Samba Member
Joined: May 22, 2016 Posts: 9862 Location: Huntington Beach, CA
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Posted: Sat May 15, 2021 11:34 am Post subject: Re: Official Fuel injection questions thread |
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gyman98 wrote: |
busdaddy wrote: |
Is the single small brown wire connected to the negative post on the battery?
Aside from that I keep circling back to the #1 wire on the coil, it has to be on the terminal the points use to get the signal to fire the injectors.
Edit, you can try a spoonfull of gas down the throttle body to see if it at least coughs, that will eliminate a few things. |
The brown wire is on the negative post. I cut the end off the wire on #1 coil terminal and put a new end on. No change. It will run on spray but quit right away |
Just to be clear. The #1 side of the coil is the same as the condenser wire terminals. Opposite side is the 15 side which is ignition power.
The number 1 side is the rpm signal for firing the injector. Without that signal the injectors do not work.
I just went through this on the 77 I flipped. Turned out to be a very large air leak at the S boot. Right under one of the ribs. I had to remove the boot to find it. On the car was barely even visible. _________________ Jimbo
There is never enough time to do it right the first time, but all the time necessary the second time!
TDCTDI wrote: |
Basically, a whole bunch of fuckery to achieve a look. |
67rustavenger wrote: |
GFY's Xevin and VW_Jimbo! |
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gyman98 Samba Member
Joined: May 14, 2021 Posts: 16 Location: Sask
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Posted: Sat May 15, 2021 11:53 am Post subject: Re: Official Fuel injection questions thread |
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I checked for continuity at the #1 coil terminal to the points and it comes and goes as I turn the engine over. I did find a crack on the S boot and sealed it up but didn’t change anything.
Thanks to you as well for the help |
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busdaddy Samba Member
Joined: February 12, 2004 Posts: 51003 Location: Surrey B.C. Canada, but thinking of Ukraine
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Posted: Sat May 15, 2021 12:10 pm Post subject: Re: Official Fuel injection questions thread |
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So lets recap.
White wiring on top of alternator attached to ground screw and not D+ terminal.
#1 trigger wire attached to points terminal on coil.
Brown ground wire attached to negative battery post.
Fuel pump runs when AFM flap poked.
Injectors click when cranking.
Runs when fed fuel down the intake.
Seems like the problem is lack of fuel, I have to ask the obvious question, there is fuel in the tank, right?
If there is it seems the fuel pump isn't running while cranking, two things control it, a wire from #50 on the starter to 86a on the double relay should run the pump while cranking, sometimes the wire connections get dirty, sometimes the double relay fails internally and loses that circuit.
The other way the pump runs is air flow through the AFM, if there's a big enough vacuum leak the engine can't pull enough air to lift that flap and turn on the pump.
The cold start valve sprays fuel when the engine temperature is cold and the starter is running, multiple crank attempts will warm it enough to shut off the CSV system, but since it doesn't even fire a little while cranking I'm lead back to the lack of pump action. The CSV is also powered by that same #50 wire from the spade terminal on the starter.
The diagram below is for a bus, but the system is the same as well as most of the component locations.
_________________ Rust NEVER sleeps and stock never goes out of style.
Please don't PM technical questions, ask your problem in public so everyone can play along. If you think it's too stupid post it here
Stop dead photo links! Post your photos to The Samba Gallery!
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VW_Jimbo Samba Member
Joined: May 22, 2016 Posts: 9862 Location: Huntington Beach, CA
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Posted: Sat May 15, 2021 12:47 pm Post subject: Re: Official Fuel injection questions thread |
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Can you take a picture of your engine bay. The whole thing, maybe from 3 different angles so that we can see all of it. Not too close, not too far away.
Also, will it sputter if you spray carb cleaner into the AFM? Can you keep it running like that? _________________ Jimbo
There is never enough time to do it right the first time, but all the time necessary the second time!
TDCTDI wrote: |
Basically, a whole bunch of fuckery to achieve a look. |
67rustavenger wrote: |
GFY's Xevin and VW_Jimbo! |
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gyman98 Samba Member
Joined: May 14, 2021 Posts: 16 Location: Sask
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Posted: Sat May 15, 2021 12:47 pm Post subject: Re: Official Fuel injection questions thread |
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There’s 3/4 of tank of fuel in it, I had my son crank it while I felt the pump and it definitely runs while cranking.
If I have the fuel lines hooked up backwards would that do it? What’s that valve on the fuel line behind the shroud? Near the starter bolt. Fuel line goes in one side and out the other. There’s another barb for maybe a vacuum hose? I never had a vacuum hose there. Wondering if that’s a check valve? |
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gyman98 Samba Member
Joined: May 14, 2021 Posts: 16 Location: Sask
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Posted: Sat May 15, 2021 12:54 pm Post subject: Re: Official Fuel injection questions thread |
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Yes it will run as long as I spray it
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busdaddy Samba Member
Joined: February 12, 2004 Posts: 51003 Location: Surrey B.C. Canada, but thinking of Ukraine
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Posted: Sat May 15, 2021 1:07 pm Post subject: Re: Official Fuel injection questions thread |
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gyman98 wrote: |
If I have the fuel lines hooked up backwards would that do it? What’s that valve on the fuel line behind the shroud? Near the starter bolt. Fuel line goes in one side and out the other. There’s another barb for maybe a vacuum hose? I never had a vacuum hose there. Wondering if that’s a check valve? |
Yes, if you swapped the lines where they leave the tunnel it wouldn't run.
The gizmo on the front tin near the starter is the fuel pressure regulator (FPR), it restricts the return line to control pressure. The vacuum line must be connected to it, not only will it run funny, the disconnected vacuum hose is a leak. _________________ Rust NEVER sleeps and stock never goes out of style.
Please don't PM technical questions, ask your problem in public so everyone can play along. If you think it's too stupid post it here
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gyman98 Samba Member
Joined: May 14, 2021 Posts: 16 Location: Sask
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Posted: Sat May 15, 2021 1:09 pm Post subject: Re: Official Fuel injection questions thread |
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busdaddy wrote: |
gyman98 wrote: |
If I have the fuel lines hooked up backwards would that do it? What’s that valve on the fuel line behind the shroud? Near the starter bolt. Fuel line goes in one side and out the other. There’s another barb for maybe a vacuum hose? I never had a vacuum hose there. Wondering if that’s a check valve? |
Yes, if you swapped the lines where they leave the tunnel it wouldn't run.
The gizmo on the front tin near the starter is the fuel pressure regulator (FPR), it restricts the return line to control pressure. The vacuum line must be connected to it, not only will it run funny, the disconnected vacuum hose is a leak. |
Ok I will try switching the lines and let you know what happens |
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