Fuel injection relief here!

[lockelandis]

Hey Gang,

I've got a 72 squareback. Its had a dieseling problem (aka run on) for quite some time. A while back, I pulled all the injectors (leaving the hooked up to the fuel line, but unplugged the wiring), and turned the key to the on position to pressurize the system. unsurprisingly two of them leaked quite a bit of fuel. So I replaced them. The replacement injections I am using are rebuilt, Ive linked them here https://www.partsgeek.com/b1fqbgh-volkswagen-squareback-fuel-injector.html

I am still having dieseling issues. I pulled them out a second time and don't see any leaks when I pressurized the system.

My cold start doesn't seem to function, but that's a separate thing. (I checked to see if it was the culprit leaking. it isn't.)


Does anyone have advice for what to check next? Could it be that these injectors just arent made well? where do you source injectors from?

Thanks
Locke

[KTPhil]

How long has this been happening? What changed, or what was repaired?
_________________
Current Fleet:
- '71 Fastback
- '69 Westfalia
Retired:
- '67 Beetle
- '65 Beetle (x2)
- '65 Bus
- '71 Squareback

[lockelandis]

This has been happening for a couple months now. Ever since I took it to a shop for a diagnosis. I was having extremely bad misfiring. I was having lots of trouble tracking it down. To attempt to solve the problem, I did all of the following.

-checked value adjustment
-checked timing
-replaced plugs
-replaced plug wires
-new cap and rotor
-new coil
-adjusted gap on electronic ignition.

The shop found the source of the misfire. It was the positive electronic ignition wire not being connected tightly enough to the coil. I guess the blade connector was semi loose.

I noticed the run on after I got it back from the shop.

[jbillow]

Hi guys, not new here but I have been away for a while, no I wasn't in jail, just life stuff. Anyway back a while ago I rebuilt my FI wiring harness for my 69 fastback. As far I as I can tell I was successful in doing a proper job. I have recently put the FI components and new harness back in. I was able to have it running and drove it for about a day when it started running poorly, (sputtering and running rich) to now it will not fire at all. I have a new 123 distributor in place and was set up per manufacturers instructions. Listed are the tests specs I have found. I'm not a multi meter expert so if I use improper verbiage cut me some slack.
coil - 3.2 0hms
MAP pressure sensor -0.5 pressure loss in more than 10 seconds (good vacuum)
MAP ohms 89 and 336 , also tried a back up, no difference
cylinder head temp sensor 4 ohms
temp sensor #2, 658 ohms
Fuel pressure 28 psi (did adjust up to 31 for trouble shooting, no luck)
I have nice blue spark at plug
I pulled cylinder 1 and 2 injectors to test, both test good with even flow using cars ignition.

So I'm really stumped here, the fuel pump is new and comes on and off maintaining pressure, the injectors spray and I have spark. I have adjusted the timing more than once but it just will not even give me a cough. As always your insight and help is much appreciated. Thanks

[airschooled]

Welcome back. Your temperature sensor readings look questionable.

The TS1 is the intake air sensor, the TS2 is in the cylinder head. Here are some applicable values I found in another thread:

Ohms resistance on the left, temp in *F on the bottom.
Robbie
_________________
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[KTPhil]

[jbillow]

Thank you guys for your responses, however I'm still a bit confused about which sensor is which. My Bentley type 3 book under fuel system on page 12 and 13 says the head temp sensor mounted to head below #4 exhaust port is temp sensor #1, one wire, and the one at the auxiliary air regulator is sensor #2 two prong plug. I don't find where it shows what the readings are supposed to be. ( thank you for the chart) Im not sure if it's different for different years but mine is a 1969. Assuming one or both of these may be bad, would it cause an extreme rich mixture? I did change the spark plugs and got it to start but again ran poorly (very rich and sputtering). I will check my ohm readings again but I'm not exactly sure which setting to be on when testing various components. Also to note on the 69 model there is a pressure switch that's mounted under the passenger side air manifold. I believe its supposed to work in conjunction with the TPS. I don't know if this could be bad or what the ohm reading should be on it, I did take the cover off and inspected contacts and also check vacuum does actuate. Thank you for your patience and input

[KTPhil]

I can't remember just which manual/edition, but the TS1/TS2 mixup has been mentioned before. The cylinder head temp sensor is TS2.

Did you measure TS2 with the wire disconnected? It can't be measured while connected. Be careful, they are brittle after all these years (connector, and where the wire is potted into the sensor itself). Also, a poor/corroded connection between the threads of the sensor and the head itself can cause bad readings.

Too high a resistance in TS2 will make it run rich, or not run at all.

Pressure switch won't affect anything except full throttle mixture, unless its shorted out somehow. Disconnect the connector for these tests to be sure it's out of the picture.
_________________
Current Fleet:
- '71 Fastback
- '69 Westfalia
Retired:
- '67 Beetle
- '65 Beetle (x2)
- '65 Bus
- '71 Squareback

[Bobnotch]

[jbillow]

Thanks for the clarification on that. I did remove both sensors and brought them inside to test at room temperature. Both readings are close to what you mention at room temperature so i’m going with they’re good, for now. However I wouldn’t pass on buying another TS1 if I could find one, the serial number ends in 001. With the replacement of the spark plugs the car does run but very rich and sputtering. I thought I found the problem today when testing continuity and proper pin locations in my harness, when I realized I had the pressure switch and the throttle position switch mixed up but it made little difference.I’m continuing to trouble shoot the ignition system and the injectors. I have yet to pull #3 and 4 injectors, so more to come. My 123 distributor is new so I hope there is no issue there.

[jbillow]

Update to my running rich issue. After all my ohms testing and checking and tightening possible loose connections, I pulled all the injectors and rechecked operation and flow and checked fine. when I re installed them I realized that they had not been properly seated far enough down into he seals and intake. It now runs clean and snappy. I’m just trying to find my right timing combination with my 123 ignition. It still is a little slow from a dead stop when warms up, maybe need to add a little timing. Thank you all for your input.