Official Fuel injection questions thread

[txasylum]

Okay, I just went out and did the timing up to about 32 degrees. So at idle it is close to 10. It seems to run a little better, but it sure did sound smoother yesterday. I know it is hard to tell, but does it sound like it is running on three cylinders?

I need to find the information on testing fuel pressure. I don't know how, so I need to find instructions.

One thing I did not do is check the valve clearances, but again it sounded better yesterday. Who knows. But I will also check those.

I'm wondering if it is not firing on all cylinders. Maybe bad plug or clogged injector?

[busdaddy]

For the cylinder check pull one plug wire from the distributor cap at a time (rubber gloves or insulated pliers) and listen for a drop in RPM, put the wire back and move to the next one, do any make no difference when you pull them?

For the pressure test go to the hardware store and buy a water pressure gauge with a 0-50 PSI range as well as the fittings to adapt it to 5/16" hose, connect it to the end of the CSV line and activate the fuel pump. We need the pressure engine off, engine running, engine off again and sitting, does it rise when you open the throttle quickly?, does it rise when you pull the vacuum hose off the regulator? Finally pinch the return line and read the maximum pressure, you can do that one engine off, key on and poke the flap in the AFM if you like.
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[txasylum]

On the plug wires, there was a noticeable difference on #4, 3, 2. When I pulled one off, no change even though it was sparking at the cap. So #1 not firing. Guess can be valves, plug or injector. I do have spare injectors in the trunk of the car, but I don't know their condition.

On pressure test, I have a fuel injection pressure set from Harbor Freight. It is 0-100. So do I "T" it in between the CSV and metal fuel line or do I put it on the end of the rubber fuel line (Not T in).

[PuddleRainbow]

Hello,

I bought a fuel pressure tester from Summit and really like it. It comes with a multitude of brass fittings including a schrader type tee fitting that can be plumbed in and left in line. The lead hose to the gauge is long enough to allow you to tape it to the rear window and do measurements while driving.

https://www.summitracing.com/parts/anm-cp7838

I t'd in at the yellow X

[txasylum]

I have a metal line that runs from the CSV to the injectors (very short rubber line between CSV to metal and metal to injectors). It looks like you have a rubber fuel line where I have a metal line, correct?

[busdaddy]

Different years have metal lines opposed to rubber, I suggested the CSV because it's easy and not needed if the engine is warm already.

No change on one wire for the wire pull test indicates an issue, try the easy stuff first, valve adjustment and compression test, new spark plugs maybe too. It could be many things, bad plug, bad wire, bad injector plug/harness, bad resistor block, or bad injector. Swapping one known good item from a known good cylinder into the dead one at a time can find it, swapping the injector plugs between the two cylinders on that side can narrow down if it's harness or resistor caused (all 4 fire at the same time).
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[txasylum]

Will try a few things for cylinder 1 before I get into testing the pressure and will get back with ya.

Thanks

[txasylum]

Welp, valve adjustment good. Swapped plugs, no change, swapped plug cables not change. I pulled out the injectors. But the rubber O rings are so shot I need to order some more. I just ordered four new ones with O rings from Rock Auto (reman with 24 month warranty). Now I have to wait until Monday for delivery.

[busdaddy]

Keep your old ones, the Amazon ones may be China's finest , NAPA sells injectors as well IIRC.
Your local Bosch fuel injection service shop can clean and flow test your old ones as well. Sometimes you can free up a stuck one by rapping it against a wood work bench on the plug end (don't bust off the plug), try powering it with a 9V battery and listen for a tiny click.
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[txasylum]

These ones I ordered have a core return. So I assume they send instructions on returning for partial refund. I actually have six of them (four in motor and two in trunk).

Thanks again for all your advice and help. I'll keep ya posted because I'm sure I'll have more questions/issues.

[txasylum]

What size/diameter is the fuel line? I will order some with SAE J-30R9 specs.

[busdaddy]

[390nellie]

Temp Sensor II

Did the FI Beetles come from the factory with a boot on the temp sensor? The Bentley manual pictures a boot being removed in figure 4-22 in the fuel injection chapter. I haven't seen one for sale anywhere repo or nos.
On mine there is no boot only a seal around the tin. Should these sensors be covered with a boot? Does anyone have the boot part number?

[MuzzcoVW]

[walarson]

I am a rookie working on a complete restoration of a 1976 FI beetle and have a probably dumb question regarding the temp sensor II.

I am not sure the sensor is in the correct position. Note the photo. The sensor is about 1/2 in above the head when positioned in the grommet on the tin. Is this correct? Should the sensor be touching the head?

There is no place to screw the sensor into other than the grommet holding it to the tin. Thanks in advance.

[busdaddy]

Hmmm...., the problem is it's not a FI head.
The sensor has to screw into the head metal, is there enough meat around that tin screw hole beside it to enlarge it to M10 x 1.0 thread? If not then you'll have to drill and tap the top of the rocker box and come up with a way to seal the air leak caused by the lower down sensor position.
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[Lost69Convertible]

On my 1979 FI engine, Temp Sensor 2 screws into the rear face of the rocker box (not the top). You need to crawl under the left rear tire to look up in there.
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1956 Beetle Ragtop: My Father's car
1969 Beetle Convertible: My first car. I loved it, I lost it, and I never got over it.
1979 Super Beetle Convertible

[VW_Jimbo]

Amazon has a fuel injected head for 176.00

IAP Performance 043101355CK Complete Dual Port Cylinder Head with Sensor Hole for VW Beetle https://www.amazon.com/dp/B0150I5D6W/ref=cm_sw_r_cp_api_glt_fabc_WK9TYFTSH6GTS6E6DR7S
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Jimbo

There is never enough time to do it right the first time, but all the time necessary the second time!

[MuzzcoVW]

[MuzzcoVW]

On second look I see that those are new looking heads. Did you or the person you got the car from redo the engine? Check the opposite head on the side closest to the front of the car and see if there's a port...maybe the heads are on the wrong side of the engine. Most new heads come with the sensor port, but its only on one head.