Official Fuel injection questions thread

[ltjohnb]

[ltjohnb]

Wanted to follow up.

She's closer to purring like a kitten.

It would figure the day I planned to do a smoke test it was really windy. In an effort to keep moving forward, I did the following:

"Cold checks"
- Verified valves still at 0.006
- Verified good seal on both valve covers
- Visual inspection of engine for any loose, disconnected, or damaged hoses
- Verified 30 ohms resistance on the AAR
- Verified AAR was open (55 deg F outside today)
- Verified greater than 2700 ohms resistance on TS2
- Put a drop of oil on the felt pad of the distributor

Started the engine and verified Dwell was at 50 deg and idle was still high (~1200 rpm)

Let the engine warm up and did the following

"Warm Checks"
- Checked timing at idle (~10 deg, but not surprised since idle was high)
- Brought the engine up to 3000 rpm and checked timing (was WAY too advanced at >40 deg)
- Adjusted timing to 30 deg at 3000 rpm (with both vacuum hoses disconnected from my distributor and plugged)

The second I did that and brough the engine back to idle it was more or less purring at 900 rpm.

I still plan on doing a smoke test because I am sure there are still some leaks I can fix, but this feels like a big step in the right direction.

Thanks to Busdaddy for the help.
_________________
74 Super Beetle Sedan "Vader"
79 Super Beetle Convertible "Mello"
19 Jetta "Blanco Muerte"
22 Taos "Betty White"

[busdaddy]

[ltjohnb]

[busdaddy]

[cphipps79]

Good evening fellers! I have a quick question about thermostat/flaps. I know the thermostat for a fuel injected car has a different opening temperature. My question are the flaps different for a fuel injected car vs a carb car? Please forgive me if I’m asking a dumb question! I appreciate everyone’s help!

[busdaddy]

The flaps are the same, as is the link bar, rod down through the head and bracket, it's just the thermostat itself that opens at a slightly higher temp.
_________________
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!

Слава Україні!

[Gman73]

so after dealing with a cold start issue, I adjusted my AAR to the max opening. It started and ran excellently until the AAR heater warmed up. So i Unplugged it and started it back up after it cooled a little and while it was running I sprayedsome brake clean to check for vacuum leaks and found that my plenum was leaking in the seam. so now tomorrow i will be fixing that. i can make a paper gasket for it, but should i use permatex #2 on it also? What do you guys recommend?

Thanks
Gary

My wife is bugging me to drive "her baby"

[busdaddy]

I'd glue one side at least, that one's awful skinny and has some long stretches between bolts, easy to suck in.
_________________
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!

Слава Україні!

[bjp98]

I currently own a 1977 Beetle with 37,100 original miles. The car runs great, except for one issue. The car will sometimes have issues starting. This only occurs when its warm out, however if I slightly press on the gas, the car starts right up. If its cold outside, the car will start just fine without pressing on the gas. An example is if I start it in the morning to drive to work, it starts without issue. However, if I come out for lunch or to head home and its warmer out, it will have issues starting until the gas is pressed or I let it crank for eternity. Could this be just a fuel pump or thermo time switch? What could cause this issue?


Things previously replaced that are in good working order (not all at once, but as needed):
1. Converted from points to electronic ignition.
2. New spark plugs and spark plug wires.
3. New starter.
4. New auxiliary air valve.
5. Not replaced but have checked all lines for leaks or cracks and did not find any issues.

All of that being said, I am a little stumped.

[busdaddy]

Welcome!, and great job on the detailed first post!

Most of what you describe sounds like the threads where the temperature sensor (TS2) screw into the LH head are dirty and not making full electrical contact. You can start by testing it with an Ohm meter: https://ratwell.com/technical/TempSensorII.html
If it does indeed read high then be careful getting it out, it may be stuck and break off.
If cleaning up the threads and retorquin it doesn't improve things then it's time to replace, sadly the Uro brand ones offerd by most sellers suck, but there's ways around the problem: https://www.thesamba.com/vw/forum/search.php?searc..._chars=200
_________________
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!

Слава Україні!

[bjp98]

That seems to have fixed the issue! My car did have the extender attached, which I thought was weird, since the issue was starting up and never anything related to warming up. So when I reinstalled the sensor, I did not include the extender, which did not seem to cause any issues.

Last night after reinstalling the cleaned sensor, I tried starting it and it was still a little rough, however I took it on a test drive and everything was fine. So I returned home, waited about 4 hours, started it again and it started without issue! To be safe, I waited until this morning to determine if the issue is gone, since I knew it was going to be warmer than normal out and would be a good testing opportunity. I started it this (warm) morning without issue, which is beyond relieving!

Thanks for the easy and fast help! As a result, I'm able to continue daily driving my Beetle!

[busdaddy]

Nice!, fixes that don't require new parts are the best!

Thanks for following up.
_________________
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!

Слава Україні!

[tommu]

[bjp98]

That very well could be true. I have never had a stock FI beetle until now, so all of this is new to me and a little confusing, if I am honest.

That being said, I went to leave work Friday and it seems the issue is back. I replaced the sensor with a NOS one (with cleaned extender) I got from my local VW parts store, which did not improve the issue any. Any other ideas on where to look? My first thought would be a fuel pump but I am not sure if that would make sense since my issue is not all the time, but when its warm out.

Also, I did replace the thermo time switch with a NOS one that came with the car to see if that would do anything, which it did not. I also took out the cold start valve and watched it shoot into a cup during the starting process. So I am not thinking they're the issue either, which leads to more confusion on my end.

[busdaddy]

[Lost69Convertible]

[bjp98]

Thanks everyone for the help! I took busdaddy's suggestion and sprayed a little bit of gasoline into the s boot and the car started. So it seems the issue is the car not getting enough fuel. When the car started, it was very rough and seemed to want to die, until I hopped in and pressed on the pedal a little.

Regarding adjusting the valves, I normally check/adjust my valves every 3,000 miles when I change my oil. I am about 1,000 miles away from being due for an oil change/ valve adjustment. However, I do not mind changing my oil and checking the valves early, if you think that would be a good idea.

Side note, when I did check my cold start valve, it was late at night in my garage, so would be around the same cooler temp as it is in the mornings here, when I do not have issues starting the car.

[busdaddy]

Excellent!, now we have a starting point.
So is this lean condition due to the TS2?, or fuel pressure?, since you've already fiddled with the TS2 a fuel pressure test is the next logical step.
Any 0-50 psi water pressure gauge will do, Home depot?, Harbor freight?, you'll also need a fitting to adapt it to a 5/16" hose barb. Install it in place of the CSV and see if the pressure drops off when parked, and if it remains low when trying to start it warm (it should jump up to 28-30 as soon as you turn the key to start).

Good to hear you are on top of the valves, some owners don't realise it's part of regular maintenance.

BTW the CSV should only operate below ~50 degrees, and only for a little short squirt when the starter is running, many have removed it entirely and it still starts fine unless it's the coldest winter day. It should be completely out of the picture on a warm engine.
_________________
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!

Слава Україні!

[plextor]

My '75 is a California model with the cat. I've replaced the muffler in the past 2 years, but I noticed that the muffer to cat connection is leaking again. Even after putting in a fresh donut and exhaust copper gasket maker it is leaking. The cat's pipe opening isn't great, so it may just be not able to make a good seal (and/or I'm doing it poorly).

Given this old cat isn't doing anything useful given its age, I can either replace it or just switch to a non-California exhaust muffler (no smog in Texas for this age of vehicle). It looks like it is an easy bolt on and drops some extra parts. Any downsides to doing that that I'm missing? (there should be no heater box etc modifications from what I can tell).

And I see some high quality JP Dansk mufflers that are spendy, but wonder if they're a better quality than the ones half the price...

Photos of the current stuff... (yes the clamps were just removed and that's the old donut etc).

_________________
1975 VW La Grande Bug (Super Beetle, 1600 EFI, owned since May 2021)