mattmondo

I have a code!

2111

mattmondo

So SMJ says RPM sensor.

I have in my possession from some time ago a "reference sensor" part 034 905 381A. Sensor that fits near the belhousing

Sound like the right thing to change?

audi_marv

There are two senders at the bell housing. One is the RPM sender, the other the Ignition Timing Sender (black end plug at firewall bracket).
Senders are interchangeable also. The sender magnets go bad due to age and heat. Possibly the magnet has picked up metal bits/flakes, and can be cleaned and re-used.

mattmondo

There were some metal flakes on the sensors. I replaced the white sensor (which was dented), cleaned the other sensor, and reinstalled. Ran out of time, will test later today!

Conman200

Most likely cause, and an issue with these cars is the fuel pump check valve at the top of the fuel pump in the tank. Winter time especially, ice crystals can block the check valve open even more. There is an upgraded check valve. The problem would be worse if the car was left sitting for a short peroid of time. How does it start cold? You could remove the fuel pump relay, and jump the two terminals in the fuse block to have the pump run steady. Let the pump run for a minute and see if the car starts. The best way is to check with a fuel guage overnight. Let me know how it works out.

turbo510

Non-starts with my '86 CS Turbo drove me nuts until I found my problem. The fuel pump relay had gotten hot; a solder joint was oxidized and cracked. Reflowing new solder, and polishing the contacts, forever solved that.

Try this when it doesn't start: Have someone crank the starter, while you tap on the fuel pump relay. If it then starts, this is a sure sign that the relay is needing attention.

mattmondo

Connman: I'll try that. I did replace the fuel pump with a new BOSCH unit about 18 months ago. Cold it fires right up, even at 10 below F. Come to think of it, I may have a new relay! The car came with a bunch of stuff and a box of new relays! I do not have a FI pressure tester; May have to borrow one to test.

Turbo510:
Like I said above, I believe I have a new relay that I'll replace and see if it does any good.

Even though I was getting a 2111 code, it seems like a fuel issue (from symptoms.) Another person has suggested that my distributor timing is JUST off enough that when the car is warmed up, the hall effect sensor and RPM sensor don't jive! Cools down and they are just 'touching' enough to send a signal!

Conman200

Good cold start would be due to the fact that the cold start valve kicks in, and a lower fuel pressure is required at start up. Did you change the check valve at the top of the pump when you replaced the pump?

audi_marv

Rust inside the gas tank can also block the check valve from fully closing...even if the fuel pump/check valve is fairly new. I had this problem with a 2yr old pump. I used a bottle of Marvel Mystery oil and water remover in consecutive fillups, and this helped a great deal. If the rust inside is bad, its kinda like changing your oil filter without changing the oil.

Speaking of filters....how's your fuel filter ?

Faulty fuel pump relay sounds like a real good possibility.

And the next time you get a no-start, try turning the key on (do not crank engine) and put a fuse in the fuel pump relay. This will turn on your fuel pump, and pressurize the system. If car starts, you may be looking at a fuel leakdown, leaky injector problem (especially if the no-start is when the car has been driven/is hot).

Also...sometimes you will get a phantom 2111 reading when you check the codes using the 5-second crank method....as opposed to getting the codes after you've run the car past 3000 rpm.

mattmondo

Back soon! Down with the flu!