Hard start and engine stalls at or just above idle, Code says 1216 - TPS

[tkohl]

I am a fairly new to this e34 side of the forum. I have done some searches here trying to understand and figure out what is happening.
Engine cranks put doesn't start. Check the codes and let it run thru a couple times. Just keeps giving the same code. The after this it will start. Then though the engine will just quit at a low idle at intermittent times. Kind of gives a quick sputter and dies. I pulled a code of 1216. I pulled the TPS and checked the connections. Put it back on and the engine started right up. Drove 18 miles to work with no issues. Started hard again after setting for a couple hours. Died several times with in town driving. Runs fine on the freeway. So today I replaced the TPS. Now it at least starts right off most of the time but it is back to stalling below 1K rpm. It continues to keep giving the same code, 1216, and doesn't stop. Can't seem to clear it either. Tomorrow I will be replacing the fuel filter because I have no idea when it was done. Any other suggestions? Thank you very much for any suggestions.

[shogun]

1216 Throttle Potentiometer This code is stored if a break or short-circuit occurs in the wiring to the Throttle Potentiometer or the potentiometer is defective. Damage at the throttle potentiometer connection is the most common cause of this fault.

BMW DIAGNOSTIC TROUBLE CODES
www.e38.org/e32/bmw%20code%20defaut.pdf

[tkohl]

I checked the connection this morning. It looks fine from what I can tell. Anything specific I should be looking for or testing? Thanks.

[danielson]

could be faulty tps but that should not keep the car from running. have you tested the crank angle sensor?

[tkohl]

I'm not sure but from what I have read the crank sensor either works or it doesn't. Correct me if that's wrong. I cleared the code today and it still was stalling and hard to start. After it was running for a bit I rechecked for codes. No codes. I replaced the fuel filter and could not get it to start at all. I replaced the pump and checked the tank. It looked pretty clean. After a few tries it finally started. Let it idle for awhile and it started stumbling a few times and then it stalled again. Restarts right off normally. Still no codes. It sat for about 4 hours and I just went out to see if it started and it started right up which it hasn't done since last Weds. Guess I will drive it again tomorrow and see how it goes. It looks so far like I have had a couple issues that came to a head at the same time. Maybe with the new TPS I might get a little better gas mileage which has been terrible.

[demetk]

I would suggest to next test/replace the coolant temp sensor. Then check the O2 sensor output voltage. At idle you should be getting a dithering voltage between .2-.8 volts that cycles every second or so. A steady voltage of < .5 volts means the engine is running lean. A steady voltage > .5 volts means the engine is running rich.

[tkohl]

So what are them symptoms of the CPS going bad? Can it work intermittently?

[tkohl]

Not it will not start at all. Not sure if I'm seeing it right but it seems like when it has finally started in the past it was right when the cel light would start flashing. Any ideas?

[tkohl]

Stomp test no longer functions either. Guess I need to figure out how to get it home.

[ross1]

Stomp test no longer functions either. Guess I need to figure out how to get it home.

Stomp test is predicated on a functioning TPS.

[tkohl]

TPS is new. Finally started after clearing codes and jump starting. Pulling intake today and testing and cleaning everything. Tired of guessing and piecing.

- - - Updated - - -

Today I ran the test on the CPS and got no reading. I tested the new on and it was 550 across 1 and 2. Replaced and still no start. Back to square one. Tested fuel pump by jumping and got fuel. Tried with the a new relay and still no start. Question. Should I get fuel at the feed hose when trying to crank the engine? I disconnected the front rail hose and tried cranking the engine and got nothing. I did with the jumper in place. Another question. Can you test starting the car with that jumper in place? Thanks for you help.

[ThoreauHD]

The fuel pump should kick on as soon as you turn the key. I can't tell you what the issue is, but I would make sure the fuel pump is engaging, then the O2 sensors, then the MAF. Those three things will stall you to dead stop; regardless of codes. If you can crank up, it's not the tps.

[tkohl]

I do have a question about how I got it started the other day. I jumped it cause the battery was almost dead for attempting to start. Could the battery have enough to crank car fine but not allow it to start?

- - - Updated - - -

Tried the jump start with no luck. No spark and no fuel. CPS, DME relay, Fuel pump relay and TPS all replaced. DME swap out next?

[tkohl]

OK. I have fuel at the front of the rail only when the relay is jumped. I have no spark. I have tested the relays power and grounds per Bentley section 120. It has a new CPS, TPS, fuel pump relay and DME main relay. Per the tests the power is there with the key on. The DME relay has a good power at term 87 and a ground at terminal 31 too. Replaced and tested the fuel pump fuse just because. CPS tested at 1k. New one tested at 550. I have cleared the codes and replaced the DME with one from the yard. Can't verify it's good but it was an attempt. I can't seem to find info in the Bentleys for testing the ignition switch. My guess would be it's OK since the voltage tests to the relays came out good. Is there anything in the instrument cluster that could keep the car from starting? The speedo and tach don't work when it's cold out till I have shut off and restarted after the car is warmed up. I am at a literal stand still now. Any more idea/help would be greatly appreciated.