Re: 85 - 318i lurching - electrical problem ? (lon (archive)

My first thought was your injectors. Here is my logic. Say an injector is leaking. There may be too much fuel on startup. Making one cyclinder fire sometimes, and miss othertimes. Same for driving long distances.

Anyway, I looked at a reference book (How to Tune and Modify Bosch fuel injection.)
They call your symptom "Trailer Hitching".
And.. They suggest:
1) perform fuel pressure test. (dealer did this)
2) inspect airflow meter (you did)
3) test temp sensor II (you did)
4) test circuits to the injector. look for bad wires
5) test the injectors. A good local shop should be able to do this for you. They test the spray pattern and also look for leaks.

I suggest buying this book, and reading it.

Good Luck,
-Lloyd-
'84 318i

Car just back from the dealers (171k miles). Not much help account can only get car to lurch on highway and not in garrage, so they cant figure out whats going on. Their suggestions: possilble ignition coil (in my limited experience, ignition coils are either good or bad, not intermittant); transistor ignition control unit (one on firewall); or, possible impulse coil in distributor.
symptoms: Car will start ok cold. Upon warm-up (just above blue line on temp), when driven will start lurching, stumble and recover in the 2000 to 2500 rpm range. Upon driving to full warm (mid range on temp), car will drive ok with no lurching. This takes 15 to 30 mins for it to straighten out. If car is turned off for 5 minutes, car will restart and loose idle/stall out. At this point, the engine has to be reved to 2000 rpm to keep from stalling. Once the car is going again, the lurching and idle problem goes away.
If the car is driven for a long time (more than a half hour) on the freeway, and then goes back to city stop and go driving, the lurching will sometimes reappear.
Whats been done: (last fall) new plugs, distrib cap/rotor, new fuel pump relay, can of dealer recommended anti-carbon solvent run through tank. (recently) new plug wires, new fuel filter, new air filter, new fuel pressure regulator, new charcoal cannister, cleaned out air meter box (works smoothly good signal out), inspected rubber connector between air meter box and throttle body (no defects), replaced vacuum lines, replaced air bypass valve hoses, cleaned and checked air bypass valve (works right in spec), checked and cleaned all under hood connectors/grounds (replaced and repaired any defects), checked temp sensor and switch (proper sig outputs, but cant tell if they become intermittant during warm-up), dealer checked fuel system and is within speck for pressure, delivery and itegrity.
Prognosis: some electical fault that goes intermittant during warm-ip and disappears at operating temp, but what ?
Idle control relay ? Temp sensor or switch ? Impulse coil ?
Suggestions ? Recommendations ? Any bosch fuel injection experts in the mid-Connecticut to western Massachusetts area you could recommend ?
Thanks for any help you can render.
Wolfgang :(

Follow Ups:

Re: 85 - 318i lurching - electrical problem ? (lon Jim Ladd 13:34 7/23/2000 (0)

[ Follow Ups ] [ 3-series (E30) Message Board ] [ Msg. Board FAQ ]

Questions, comments, or problems, please visit the Roadfly help desk.