Cold start and rough running issues

[zaffer]

I looked in the FAQ's and DIY section for information and while I found some, the links for the WUR are no longer working. I have a CIS book that details how the components work, but nothing about settings and such as it's a general overview of the CIS system, regardless of vehicle.

Here is what's going on:

- On cold start, the car will start, run for a few seconds, then die. I figure the cold start injector is working and it's starting from that. Haven't pulled to verify, though.
- If I can keep it running, I have to lay into the throttle to keep it running, at generally that's above 1,500 RPM's.
- Once it's warm, it will stay, running, however the idle must be above 1,500 RPM's or it will die. I have actually had to adjust the throttle cable to keep it running as there isn't enough adjustment in the idle screw to maintain idle.
- I checked for vacuum leaks and found a few: throttle plate linkage, charcoal canister, and one other, but they are all VERY minor.
- I checked fuel pressure and it is a steady 70 psi at the fuel distributor.
- Once the engine has warmed up, it runs better, but only above 1,500 RPM's, and even there it's not steady.
- I did time the engine once it was warmed up to make sure that wasn't a factor and timing was off, but still having the same problems.
- I have not tested the pressure accumulator, but starting when warm is much better.
- I don't have a repair manual, so I don't know what the setting for the air plate on the distributor is supposed to be when the engine is off.
- I have messed with the mixture screw in the top of the distributor, but did a rough adjustment: Pulled an injector, turned the screw until fuel just stopped coming out of the injector, then turned it another 1/8 of a turn.
- I disconnected the O2 sensor in case that was an issue, but no difference in performance.
- Both the WUR and the air bypass valve are rebuilt units from Fuel Injection Corporation.

I pulled the intake boot between the distributor and the intake manifold: the plate moves freely, but there is a film of oil/dirt on top of the plate. If I lift the plate while activating the fuel pump, I can hear fuel moving through the injectors.

I am re-learning the CIS system, and this is the first time I've had to figure it out on an e21.

Thanks for any help!

Any ideas/suggestions at this point?

[320iAman]

Hello: In FAQ's E21 Fuel Distributor Rebuild , I added it in there. Post #4 in the link below has pictures of tear down and putting it back together and a test of the heating element. You'll need a Bosch K-Jetronic CIS Fuel Pressure Kit to check and adjust the Warm up Regulator-WUR, S and G Tool Aid 33800 and 33865 gets the job done nicely plus checks System Pressure(Fuel Pump), rest pressure, hot and warm control pressure(WUR). I have the 33800 kit-two of them, one for back up. I got a super deal $50 for the back up one, 33800 was ~ $100.00.

https://www.bimmerforums.com/forum/s...tor-Adjustment

As far as not running after start up ,could be the fuel accumulator is bad , can test it, faq's has the method, testing the WUR and keeping it in specifications of ~ 20/50 psi cold/warm is necessary as well.

FAQ's

CIS trouble shooting:

3 - Leaking Accumulator - A leaking accumulator will cause hard warm starts, but if it's large enough it can bleed off enough pressure to keep the car from starting at all. To check for an accumulator leak, disconnect the small rubber line from the back of the accumulator and plug it with a golf tee or bolt and clamp it. Shove some fuel hose onto the nipple on the back of the accumulator and run it into a gas can. Jumper the fuel pump. Some fuel will spray out of the accumulator, this is normal as the rear chamber will have some fuel in it from the in-tank pump (the fuel line we disconnected). If the fuel flow does not stop then the diaphragm is leaking and it needs replaced.


Randy