3-Series (E21, E30)Chat relating to the BMW 3-Series from 1975-1983 and 1984-1991 line. Specific models: BMW 315, BMW 316, BMW 318, BMW 318i, BMW 320/4, BMW 320i, BMW 320/6, BMW 323i, BMW 320i. E30 Family models include: BMW 325e, BMW 325i, BMW 325is, BMW 325ix.
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We have in our workshop an 84 318i with a stalling issue, and it's got us stumped for now.
The BMW was brought into us by another workshop that could not fix the problem, so let's see if I can test your brains for a hint as you guys seem to know BMW's left, right and center .
Problem: Stalls when engine starts to warm.
Known issue: All Injectors are pulsed full power when stalling occurs, causing engine to flood itself.
What's been done: The last workshop has changed the ECU to a second hand one, changed the TPS and Air Flow Meter.
What we know: The CTS does not cut out (which can caused to computer to put full power pulses to the injectors. Our signals are all being received at the ECU correctly. Engine main relay has been checked, all seems good.
After it has stalled, disconnect one or two injectors to easy the flooding, and she'll start back up and run until the problem comes back. What I also know is that it can be a random occurrence, ie, I've had it running for 5 minutes and it stalls, or 30 mins. What I also know is that if you give it a good boot full of revs, this can also cause the problem to arise.
Wrap ya heads around that, and see what you think, any and all help would be fantastic .
stupid Q but any check engine light?
hmmm thats weird..... I'll be thinking of this one all day and check my bently on wiring....
__________________ 1991 Ford Taurs SHO 5 Speed White on Tan
1996 Chevy Lumina LTZ Rep 3.4L
1992 318i Coupe parts car
1992 325i Ls1 swap with a T56 6 speed 12.2 quarter mile
1976 Mercedes Benz 300D with a Ford 5.0L Fuel Injected soon to be Modded I am Captain Obvious
1) thermo time switch on the t-head to make sure it is working. If it isn't, it's going to feed information to ECU that engine is operating COLD and the car will forever be feeding more gas than it should when engine gets warm.
2) check integrity of the Throttle Switch and if ok, recalibrate. The potentiometer inside the TPS measures the opening of the throttle body relative to the airflow. In turn the information is communicated to ECU, the resultant of which increases or decreases the injector opening time, as the case may be...
*TIP: 84 models would still have the cold start injector.... it just might be stuck open
Not until it has fully stalled, and at that time all the lights are on obviously.
Quote:
what is CTS, please?
Coolant Temp Sensor
Quote:
1) thermo time switch on the t-head to make sure it is working. If it isn't, it's going to feed information to ECU that engine is operating COLD and the car will forever be feeding more gas than it should when engine gets warm.
2) check integrity of the Throttle Switch and if ok, recalibrate. The potentiometer inside the TPS measures the opening of the throttle body relative to the airflow. In turn the information is communicated to ECU, the resultant of which increases or decreases the injector opening time, as the case may be...
Thermo Time Switch and CTS are both fine, and TPS is correctly tuned against specifications. The Cold Start Injector is the only on not affected at time of misshap. You have have that disconnected and it won't affect the engine at all when it's warm. Remember, Cylinder Injectors 1-4 are pulsed full power at time of problem, regardless of RPM .
check the spark plug model... platinum plugs do not work well with early production bimmers.
when the car stalls what is the condition of the plugs in ALL cylinders? wet...? dry...? dry-black? dry-brown? is the condition "uniform" for ALL cylinders, or are the shades in one(or some) cylinders different from the rest.
when you have the answers to the above... u know what to do
The plugs are going to be a bit black because the engine just flooded itself. But either way it's a flooding issue not a spark issue .
yup... but my frst line of checking rich or lean will be plugs
what is your measured fuel pressure & how many grams of air per second are u reading?
*from reading the posts i get a feeling that your injectors might we worn out. for a 28yr old car, thts very possible. even if u r getting full injector pulse, if they don't close fully due to worn seats, you will get the symptom complained of.
The injectors are fine, they were replaced 12 months ago, and were checked by the previous workshop.
What I now know is that even though the Air Flow Meter was changed, it seems it is the cause of the fault. Whether the previous fault was rectified and this new AFM happens to cause the same problem is ironic. But the AFM is producing a varied signal on one wire when it's operating fine (usually around 4 volts at idle) will shoot up to 12v when the problem occurs, on both the input sense wire and output sense wire, causing the ECU to go into confusion mode, and tell the Injectors to open fully. Tomorrow I'm going to replace the AFM, and the problem should stop. I'll let you know how it goes, but from everything I've tested time and time again, this to me is what the fault is.
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