1500 FI stalls during warm up phase

You mentioned that you had a spare heater valve....try this experiment.

1. Install the heater valve in place of the AAV.

2. Secure the heater valve to some part of the engine (or preferably the chassis) using hose clamps, wire ties, mechanic's wire, etc.

3. For the duration of this experiment, remove the distributor access panel in the spare tire compartment.

4. Rig up a spare hand choke/hand throttle push-pull cable and and then secure one end to the operating lever on the rigged up heater valve. Bring the other end into the passenger compartment thru the distributor access panel and position it so it's handy to you in the driver's seat.

5. Set the position of the cable to open the heater valve almost all the way, allowing a lot of air to pass thru the hoses.

6. Start the car, and immediately adjust the position of the cable to give you a fast idle of say 1400 +/- RPM

7. As the car begins to warm up, you would expect the engine speed to increase. Continue to adjust the cable to give you a fast idle of say 1200 RPM. One would expect that your adjustments are going to gradually reduce the airflow thru the heater valve.

8. If you can use the cable position to control the idle so that it maintains a normal to 1200 RPM throughout the full 5-10 minute warmup to operating temperature, and then eventually be able to fully close the heater valve and the engine achieve a normal hot idle, you have proven that your original and replacement AAV were not operating properly, or may have been wrong for your car.

9. One solution would be to continue to work on adjusting the AAVs you have, or modifying their function, or trying to acquire a better AAV.

10. Another solution would be to consider the heater valve experiment a proof of concept, and then go about locating some sort of valve that would fit and function to your liking, and install it and consider it a "hand choke" of sorts.
 
Max, if you really doubt about the classic oil you use. Change it to 15w40. Just to see if it changes the situation. If not, you can take it of the list of possibilities.
 
*Dan i did that and that works. It is more or less the same as adjusting the idle screw to higher idle when cold and normal idle when warm. The original aav is working as should. I verified that by looking through it and seeing the valve (small triangle) close when connected to a battery. My other aav does exactly the same.

*budget verified that many times. I have this problem now for more then a year and i start to recheck the same things over and over. Drives me nuts.

Could it be the friction of the engine? I have not changed much in that area. Change oil, change exhaust, air filter, distribution belt, temperature sensor, oil filter, spark plugs, ... :wall:
 
The original AAV may be working somewhat, but for whatever reason it is no longer allowing enough air thru to maintain the warming-up idle where you want it to be.

If you've done the experiment with the heater valve, and it allows you to apply manual adjustments (say, once every other minute for the 5-10 minutes it takes to get up to full operating temperature) that keep the idle where you want it to be during the warm up phase, then you can develop that experiment into your normal operation of the car by refining the execution of the experiment....for example, researching a better valve, working out the details of the cable control, etc.

Perhaps even having a look at early cars that came from the factory with a manual choke (in the USA, only the '74 cars had a manual choke) and installing that control mechanism in your car....IIRC, the USA manual choke cars had the choke knob next to the hand brake.

Another option might be doing research into the differing part numbers of Bosch AAVs. Here in the USA, many European cars of the era (say '82-'89 or so) came with the LJetronic system. Maybe if you could try AAV from cars with larger engines to install on your car, as it would seem logical that an AAV for a larger engine would need to pass more air or possibly stay open for a longer time than the original X1/9 AAV .
 
I can't imagine the oil viscosity causing your problem. It has to be something either ignition (coil, spark strength or timing) or fuel injection related.

Have you tried with the O2 sensor unplugged? This can rule it out as a contributor.

Something that bogs the engine down so reliably is likely a bad sensor or sensor wire.

Does your car have A/C? There are components in cars with A/C that could contribute.
 
The original spec for the X1/9 trans calls for GL-1 gear oil, which is a pretty thick-bodied oil.

Many X owners in the USA have switched to Redline MTL or MT90, a synthetic gear oil. The MTL is the lighter weight and the MT90 is the heavier weight.

If you think the thick, heavy GL1 might be creating too much drag on your engine to idle properly until it warms up, then you could consider switching to a locally available equivalent to Redline MTL.

http://www.redlineoil.com/Products.aspx?pcid=7
 
Also...

Also, you can rule out the AAV being to quick to close by unplugging the wire connector to it. This means the internal heater won't be on, but the AAV will still close due to block heat warming it up, just more slowly. If this helps then the AAV may need cleaning or adjusting, or be worn out.
 
The reason why i think it has to do with the vicosity of the oil, is that when i start the engine after it has cooled down for 6 hours ( engine is cold except for the oil), it idles as one expects. That seems to indicate that it technically works as should.

I have to admit, i found it also difficult to believe. That why it is one of the latest things to try. I keep you all informed.
 
No cure

Tried this morning with the different oil. I was able to keep the engine running, but still not idling good. Now keeps running at 500 rpm, but expect 1200 or so.

No a/c. And yes i tried it also without O2 sensor.

I know it is getting extra air through the aav and the afm measures that and provides additional fuel (longer shots). Should the ecu in this period tell the injectors to stay open longer because the engine is cold? I can't find that in the technical ljectronic manual.

*edit*
Found it. It's in the pulse devision section. The duration of the fuel injection pulse depends on:
1. Speed + Air quantity . Information provided by the AFM
2. Engine temperature. Comes from the CTS
3. Air temperature. Come from the temp sensor in the AFM.
4. Vehicle voltage. Low voltage causes the duration to shorten.
 
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Mxgrds said:
I know it is getting extra air through the aav and the afm measures that and provides additional fuel (longer shots). Should the ecu in this period tell the injectors to stay open longer because the engine is cold? I can't find that in the technical ljectronic manual.
Click to expand...

The AAV is just a way to provide more airflow thru the engine without this extra airflow passing thru the throttle plate, which would otherwise open the throttle plate and thereby thru the throttle position switch tell the FI ECU that the engine is operating at part throttle rather than at idle. The AAV is not controlled by the AFM whatsoever.

If you follow the path of the airflow thru the AAV into the engine, you see that it starts downstream of the AFM (air flow meter), so any air that flows thru the AAV has already been accounted for by the AFM which means it will ensure that the injector pulse width is lengthened to accommodate that air which is flowing thru the AAV, bypassing the throttle plate, and directly into the intake plenum.

The FI ECU gets two temp inputs:
1. The air temp sensor built into the AFM.
2. The coolant temp sensor (CTS) in the thermostat housing.

Of the two, the CTS is more important to cold starting and driveability and is what the FI ECU depends upon the most to determine how much longer the injector pulse width should be to compensate for a cold engine.
 
I have tried starting with a second cts not in the thermostat, so not measuring the engine temperature. Nothing happened. No additional fuel. Is it a wiring problem then? If there is no connection to the cts, the engine doesn't start.is it possible that the ecu is not reacting on the cts sensor? Is it possible that a part of the ecu doesn't work?
 
If you take the CTS resistance measurements at the contacts in the big connector that clamps to the top of the FI ECU, you are also checking the wiring between the ECU and the CTS.

BTW, the ground wire for the CTS is in the main FI harness bundle, and terminates as one of the two FI grounds on the cam cover studs...the CTS ground is the rear stud.
 
Dan Sarandrea (Phila) said:
If you take the CTS resistance measurements at the contacts in the big connector that clamps to the top of the FI ECU, you are also checking the wiring between the ECU and the CTS.

BTW, the ground wire for the CTS is in the main FI harness bundle, and terminates as one of the two FI grounds on the cam cover studs...the CTS ground is the rear stud.
Click to expand...
This is a very good point.
When I was trouble shooting my FI system, following the guide, which tells you to check resistance at the harness end as Dan suggests, doing it this way also has you checking the wiring. I had a corroded ground wire (the very one he references) INSIDE the wrap, after dissecting (carefully) the harness and fixing the ground wire, I was back in business. Run your tests at the ECU connection and simple continuity checks between ground and the sensor's ground wire can confirm whether or not the thing is indeed grounded decently.

One of my threads in a similar vein
http://xwebforums.com/forum/index.php?threads/20881/

and the culprit of an earlier exploit;
wire49_zps9ed403d1.jpg


this is nice
CTSwiring_zps5cb9af42.jpg


these can be problematic
corrodedterminal_zpsdca8638d.jpg
 
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Thanks again guys for the suggestions.

Checked CTS resistance at the ecu side of the harness: 2 to 3k when cold. Is according specs. Didn't measure it when hot, but I have no problem when hot.
Checked all wires individually: 13, 49 and 5. Ground was an issue on top of the cam, but repaired it. Connector number 5 looks like the one depicted in the previous post. But managed to clean it and bend it back in proportion. Hope it does connect to pin 5 of the ecu, I think it does. That part is difficult to check. I have ordered new pins.
Checked if I didn't switched the connectors of the AAV and the CTS. I didn't.

I my feeling I have ruled out (by checking) all causes in the CTS or harness. The only thing I am unable to check is if the CTS signal comes into the ECU and if it does, does de ECU respond to it as it should (given a longer pulse when cold)?
 
An update. New head gasket, valve timing adjusted. Engine runs much much better and has much more torque. It also idles higher when cold and doesn't stall anymore. I am not sure what has solved the problem, but i guess it is a combination of all the work.

Thanks for the tips.
 
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