WHITE EXHAUST............., After warming for 60+ seconds, starts to run very rich, exhaust turns white Options

[ctc911ctc]

To all ECU/MPS/TS2 people!

I have a '74 2.0L that I am resurrecting to be original equipment with the exception of all of the Hell-Hole parts which are Rest-Design or other vendors.  The problem that I have been admiring for 2-3 weeks is one of White Smoke, or richness that begins after the engine has been running for 1-2 minutes.

Background: ’74 2.0 barn find, 20K miles all indications are this is accurate (brake pedal wear, rotor wear, seat wear, all other used car tricks, etc….)
Replaced fuel system tank to injectors
Replaced all vacuum hoses
Replaced all other fluids
Replaced Hell hole, longitudinal, floor pans.
Body – perfect, really, really good.
Engine started, sounds like a swiss watch – no mechanically ‘noise’ just mechanical music….
A little rough, however – too much engine motion in the bay

As the engine warms, the injectors are told to put way too much fuel into the system, white smoke and rich exhaust smell start after 40-60 seconds of operation.

Here is what else I did so as to learn as much as possible about the process. I bought a second MPS from a 911World - great guy, very engaged and supportive (THANKS!). I also bought an ECU from him. When I received them, both checked out as ’74 2.0 numbers. Great, though the new MPS is a bit leaky, it compares to the numbers of the one I had which I replaced the diaphragm

I put the two MPS units (the one I  got with the car and the one I bought) on the bench and here are the numbers - very similar - My H meter is not calibrated so I believe since the two are VERY similar that I have a calibration problem…

 Setting____Reference__New Diaphragm___Purchased though leaky
0 inHg._____1.45_______1.06______________1.15  
4 inHg--------1.24_______ .94_______________ .96  
15 inHg______.75_______.66_______________ .66  
 
1. I have tried both MPS units – operates the same, white smoke starts after a minute or two.
2. I Swapped the ECU units – operates the same, white smoke starts after a minute or two.
3. Replace the TS2 with a rheostat (variable resistor) tried it at 1K/500/300 - I believe it changed the time before the white smoke….takes a bit longer, have not timed this effect yet.

I have not done anything with TS1 (Air temp sensor) since it has a marginal effect on mixture (see https://members.rennlist.com/pbanders/ecu.htm Common Questions)

Talked to the guy who rebuilt the injectors and he has never seen a stuck injector which would stop being stuck when the car is off. (The fuel rail holds 30lbs for hours so injectors close when off).

I am centering the MPS/ECU/TS2 part of this equation.

Will keep digging, ANY advice would be very welcome!

[ChrisFoley]

Does the idle change when it starts smoking? The idle should drop and get rough if it's going that rich.
Have you driven the car?
If it was too rich, enough to cause smoke, the engine would run poorly and have low power.
Have you tried adjusting the idle mixture knob on the ecu? If it has a noticeable effect, the mixture is fine.

Sometimes oil collects in the exhaust pipes or muffler and when they start to heat up after a minute or two, the oil starts smoking. The way to eliminate the smoke is run the engine long enough to burn it all off. It may take 5 or more minutes of driving to completely eliminate the accumulated oil.

[ctc911ctc]

Tangerine Chris,
Great to hear from you in this thread!

Yes, a few seconds from the smoke starting there is a drop in RPM.
Cannot drive the car until I get the calipers back ( and weld some panels into the floor so I can re-install the seats...grin)

Good tip as to the idle fine tune knob on the ECU - will try that today,

Thank you, Chris,

CTC

Does the idle change when it starts smoking? The idle should drop and get rough if it's going that rich.
Have you driven the car?
If it was too rich, enough to cause smoke, the engine would run poorly and have low power.
Have you tried adjusting the idle mixture knob on the ecu? If it has a noticeable effect, the mixture is fine.

Sometimes oil collects in the exhaust pipes or muffler and when they start to heat up after a minute or two, the oil starts smoking. The way to eliminate the smoke is run the engine long enough to burn it all off. It may take 5 or more minutes of driving to completely eliminate the accumulated oil.