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240 Hi from Chile/ new here with a 1993 240 wagon. Blk smoke soot and craps!

PardoR said:
I have a thought: if were installed an ECT for LH 2.2 instead the ECT for LH2.4, the ECT 2.2 has two pins: one ground and other is signal with current. This current was delivered completely to the ECU and fried the driver transistor for injectors.... I guess that this current must be divided by two (thinking in two computers :ECU-EZK)
What do you think ? Am I wrong?
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No, it is not possible your LH2.2 ECT damaged anything except the washdown of the cylinder walls from all that fuel.

The "current" used to measure the thermistor is very small, and in the case of the wrong sensor, both EZK and LH computers saw that it was extremely cold, because that current did not flow through the sensor. Both computers supply the same reference, so the net result electrically was the same as if no sensor at all existed in the car.
 
Noisy belts CAN be from bad bushings=misaligned belt.

That sure is black smoke alright. It could be oil smoke, but that is blue. Does it SMELL like raw fuel? I see the CEL is still on. My 1990 240 was low on water from a pump leak and it got hot. The CEL illuminated and threw an ECT code. It would sputter sometimes from a stop. I reset the ECU after I fixed the leak and sputtering went away. Point of that story: it WASN'T the ECT.

Disconnect battery to reset ECU and see if the codes come back.

Voltmeter to 02 sensor signal wire and see if it swings back and forth between .1-.9v once its nice and toasty.
 
Hi guys!

Some news: I changed and put the OEM FPR from iPD and the car still throws black smoke .now my curiosity lean on the CEL. is off!! So, the next thing to try will be change the injector driver on the ECU but now I am losing the faith .... Maybe a lack of vacuum? Some inner engine damage? My illussion begins to fall with this volvo....

http://youtu.be/MiRB2Xgt9ls
 
I haven't read the whole thread, but have you pulled the injectors and pressurized them to see if any are leaking?

The CEL will go off when the battery is disconnected even for a second. Also, the bulb could have burned out:lol:

If the battery has been disconnected at all, it may take a few miles/ little while of driving for it to come back on.
 
93Volvo240 said:
I haven't read the whole thread, but have you pulled the injectors and pressurized them to see if any are leaking?

The CEL will go off when the battery is disconnected even for a second. Also, the bulb could have burned out:lol:

If the battery has been disconnected at all, it may take a few miles/ little while of driving for it to come back on.
Click to expand...

Yes, the injectors were tested in a Bosch service center.
Maybe tomorrow it will go on when the car be driven.
 
So it's a 93 lh2.4 car and the injectors are dumping way too much fuel (but not continuously to where it won't run?) how does the car run when you drive it as of now.
 
PardoR said:
I guess the ECU, precisely the injector driver, a Darlington transistor
Click to expand...

Well I'd think it needs a signal from somewhere. I guess the crank poison sensor tells them to fire x amount of times and stay ope x amount of time (duty cycle?).

So maybe something is causing the signal to stay on too long causing them to stay open for too long.
 
93Volvo240 said:
Guys, what sends the voltage to the injectors to fire? Does the crank sensor?
Click to expand...

Crank sensor goes directly to the EZK ignition box. It tells the EZK how many RPMs the flywheel is spinning. LH Box senses LOAD via MAF and then shoots that information over to the EZK so it can compute proper ignition timing. EZK also talks to the LH box and tells it the RPM. When crank sensor goes out, you will not have spark OR fuel injector pulse. Modern cars dont have a computer for ignition and a computer for Fuel. It's just an old Bosch/Volvo thing.


The injectors always have 12v to the positive side of them with key on. The ECU GROUNDS the injectors for a matter of milliseconds to pulse them.


Black smoke usually means running rich. It can also be burning oil, but oil smoke is more of a white with blue tint. Sometimes it can be hard to tell them apart. It could mean bunk MAF (bunk MAF usually creates lean condition), bunk O2 sensor, bunk ECT sensor, excessive fuel pressure, leaking fuel injector or even leaking cold start injector (not common on Volvo for leaky injectors, but I guess it could happen. (Do a fuel pressure leak down test to determine if injector is leaking after shutdown.)


Use the multimeter to look at the 02 sensor at idle. It will oscillate between 0.1-0.9v once hot. If stuck at either extreme, bad. You can also remove it, put it on the bench, and hit it with burning propane and it will make voltage (NOT EVEN CONNECTED TO ANYTHING!) .9v=rich (when burning fuel is touched to it).

Repeat your diagnosis of the ECT sensor circuit. Also inspect the plug for it carefully. The pins can get pushed back into connector, corroded, or damaged. Unsheath the LH and EZK computer connectors and backprobe the pin for the ECT sensor and look at resistance readings with the connector unplugged.


I am sure finding somebody with a tailpipe gas analyzer will be difficult. Here in California, we have to get emissions testing and on older cars they shove an exhaust gas analyzer up the tailpipe and measure pollution levels. By analyzing the Hydrocarbon and Carbon Monoxide levels, it is possible to determine if the car is running rich or lean.

93Volvo240 said:
(the injectors) stay open a certain amount of time
Click to expand...


The percentage that they are open vs. closed is percentage duty cycle. Time OPEN is pulsewidth. Duty cycle is a function of pulsewidth. Confusing. I know. It has taken me years to get to the level I am at.

Ever hear of Pulse Width Modulation (PWM)? The IAC on our car is PWM (aka) duty cycle controlled. So is the EGR vacuum solenoid. The computer sends PULSES to the component. Not a varying voltage. Modern cars use a lot more PWM controlled devices. The mechanical fan on modern Fords for example has a clutch that is controlled by the computer to be 0-100% duty cycle on/off. Modern cars also have PWM fuel pumps. It doesnt just get 12v all the time. It gets told how hard to work by the computer. Makes the pump last longer too. It's not going full blast like on our Volvos.


"What is duty cycle?" :

http://en-us.fluke.com/training/training-library/measurements/electricity/what-is-duty-cycle.html
 
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TB is being a bitch right now. It is barely working....anyways...


Put a multimeter on the 02 sensor wire and read the voltage. It goes from 0.1-0.9v. Anything above .450V means rich. If you are rich enough to blow black smoke, I would expect it to be pegged near .9V (full rich) Could be a bunk 02 sensor, OR an accurate reading. Further testing needed. If pegged at either extreme, remove 02 sensor and bench test with propane.

Bad 02 sensor video: (scanner danner knows his stuff.)
https://www.youtube.com/watch?v=ClCuoi3JxEI

Playing with fire to test 02 sensor.

https://youtu.be/stFhLSHsOGg

Does it run OK cold? EDIT- Sounds like it blows black smoke right from startup. The computer doesn't listen to the 02 sensor when cold, but take a look at the voltage anyways. Does it run OK full throttle? I guess the computer could be dumping fuel. If it were an OBD2 car I would be looking at the fuel trims, but you cannot do that on older cars. You need to look at the 02 sensor voltage to get a rough idea of if it's running rich or not, but an exhaust gas analyzer would be able to tell for sure.

What codes are you currently getting?
 
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PardoR said:
The EZK connector at pin 2 and ground (cigarrette lighter): no read, just an 1
Click to expand...


You need to repeat this test. You need to have the proper resistance reading to the EZK and the LH Box. It sounds like you do NOT have a ECT sensor signal going to the EZK box. You should have approx 2300 ohms at 63 degrees F/ 17 degrees centigrade.

If you still do not get a reading, test for continuity between the EZK pin 2 and the corresponding pin on the ECT sensor. Reading should be close to zero ohms. If open, you have an open circuit in that wire.

My current theory is that your ECU is in "limp mode" where it will default to RICH because of missing ECT signal.

What codes do you have and which pin are they coming from (2 or 6)?
 
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Wow lots of good info there. I always thought the injectors ran on like 6v for some reason and 12v was too much, idk where I read that.

So they have a constant 12v but are only firing when the ecu grounds them? Could this rich running issue be from some kind of short in the injector wiring, causing it to ground intermittently when it doesn't need to, making it rich?
 
ZVOLV said:
You need to repeat this test. You need to have the proper resistance reading to the EZK and the LH Box. It sounds like you do NOT have a ECT sensor signal going to the EZK box. You should have approx 2300 ohms at 63 degrees F/ 17 degrees centigrade.

If you still do not get a reading, test for continuity between the EZK pin 2 and the corresponding pin on the ECT sensor. Reading should be close to zero ohms. If open, you have an open circuit in that wire.

My current theory is that your ECU is in "limp mode" where it will default to RICH because of missing ECT signal.

What codes do you have and which pin are they coming from (2 or 6)?
Click to expand...

On the weekend will have more info about the car. A truck bring the car near to my home....
I have discarded the ECT issue because the error code (DTC) has gone by putting the right ECT for the LH2.4 instead the wrong one installed before (an ECT LH2.2)
So:
-The ECT code has gone putting the right ECT LH2.4 =the engine behaves a little better
- replacing the OEM bosch 3 BAR FPR instead the older perforated fpr: the engine get better a lot! The strong engine shakes were gone and the huge amount of black smoke has almost dissappeared.... But not at all, so the next step (tell me your opinions) will be replace the injector driver transistor on ECU. Is cheap... OR perform the injectors test with the obd test mode 3
 
93Volvo240 said:
So (the injectors) have a constant 12v but are only firing when the ecu grounds them?
Click to expand...

Yes.


93Volvo240 said:
Could this rich running issue be from some kind of short in the injector wiring, causing it to ground intermittently when it doesn't need to, making it rich?
Click to expand...

I like that you have come up with such a thought, but that won't be the case here. If some injector happened to be grounded all the time via a short in the loom, there would be a steady misfire on that cylinder. This scenario, based on the information and videos, it seems the OP has a car that runs and drives right now, but smokes at idle and throws a CEL.

A misfire at idle is easy to detect because you will feel the car shake, at least on a 4 banger, possibly a 6, 8 banger you may not feel a dead cylinder. The best low tech method I like for detecting a dead miss at idle is putting my hand over the tailpipe. Go try it yourself. Go start your car, feel exhaust, disconnect an injector; NOT a plug wire. Unburned fuel in exhaust can damage cat, and NOW go put your hand over the exhaust. You will feel the a very different and distinct pulsing of the exhaust due to the misfire on a 4 banger Volvo strongly with just your hand near the tailpipe.

I fried an ECU once by forgetting to put high resistance injectors in and everytime I turned the key on, the injectors WERE going full blast. Car wouldn't start.


"Limp mode" is when a computer is missing a very important signal, like coolant temp (ECT sensor) or MAF sensor. It doesn't know if the engine is cold or hot, so it cannot compute the correct mixture, so to be safe, it opts for a very rich mixture. Lean can blow and engine and cause misfires. Misfires can damage the cat very very fast.


AGAIN, OP needs to check the resistance readings for the ECT sensor by backprobing at the EZK box, and also at the LH box. Make sure the signal is getting all the way to the computer and is an accurate resistance reading. Simple resistance reading between each pin and a good clean ground.
 
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PardoR said:
(ECT error code gone)
Click to expand...

That is good!

PardoR said:
...next step...replace the injector driver transistor on ECU.
Click to expand...

The car runs and drives, so I don't see why you think it's bad.

PardoR said:
perform the injectors test with the obd test mode 3
Click to expand...


The car runs and drives. Your injectors and computer ARE working.


You need to test the fuel mixture at this point. Start with measuring 02 sensor voltage. Find the single wire for the 02 sensor. Check voltage as I mentioned. Create and airleak (lean out the mixture) by disconnected a hose or two and see if the smoke goes away....???? That would be an easy test.


You also should check fuel pressure. Restricted fuel return line could cause the fuel pressure to be too high=rich.
 
Well, after some days here I have an update:

I have not enough time to attend the Volvo, so I left it on a indy shop. The mechanc guy was trained in Sweden by volvo for over 17 years, so I guess there is no best hands to solve this issue.
The guy found: pre pump not working, the wrong spark plugs (bosch wr7dc) and too high compression due to soot. Everything else is ok. But the thing that is making me noise is: the guy said the pre pump is not working and the fuel pump is caught fuel with a lot of bubbles (Wtf?) , so the ECU is crazy receiving wrong info due the bubbles. The alternator belts are loosened , noisy and wasted , and the battery not charging properly. So after all this he said that if everything are fixed, the car could stop the high consumption and black smoke and soot.
What do you think ?
For me has no sense the bubbles...but if he was trained at volvo..... Let's see how it goes
 
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