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So I've been trying to diagnose this issue for about 3 days now and can't seem to get anywhere. A few months back I had some intermittent starting issues, I'd try to cold start it and it would just sit and crank. I'd wait a couple hours and try again, and up she went. Went about my business for about 3 months and everything was great.
A few dats ago I was driving around about 45mph @ ~3k rpm, and it started tripping on itself. Would "misfire" for a split second and return to normal repeatedly. I gave it some gas and it accelerated with full power. Hopped on the interstate and was cruising about 70 at the same rpm as before and this time I had more noticeable stumbling and reduced throttle response when I tried to power through it. I got worried and parked it.
Next morning, same problem as 3 months ago, cranking but no start. Replaced plugs, replaced coils with working used coils, and replaced the crankshaft position sensor (PIA). All for nothing. I haf it in my garage and could smell the unburnt gas for the exhaust. I'm going to get a spark tester tomorrow. Any insight would be appreciated.
shade tree mechanic
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Do you have a fault code reader? Any fault codes?
Tested the crankshaft position sensor already? http://bmw-e36.com/repair/210-the-cr...ensor-m50.html
http://bmw-e36.com/repair
There is quite a confusion about the CPS, 540 +/- 10% m 1280 Ohm, hall effect or inductive, volts
https://www.bimmerforums.com/forum/s...on-sensor-ohms
https://www.bimmerforums.com/forum/s...ing-Every-Year
Last edited by shogun; 02-12-2018 at 10:19 PM.
Shogun tricks and tips for the E32 series are HERE!
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No check engine light and tried the stomp test. Would those be enough or are the fault codes stored differently? Tried to test the sensor, but my multimeter was dead....
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Finally got a good multimeter and the CPS tested at 645 ohms. First time I've gotten a Beck-Arnley part bad right out of the box, guess I'll be ordering a different one this time around.Originally Posted by shogun
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It's a '94, no codes to pull. He might find joy with the stomp test, but there are no codes as in the OBD II cars. If the stomp test can be initiated, he should get 1000, maybe 1444, but 1000 is the code he should see.
My '94 had a dead battery, deader than a door nail. I put the charger on it, no joy after hours. I connected it to my F150 with the jumper cables, still no joy. The AAA showed up with a booster box and, boom, instant start. New battery, no more troubles. You need to consider the idea that the battery is dead.
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Did you turn the engine by hand to see if the CPS changed as the tone ring went by?
The sensor is looking at a tone ring, sorta like the sprocket of a crank of a bicycle, as the teeth go by, the sensor changes state. There is little to no value in measuring a sensor that reads a tone ring in a static condition. Speed sensors are similar. The tone ring turns, the sensor creates a square wave that is a clock pulse. There is a reference pulse that is just two sprockets filled in so the pulse is elongated. It is all but impossible to have a failed CPS, and not have a Check Engine light.
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Hmmm, I didn't try that. Everything I've read on testing it and I don't recall a mention on the tone ring. That might save me a warranty and removing that pain again. I also ordered a new main relay in case, mine looked a little crispy anyway. Ill test the crank sensor again, but I do have one concern. What point on the tone ring is supposed to be 540 +/- 10%? Mountain, valley, in between? If in between, what are the min and max values? Or is that reading separate?
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Did get 1444 as a result of the stomp test, reset, and got 1000.
Nothing has led me to believe the battery is dead. It was recently replaced and cranks strong. I'll try anything at this point though, I'll trickle charge and load test it tomorrow.
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Battery tested fine.
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How old is the oxygen sensor? If it's over 60k then replace it. Run a couple bottles of injectors cleaner over the next couple tanks of gas, get CRC GTP or royal purple cleaner.
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I'm sure it's as old as the car. I'll replace it, but wouldn't there be a code associated with it? I would think it would still start even with the O2 sensor out. I run injector cleaner every 6 months.
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Wife's 1994 reads fine in INPA using almost free ads interface
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Diagnostics aren't the be-all and end-all people think. For example wife's 325 would crank easy but not run and no fault codes a while back. The ECU would have spotted a fuel pump relay missing (low current circuit) but not the lack of fuel due to a faulty immobiliser cutting the fuel pump.
Another fun one I had recently, changed oil on it, started fine, then would not start. Diags showed the EWS systems was not letting car start (no faults as working as intended)
Turns out the drivers door handle on the outside was stiff and the handle was sticking out and that was the cause...........I did not even see a ref to this in the EWS 1 manual!
In spite of the fact it may not help if I was you, and I am not, I would get INPA and ADS interface and mistreku.zip
- - - Updated - - -
Wont stop the car running, no need to speculatively replace
No warranty of any kind implied or given and no liability for any loss, damage or injury, no matter how incurred accepted.
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Run the fuel pump manually to see if it runs, but do not try to start the car doing so.
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Sorry for the late reply everyone. So I went to my dealership and ordered in a CPS to test. Tested perfectly, bought it, installed it, and the car starts and drives, but it runs pig rich. Any solutions?
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Vacuum leaks, smoke test it if you have to. Then replace the oxygen sensor.
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Already have an O2 sensor just in case my leak check comes up empty. I've also read up on FPR problems raising the pressure on the rail. Could this be another thing to check?
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Wait, vac leaks for Rich? Really? Vac leaks makes Lean, not Rich.
As for "where on the tone ring..."
No place in particular. I meant that if the tone ring happens to have a peak of a valley directly under the sensor, then the resistance might be different. The tone ring sets up a square wave that the computer then counts to understand where the crank is. The sensor is a magnet, and the teeth on the tone ring cause the magnetic field build and collapse which changes the electrical characteristic of the circuit, which gives the square edges that the computer can count.
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Sure, if the rich comes from idle speed conditions.
The fuel pump delivers some number of pounds per square inch. I believe the number is about 60 psi. The fuel pressure regulator opens at high vacuum -- idle -- to shunt the excess fuel, fuel supplied but not needed, back to the gas tank. As the fuel demand goes up, the regulator closes to keep more fuel on the fuel injector rail. Let's say that the pump gives 60 psi, but at idle only about 20 psi is needed to supply enough to keep the fuel ratio correct, the regulator is the device that diverts the extra fuel back to the gas tank. As the load increases, the fuel demand increases so the regulator closes to force more fuel to be available to the injectors. Fuel Ratios are a function of injector on-time and fuel pressure. If the pressure is 25 psi and the on-time is 1 millisecond, then the engine will do one thing, if the pressure remains at 25 but the on-time increases to 5 milliseconds, then the engine does something else. It's possible that an on-time of 5 milliseconds will cause the pressure to drop enough that a lean condition will exist, so they want the regulator to close so that the pressure goes to 60 psi so that injectors do not starve. I have no clue what the actual pressures or timing is, but the idea remains even if I give wrong numbers. There's a Fuel Delivery Map in the Bentley manual, but I have not studied it. It illustrates the fuel delivery over time and load.
Usually, the Regulator Opens sufficiently, and remains open, to cause the fuel pressure on the injectors to go low, creating a lean condition, or it allows so much fuel to bypass the injectors that the engine will not run at all. It is odd that the Fuel Pressure Regulator will result in a Rich Condition.
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It seems to be rich at all RPM, I just noticed it the most at idle because I could see the smoke. Getting it up the rev range is when I started smelling it. I have a lowered car too. A friend mentioned that I could've bottomed out and scraped a hole in the exhaust. I know someone said that "check engine lights aren't the be-all and end-all," but if I had a hole in the exhaust before the O2 sensor, I would think SOMETHING would show that. Whether it's a code, a check engine light, fuel mileage, power loss. But I haven't bottomed out since fall...
Edit: Checked plugs and they were wet, checked exhaust and there is definitely soot in the pipe.
Last edited by MadRomeo; 03-01-2018 at 11:18 AM.
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Anyone? I also checked the plugs and they were wet with fuel, also had oil in the threads. Compression check was good, 190 +/- 10 psi.
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Engine coolant temp sensor? There are 2 sensors on the side of the head under the 1st and 2nd intake runner area. One tells the ECU temp and one operates the gauge. If the ECU thinks the engine is cold it adds fuel. The explanation above for fuel pressure is close but the exact numbers for fuel pressure are 3.5 bar (about 51 PSI) with the vacuum line disconnected and somewhat lower with it hooked up. Lower 40s PSI is usually the pressure at idle.
The reason that the vacuum needs to modify the fuel pressure is that the flow through the injector is a function of the pressure difference ACROSS the injector, which is (fuel rail pressure - intake manifold vacuum). Not the pressure in the fuel rail relative to the outside atmosphere.
At wide open throttle there is almost no vacuum in the intake manifold because the throttle is wide open, and the fuel pressure regulator will raise the pressure to 3.5bar (51 PSI) so the pressure drop across the injector is 3.5 bar - 0 (no vacuum in the manifold) = 3.5 bar (51PSI) pressure difference. This is why you test fuel pressure both with the line connected and disconnected.
At closed throttle the vacuum is high so if you test fuel pressure with a gauge, the gauge is referencing atmospheric pressure (it reads 0 if nothing is hooked up to it), You might see about 40 PSI on the gauge, ideal vacuum is -14.7 PSI at sea level but an engine is not 100% efficient vacuum pump so it will actually be around -11 or -12 PSI on a healthy engine. 40 PSI in the fuel rail - 11 PSI vacuum = 51 PSI or 3.5 bar.
'94 325i Sedan, Arctic Gray: UUC LTW FW, EVO 3 and DSSR, +.020 Maxsil pistons, ASC delete, Eibach shocks/springs, 16" contour reps 238k
'93 325is Coupe, Schwarz, work beater 299k
'89 325i Vert, Alpine White: 5spd swapped. Sold
'04 Toyota Sienna XLE Limited AWD, In progress swapping to M50/G250, http://www.wibimmers.com/board/index...nna-25i-build/
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'85 Toyota LandCruiser: Lifted, gas hog. 205k
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Now I'm not so sure about this. The car is smoking out the tailpipe, blue tint is obvious on startup, but gets more white as it runs. The compression check was good, and I even checked the coolant reservoir for bubbles to make sure it wasn't a head gasket. The valve cover gasket is leaking into the plugs tubes as well. Sorry about all this information, I'm discovering new things and questioning myself at every opportunity. Someone on another thread mentioned a CCV valve. Where would the DME coolant temp sensor be?
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DME coolant temp sensor is under the first or second intake runner on the side of the head. There are two sensors, it is the same part that E30 325 cars have, the blue plug if I am not mistaken.
Blue at startup could just be oil, my car does that but I expect it with 284k miles on it. The spark plug tube seals will eventually cause a problem if too much oil gets in the tubes but it won't get to the combustion chamber because the spark plug is sealing that hole.
White smoke is likely coolant or water, you can get a decent amount from condensation depending on if you frequently take short trips so don't panic. Have you had to add coolant? The "CCV" valve is near the front of the valve cover and it is just a plastic fitting that has a small and larger hose coming from it. The larger one goes to the intake boot elbow and the smaller one goes to another plastic fitting under the intake manifold. You can unclip it and make sure it isn't clogged with slime very easily. Check that out and see what it looks like.
'94 325i Sedan, Arctic Gray: UUC LTW FW, EVO 3 and DSSR, +.020 Maxsil pistons, ASC delete, Eibach shocks/springs, 16" contour reps 238k
'93 325is Coupe, Schwarz, work beater 299k
'89 325i Vert, Alpine White: 5spd swapped. Sold
'04 Toyota Sienna XLE Limited AWD, In progress swapping to M50/G250, http://www.wibimmers.com/board/index...nna-25i-build/
'05 Volvo V70 R, 6mt, mostly stock, kid hauler 200k Sold
'85 Toyota LandCruiser: Lifted, gas hog. 205k
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Is there anyway to test the sensor?
I'm replacing the valve cover gasket and tube seals as well as getting new grommets.
I have been adding coolant, but I've also been in the cooling system recently. At first I replaced the water pump and bled that until the Check Coolant Level message stopped popping up, it was good for about two weeks until the crankshaft position sensor bit the dust. Had to remove the lower radiator hose and have driven it much since. I'm still filling it every heat cycle, but I assume it's because I haven't bled it all the way. My longest trips around my town are about 20 mins long. Would the CCV cause any misfiring if it's clogged?
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