Messages

1

Engine + Driveline / Tank empty but fuel gauge 2/5 full?

« on: August 16, 2008, 10:38:39 AM »

I read many threads about gauge showing empty on a full tank. But is it possible to have a fuel gauge pointing about 2/5 full with an empty tank? I am asking because I couldn't siphon even a drop out of the fuel tank while the gauge consistently settle at the 2/5 position when the key is turned "on".

Thanks

2

Electrical / fuel pump/non-start issues - been doing lots of research, still NEED HELP... please >

« on: June 04, 2008, 09:56:45 PM »

you must check what is wrong with the compression...It is too low...i do not believe that you have a problem with the pistons or the piston ring , you should check for a crack in the cylinder head...There is no way the car worked fine and imidiatly droped pressure from the pistons...check your timing , remove the valve cover , and read from a manual about timing and where all the parts should be , check it and see if you have any timing issues...

edit : if there is wrong timing , the valves would be open and no compression would be possible....

Still googling on similar issues. One guy had a low-compression problem b/c no spark in two cylinders and the gas washed off oil sealing the rings. I may also have blown gasket.

Severe T-storm with wind gusting 60+mph this afternoon. my cherry tree in the yard was blown over. big mess.... Strong storm continues Thu and Fri...
Will open the hood after that.

3

Electrical / fuel pump/non-start issues - been doing lots of research, still NEED HELP... please >

« on: June 02, 2008, 08:33:02 PM »

No one can offer some ideas?

4

Electrical / fuel pump/non-start issues - been doing lots of research, still NEED HELP... please >

« on: May 31, 2008, 07:32:40 PM »

I find it hard to believe that one day it runs good then the next day won't start with no compression.
How did you perform the compression test ?
Are you sure your compression tester o ring was good ? I would try another tester to be on the safe side .
It just doesn't add up ..............................I may be wrong though:confused:
good luck

RED IS 91 -

I tested the compression with a brand-new compression tester from Advanceautoparts for $25. The tester come with an extension hose so I can reach down the deep plug hole. With all plugs, main relay and fuel pump relay out, and the tester fitting screwed in (o-rings seated well at fitting-to-hose connection), my neigbour cranked over the engine while I watched the tester dial until the pressure reading stables, after about 5-6 revs.

You raised a good question: How did the engine run ( I forgot to mention that it had never burned oil) with such low compressions. As I mentioned in the last post. The "wet" compression test raised the compression from 35psi to 80psi, right above the minimum ignition compression of 65-70psi. Maybe the car kept running just b/c I never let it sat off road for too long so the oil helped sealing the worn piston rings by pure luck for so long? But it still doesn't explain why it didn't burn oil with all the worn rings. I plan to put some thicker oil in each cylinder tomorrow and see if it make some difference.

Another possibility: maybe a skipped timing chain (Just like Cobra Jet suspected) messed up with valve timing  so the valves are partially open in the compression stroke so the pressure is low?

Have anyone heard of M42 very-low-compression issue before and know how to diagnose/fix it? I am all ears.

5

Electrical / Problem found

« on: May 30, 2008, 09:20:51 PM »

The good news is I may just found the culprit. The bad news is that the problem may be serious.

The compression in the 4 cylinders reads:
cylinder 1:  40psi
cylinder 2:  75psi
cylinder 3:  32psi
cylinder 4:  35psi

Then I did a "wet" compression test with cylinder 4. With some 10w-30 oil to seal the rings, it read 80psi.

That tells me that I may have:
worn piston ring and/or cylinder wall, or
worn piston ring, cylinder wall and valves

I remember reading an article that for an engine to start there need to be at least 65psi pressure in cylinders. So low compression caused the no-start issue?

I would think that a worn engine would develop chronically aggravating driveability issues long before it fails. Yes, the car did not accelerate quick. but it constantly gave 25-30 GPM fuel efficiency. Shouldn't a worn engine turn much worse MPG? Besides, the engine just passed 155K mils mark. I have heard a lot of bimmers with 200K+ miles on them and still running great. So is it normal for this one to be so worn

So the puzzle is why the engine ran well on Saturday and suddenly stopped working next Monday? One possible explanation may lies on what happened on Saturday. I was checking the brake pads and had to roll the car up and down the driveway a couple of times trying to find a good jacking base. Each time the engine ran for a few seconds. In doing so unburnt fuel might flooded
the piston and washed off the oil. As I mentioned above, Cylinder 4 reads 35psi in "dry" compression test and 80psi in "wet" test. Assuming it's true that the engine need at lease 65psi to fire up, the oil being washed away removed the seal b/w the rings and cylinder wall and reduced the compression below 65psi threashold thus cause the engine not to start, even though everything else works normal.

But every time I crank the engine, Shouldn't oil be pumped to the piston rings and cylinder walls and seal where they contact, thus restore compression? Anyone have a good explanation for this?

Another thought is that if the above is exactly what happened, may be I could revive the engine by changing to thicker oil like 20w-50 and feed a tea spoon of oil through each spark plug hole. The risk is that every time I let the engine sit for a couple of days, I may not start the next morning.

Anyone have experience fixing a low compression problem? Does that require special tools/equipment, skills and a lot of hours? How much could it cost to have a repair shop open the engine and change rings, pistons or both?

What to do now? Any suggestion is welcome here. I am still not ready to give up.

Cobra Jet, I saw you started another popular thread on #87 gas. I have used #89 for the past 3 years. But after going through these compression diagnostics, I guess an older engine with lower compression can probably use #87 safely simply b/c the low compression won't detonate the lower-oct gas. Do you agree?

6

Electrical / fuel pump/non-start issues - been doing lots of research, still NEED HELP... please >

« on: May 29, 2008, 06:48:40 PM »

318i91 -
How old are or how many miles are on your timing components or do you know if any of the timing components have ever been replaced?  The reason I am asking is another type of non-start issue that could occur IF you do have spark is that the timing components are no longer within spec or alignment.  If somehow the timing chain skipped, the chain broke or the timing sprockets have become misaligned, then the engine timing will be affected which could create non-start issues.  

155K on the engine and I don't think the timing chain has ever been replaced. I wish the timing chain did not skip b/c I may lack the skills and equipment to fix it.

- If you are indeed getting spark then the car should fire up providing you are also getting fuel AND air to the engine...  You have said you are getting spark for sure, so it would seem that your ignition coils are productive and the CPS may be functioning properly (or at least within spec).  Also, from what I was told in this very thread, if you see the check engine light when you turn the key to the "on" position and are able to get it into the code extraction mode, then the DME Relay is good, the DME is getting power and supposedly is working.  I suppose a DME could have other issues which may affect it's internal data operations, but I don't know how to diagnose DME internal failures.

I am crossing my fingers on that.

What was your CPS readings?  Did you take a reading w/ the CPS removed from the car and also take a reading w/ it installed?  
Just curious too - when you removed the old CMP, what was the reading w/ it removed from the car?  If you still have it, see if it still tested out at "0" as it did when you initially tested it.

The CPS has 520-ohm resistance. I did not remove it as it's not easy to access. The OLD cam sensor didn't have a reading when it was in. Then I removed it and actually could read 1260 ohms which is in spec. After careful check, I found a crack right where the cable going in the sensor head. I think the the cable has poor connection at the crack so the sensor did not read, but once removed the cable could flex to better connection and read ohms. The NEW cam sensor reads 1420 ohms, really at or off the upper boundary of the spec.

What is puzzling is you are saying you have spark...  Is the AFM and ICV within spec too (both components regulate air into the engine)?

When I took it out of the car, The ICV initially read 8 ohm which was in spec. After soaking it in cab-cleaner for 30mins(not sure If I damaged the coil by doing this), it read 2-3 ohms but the valve still operated when 12V was applied from a power adapter. Now, the ICV's  does NOT move when I put it back to the car and turn the ignition to "ON" position. I could hear very faint buzzing only with ears directly on it. but the metal valve does not move at all (looking from the openning). The cable to the ICV valve does have 12V reading on it.

There are 5 pins in the AFM. Which pins should I check?

If the fuel pump is working is fuel definitely getting to the injectors is each injector firing or spraying fuel as well?  Have you tested the fuel pressure?

How do you check if the injectors are working?

Going to buy a compression tester now and check compression tomorrow after work.
Thanks

7

Electrical / Problem yet to be solved

« on: May 28, 2008, 09:02:30 PM »

If the cam sensor is faulty the computer won't be able to tell the injectors when to squirt fuel into the cylinder.

I replaced the cam position sensor yesterday. The bad news is that the engine still won't start. So let me recap:

1.  There is spark
2.  Fuel pump relay and fuel pump works and the engine should be getting fuel. I could smell gas in the tail pipe after crank-overs
3.  According to Cobra Jet, if there is spark the CPS and DME should be working. The CPS did read a resistance in the spec (could a faulty CPS still fire up the sparks but mess up the spark/injector timing?)
4. The ICV should be working and I cleaned it.

So why the engine cranks normally but won't start? Did I miss anything?

I am going to follow B318M42W's word and test the compression next. But my gut feeling tells me the problem lies somewhere else. I am saying so b/c the car was operating normally the day before the no-start. Can all 4 pistons or the valves be damaged all at once without warning signs?

This must be among the most mystorious no-start problems. Thanks to you guys for stay with me and I still need advice.

BTW, Looks like there is continued interest on this topic. Colo318IS, good luck.

8

Electrical / fuel pump/non-start issues - been doing lots of research, still NEED HELP... please >

« on: May 17, 2008, 10:24:12 PM »

If you tested your camshaft position sensor  and it was faulty why haven't you replaced it ? :confused:
These sensors all work together through the computer.

I didn't know the cam sensor was bad until last Thurs. I did google search and learned that a faulty cam sensor (also called cylinder identification sensor) cause some issues, but was not convinced that a bad one would prevent an engine from starting. See this article: http://www.diagnostic-assistance.co.uk/cid.htm
Besides, I have been as puzzled with my DME code as Cobra Jet with his b/c the it never returned a faulty code 1244 (for cam sensor problem)1444 code, even with the cam sensor disconnected!

So I am not sure the cam sensor is the culprit for the no-start problem.

That said, I am placing an order for a new one and hope it will solve the problem. Will keep you updated when I receive it.

The ICV is now cleaned and functions well. Thanks to Cobra Jet's advice.

9

Electrical / fuel pump/non-start issues - been doing lots of research, still NEED HELP... please >

« on: May 16, 2008, 07:18:14 PM »

Ok. The ICV reads about 8 ohms on multimeter, in the correct range. The valve did activate when charged with 12Volt, but there is some black soot in there I will clean out.

The air filter is fine. The temperature sensor in the AFM is clean and the duct is clean, too. There are 5 labeled pins on the connector but can some one tell me which pins I should check with multimeter and what is the correct ohm value?

With the ICV and AFM off, I tried to crank over. Still won't start; but for a few cranks it felt like the engine was almost trying to start for a split second but couldn't. After that, the DME did return the correct faulty code 1262 (ICV problem b/c I disconnected it)

If the no-start was due to no air getting in, why won't it start with open air ducts?

Cobra Jet, if the camshaft sensor helps the DME on sequential fuel injection control, could a faulty cam sensor mess up the fuel injection or spark timing and cause no-start? I am asking b/c I read from the thread (
http://www.m42club.com/forums/showth...amshaft+sensor) that engine should run with bad cam sensor. (I posted the question there, too)

Thank you folks for giving lots of help on this. I am going to get some carb cleaner now.

10

Engine + Driveline / faulty cam sensor and no-start

« on: May 16, 2008, 12:19:16 PM »

I think the car will run with a faulty camshaft sensor. It will simply fire a spark everytime the cylinder comes up instead of just during the actual compression stroke where it would fire if the cam sensor were working. Not sure if you actually need one or were thinking it would fix a not running at all situation.

Do you mean that a faulty cam sensor alone will NOT cause no-starting issue?

I have a no-start situation with my 91 318i with M42. I have been doing all testing for over two weeks and the only broken thing I found so far was a faulty cam sensor (no ohm reading on multimeter). I am going to test/clean ICV and MAF this weekend.  Thanks.

11

Electrical / The camshaft sensor is probably bad.

« on: May 15, 2008, 08:17:14 PM »

The DME is apparently working, because if you get or see the check engine light come on when turning the car on - OR you are able to extract any codes from it, it's working.

Have you tested the resistance values for the CPS sensor and the cam sensor?  If you have not tested for these values, I would definitely get a multimeter and ohm test each of those sensors to see if they are within spec.

In the event I may have missed how you determined spark - did you do the method I did by pulling 1 spark plug wire off, inserting a plug into it, grounding it to the engine or chassis and having someone crank over the engine?

Try and test out that FPR - let's see what reading you get from it too.

Hmmm.....   have you tested your ICV valve???  I'm asking this because I also had another prior non-start that had occured a few weeks before this last non-start issue due to the ICV valve not functioning...  Quick test for ya - turn the key to the ON position, then put your hand on the ICV valve...  The valve if working SHOULD be humming or "buzzing" - you can feel it and if close enough you can also hear it.  If you do not hear ANY hum or don't feel any buzz - it's not operating.  If not operating, you'll never get the car started either...  Take the ICV off, clean it out, tap it a few times on the outer casing, reinstall and see if you get it to come back to life...  About 90% of the time after a good cleaning and tapping, they come back.  The internals get jammed up w/ carbon which prevents the spring/plunger mechanism from operating 100% and will either not allow any air into the intake or too much air...  TRY IT (if you have not already)...

Update today:
1. There is no ohm reading b/w terminal 1&2 of the camshaft sensor. I tried both a digital and a analog meter. So I bet it's faulty.
2. The crankshaft sensor reads 520 ohms in previous test.
3. The ICV did buzz but very faint as I can barely felt it with fingers on. I took out the ICV and checked inside. It looks clean without much deposit or soot. I am not sure how to test it, though.
4. After camshaft sensor and the ICV disconnected, I checked the DME code using the "pedal pump" method, and still getting 1444! Shouldn't the DME return some faulty code? I am saying b/c last time when the MAF connector was loose about a year ago, the DME did return the correct doe.
5. I did use your method to check the sparks. after that I even pulled out every one of the plugs from head cover to check. They all fires normally.
6, The FPR is not easily accessable so I have not tested it. But for sure the pump was working and I was getting gas in the cylinders.

Would a bad camshaft sensor cause no-start situation? I am not sure what the sensor does and if it must be replaced.

One more thing, when I pulled a rubber hose (don't know what it's called but it's close to the front, or the radiator side of the engine, one end is connected to the head cover, the other end to another hose with "T" connector, under the intake manifold), some clear water (not a lot) came out of it. The inside of the hose was covered with some yellowish foam like stuff. Should there be water in the hose?

B318M42W, I used the car for daily commute (less that 5 miles each way) and it was running normal. The idle sometimes went rough slightly at stops for a few seconds, but not often. While testing the sparks, I grounded the plugs to the cylinder head cover and spark fired normally, so I guess the engine ground is good.

Thanks.

12

Electrical / Still puzzled

« on: May 14, 2008, 08:47:30 PM »

I found this  article very helpful .
Scroll down until you get to the no start check section.
http://www.bavauto.com/newsletter/2007_n407_newsletter.pdf

I am glad that Cobra Jet fixed his car.

This is the testing I did today:
1. All plugs were wet with gas after crank-over
2. All plugs have sparks
3. The engine did not start.

Based on what I read from all sorts of online posts, If there is spark and the fuel pump runs, the CPS should be working, right?

If there is fuel, spark and cranking, why didn't it start?!

The only things I could imagine are a broken timing chain(causing no-compression) or faulty ECU. But:
1. I have never heard any rattle noise indicating a failing or broken chain before and after the engine failed to start.
2. If the ECU is intact, shiny without loose joints and burnt components, can it be faulty while returning "1444" code and operating the relays and fire the sparks? Is there a simple way to test if the ECU is faulty?

I am totally puzzled. Really want to save this E30 but somewhat frustrated.

Thanks

13

Electrical / fuel pump/non-start issues - been doing lots of research, still NEED HELP... please >

« on: May 13, 2008, 07:24:47 PM »

Make sure you crank it over some before you pull the plugs.

The rain finally stopped. But there wasn't much daylight left after I got home.
The original plan was to pull the plugs, check their condition; then put them back and crank it over and then check again. But it was just getting dark outside as I was pulling the plugs, so I decided to leave the 2nd part (crank and check) for tomorrow.

The plugs (Bosch Platinum +4, 3yr old) came out moist and with gas smell. There was also strong gas smell coming out of the plug holes. The electrodes  look like in normal condition with some carbon deposits(a few carbon particles like the size of small ant). There is some liquid residue on the threads looking like water condensation? With a LED light torch I could see the piston tops, they seem moist (not wet) and covered with a thin and smooth coat of carbon deposit.

Now I remember that I actually rolled the car back and forth for a few feets on the driveway on 5/4, the day before the start failure (to find a solid jacking ground to check the brake pads); so the engine ran for about 10 secs each time.

If the engine was flooded, how long does it take for the cylinder to dry up by itself? I just left the plug holes open and hope all liquids will evaporate overnight. Will crank it over and check again tomorrow.

Thanks.

14

Electrical / fuel pump/non-start issues - been doing lots of research, still NEED HELP... please >

« on: May 11, 2008, 07:35:09 PM »

Good point. It is raining outside. Will pull the plugs to check if the rain stops tomorrow after work. I will let you know. Thanks.

15

Electrical / Cobra Jet, have you solved the no-start problem?

« on: May 11, 2008, 04:17:09 PM »

I forgot to mention that:

8. The check-engine light and all other lights are on, so I assume there is not fusible link issue.
9. The DME return code of 1444, which means no fault.