E30 broke down on me...

[Seawolf]

EDIT: I keep reading something about a fuel check valve... what the hell is this? Is it in the fuel pump? Do I have to worry about it if I changed the fuel pump?

Another EDIT: Yesterday when I tried driving it, it flashed a CEL. So I checked the code and it was 1215 which is for the AFM. This same code showed up last year when my car was broken down at this exact same time. I just changed the fuel filter and it went away. What do I do this time?

The check valve is in the fuel pump.

As to What do I do this time? - You need to systematically diagnose the problem and eliminate systems to narrow everything this could be down to the root cause rather than trying to remediate symptoms.

I really recommend you get one of these ($20), it will always be very useful:

http://www.harborfreight.com/fuel-injection-pump-tester-92699.html

This has everything you need to diagnose the fuel delivery system. A dead end test should give you 80 - 100 psi maintained at the fuel rail feed and a consistent 43 psi inline with the engine running. If all this checks out you KNOW that it isn't fuel delivery and you can focus on the other remaining systems.

If you need help on fuel pressure test procedures let me know and I'll write it up.

If fuel delivery is good I'd swing my attention to the HT ignition system, I see you replaced a lot of stuff but what about the coil ? Your symptoms could be the result of an ailing coil - is your plug spark bright blue or orange ? If it's the latter then the coil is suspect but there is a test procedure to confirm this before throwing another $100 at it.

Provided these systems both check out then you are left with engine management (fuel and ignition metering) which are trickier but all doable. And there are some weird things that may surface (e.g bad alternator, dry DME solder connections) but at least you know it isn't basic stuff.

[E30_Narek]

are your lights dim by any chance? I was having similar issues; bad idle, choppy throttle response, etc. I thought either my injectors were clogged because I had recently ran the tank reeeeally low, or I had some other fuel related issue.

BUT, I changed my alternator and got a new battery and so many of the problems I was having are solved. car cant run right without enough power, crazy right? haha

since it happened slowly over time I didn't realize how dim my lights had been lately, should've been an obvious sign I was losing juice. both the battery and alternator are easy to remove and go get tested. I skimmed through the thread, not sure if you replaced them or ruled them out already but yeah, check those out. good luck man! I know the struggle.

All those are good. The battery is off my dad's car which he replaced recently. The battery did die on me about 3 weeks ago because I left my electric fan on overnight but that's about it. It's been doing this before that though. Lights are fine.

EDIT: I keep reading something about a fuel check valve... what the hell is this? Is it in the fuel pump? Do I have to worry about it if I changed the fuel pump?

Another EDIT: Yesterday when I tried driving it, it flashed a CEL. So I checked the code and it was 1215 which is for the AFM. This same code showed up last year when my car was broken down at this exact same time. I just changed the fuel filter and it went away. What do I do this time?

[J.Rizo]

I'm somehow just going to limp the car to a mechanic. I've had this same problem for 10 or so months and I'm tired of dealing with it.

are your lights dim by any chance? I was having similar issues; bad idle, choppy throttle response, etc. I thought either my injectors were clogged because I had recently ran the tank reeeeally low, or I had some other fuel related issue.

BUT, I changed my alternator and got a new battery and so many of the problems I was having are solved. car cant run right without enough power, crazy right? haha

since it happened slowly over time I didn't realize how dim my lights had been lately, should've been an obvious sign I was losing juice. both the battery and alternator are easy to remove and go get tested. I skimmed through the thread, not sure if you replaced them or ruled them out already but yeah, check those out. good luck man! I know the struggle.

[E30_Narek]

Maybe so but did you test your fuel circuit pressure (dead end and in circuit test) ?

Unless you can categorically eliminate individual systems (e.g. Fuel delivery, Fuel metering, HT Ignition & Engine Management) throwing parts at this problem can get very expensive very quickly.

I'm somehow just going to limp the car to a mechanic. I've had this same problem for 10 or so months and I'm tired of dealing with it.

[Seawolf]

UPDATE: Well it wasn't the fuel pump. Spent $100 for nothing.

Maybe so but did you test your fuel circuit pressure (dead end and in circuit test) ?

Unless you can categorically eliminate individual systems (e.g. Fuel delivery, Fuel metering, HT Ignition & Engine Management) throwing parts at this problem can get very expensive very quickly.

[E30_Narek]

UPDATE: Well it wasn't the fuel pump. Spent $100 for nothing.

[dnguyen1963]

Take the lead out of your foot. Seriously, only a properly tuned car would give the best mpg.

[E30_Narek]

Alright so today I had to drive my parents' VW Passat to school and I did a bit of testing with the MPG and compared it to my car. The Passat on $10 of gas (which is like 3.3 gallons) gets 60 miles until it's completely dry. My car on $10 of gas gets about 55 so I'm starting to believe that my MPG isn't bad at all and it might indeed be the fuel pump that's causing all this to happen. I believe my way of driving makes me get worse MPG than I should be getting (I shift at like 4k RPM first gear and 3-4k second gear and 3k on 3rd gear). Can anyone give me some tips on how I can improve my MPG by driving more... economically?

[AndrewBird]

Fuel pressure regulator could be bad. I would start by checking fuel pressure at the rail, preferably while the engine is running and at different rpm.

[E30_Narek]

I had it smoke tested about 2 months ago. I had no vacuum leaks. I doubt a vacuum leak would cause all this though. This only seems to happen when I get below a quarter tank of gas and I also get like 14 mpg.

I'm with Jeff on this. I think you have at least two problems. One is fuel starvation because of the crud in the tank. Two is leaky injectors (poor gas mileage). Did you perform the smoke test with the exhaust plugged up? It needs to be done at about 2-4 psi; otherwise, you can miss critical leaks that can only be observed when the engine is warmed up.[/QUOTE]
Mechanic performed it while I wasn't there so I don't know how it was done.

[dnguyen1963]

There is reason enough here for me. Plus, a smoke test will probably save you a lot of money down the road.

I had it smoke tested about 2 months ago. I had no vacuum leaks. I doubt a vacuum leak would cause all this though. This only seems to happen when I get below a quarter tank of gas and I also get like 14 mpg.[/QUOTE]

I'm with Jeff on this. I think you have at least two problems. One is fuel starvation because of the crud in the tank. Two is leaky injectors (poor gas mileage). Did you perform the smoke test with the exhaust plugged up? It needs to be done at about 2-4 psi; otherwise, you can miss critical leaks that can only be observed when the engine is warmed up.

[Cephas]

Not able to speculate on that. Do the tests and go from there. My car didn't exhibit the problem all the time either. It was sporadic, but did get worse over time.

If you search you will find there are others who have dealt with this issue (jlevie posted in a george graves thread about the same thing).

[E30_Narek]

As I mentioned in your other thread - this is most likely one or more of your injectors leaking. If you don't want to spend money to check this you can try one of a few things.

1) Check fuel pressure after you turn the car off. There are many tutorials on how to do this on this forum. You will notice that you lose fuel pressure far too quickly as the injector spits fuel into the cylinder. These cars should hold fuel pressure for quite a while after shut off.

2) Shut the car off and use a mechanics stethoscope (or your ear) to listen to your injectors. If one is leaking, you will likely be able to hear it happening. (This was the case with my car. I could actually hear what sounded like a leak in a garden hose from my #1 injector).


I know the 1221 code threw you off. Here's the deal: that code doesn't necessarily mean that you need a new o2 sensor. It simply means that the o2 sensor is showing a lean or rich condition. A leaking injector = a WAY too rich condition and is very dangerous to drive a car this way as well.

Talk to MEPEH on this forum. He sells rebuilt and flow tested injectors for our car for a really, really reasonable price.


Also, so others can see - here is the other thread:

http://www.r3vlimited.com/board/showthread.php?t=371736

Get those injectors done. May as well do a new fuel pressure regulator and BMW injection hose as well!

But if my injectors were leaking, wouldn't the problem persist all the time? My problem is getting worse as the fuel level gets lower.

[Cephas]

Alright, the problem began December of last year. The car was barely driveable and was doing these exact same symptoms. I changed the intake boot and tried on a new AFM at this time. Nothing happened. Then, I cleaned out my AFM, the ICV, and the throttle body. Again, nothing happened. I finally changed the fuel filter and that almost fixed all my problems. The car was driveable now but it started to have a rough idle when I started it while hot. Then as time progressed, it started hard starting at times when the car was hot along with the rough idle. I started changing some things here and there but they didn't do anything; didn't improve it or make it worse. After a while, it started doing those hiccups/stutters/fuel-cuts but there were very rare. It started throwing the code 1221 which is o2 sensor but after a while that code went away (though I did eventually change this sensor, which changed nothing...). Now, the problem's worse than ever and I'm stuck without a car.


I'll check the resistance on that today. Don't want to throw money at it for no reason anymore haha.

As I mentioned in your other thread - this is most likely one or more of your injectors leaking. If you don't want to spend money to check this you can try one of a few things.

1) Check fuel pressure after you turn the car off. There are many tutorials on how to do this on this forum. You will notice that you lose fuel pressure far too quickly as the injector spits fuel into the cylinder. These cars should hold fuel pressure for quite a while after shut off.

2) Shut the car off and use a mechanics stethoscope (or your ear) to listen to your injectors. If one is leaking, you will likely be able to hear it happening. (This was the case with my car. I could actually hear what sounded like a leak in a garden hose from my #1 injector).


I know the 1221 code threw you off. Here's the deal: that code doesn't necessarily mean that you need a new o2 sensor. It simply means that the o2 sensor is showing a lean or rich condition. A leaking injector = a WAY too rich condition and is very dangerous to drive a car this way as well.

Talk to MEPEH on this forum. He sells rebuilt and flow tested injectors for our car for a really, really reasonable price.


Also, so others can see - here is the other thread:

http://www.r3vlimited.com/board/showthread.php?t=371736

Get those injectors done. May as well do a new fuel pressure regulator and BMW injection hose as well!

[jeffnhiscars]

When you said it got worse at 1/4 tank I suspected twnK crud. Now that you say changing the fuel filter helped Im back to the tank.

Pull the back seat, remove the access cover and do a visual on the inside of the tank. No smoking please