E30 broke down on me...

[E30_Narek]

For a few months, my car's had a pretty bad idle and hard starts when hot sometimes. Recently, it's had all that + the car hiccups/hesitates/fuel-cuts when accelerating. I was driving today and it was hiccuping more than usual. On my way home, the car jerked violently every time I gave it gas. If I revved it in neutral, it just seemed to hesitate to redline, fuel-cutting the whole time. I believe this is a fuel related problem. The things that are new on the car are: fuel filter, spark plugs, spark plug wires, timing belt (doubt this would even matter in this situation), intake boot, a couple fuel lines, both coolant sensors, oxygen sensor, distributor cap and the rotor. The car currently isn't in any state of driving. The check engine light is NOT on. I did the stomp test anyways to see if it'll throw any codes and I got 1444 which is "no faults." I also tried on a new AFM to see if it'll fix it, but it didn't so I put my old one back on. What could be causing these problems?

[jeffnhiscars]

You don't say whether the problem began around when you did any of those maintenance items which would make a big difference. You changed a lot of parts and there's always a chance that a new part is defective.

Otherwise, I'd start with checking all your electrical connections particularly grounds, then a smoke test which will often diagnose bad idle problems, then check fuel pressure preferably while driving.

This all assumes everything is connected right, that there is no contamination in the fuel tank and that your injectors and fuel are good

[Ether-D]

I don't see a crank position sensor on you list of replaced parts. That'll do what you describe.

[E30_Narek]

You don't say whether the problem began around when you did any of those maintenance items which would make a big difference. You changed a lot of parts and there's always a chance that a new part is defective.

Otherwise, I'd start with checking all your electrical connections particularly grounds, then a smoke test which will often diagnose bad idle problems, then check fuel pressure preferably while driving.

This all assumes everything is connected right, that there is no contamination in the fuel tank and that your injectors and fuel are good

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 don't see a crank position sensor on you list of replaced parts. That'll do what you describe.

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

[dnguyen1963]

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

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

[E30_Narek]

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

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

[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

[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!

[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]

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).

[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.

[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.

[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]

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?

[dnguyen1963]

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