Misfires and GT1 issues

TrickerZ · #1 01-28-2013, 11:12 PM

I've been having misfires on my 2000 X5 and finally decided to get a diagnostic head to figure out what was going on. I have the OBD2 head (BMW USB OBD Diagnostic Cable Inpa Ediabas NCS Expert Dis V57 SSS V32 Progman GT1 | eBay and was able to pull the codes and found that all cylinders are misfiring. I'm guessing it's either a vacuum leak or a fuel pressure issue. I don't drive the car much, and it seems like it takes awhile after I start driving it again before it starts to misfire and shut down cylinders. Subsequent restarts reveal misfires soon after it reaches idle. If a fuel pump is going, would it act like that? What's the best way to find a vacuum leak? Starter fluid?

Secondly, I'm guessing I need the round diagnostic head to really use DIS. Can I use one of those OBD2 to round adapters, or do I need a special head for DIS? I also need to remove my suspension from the sequence and would like to know if I need a ZCS code if I use DIS v44.

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upallnight · #2 01-29-2013, 12:12 AM

If you have the round connector in the engine compartment you will need to get a connector for it. There are various connectors available, round to OBD II, round to USB and round to serial port (I have one from my days of owning a E34).

From the link that you provided you will have to order the round connector to USB or round connector to OBD II. If you brought the cable from this seller, just buy the round connector cable from him.

The round connector allows you to access coding modules, while the OBD II connector inside the car allow you to read fault codes, and live data from the DME.

TrickerZ · #3 01-29-2013, 08:45 AM

Thanks, I just ordered the round connector adapter. I sent a message to the seller and found out that some of the Chinese cables are missing a wire in them for ignition. He pointed me to one that will work, so we'll see how it goes when it gets here.

Any ideas on what I should start checking? Would the MAF cause issues over time? It seems like the misfires only happen after the car has been driven for awhile. It usually happens shortly after the second or third start while the car is warm.

SlickGT1 · #4 01-29-2013, 09:00 AM

Maf can cause these issues.

Do a smoke test to look for a vac leak.

What do you mean remove suspencion from sequence? Delete air ride? Use NCS expert and remove it from your vehicle order.

SlickGT1 · #5 01-29-2013, 09:00 AM

Maf can cause these issues.

Do a smoke test to look for a vac leak.

What do you mean remove suspencion from sequence? Delete air ride? Use NCS expert and remove it from your vehicle order.

upallnight · #6 01-29-2013, 09:31 AM

Do you have an error code? You need to find out which cylinder(s) is/are misfiring. If the misfire is so severe, the computer would turn off the injector(s) to prevent damages to the cat converter. Perhaps that's is what happening, you have a misfire in a cylinder but only after x amount of misfires the injector to that cylinder is turned off. This is why you feel the misfire after driving for a while.

sockethead · #7 01-29-2013, 09:42 AM

Fuel pump would probably give you lean codes on the O2 senors as well...

Just throwing this out there... on our 2001 4.4, it was getting misfires on all cylinders until we put new plugs in it then it ran great... how old are your plugs?

TrickerZ · #8 01-29-2013, 10:05 AM

Quote:

Originally Posted by SlickGT1

Maf can cause these issues.

Do a smoke test to look for a vac leak.

What do you mean remove suspencion from sequence? Delete air ride? Use NCS expert and remove it from your vehicle order.

Yes, delete the air ride computer from the order (sorry, sequence was the wrong word). I had read before that you needed a ZCS code to do that; is that not the case with NCS Expert?

TrickerZ · #9 01-29-2013, 10:10 AM

Quote:

Originally Posted by upallnight

Do you have an error code? You need to find out which cylinder(s) is/are misfiring. If the misfire is so severe, the computer would turn off the injector(s) to prevent damages to the cat converter. Perhaps that's is what happening, you have a misfire in a cylinder but only after x amount of misfires the injector to that cylinder is turned off. This is why you feel the misfire after driving for a while.

I have misfire on all cylinders and an injector code. I can't remember the wording for the injector, but it sounded like it wasn't firing. That may be to indicate that it turned them off?

I'm pretty sure it was turning off the injectors since it would start and run fine for a minute, then start running on fewer cylinders.

TrickerZ · #10 01-29-2013, 10:16 AM

Quote:

Originally Posted by sockethead

Fuel pump would probably give you lean codes on the O2 senors as well...

Just throwing this out there... on our 2001 4.4, it was getting misfires on all cylinders until we put new plugs in it then it ran great... how old are your plugs?

No lean code. I just replaced a damaged spark plug, so I'll have to clear the codes and see if that plug is the only one that doesn't misfire. I'm not sure how old the plugs are, but they look to be in good shape. That was the first thing I was thinking before I found out all cylinders were misfiring. It seems unlikely to me that all plugs would die at the exact same time. I'm thinking either a grounding issue or vacuum/MAF issue, but you'd think a lean code would be thrown with vacuum/MAF as well.

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