e30 is running very rich..

[ashton]

i have an 88 325i that i just resealed the tank onand put a new walbro 255 fuel pump in it. i drove it aound for a good 2 hours and then it started backfiring and then it finally wouldnt start. i pulled the spark plugs and they had so much carbon built up on them. i cleaned them and drove it home..but still on the way home i could smell it running rich and im not sure what the problem is...if you have any ideas about what my problem is please let me know..btw it has the stock ecu and i always run 93 octane 100% gasoline. thanks


Ashton.

[jlevie]

Back firing is most commonly the result the engine running lean or interruptions in spark. Either can cause coking of the plugs from misfires. The first thing I'd do would be to test the fuel system and have a smoke test run.

[ashton]

Back firing is most commonly the result the engine running lean or interruptions in spark. Either can cause coking of the plugs from misfires. The first thing I'd do would be to test the fuel system and have a smoke test run.

I've already had a smoke test run and all intake leaks fixed. What should I check on the fuel system? Could it be the ecu?

[E30-325iS]

I would start by looking at your fuel pressure regulator. If you have access to a fuel pressure gauge check that it is within spec, 3 bar and that it is not leaking back thorugh the vaccuum hose.