Question about BMW Z3

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My 1997 BMW Z3 2.8L Manual is experiencing poor acceleration under load at around 3,000 RPM and sounds as though it is pinging. I have changed gas to Chevron premium and added techroline concertrate

I have changed gas to Chevron premium and added techroline concertrate to the last 3 tankfuls, but the problem has become much worse. Now the car has lost what feels to be about 70% or more of its power and is on the verge of being unsafe to drive on city streets the acceleration is so bad, it also started to buck and surge at one point when trying to accelerate in 3rd gear. the car recently threw P0420 and P1423 trouble codes. I suspect that the catalytic converter may be clogged but have no way to verify that assumption. Do you have any thoughts?

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Pull the 02 sensor in front of the catalytic converter (between the engine and converter) or loosen the exhaust pipe at the exhaust manifold. This will give the engine breathing room, if the converter is clogged. Power will pick up dramatically. Also a bad converter will cause an enormous amount of heat coming out of the tail pipe. Don't touch it. Normally you could grab the tail pipe for a few seconds before it got too warm.

Posted on Nov 11, 2014


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Posted on Jan 02, 2017

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SOURCE: engine surging , won't accelerate over 3000 rpm ! IS chocking is like is not enogh gas

Do you have a check engine light with this?
What can happen is a code has caused the engine to protect itself. For example in a low coolant situation when the engine heats up too much, the engine can Knock causing an Engine Knock fault.
If that occurs you will recieve a fault for each of these items. Fill the engine with coolant. Then reseting the code will let your engine accelerate normally.

Posted on Feb 10, 2009

  • 116 Answers

SOURCE: Surging under acceleration

Sounds like the engine is being restricted by something. Here's the three basic things an engine requires to run correctly. Spark, fuel, and air. So, in this situation, I'd definitely recommend that you check the air filter. If the air filter is dirty and restricting airflow, the engine will actually hesitate under full throttle as it isn't able to get the right amount of air to make the correct fuel to air mixture.

If this isn't the problem, then I'd check into fuel delivery. First things first would be a fuel filter. This can have a serious impact on the performance at full throttle. If the filter isn't letting enough fuel into the engine, then it's not going to be able to run correctly at full throttle.

Try those two first, if they don't seem to make a difference, I'd then check into the mass airflow sensor, and possibly the fuel pump/fuel delivery (fuel injectors or carbuerator). Something is definitely restricting that engine, and I'd find out what it is.

Posted on Sep 10, 2008

  • 6674 Answers

SOURCE: '99 Accord: P0420 and Sometimes Engine Hesitation & Rough Idling

First thing I'd try is some "heet" or similar additive in tank to remove moisture, then refill with gas from a busy station & drive it for a while and see what happens.

Posted on Jan 02, 2009

  • 184 Answers

SOURCE: '99 Accord: P0420 and Sometimes Engine Hesitation & Rough Idling

If the converter is failed (i.e. plugged) it can cause drive-ability problems (i.e. the engine can't get the exhaust out like it normally can). FYI,

Fix the known P0420 code first, then if the rough idle, etc continues, continue diagnosing. IMHO, don't worry about the MAF, etc. until you fix the "known" problems.

Posted on Apr 15, 2009

  • 76164 Answers

SOURCE: 1997 Ford windstar Low power and very poor

35 is low fuel pressure, should be around 40-44 PSI and 46-50 PSI under a load, replace the fuel filter it may be clogged.

Posted on Oct 21, 2009

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