1995 525i code 1222

[lloesch]

Hello All,

First off, sorry for the long post. I'm at my wit's end with this car.

I'm having major issues with a 1995 525i (build date 11/94). When the car is driven on the highway for about 30 or 40 miles in warm weather (over 85F) it pretty much freaks out at the end of the trip. The warmer it is the more likely the failure.

The symptoms are no power, engine will barely rev when taking off from a light, check engine light comes on, hard starting and a stored code 1222 in the ECU. Sometimes when you rev it the check engine light will go off after a few seconds and when it drop to idle it comes back on. Other times it just stays on.

It's very temperature sensisitive, the warmer it is, the more likely it will do this, UNLESS we get near a shop. Then it runs perfect no matter what (really!). We actually got a dealer that was willing to bring us in no notice if it was running bad. Took it for a long drive, got it to fail. Started to bring it it, ran fine, turned around and it started running bad gain. Did this THREE TIMES!

Various shops/dealerships have replaced the following:
Fuel pressure regulator (twice)
Mass Air Flow sensor
ECU coolant temp sensor
O2 sensor
Idle Control Valve
Fuel Pump
Intake Air boot (from MAF to throttle body, the orginal was split)
Various vaccum hoses and tubes
Two ignition coils
New plugs
All new Ebox relays (ECU, Fuel pump, O2 heater)
Fuel filter
Air filter

I've also changed brands of gas, run some good quality injector cleaner through it and looked for vaccuum leaks. Nothing makes a difference.

At this point the shop is saying bad ECU, but I'm not willing to drop $1300 for a dealer to put the part in unless I have an ironclad guarantee that it will fix the problem. The dealer is being edgy about putting in a used ECU since they can't guarantee they can code the EWS to the car.

I've read one reference that says the crank sensor can cause this problem so when I get home tonight I'm going to take a look at that. I'm also thinking of yanking the ECU and looking it over for cracked solder joints, etc. I have access to a static safe workstation.

I guess my main question is, what could have been missed? Any suggestions on what to try next? When it runs it's a great car and I have a ton of spare parts for it from a wrecked E34 (no ECU, sadly). I'd like to salvage this beast...

Thanks in Advance!

Larry Loesch

[gtopaul]

The first thing that comes to my mind is a stopped up catalytic convertor. Symptoms usually occur once the engine is hot and the exhaust can't find it's way through the convertor. Usual indication is a loss of power especially when trying to accelerate. Sometimes it will actually smell hot. Also sometimes the convertor will actually glow red under severe use. Best to have a competent shop run a convertor test and see what happens.

Paul