MyE28.com

I’ve only driven the car twice since purchasing it and it’s been stuck with the mechanic for various small things from broken windows, locks etc…

So my impression is that the engine seems to be strong. The odometer is broken and the maybe replaced previously since it reads 10,014 km only. But it feels like it’s at least 100,000 km the way the interior and mechanicals looks. Problem initially was the car overheats in traffic. And the brake warning light lit a bit then brake pedal started feeling soft. While the transmission seems like it was hunting gears occasionally especially in economy setting. It’s a bit better in sport but still there but in 321 mode it pulls strong and shifts ok.

Then when testing it the second time, the engine starts to hesitate, like from fuel starvation but full acceleration and idle seems ok when warm. ( I wasn’t able to observe from cold start since mechanic picked me up to test drive it). The car got warm in traffic but we didn’t have to stop to cool down. This prevented us from diagnosing the transmission if there was any improvement when engine is not overheating.

Bentley manual just arrived and reading through it. Just looking for some quick advice since parts ordered from USA takes 3 weeks to get to Philippines by air. Just need to preempt items needed to be ordered especially since most of the parts might still be original since new.

Questions

1. Does brakes get affected when engine overheats and RPM goes below 800. Is the power steering pump/brake pressure goes down with rpm?
2. Ordered new fan clutch, water pump and thermostat and thermo switches. What else should I look at fo overheating?
3. New rotor and cap ordered. Read that it might be the cause of the hesitation. TPS looks like it’s adjusted properly and car idles well.

Will put my transmission question in another thread. Thanks!

Always first address vacuum leaks then a couple ideas.

There is a switch on the throttle body (TPS) with contacts for idle and WOT you should test. One initiates idle control and the other wide open throttle/open loop operation. Proper idling has often been altered on these car by some tinkering with the AFM or the idle air bypass system instead of proper repairs. That might make it seem to idle OK. Sometimes the slight hesitation is simply poor adjustment of TPS for on/off idle control and many threads discussing this. Another suspicion would be an issue with the oxygen sensor if it has one which is where it operates everywhere in between. If it has an O2 look at that and make sure it is dithering at light and part throttle. When at WOT is just looks at AFM (air flow) and dumps in fuel and they tend to run well like that. In fact if you have an O2 just unplug it first and see if it runs better.

Another very common issue is the CTS (coolant temp sensor). If it is out of range or bad it can cause all kinds of issues and it is one of the few parts I would just plan to have on hand in your case. If you are making a parts list like: hoses, belts, O2 sensor, dist cap, rotor, plugs, t-stat, etc I would add the CTS and often overlooked main & fuel relays, and a voltage regulator which can all disable the car.

The mechanic is trying to do the adjustment but so far idle remains stable but when in drive, there is still hesitation and only full throttle seems to work fine.
Throttle position switch by Alvin Sandoval, on Flickr
Throttle position switch by Alvin Sandoval, on Flickr

My tps is for the eh transmission and looks in bad shape. Is there a way to repair this? A new one costs a lot of money and doesn’t show pictures of what it looks like or what’s included. Cant find it eBay either.

Tps problem solved. The mechanic tested it and found uneven readings at part throttle position probably confusing the ecu. Cleaned it till readings were consistent. Now engine and transmission working well. Just have to solve overheating issues. Solving things one by one. Thanks for the help!