kathleenkmh

I have a 1993 SC300, 5 speed. I bought it with 86,000 miles and now have 111,000. It's been a dream until just recently. It starts fine when cold, but when I make a short trip (to the store, etc.) I have real problems. The car starts with no problem, but then it acts as if it's out of gas, and dies. I have to rev it up VERY high to get out of the parking lot. Once i'm started, it's fine. It never happens when the car is cold, or has sat for a period of time. I just had a tune up, new plugs, new fuel filter, new air filter.... still have the problem. Someone please help....

London Bill

Kathleenkmh;

sound very much like the fuel pump ECU, see my site below for more info in the Electrical section.

SC300T

I think its fuel related...
I have the problem as well... Upon a hot start, the ECU directs the fuel pump to raise the fuel pressure to compensate (but perhaps not enough). When the vehicle sits and "hot soaks" the fuel can percolate causing loss of fuel pressure. Its only temporary. On my car, the air/fuel gauge reads a lean condition. Even with premium fuel, mine does it a little during summer months. I'm not sure that there is a real solution to the issue. After a bit of cooler fuel is run through the lines, the problem goes away. Usually only takes a minute.

kathleenkmh

checked out your website... very nice, and you're right, it sounds a lot like a problem with the fuel pump ECU. Ok, I'm a novice ... ECU means????

Hermosa

Your car is getting up there in years. Check your intake tubing after the MAF. If there is any degredation of the seals or cracked tubing you may develop an air leak and once the materials heat up they are more pliable possibly letting even more air in. If enough air sneaks in then you have inaccurate air flow readings and your engine could cut out.

Does the idle become sporadic and jumpy for a bit right before it cuts out?

Does this only occur once the engine heats up?

The assembly before the throttle body is pretty easy to take off and/or inspect. I would do this before taking the car into a shop.

London Bill

kathleenkmh;

The ECU or "Electronic Control Unit" is basically a relay, just a damn sight more expensive, try the jumper fix next time it wont start, this will verify if the ECU is at fault as it is quick & easy to do before going on to other possible causes.

I can assure you that 9/10 hot start problems on older Soarers are related to the fuel pump ECU, we have resolved several similar issues in the UK & Oz.

London Bill

SC300T;

You could well have a fuel evaporation issue but bear in mind, when the fuel pump ECU starts playing up it gets stuck midway between switching from 9v to 12v (or vis versa), this leaves the car with 0v going to the fuel pump. After a little while the ECU cools down and continues normal operation giving the same symptoms as fuel evaporation.

I heard (on this forum) of an owner/garage that chased this fault for several weeks before identifying the ECU as faulty. My TT had a faulty ECU for months which I had attributed to the overboost fuel cut-out (it only happend on flat-out gear changes) but when the ECU was changed for the non-starting fault the other issue dissapeared.

awj

Has this issue been resolved kathleen?