Questions and Answers

Volkswagen Golf Hard Hot Restart Q. Hi Vincent, And thanks for your help. Here's what I've got: 1987 Volkswagen Golf 1.8 liter 4-cylinder engine 5-Speed manual Transmission 80,000 miles Fuel-injected Power rack and pinion steering

The problem I'm having with the car, which it's been doing for at least a couple of years, is that it's difficult to start again if it's been running and then is left to sit for, approximately, a half hour to an hour or two. Once it does start, it runs rough for 10 or 15 seconds, and then runs fine, no missing, no erratic idle, no stalling.

It starts fine and runs well if it's cold, even if it's real cold in the winter, and it restarts fine and runs well if it only sits for a few minutes once it's hot.

I've run lots of Techron through it, to no avail. One mechanic thought it might be dirty injectors. Does that make sense if it's starting and running well except on warm restarts?

Thanks,
Dave

A. It sounds to me like you have an injector(s) leaking down. If they are, they will flood the cylinders and an hour is not enough time for them to dry out for a normal start. However overnight is enough time for the cylinders to dry out and give you good starts in the morning.

The injectors in the CIS-E system open at a preset pressure. Fuel is always present in the lines between the fuel distributor and the injectors to ensure good starting. As pressure in the fuel distributor increases, when the engine is started, the valves open and spray a constant stream of fuel. The amount of fuel injected will be determined by control pressure and the position of the air flow sensor. When the springs in the injectors get weak, they don't seal completely and cause the leak down. One way to check for this is to put a fuel pressure tester on the fuel system.

Connect the fuel pressure tester and run the engine until it reaches normal operating temperature, usually when the cooling fan cycles. Then shut the engine off and observe the fuel pressure tester.

Normal fuel pressure is 5.2 to 5.6 bar (75 to 81 psi). If there is a steady drop, and with the symptoms you describe, it's a pretty good bet the injector(s) are leaking down.