Passat won't start in hot weather

Passat won\'t start in hot weather

My 96 TDI is having starting problems that only seem to occur when it's very hot outside, and the car has been sitting for a few hours (I now park on hills!). I suppose it's the ignition, but I thought I had better solicit some opinions before spending the dough. The starter has been replaced already. Any ideas?

Re: Passat won\'t start in hot weather

You are probably correct in blaming the electrical system, specifically the ignition switch (unless yours has been replaced).

Failing this, I don't suppose it could be your fuel system losing prime?

Re: Passat won\'t start in hot weather

Do you get any smoke when it does start up?

Usually hard starting hot is (in no particular order)
Starter
Battery
timing (especially if smoke on startup).

I assume by "hard starting" you mean it cranks for more than 1 revolution prior to catching.

I'd have the battery checked, since it's cheap and easy to do. Since you believe your starter's good, I'd next check the timing.

Re: Passat won\'t start in hot weather

It's not the battery, and when it happens, it doesn't crank at all. Sometimes I get a buzzing sound, but sometimes no sound at all - just the ignition lights.

I don't think it's the fuel system either since the engine doesn't crank.

It's more than coincidence that it happens when it's hot out. Sometimes it will kick after a few tries though. Thanks.

Re: Passat won\'t start in hot weather

No nothing but buzzing? Mine did that a couple of times, but here it's hardly ever hot.

Clean all of the grounds. Get under the hood, under the battery and on the driver's side of the engine, find everywhere that a wire is grounded. (disconnect the battery of course first). Clean them up, sandpaper, steelwool, etc. Then reconnect them.

I had this twice in about a week - buzzing, strange flashing of various instrument panel lights, and no go at all. I'd disconnect the ground of the battery, reconnect, and it'd start. Then I cleaned the grounds, and for months and hundreds of starts, it hasn't come back.

It's easy, and might actually work.

Re: Passat won\'t start in hot weather

Thanks. I will try cleaning as you suggest.

Re: Passat won\'t start in hot weather

When mine wouldn't start when hot, it ended up being the ignition switch. I had it replaced once, which solved the problem for a while, but the problem came back (despite the new ignition switch). I talked to an electrical shop and they installed a push button to start the car. So, I kept the second ignition switch, but to start, I have to turn the key to the "on" position and then push the button. It's been working flawlessly for over 3 years. That's how I always start the car now. Occasionally, when it's hot, I will try starting it with only the key but I would get the same, no-nothing symptons from my pre-button days. So, I would suggest the push-button.

But the buzzing sounds like a voltage problem to me.

edit- the push button itself cost about $5 from Radio Shack. If you are electrically competent, you could probably install it yourself, but I had the electrical place do it and believe I paid $75 or so.

Re: Passat won\'t start in hot weather

Brownnugen:

Interesting approach to the problem! Would you happen to know any of the details of the installation (i.e. which wires were used, wiring diagrams/descriptions of the switch connector, etc.)? I'm assuming since you occasionally try the standard key method that the installed the push-button in parallel (wires to both the push button and key)...

Greg

Re: Passat won\'t start in hot weather

Have you replaced relay 109???

DSLDAV

Re: Passat won\'t start in hot weather

Yup...only symptom is very difficult to engage in hot weather: cools down, no/much less problem...once I hit the cylinder w/ some electrical component cooler and it worked well enough to enable starting...

at least in my case, forgot that Jesse was the originator of the thread, sorry...

Re: Passat won\'t start in hot weather

Brownnugen:

Interesting approach to the problem! Would you happen to know any of the details of the installation (i.e. which wires were used, wiring diagrams/descriptions of the switch connector, etc.)? I'm assuming since you occasionally try the standard key method that the installed the push-button in parallel (wires to both the push button and key)...

Greg

Click to expand...

Unfortunately, I did not watch the electrical shop do the work so I don't know any of the details.
-Nick