Hot Weather Starting Problem

[CazzaVR 0]

Right, this has happened to me twice recently (also happened a couple of times last summer) after going to start the car when it has been sat in the hot sun all day. Had to call the RAC out first time. Basically, the car turns over fine, but won't fire up at all. He thought it was def a fuelling problem and thought it was probably the blue temp sensor. He showed me a neat trick to get it started by spraying carb cleaner into the intake. It started straight away, so not the fuel pump. Had a brand new OEM blue sensor at home, so fitted it and all seemed well until yesterday, when exactly the same thing happened again. Only difference this time was a small 'pop' on the first go with the key :( Thankfully I bought some carb cleaner just in case!

 

I'm a little stumped now. I've tried a different fuel pump relay and it doesn't seem any different. I guess there's a chance that they're both duff though, so may just get a new one.

 

Any ideas?

[davidwort 0]

if carb cleaner helps start it then I'd say you've either got a weak spark or too little or poorly atomised fuel, the carb cleaner is very volatile so just gives it something to fire on really easily, like 'easy-start', if it runs once started then I don't think it's going to be the fuel pump or relay, as if one of those gives up, it gives up and the car fails to run, at least that's what happens with the relay sticking or failing.

Usually electrical problems occur when it's colder and resistance is high, I wonder if the fuel delivery or injector spray pattern is weak then when hot the ecu will be adding to the problems and reducing the fuel delivery?

What condition is the MAF in?

[CazzaVR 0]

Thanks David. MAF seems fine, but will take it off for a proper inspection. I'm thinking maybe injectors. Will look at getting a cheap second had set to send off to Mr Injector ;)

[Rams 0]

I've got my injectors available also, I'm a good salesman huh! Cross my palm with gold and they are yours.

[CazzaVR 0]

Rams how much are you looking for? Send me a pm if you want.

 

Failed to start again yesterday. This time it was in the morning though, so it was cold. First time it's done that. Started it with the carb cleaner again. Started fine in the afternoon though... will have a proper look tomorrow.

[Harrier 1]

Strange one , Fuel pressure regulator ? Low pressure from fuel pump ? has your fuel filter been changed recently ?

[Rams 0]

How r u getting on matey with the C?

 

Also I posted those injectors to my list today, £50 for the set if your interested.

[CazzaVR 0]

Still very tempramental with starting :( Changed fuel filter as I had one in the garage, but no different.

 

That's a little more than I wanted to spend to be honest mate. I might get back to you if I can't get it sorted. Need it on VAGCOM really...

[CazzaVR 0]

Well thought I'd fixed this when I found the inlet pipe was split underneath. Has been fine since changing it until yesterday. Wouldn't start at all. Had to spray some carb cleaner into the inlet again to get it started. Felt very lumpy for a while afterwards. Was also lumpy a couple of times accelerating gently on part throttle. It's done this before, but not very often.

[Kevin Bacon 5]

If the engine continues to run after being force started, it sounds to me like a bad battery or bad earth. The fuel pump and / or ignition coils aren't getting enough juice during cranking. The earth could be fine to the starter motor as it's a chuffing great strap direct to the battery, but the ground stack under the battery could be corroded up.

[CazzaVR 0]

Definitely not the battery. Turns over fine and the voltage on the gauges is always strong. Will check the earth and ground stack etc though.

[robrado974 1]

Hi Cazza . Obviously you have checked for correct spark . So fueling is the problem . I would get a fuel pressure check it will save alot of money , i wish i had done so first . This will rule out everything from the rail back . When i had mine in the garage recently after trying to sort it myself , the bloke said to me i doubt very much it will be the injectors . The first problem was the temp sender , the second was the fuel pressure regulator was on its way out . My vr is now running as normal . Hope this helps .

Rob

[CazzaVR 0]

Thanks Rob. Will get a fuel pressure test when I get it serviced.

[CazzaVR 0]

Been doing it more and more lately, so after running out of ideas decided to check the ignition switch. Was sure I'd changed it when I first bought the car, but was obviously thinking of my previous VR (had so many now, I forget which is which! :lol: ). The car still had the original white switch fitted, so swapped it out for a new black one I had in the garage. Starts perfectly now 8)