Hot engine bay and... AAN fuel pump relay... should it prime?

[RS2]

I have an AAN in one of my Volkswagen Transporter T3 Syncros and the engine bay gets hot... I mean really hot!

The engine lid is probably around 5mm away from the wastegate. The lid itself is fibreglass and there is a thick rubberised/foam sound deadening matt on top of that. After a run down to Cornwall last year, I realised that the matt had actually melted to the fibreglass lid.

I have fixed an aluminium plate to the lid now above the wastegate in an attept to reflect the heat back down.

Also I am looking at building a head shield with an inlet and outlet, 4" and I have two 4" inline fans coming shortly to blow cold air into the head shield and draw it away to the back of the van.

When the engine is hot, I think that the fuel is being boiled off so starting it is a pain. It'll crank for 30 seconds before trying to fire.

I have a 7A in another of my T3 Transporters and this primes the fuel pump before the engine fires, the AAN system does not.

Should the AAN fuel pump prime the system first? I can't thinking that priming the system to build up the pressure would help with the hot starting issue.

MG

[AndyP]

No, the AAN/ABY and 3B only start the fuel pump when the engine is cranking.

The engine bay in a standard S2 gets really hot so I'm not suprised your having problems if yours is smaller!!

[RS2]

Ah ok. Thank you. It's good to know that it's working as it should then.

Here's the engine bay.



MG

[UrS4boy]

J17 Fuel Pump Relay Information and why it is so important

a) agree that the AAN fuel pump relay is only triggered during cranking and only if the battery is strong enough to spin the engine at more than 13 RPM, otherwise, the ECU does not trigger the J17 fuel pump relay. J17 FP relay info: http://forums.quattroworld.com/s4s6/msgs/22583.phtml

b) the underside of the bonnet (hood) in a C4 UrS has i) a fiberglas insulation pad to keep the heat in and ii) that pad has an aluminum foil section that is above the wastegate and turbo to further protect the hood (bonnet) from the turbo/exhaust heat. You might want to find a wrecked C4 UrS and confiscate the hood (bonnet) pad and adapt it to your T3 engine cover.

[RS2]

Does anyone know of replacement relay that does prime?
The pins on the relays are not compatible between the AAN and 7A.

MG

[UrS4boy]

Does anyone know of replacement relay that does prime?
The pins on the relays are not compatible between the AAN and 7A. MG

If you read the info in the link that I provided, you will see that it is the ECU that controls the AAN Fuel Pump Relay via pin 3 taking the J17 relay to ground only if the engine is rotating at more than 13 RPM (= safety feature in the event of an accident).

So it is NOT a relay issue. What you do with the grounding information is up to you.

[RS2]

URS4boy, if you read my reply above, you'll see that I replied 'OK it's good to know that it's working as it should'.
Please read the reply properly before thinking that I haven't read your reply?

I asked a very specific question.

Is there a relay that can be fitted that will prime?

Thank you

MG

[UrS4boy]

URS4boy, if you read my reply above, you'll see that I replied 'OK it's good to know that it's working as it should'. Please read the reply properly before thinking that I haven't read your reply?

I asked a very specific question.

Is there a relay that can be fitted that will prime?

That reply was NOT to me. (But I did read it and then provided you with more info about how the J17 FP Relay works).

The answer to your VERY SPECIFIC question is "NO"

However, if *you* read what I said, "So it is NOT a relay issue. What you do with the grounding information is up to you.", you have a way forward, if you want to take it.

Good luck.

[RS2]

Once it had become obvious that the relay was functioning correctly, I was asking if there was a relay that could be fitted in it's place that would prime.
You seem to take offence at the idea of someone doing something out of the norm?
I read your reply very carefully and have studied that information very closely previously when I was installing the engine.

Obviously I've hit a raw nerve here?

My apologies for upsetting you.

MG

[UrS4boy]

I was asking if there was a relay that could be fitted in it's place that would prime. You seem to take offence at the idea of someone doing something out of the norm?

I repeat "So it is NOT a relay issue. What you do with the grounding information is up to you, you have a way forward, if you want to take it."

HINT: (Because you are apparently missing it), Add a switch that takes the FP relay pin 29/S to ground, independent of the ECU.

[RS2]

I repeat "So it is NOT a relay issue. What you do with the grounding information is up to you, you have a way forward, if you want to take it."

HINT: (Because you are apparently missing it), Add a switch that takes the FP relay pin 29/S to ground, independent of the ECU.

Ok, Hint appreciated. Thank you

I'll see if this improves matters when it comes to hot-starting.

I may put a pressure gauge on the system to keep an eye on what's happening.

MG