Fuel pump & regulator query

[00mike00]

My ’81 Mazda 626 2.0L was giving me some jip at the weekend and I’m just posing a few questions here before I take a look.

The pump has been uprated since the installation of the Weber carb. It has been working fine since purchase (April 203) on setting 1 ½. I had a new rad installed about 3 weeks ago and when the guy was messing under the bonnet he accidentally set it back to 1. So when I took the car away, going uphill the car started jolting due to lack of fuel. A quick check under the bonnet and I realised he had incorrectly set the fuel to 1 and so I set it back to 1.5.

Since then the cars been running fine until Saturday when I topped up the oil, filled the tank and drove out of town. The car starting jolting a little when under acceleration, instantly I thought of the regulator but remembered I had set it back to 1.5.
I needed to get to London so I tried it on setting 2. I didn’t have a problem for the entire journey after that. When I got to London I tried it back on 1.5 again for the journey back but the same thing happened…so it was back to setting 2 and again, no real issue on the way back.

So what could be causing this issue? I’ve thought perhaps a dirty K&N, not giving enough air flow into the carb? Or perhaps the fuel filter being blocked.
Any suggestions welcome.

Thanks

Mike

[retrowrongun]

If its a metal fuel tank before anything else would check the fuel filter and change that first mate

[00mike00]

Apr 28, 2014 12:21:09 GMT retrowrongun said:

If its a metal fuel tank before anything else would check the fuel filter and change that first mate

That was another thought of mine, i had the same problem with the Scirocco.
Thanks!

[retrowrongun]

What happens on metal tanks is that most people over life time of car don't run the tank full all the time ,especially if car at some point was laid up it will cause a rust-ring around the level of fuel inside tank .... Sometimes especially if recently the tank has been brimmed it will dislodge some of said rust ring and drag it into the pump or filter ,causing alsorts of issues

I always cut open the old filter if its the external metal canister type after removal in a clean bowl and have a look at the state of the left over fuel in it see how manky it was .....

[Hillmanjames]

What retrowrongun said! Opening up the filter tells alot about the state of the tank.

Same goes for the oil fliter

James

[00mike00]

The good news is the filter was doing a great job. The bad news is it was FULL of rust and i mean full. All sorts in there. The car runs brilliantly now but for how long??
Best advice for a rust remedy?

[welshpug]

new or refurbished tank!

[retrowrongun]

There's actually a tank repair resin mate that you can get mate to coat the insides of tank to help stop it but can't for life of me remember what it's called lol

Either way its that ,new tank or keep changing filter regularly ,although the latter not being great long term

[00mike00]

Yeah I've used the resin before on a small motorcycle tank and it appeared to work well, the issue I imagine with the car tank is the size, I had to rotate the tank a lot to spread the resin and then it gets very hot before settling to a hard finish.

I'd probably only be able to sort my tank as I don't think I'd find another in a reasonable condition. I'm not sure how much a recon would cost though.