I'm pretty sure this happened after the last rolling road tune because well. It's fairly obvious that the fuel indicator drops when I'm idling and then rises again when I accelerate and I'm sure I would have noticed it before. The change is roughly 1/4 worth, or just a little under. I'm also having a really horrible time idling, it always wants to stall if I sit too long unless I pull the choke out, which is also new after the rolling road tune (except it didn't start until two days after...) Call me crazy but is it possible the fuel pressure is too low or is the DMTL designed to work with the standard pressure regardless of what jets you put in it? In which case does it sound more like an obstruction in the fuel system?
I don't think the jets make a difference, pretty sure the fuel pressure is what it is to work the needle valve on the float properly; too little pressure and the float bowl wont fill, too much and the float will be forced to sink and the bowl will overfill!
The fuel gauge float/arm in the tank is oriented in such a way that when going downhill or braking, the dash gauge under-reads; when going uphill or accelerating, it over-reads. Wouldn't think this would explain the magnitude of the changes you're seeing though. What's your battery voltage with engine running?
No idea. Think maybe alternator failing not enough power to run the pump properly? From a standstill accelerating, I can see the indicator move for about five to ten seconds. For some reason increases seem to be much more obvious than decreases. uuuh. hm. kinda want a new battery.
You can pick up an adequate multimeter for measuring it for next to nothing. Or borrow one for 5 minutes? Do you not still have a mechanical fuel pump? I don't know what might be causing your idling problem. I was just wondering if your charging voltage is varying with revs, and somehow affecting the gauge. (Not even sure if that's poss. TBH; dash instruments run on a separately regulated supply, but maybe gauge sender info might vary with batt. volts).
are all the other functions on the dash ok , because there is a voltage regulator in the alternator that holds the voltage at 14.4v so when the engine revs rise the voltage remains the same , it sounds as if this regulator is damaged so when the car idles the voltage drops to 12v and when you accelerate it rises to 16-17v , this will cause the pump voltsge to vary and maybe the symptoms you describe, also the stalling at idle will be due to a weak spark probally caused buy the same problem. try putting on the main lights and rev the engine, if the lights get alot brighter with high revs and dim with lower revs then the regulator is dead, it is attached with the brushes you can replace without removing the alternator.
This could be a problem that's very common on VW t4 vans. There's a solder joint on the circuit board at the back of clocks. Another drop of solder on there sorts it on the vans.
Hey you know what I've had this funny problem ever since I got the car where sometimes when I start it up and turn on the lights the NS lamp won't come on properly until I rev the engine. Does that sound like vreg failure? I don't think it happens all the time and I can't say I've ever noticed it dim and brighten with the engine while it's moving. The dash seems fine except one of the dash lights has been out for a few months haven't really noticed anything funny with the other dials. Could a faulty vreg also be responsible for the very bad interference I've just started getting in my amplified speakers? GSF lists two... One Bosch and one Valeo do I need to match the vreg to the alternator? Any reason the Valeo is double the price?
Yes you do need the right one to suit your alternator, but don't buy anything 'til you've measured some voltages and confirmed that there is a problem! If you can get a pic of the rear end of your alternator, I, or someone else, will probably be able to tell you whether it's Valeo or Bosch.
Could it not be the voltage stabiliser at the back of the clocks? I think it gives problems like this when its on it's way out. You'll need multimeter to test it though. I got a mini multimeter for 99p from ebay and its amazin!
I think I still have a friend's multimeter kicking about. It's just a bit hard to measure the voltage and step on the accelerator at the same time. To test the reg on the clocks wouldn't I need to remove them first?
Yeah you'll need to take the clocks out and check it disconnected. It's a tiny screwed in black box 1sq cm with three small 'forks' coming of it that are plugged in. You need to give it voltage and test between the points. it's in the BIG RED BOOK, check in the back under troubleshooting/diagnostics about gauge readings and it will tell you the page number and what to do coz I can't remember exactly soz! It will tell you if it's duff.
Doh! ya the big book o lies says if your gauge readings increase with engine speed it's a faulty vreg. Interestingly the index lists faulty regs under chapter 12 electrical systems but the actual instructions for it's removal is in chapter 5d starting and charging systems. Now that Im paying more attention to the gauges it seems like the temp needle also wavers ever so slightly when giving it gas. Nowhere near as much as fuel though. One last thing, if Im running lots of high power ice (4x 125w RMS plus 2x 50 on the HU) should I think about changing the alternator to a 90w one? Wait one more, sometimes I get this weird problem when starting I don't hear the starter motor cranking it just clicks kind of like when the battery is nearly flat, but after a few goes the engine starts anyway and sometimes the motor will kick in. Related?
maybe need an uprated battery too? I'm not too clued up on ICE though..... but if your not driving much and constantly with power drained from the ICE and if your votage reg is on the way out or worn then maybe all this?...
OK well the bad news is its not the reg measured it this morning and the battery just kind of hovered between 13.7 and 13.9v yes I did check it on DC mode. So maybe it's the regulator on the back of the clocks? I really don't want to take them out ... But then again it gives me a chance to replace that dash bulb...
It's quite simple.....just be careful with the back. Just a pain to take all the front off. and the connectors can be akward. dont forget the spedo cable and the mfa vac tube. Make sure you properly put the spedo cable back in or it will pop out at 80 on the motorway like mine did It doesn't register the miles you do with the cable out so i think I gained about 30 miles! Bit scary though
