runnjng no isv?

[freakytate]

Hi. Whats implications of running aby with isv unplugged? Seems to raise idle a little but smoother. My isv is rotating too ive tested it. Got little miss / hesitation. Otherwise could be lambda. Wot is ok.

[UrS4boy]

Missing and Hesitation Diagnostic

Hi. Whats implications of running aby with isv unplugged? Seems to raise idle a little but smoother. My isv is rotating too ive tested it. Got little miss / hesitation. Otherwise could be lambda. Wot is ok.

If the ISV is moving easily, your ABY miss will have *NOTHING* to do with the ISV. It is more likely to be an ignition issue. See below:

ISV Info: http://forums.quattroworld.com/s4s6/msgs/21853.phtml

Missing and hesitation diagnostics: http://forums.quattroworld.com/s4s6/msgs/22611.phtml

Good luck hunting.

[freakytate]

I pulled each inj plug and they all seem to make a difference to idle and a much more pronounced miss when throttling..its not like a positive miss just idle bit irratic sometimes and hesitates on cruise. Wot is ok but partial throttle and cruising is a little hesitant and idle is a little irratic. Could my lambda be causing issues. Since I played with wires coming from top of lambda yesterdsy it seemed to get better and my mpg increased. Managed 25 up from usual 19mpg.

Il read pos unit info when I get a minute

[UrS4boy]

G39 Lambda and G70 MAF sensor info to check out.

At least by pulling the injector electrical connectors you now know (hope) that it is not ignition. Definitely not ISV which is only active when the idle switch on the throttle potentiometer is closed.

Might be G39 Lambda: http://forums.quattroworld.com/s4s6/msgs/21012.phtml

*BUT* more probably the G70 MAF sensor (the first thing I list in the missing and hesitation diagnostic): http://forums.quattroworld.com/s4s6/msgs/20442.phtml

[Error404]

What fault codes are you getting?

[freakytate]

Thanks. Im getting 00525 g39 lambda intermittent signal. I played with wires on top of it yesterday and it did get better and mpg went up. Gone back same today. Im sure it looks like one of the cables insulation has come away at the point it leaces the lambda. But im not 100% sure on that

[UrS4boy]

Thanks. Im getting 00525 g39 lambda intermittent signal. I played with wires on top of it yesterday and it did get better and mpg went up. Gone back same today. Im sure it looks like one of the cables insulation has come away at the point it leaces the lambda. But im not 100% sure on that

So it doesn't look like this?



This close up shows the connectors, the 1 pin spade connector for the ECU signal and the 2 pin connector for the O2 sensor heater element. Sounds like the single wire and connector is your issue.

[freakytate]

Yeah it looks like that but im sure where cables leave top of lambda the insulation has broken down a little. I going to run vagcom on it again. Need to know measure blocks for heating element and how much the readings should fluctuate

[Rusty]

Get a new lambda & also do a compression test.

[freakytate]

A what test what figuires would I be looking for accross the board. She done high mileage but in fairness runs well and quiet. Only power steering pump noisy. I f##king love this car

Any preference as to make of lambda?

[UrS4boy]

Any preference as to make of lambda?

Bosch.

The G39 O2 sensor has a finite life and will need to be replaced periodically,e.g. every 60K miles, or so. The OE Part No. for the UrS4 is 034906265F (Bosch 0 258 003 957). For the UrS6 the OE PN is 077906265. The Bosch 0258003957 is also traded as = Bosch USA 13019 = Bosch USA 13957. Also 13953 Bosch 3 wire (92 V8 Mustang, 16.5" long wire, $40 @ Autozone) probably works and maybe Bosch 13913 3 wire Universal (under $40 at Autozone). Volvo 940Ts used the 13957 and can use the 953 and 913.

Bosch 0258003957 (13957):