No boost after engine/turbo upgrade

[gmac78]

I've only just bought the V stream chips and R201 resistor from S2Central. We were in discussion regarding my setup so not sure which ones he supplied. Having the R201 resistor was a requirement for the software he supplied though.

[gmac78]

I'm holding off opening up the ECU and changing the chips unless i have to. The more it is opened and closed the more potential for some something to be damaged i guess. But yeh it's a good sanity check.

I guess i'll trace the wiring from the sensor back to the ECU so see if theres any issues. If the G40 is failing where is the best place to buy one? Are 3B and ABY sensor the same part number?

[twoqu]

Sounds like the V Stream is for RS2 with the resistor change. However you will have the opposite problem if the other TS chips are not also RS2 based if you see what I mean. If you have changed the resistor it will be incorrect.

[gmac78]

Yeh i see what you mean, i bought the TS chips from a forum member who used them with the R201 change so should be ok. I guess sensors do fail, just strange when it happened. I don't think software alone would trigger that fault code though?

[Error404]

Sounds like a poor connection if the fault is showing an intermittent short

[gmac78]

Whats the deal with these sensors, wheres the best place to buy a 3B one? Best stock up just in case!! Hopefully a loose connection somewhere though, WG spring pressure is just not enough to arouse the senses!!

[twoqu]

As Alex has suggested, check the relevant pin in the ecu connector as sometimes they can be pushed out when reconnecting ecu's.

[newsh]

Could be the dizzy gear, is it a brass one?

[gmac78]

The dizzy was upgraded to the metal one when i very first got the car so should be ok. It looked good when it went back in recently. Good shout though!! That was my S2 ownership first problem.

[newsh]

Ok cool, well I'd just give the timing a quick check anyway just in case it's "settled" since the cam belt job.

[UrS4boy]

AAN ECU pin-out info with hyperlinks plus ABY pin-out

As Alex has suggested, check the relevant pin in the ecu connector as sometimes they can be pushed out when reconnecting ecu's.

Pins 8 and 12 http://forums.quattroworld.com/s4s6/msgs/21009.phtml

Removing/checking ECU pins: http://forums.quattroworld.com/s4s6/msgs/212815.phtml

[gmac78]

A bit more investigative work today on the wiring side of things.

Removed the 3 pin connector on the dizzy and ECU 55 pin socket and checked continuity on pin 8, 12, and ground, no issues found. Wiggled the cables at the dizzy and ECU end which made no difference, the readings were steady with no obvious breaks in the wire. One thing to note is the wire colours on the dizzy 3 pin connector are different to the pictures i had seen on the forum but they were for ABY with the hall sensor mounted differently.

With a DVM across pin 1 and 3 with ignition on i was seeing 4.99v

With a DVM across pin 1 and 2 with ignition on i was getting 4.85V

The pins in the ECU 55 pin connector were found to be clipped in tight so no issues that end.

Timing checked, all spot on as far as i can see.

Then i went for the first start of the day only to find it won't even start, just turns over for a few seconds and then does a kind of kick. At first i thought the battery was going flat so turned it over again. Same again, spun over then kicked. Tried several more times, same result. Disconnected the 3 pin connector on the dizzy and spun the engine over. Spins no bother with no kicks??

Reconnected the dizzy connector and went for another start, same again, spinning over then a kick.

Can anyone explain the kick? Does this sounds like the hall sensor has completely failed? No codes apart from the normal G28 when the car is off.

Regards
Gordon

[newsh]

I *think* if the hall sender fails you can get one spark per revolution at TDC on no. 1

[gmac78]

Hmm that would explain the kick i was experiencing. Hope you right and it's nothing more sinister. Ordered a new G40 from EFi so a waiting game now. Guess i'll whip out the distributor and strip it down in the mean time.

[newsh]

Do you know anyone with a scope you can put on it? You can see the flywheel and hall on the same screen and see if they look correct. There's pics on here.