ALPINE DIAGNOSTIC UNIT

Has anybody borrowed this off Dave yet ????

And if so, with what results ???

The £25 a go is cheap, but I think you'd need it for at least a week, incase you need parts and what not.

Truthfully, you can keep it for as long as you like if you have to order sensors (within reason!), or until the next guy starts hassling me.

If everything appears to be working fine, is there any point in hiring it? Could things be broken with the car working seemingly well??

Its not that there could be a fault, but the sensors can be out of calibration if there old which can affect performance and economy. For instance, the coolant temperature sensor runs at a very low ohmage (0.3) and any resistance in the old original wiring can make the ecu think 90 degrees is 50 degrees, so it retards the ignition and overfuels as if the engine is warming up, same with air temp. Knock sensors can go out, retarding the ignition prematurely when on boost. Throttle pot should be setup corectly, again if this is in the wrong place, you may not get the wide open throttle extra fueling, or it may idle at irregular revs. MAP sensor..this will read out if there is dirt in it, or in the pipe feeding to it.

Ive had nearly all of these problems on my car, and not a single light up on the dash. I still have an ecu electrical problem, as somewhere in my loom, one of the sensor lives is earthing out, and it brings all the sensor values down. Im nowing having to remove all the old ecu and original loom, and fit aftermarket management from scratch.

To anyone else, the car goes well, but I knew it wasnt quite right.

Admittedly its better to use it if you have the light come up on your dash, but as I said, if a sensor is out of range and not faulty it wont show on the dash.

David, does your diagnostic unit come with instructions, explaining what all the sensor are, what the values should be and the effect of incorrect measurements does to the car, like the description you have exampled in your post above?
My engine has a bit of a mis-fire at idle sometimes, revs to 1500 for some seconds after start up, can be rough accelerating gently for the first 2,000 revs (even when warm), pops (maybe even flames from the exhaust) when changing hard at 6,000 revs from 1st to 2nd gear and probably has a few other ailments that I have not noticed yet.
Each issue seems minor on it's own, but I guess they could all mount up to a horrible failure/stoppage soon.
I think I will be on to you soon for a loan.
Simon.

That can be that the throttle pot sensor is out. The ecu uses this as a base idle, and if its out, it will jump up in revs when you first start it. Ive had the same on my car.

I can enclose a sheet with all the required values, but truthfully its very easy to use. On the display for instance, the coolant temp reading will say in degrees what it is picking up, and the throttle pot will say either low,mid, or high and a voltage output from 0 - 5v, and if you move the throttle pedal it will change on the display.

Hey this search facility is fantastic!! I thought i'd crash the server searching for electrical and fault! Anyway i have a bit of a random problem, just wondered if anyone had any ideas for me to check...

My electrial fault light and service light came on yesterday, every thing seems ok, car drives fine, checked all fuses and checked earths, it was only after finding this post that i think i might have a similar (if unrelated) thing to Simon where my car revs to 2000 on start up for a few seconds but it's been doing that for about 2 weeks now.

Other than that, the only other wierd things that have happened electronically is that my alarm now appears to be working fine now since the light came on, before it didn';t always do the central locking and even more oddly, the funny noise the indicators make has stopped although they are working fine...In a way this could almost be regarded as a result but i wondered if there was any other basic things to check before seeing if i can borrow this diagnostic tool