'blip'

[baxter]

does the 325i engine have a throttle postion sensor,

as when i open the throttle fast'ish' the engine goes to stall then will pick up again

i had this happen on my corsa engine, but that had a MAP and TP sensor, not an AFM

on saying that due to it having an AFM it wont have a TPS lol

so what can cause this?

[GDBN]

TPS is under the throttle body.

[baxter]

strange that, as its ether one or the other on most cars,
im not buying one tho, lol

the old owner did the engine conversion from a 320 to 325 and had used the 320 TB and all the sensors, would fitting the orginal tb (in the boot) fix this problem?

[Rosc0PColtrane]

TB= throttle body, then yeah do it!!! Some peeps with 320i's put the 325i TB' s on as an upgrade, indicating it will make a difference!!!

[Turbo-Brown]

There's a throttle position switch under the throttle body which tells the ecu that the throttle's fully shut and so to apply idle settings, or fully open so to apply full load fueling etc.

Mine used to do the cough if you blipped the throttle, engine died before I had a chance to properly investigate the cause although I suspected the IACV.

[cliffybabe]

hmm this may fix my problem, so there a switch under the TB, Does it make any difference that I have a BBTB??

[Geeman]

So you've got a 325 engine with a 320 throttle body? So then, that means you've also got the 320 inlet manifold. This is not much good for the 325 engine... it'll be quite restrictive. The ports on the head / manifold won't match up for a start.

You've got proof that it is actually a 325 engine, right?

[mrLEE30]

no your BBTB will still have a switch (assuming you put a 325 TB on there), if you listen very carefully you can hear it click as you opererate the throttle by hand under the bonnet and move from open throttle to closed throttle the click should be there as the throttle closes. only way to be sure however is to check with a multi meter set to resistance and check accross the contacts.

[cliffybabe]

no your BBTB will still have a switch (assuming you put a 325 TB on there), if you listen very carefully you can hear it click as you opererate the throttle by hand under the bonnet and move from open throttle to closed throttle the click should be there as the throttle closes. only way to be sure however is to check with a multi meter set to resistance and check accross the contacts.

na i've got a 325 engine and TB, im gonna have a play when i get home, if i get th steering cupling fitted

Sorry about hijacking the thread

[mrLEE30]

ah ha, should still have the switch, you should see some electricla type wires coming off the bottom of the TB, pull out the socket and you should find a few pins, two will be either open circuit or closed circuit depending on whether you throttle is open or fully closed.

[Rosc0PColtrane]

sorry for the hijack, so how visually can you tel a 325 apart from the 320? I don't know?

[baxter]

due to the engine numbers and log book

[johnono]

in an ideal world, in which all is as is from factory

the m20 320 will have a visible "angular" look to the inlet manifold
the m20 325 will have a more rounded flow on the inlet manifold

blockwise, the difference are minute, only crank and piston differences, and the possibility of enlarged sumps for alpina / hartge 2.6-2.7 machines

the heads are also different in the sense that the piston faces or crowns have different profiles to each other, and the heads follow acordingly. ports and valves are also larger on the 2.5

[gcorky]

heads have numbers on 731-2.0 and 885-2.5....look for these...

[Andyboy]

320i has rear drums not discs. Easiest way - under front bumper is a long thin plastic fill in panel. On the 325i these slots are left open for the oil cooler.