So I have this problem.

[nu-B]

Ok I have a 87 325e converted to 2.5i everything is stock in nature. So what my problem is , when I start the car and let it warm up it runs fine the whole time. Starts out at maybe 800rpm and backs down to around 650rpm. Then I'll take it on say a 20 mile drive park it for a little while and come back out to it go to start it and it seems like the rpms are all over the place. So as it starts off the rpms will be below 500 and the oil light comes on, then theres some fluctuation and the rpms climbs to the 650 mark. When you drive it everything seems fine but every once and a while it kinda stutter but its very faint. Any ideas??? Thanks.

[TurboJake]

I have nothing to say on the problem at hand. But I like your username. Someone that actually recognizes what they are is a rare and very good thing.

I hope Jlevie can chime in and get you in the right direction, because you deserve it.

[nu-B]

Thank you sir. Ive been messing with it all day. Checked vacuum,tested fuel pump relays,pulled out my back seat and the cover for fuel pump and its humming, fuel pump on frame rail is buzzing,newer fuel filter,older coil,<but cleaned connections, older plug wires, <but I ordered new wires from ireland today,Valves were adjusted about 2500 miles ago,<I set them at .10mm on cold and checked once warm and they were really snug at.12mm,carb cleaned the icv,New coolant sensors,thermostat,added grounding with2 shielded ground wires,I replaced the motronic sensor maybe 8000 miles ago,spark plugs are newer,New cap and rotor,anyone want to buy a car? jk

As I wrote all the bs I pissed my money away on the only thing I haven't messed wth are the maf and tps sensor. But Thats about it. maybe ill just but those 2 parts and there should be nothing left to be replaced. Still pulling hair out. I like this car a lot and Ive learned a lot working on it. I want it to be a reliable and fun.

[paperplane94]

The TPS is adjustable, do that first. Strange though that it would act up after a warm start.
Maybe the check valve for the fuel pump isn't holding pressure. CAn you test the fuel pressure and leave the gauge on for an hour to test the leakage.

[nu-B]

Where is this check valve you speak of?

[paperplane94]

^Nevermind, the check valve will only cause a longer warm start up time.

[nu-B]

Alright. What is that hose with the plug on it. It goes between charcoal canister& intake manifold? looks suspect....

[nu-B]

Does anyone have any tips on adjusting a tps sensor? Kinda looks like the bolt/screw on the tps sensor,if your looking at it in the car it would on be skiers right. can you get to that with out taking the TB off to adjust it? kinda looks like the manifold runner is in the way. And if you dont know skiers right it would be bolt closest to firewall.

[paperplane94]

That thing you first described is the EVAP purge valve. It's an emissions thing that inject gas fumes into the throttle under certain conditions.

If you have the 3 pin TPS then all you need to do is hook up a multimeter to the pins ( I forgot which, search the bentley) Then you should have continuity when the throttle is at idle position. IF it isn't, loosen the 2 screws and turn the tps until there is continuity.

The easier, cheater way is to just loosen the screws and turn the tps so it just makes the click sound at idle.

[Kvasi]

Valves were adjusted about 2500 miles ago,<I set them at .10mm on cold and checked once warm and they were really snug at.12mm,

Dont know about your weird us-models, but the euro M20 is supposed to have 0,25mm cold.
Wouldnt be the solution here, but anyway..

[nu-B]

Paperplane94 thanks for your info. tomorrow ill look into setting the tps.

Kvasi you have me scared. I'll check that out tomorrow as well.

[nu-B]

I just figured out the valve gap was set .254mm. From looking at the shims I remembered .010 of an inch not the mm's. I only messed up here. cars good!

[IRON-E]

I know JLevie is good at diagnosing, these kinds of issues but I'm going to say your sputtering issue is gonna be somewhere with your AFM & CPS.
I only speak from personal experience, so take it for what it is but it couldn't hurt to try.

Good luck & welcome.

[ohthejosh]

Check your intake boot for holes? My intake boots has some serious holes and it sputters then stalls. When the holes are kinda closed up from applying pressure the rev will fluctuate. I dont know if that makes any sense but just check for holes in your boot or cracks.

[jlevie]

The very first actions should be:

Smoke test the intake and fix the teaks it reveals
Check the rail fuel pressure and repair if indicated
Replace the O2 if it has 100k on it
Replace the plugs with NGK ZGR5A plugs if that isn't what is now in the engine