starts missing around 3-4k rpms

[R1ckM]

I got another e30 an 88 325ix. Got it looked over and it checked out good.
Took it on the hwy and i noticed that when I get to around 3.5-4k rpm it starts to miss and cut out a bit. Runs great besides that and at other rpms.
Its not throwing the CEL either.
Any ideas as to what it may be?

Heres a video based off my 2nd post:

[TobyB]

AFM,

fuel pressure if it does it over 4k consistently,

plugs, wires, cap, rotor...

t

[R1ckM]

It had a engine put it in recently before I bought it. I am familiar with the shop that did it and even asked them about the ix when i saw it parked there. (months before it was for sale)

Today I was cleaning the car inside and out (was dirty and meh). I turned the car wash sprayer on spot free for less preasure and cleaned the engine bay tracks out (lots of dirt and stuff collects there).
After that I took off and shortly after it started missing and cutting out. The engine would die under a load. It would start right back up and idle ok. Soon as I took off though it would start to sputter, cut out and die after about 30 seconds under a load.

I don't know if that had anything to do with the previous issues but after letting it sit for the day it still is doing the same thing. Maybe I will need to give it another day to dry if I got anything wet that shouldn't be.

I checked the vac lines and intake boot, seemed crack free. The intake inlet by the front bottom bumper that goes into the air flow sensor and intake. The tube that connects to draw air through the bumper wasn't connected and doesn't seem like it will be able to for some reason. It comes up short.

So for the rpm cutting issue, should I just adjust the AFM and make it run a little richer?
The shop that worked on it and put the engine in isn't really a bmw specific shop so maybe they didn't get it tuned to spec if anything was a little off.

[TobyB]

After having seen 2 or 3 AFM's full of water, I'd look there...

if the cap seal cracks, they seem to fill up pretty quickly...

just my kick recently...

t

[R1ckM]

The top is sealed very well on it, i will try and get it off there. Would like to set it to run a tad richer.
I pulled the plugs and there were some old champion brand plugs, they looked a bit funky. A little white dust around the threading and dark n crudy at the end.
The wires are very limp and soft, i find it unusual for spark plug wires to be like that but maybe i am wrong.
I am going to order some plugs and wires today, maybe a distributor cap and coil as well.

[R1ckM]

Ok, I adjusted the afm 3 notches left. Removed the battery for a couple minutes then connected and let it idle for 5 mins or so.
Changed the spark plugs, no wires b/c they wanted $250 for a set...

Starts, runs and drives now but misses when under a load.

Will try and clean the icv and tb tomorrow and see if it helps.

It was running without missing until 3.5-4k rpm until i sprayed the engine bay just a bit and not directly on the engine just the outer tracks to get dirt and leaves that were all mushed in there by the hood.

Anything a little water could make not run well?
Its been a full day since then as well.

Also, where can i get a set of wires without spending way too much?

[101]

I got a set of Bremi wires on Amazon for $129. That was about the lowest price I could find for a name brand set.

[BruceJ]

wires link: There's many for much less than $240

http://www.ebay.com/itm/BMW-e28-528-e30-325-ignition-Spark-Plug-Wires-cable-Set-cabling-cables-/231283327332?pt=Motors_Car_Truck_Parts_Accessories&hash=item35d98f8164&vxp=mtr

http://www.turnermotorsport.com/BMW-...lug-wires.aspx

Check the coil connections - coil wire is very susceptible to moisture and will rust at the wire/coil connection. Will def cause ignition problems.

Good Luck
Bruce

[R1ckM]

It runs way better now after cleaning the icv but still misses when I rev it around 4k rpm. Putting a new fuel filter may be a easy cheap alternative.
The way it behaves remind me of my e34 535i, it had a bad tcu. Not sure if manuals have these though.
Gonna try the plugs, probably get a rotor and cap too, maybe even a new coil.

Its not throwing a cel which is annoying. Theres a problem if its missing under a load at x rpm.

Also, whats that extra wire with a plug goin from the plug wires? (not the coil wire)

[Hooffenstein HD]

Also, whats that extra wire with a plug goin from the plug wires? (not the coil wire)

Cylinder identification sensor. Some people say it's not necessary since some aftermarket lead sets don't have them. I lean more towards the theory that BMW put it there for a reason.

[ak-]

Coils rarely go bad.

Check your CPS and see if it has come loose. My car used to hit a brick wall at around 4900 RPM and it turned out the CPS's nut that holds it was loose and vibrating at that speed.

[Ryan1642]

Did you try unplugging the ICV or the AFM, I had a problem revving my '91 IX past 2k until I unplugged my ICV, the ecu will then go off a preset value. you can fool around with different combinations of the ICV/AFM plugged in or unplugged and it might help you determine whats wrong. check the connectors and wires for both too. ICV's are the root of all evil.

[R1ckM]

Check the cps, cleaned it up and checked the nut, it is on there tight. Couldn't get it lose actually by hand, need to go buy some hex sockets and give it a go.
I will try unplugging those and trying them out one by one. The car runs and idles fine but trying to get some power under a load it miss fires.
I want to suspect a injector, when i pulled the plugs cylinder #3 looked like it was running lean.

[TobyB]

If you don't trust the wires, I'd still suspect them. It doesn't matter that they're
expensive, it only matters that they're bad.

And if you have an i engine, you need that sensor on #6. Otherwise you may get
a different set of problems from fuel pulsation...

t

[Kershaw]

Did you try the fuel pump?