car jerks at randomly need help

[88e30dippin]

okay so my 88 e30 is giving a weird issue that i can't figure out.

it runs and drives great with lots of power. randomly once in a while, if im doing either 45 or 60 (cruising speeds) around 2k or 3k rpm it will sputter a little. it would just jerk once or twice then be fine again. every time i run out of power steering (atf) fluid (my steering rack leaks) the car jerks at those times. after i fill it up it will be fine. but now its full and its still doing it. so idk whats wrong with it.

i have replaced distrbutor cap, rotor, spark plugs, m50 injectors, throttle body, and did lifter adjustment.

what could it be?

[scottinAZ]

AFM could be taking a crap. I did an adjustment on mine to get to fresh carbon track, and bodged it a bit. car ran like SHIT, bucking and snorting much like yours. Try a new AFM.

[DmcL]

i had a similar problem that turned out to be the ICV taking a crap.. might be worth swapping another if u have a spare laying around before u go diving into things like AFM and whatever else.

[88e30dippin]

alright thanks i'll try the the icv first. whats the afm?

[scottinAZ]

air flow meter, attached to the airbox

[u3b3rg33k]

ICV shouldn't cause the car to sputter once you're at cruising speeds. If anything, it would hurt engine braking.

I'd consider checking on the crank sensor if it gets worse, otherwise, my vote is for AFM.

[StereoInstaller1]

What does the tach do when it jerks?

Watch it closely, post it up.

[dinanm3atl]

Number of things.

AFM
Crank Sensor
Could be ignition related - Plugs, wires, distributor or coil and all associated connections.

I would start there.

[88e30dippin]

the tach doesn't move at all. if im doing 60 on freeway at 2300rpm to 2500 if im sitting on or in between those rpms it would sometimes just jerk like a back fire and then work fine. i have put new plugs (ngks), new distributor cap and rotor, and as for coil i am using stock one and have tried an aftermarket one and it did the same. right now im running oem coil connected to a jacobs racing ignition system. it did the jerking thing before the ignition stuff was added.

when it first started i changed the injectors, o2 sensor, afm, and the throttle body thinking the tps was bad. after i did all that the car worked fine till a few weeks ago. worked just fine for 4 months after doing the 5 speed conversion. its running a 89 525i 5 speed ecu. i keep thinking it might be because of my afm and that my steering rack leaks inside the rubber boots.

i was also wondering how to delete the power steering correctly?

[mkcman17]

i just cleaned out my icv and taped up some gaps in my icv boot. i have been having trouble starting the car when hot and occasionally having issues around 3k rpms, so i'm hoping that'll solve it.

also, some days my car is a total dog, and now and then it's a total rocket. don't really get why...i'm going to clean out the injectors next methinks.

scott, 23.1 mpg? i hope it's an eta..

[u3b3rg33k]

if the tach doesn't drop, it's probably not the CPS.

I think it has absolutely nothing to do with the power steering. think about it. At idle, if you try cranking the wheel past full lock the ps belt will slip/squeal, even if properly tensioned. Do you think that the belt would do anything but burn off at cruise if the pump seized?

TPS only affects things when the throttle is closed, or WOT. in the middle it does nothing, therefore while cruising it should have no effect.

Oh, have I mentioned that my car does the same thing you're describing, but only at WOT above 3500rpm? I've currently got 6 injectors being cleaned/restored/flowmatched, and if that doesn't solve it, MAF+WAR chip is next. AFM be damned.

I did replace my plug wires, and that helped, sort of (it no longer hangs at 4k rpm when it's horribly cold and wet) but it didn't solve the problem.

[Danny]

Afm

[88e30dippin]

hmm i guess im going to try the afm then. i might just get a cheap good one that works and just get the millar maf and war chip too.

can someone give me a diagram or place i can go to and get wiring for a maf sensor. i have a maf sensor off a 95 volvo turbo and i would like to use that since its the 4 wire maf sensor. all i would need then is the war chip. i saw a guy have a conversion on his 318is and he had wires running from the 3" mazda or ford maf sensor because you have to run 12v or something like that and get a chip that will tell the computer to not run off the afm anymore. can someone steer me the right direction? lol

[u3b3rg33k]

Herein lies the problem. unless you're putting in a NEW afm, how can you be sure? I've tried other "known working" afms, and no dice - I get random quirks that show up at some point. We've got AFMs on a few of our older L-jet cars, and they are also a constant source of quirks.

[scottinAZ]

scott, 23.1 mpg? i hope it's an eta..

yep, its an Eta, 23.1 is down from 27 in the winter when I dont use ac.