E30 running lean, chokes with fast blip of the throttle HELP!

[E30killer13]

Hey guys


just changed out my plugs for some new ones. looked at all the plugs and they are really white....with some of them having small black spots on them.
I'm wondering if with all the mods i have I've advanced the ignition to far hot and it's not getting enough fuel.
My fuel pressure was set to 60psi but i backed it down to 50psi and now the car pulls a little better down low but has lost some noticeable high end power. what's everyone running for fuel psi? i wanted to turn it up even more but i wanna ask first before i blow something up. thumbnail_image2.jpgthumbnail_image4.jpgthumbnail_image1.jpg
i also moved the AFM richer by 4 clicks but don't really notice anything, car starts perfect but idles at 600rpm and doesn't run the best until it's warmed up, it will shake sometimes.
I also think my alternator is on its way out considering when is tart the car all the dash lights are on and i have to rev it to 2k to get them to turn off.
while driving the car runs well and pulls good as it should for a modded NA 2.5. i'll list my mods down below, i'm just wondering how i can get the car to run richer..... i'll list down below a picture of a few of the plugs i pulled out, they have less then 7000km on them.


any advice is helpful!
car has 245km on original engine.




Mod list


Front/rear Konie Coilovers
eibach front strut brace
MSD ignition
Stage 3 clutch
Fuel Pressure regulator
AC delete
Z3 2.7 steering rack
cat delete
resonator delete
Full headers
Scorpion stainless exhaust
cone intake off of afm
stock internals
Bucket seats
rear seat delete
truck is gutted
short throw shiftier linkage
Bavarian auto sports Chip tune, raised rev limiter, said 15
rear strut brace


run it on 100ll mixed with 91 shell

[T77911S]

why did you advance the timing?
that's the worse thing you can do if you suspect you are lean.
timing needs to be set using a dyno.
the only thing I see you have really done to the engine is a header?

its probably leaning out at hi RPM due to the header.
I am not an EFI guy (more CIS) but I would suspect your fix is a programmable EFI like megasquirt if you want to start modifying the engine

[E30killer13]

The cam timing is stock, by advanced timing i meant by the MSD ignition and wires. i'm worried all the preformace mods i did have made it to hot of a spark and it's getting lean...

[E30killer13]

lol found the problem

cylinder 1:145
cylinder 2:148
cylinder 3:148
cylinder 4:139
cylinder 5:120 with oil 170
cylinder 6:140


time for rebuild

[thejlevie]

While a rebuild is a good idea, I suspect your problem is an intake leak or clogged injectors. The engine should run perfectly fine at the normal 43psi rail pressure.

Also an MSD ignition is no better than the OE configuration if the coil, ignition wires, and distributor are in good condition.

[E30killer13]

it does run fine at normal rail pressure, but if i raise it to say 60psi, it gains a lot more power up top, so much so that putting it to stock FP takes away that powerband and makes the mid range a little better but robs the top end.

and how so? going from stock to MSD plus BAV wires made it quite a bit more punchy. i can't see BAV and MSD selling a product that does nothing, but what do i know lol

yeah i'd like to rebuild it, that solves the idle stumble and other problems, i wonder how much hp i've lost due to bad bore/ rings



does the M20b25 have sleeves or? id like to do that if i can when i get it all apart, i may just re ring and clean carbon up but sooner or later she will need a full rebuild.

[thejlevie]

A leak down test will tell more than a compression test in that it can indicate (by sound) where the air is leaking. Which could be the rings, valves. or both. If air is leaking past the valves, that is pretty easy and relatively inexpensive fix.

The M20B25 has bored cylinders, not sleeves.

[E30killer13]

Thanks!

but wouldn't a wet comp test tell? if the comp is 120 and with oil its 170. doesn't that mean that the rings are the worn part? if it was the valves it would be a little bit higher or the same no?

and how hard would you say it is to pop all the pistons out, clean them up an re ring them till i can fully rebuild the engine next year???

[thejlevie]

Oil can seal a leaking valve just like ti can rings. A leak down test can confirm where the leak is by the sound of the air leaking.

Simply pulling the pistons and using new rod bearings a, bolts, and rings.ma not work. Even if the cylinder wear is within spec, if the cylinders aren't cross hatch honed the rings may take a long time to seat, or may never seat.

[aaverhulst]

I would set it up back to stock to see how it runs. That appears to be to set fuel pressure back to 40's, put old chip back in and the AFM adjustment. Then look at your reading after you have driven it for a time. If you keep pushing that engine that appears to be tired, you not need a rebuild, you will need another engine!

[E30killer13]

This engines has a bad 5th cylinder for the last 70 thousand km. i just recently comp tested it and thought hey maybe i should do something about it.

and i've put everything back to stock and it just makes the car run slower. Setting the FP back to stock makes the car lose a bunch of top end and gain a tiny bit of low end.

so what you're telling me is re ringing it would be pointless? can't you just hone it a bit to get the cross hatch and put it back together? i want to fully rebuild the engine next year. so limping it another 40k is what i have in mind, i don't think at this rate, the engine will last till next year like this.

[aaverhulst]

Tentative problems with a re-ring. Lot of work - cylinders may be tapered - may increase compression that will cause valve problems and oil consumption, also condition of rod and main bearings and crankshshaft. Me I would save my time, effort and money for a rebuild if that is what you want to do

[E30killer13]

so just run the engine till next years rebuild/blows up? if the bore is messed up i'll have to over bore it or get a new one anyway.....i would like to leak down test it and see if it really is rings, if it's the head then that's a lot easier....