Author Topic: my supercharged M42... issues (Read 10326 times)

B318M42W · « **on:** October 05, 2010, 11:31:04 PM »

I just finished assembling my M90 s/c and decided to give er a try and see if she'll start...

She starts all right!!! however, it idles at about 2000 RPM when cold, then bounces between 1500-2000. also, once slightly warmed up, i beleive i have detonation? unsure of what it sounds like but it doesn't sound good!
took a short video, can mostly hear it by the end...

http://www.youtube.com/watch?v=VvwXr_DH8Co

A little bit of details:
- 5psi boost
- currently on #44 injectors with 3 Bar FPR
- 250 LPH TRE fuel pump
- 1 step cooler plugs
- STOCK ECU (piggyback isn't working:() (had a chip before, put the stock one back, ECU had no power for a few days)

other interesting facts... before i got the #44 injectors in, i tried to run 4Bar FPR with stock injectors. managed to idle at 700 rpm but was reallly lean
with the larger ones, it maintains a healthy 13:1 @ 2000rpm....

so my questions are: - why is my idle so high???
- what's that sound in the video and what can i do about it?

Thanks!!!!!

1991 E30 M42 · « **Reply #1 on:** October 05, 2010, 11:54:18 PM »

did you remember to put oil in the engine?

dkbmxer002 · « **Reply #2 on:** October 06, 2010, 01:07:14 AM »

13.1 in a boost application is healthy?

bmwconnect · « **Reply #3 on:** October 06, 2010, 02:09:29 AM »

Injector part # please
Your motor will simply not run on 44# injectors unless you have decreased idle fuel pressure and or have changed the mapping

bring your baby up to Ottawa and I will tune it correctly for you before it blows up:)

midnight-tuning@rogers.com

bmwconnect · « **Reply #4 on:** October 06, 2010, 02:30:45 AM »

Quote from: dkbmxer002;97175

13.1 in a boost application is healthy?

for light acceleration this is a ok afr, but in boost for a supercharger 11.5-12.5 should be your target for safe operation with correct ignition timing

nuvolarossa · « **Reply #5 on:** October 06, 2010, 02:38:24 AM »

sorry, could you post some pics so we can see if there is something wrong in piping or setup?
you already calculated pulley ratio?

you need fuel (& ignition management if you can), either rrFPR OR stock ecu tuned for those injectors OR piggyback OR standalone.

fabe · « **Reply #6 on:** October 06, 2010, 02:48:28 AM »

the SMT6 shud work if you wired up everything correctly...
Let me go search for the wiring diagram. The new diagrams posted in the perfect power website is not user-friendly.

nuvolarossa · « **Reply #7 on:** October 06, 2010, 05:55:44 AM »

Since there isn't a SMT6 diagram for the e30 318is, I uploaded the diagram of SMT7 for E30 318is AND SMT6 installation manual.

You need to read the SMT6 manual to check the SMT6 pinout since they're different from SMT7 diagrams and follow the engine wiring pins from the SMT7 diagram.
Doublecheck them with BMW ETM if you can.

SMT7 wiring for E30 318is
www.studentipolito.it/download/SMT7-bmw318isE30.pdf

SMT6 Installation Guide V1_3.zip:
www.studentipolito.it/download/SMT6 Installation Guide V1_3.zip

let us know.

B318M42W · « **Reply #8 on:** October 06, 2010, 06:45:31 AM »

I wish i could drive it to ottawa! however it's over 800km from here:(
i don't know the injector part #, greentop bosch.
AFR of 13.1 at "idle" and goes down to 8.5-9.0 under load (1200rpm)
i'll post a pip�ng diagram later today
I did calculate the desiered pulley ratio to get 5-7 psi, which i do have ( Pulley ratio is very close to 1:1 with crank)
I have an SMT6, with a comm problem along with a deep desire to chuck it as far as i can...

Thanks for the support!

fabe · « **Reply #9 on:** October 06, 2010, 08:37:05 AM »

this is the diagram I printed from PerfectPower's site when I installed the SMT6 few years back.. a more 'visual' diagram...

A total of 7 wires from the SMT6 harness would be used and 5 from the engine harness...
need to tap signals from:
- Power
- Ground
- TPS signal

And then cut 2 wires:
- AFM signal
- Crank sensor

This diagram was not compatible with my ECU diagram, so I have to trace the the correct wires.

But there was an issue with the crank sensor signal. the signal (after going thru the piggyback) seem to be a bit weak to be read by the ECU during cranking. Symptom was like a slipped starter (not too sure how to describe it). So I came up with solution using an electromagnetic relay. During cranking, the crank signal would be direct. and then switch over after engine started. it solved the cranking problem with just a minor dip in RPM during the switchover. Power for the relay is tapped from the ignition key barrel..

bmwconnect · « **Reply #10 on:** October 06, 2010, 10:09:49 AM »

Quote from: B318M42W;97190

I wish i could drive it to ottawa! however it's over 800km from here:(
i don't know the injector part #, greentop bosch.
AFR of 13.1 at "idle" and goes down to 8.5-9.0 under load (1200rpm)
i'll post a pip�ng diagram later today
I did calculate the desiered pulley ratio to get 5-7 psi, which i do have ( Pulley ratio is very close to 1:1 with crank)
I have an SMT6, with a comm problem along with a deep desire to chuck it as far as i can...

Thanks for the support!

says your in montreal? only 150kms away
I cannot help you till we get a injector part number...they are located on the injector

deekay · « **Reply #11 on:** October 06, 2010, 03:08:54 PM »

single-digit AFR under boost is pig fucking rich.

what did the AFR look like with stock injectors and the 4bar FPR?

B318M42W · « **Reply #12 on:** October 06, 2010, 08:01:39 PM »

4 bar stock injectors resulted in 650 rpm and a 16:1 AFR, and a really lean (around 18) AFR at higher rpm (not even load, just rev)

Thanks for the hard work put into the SMT6 issues, but i've given up on it since i can't get it to communicate properly (sure it would of been great to get it to work right, but at this point it's already wasted 9 lives, it's dead now... so far, the wiring i had was correct, i was using the ETM along with the developers manuel (has all smt6 wires and wire definition) to plug it in right and still no results. pretty sure the unit and/or the comms port is fried...)

Here is how she's all plumbed up!

deekay · « **Reply #13 on:** October 08, 2010, 02:09:26 AM »

Quote from: B318M42W;97215

4 bar stock injectors resulted in 650 rpm and a 16:1 AFR, and a really lean (around 18) AFR at higher rpm (not even load, just rev)

i hate to say it, but i think you probably borked your bottom end running that lean. detonation is bad enough on a naturally-aspirated engine... with FI, it's pretty much instant death.

this is, if nothing else, a good object lesson in why research is key before undertaking a project like this.

fueling is not a matter to leave to guesswork or trial-and-error... and even the most cursory of research would have led you to find that a boost-dependent fuel pressure regulator probably would have been satisfactory for your power goals (@ 5psi positive manifold pressure).

sorry if i sound harsh... i wish you'd also asked for advice on fueling when you were figuring out how to mount the blower.

B318M42W · « **Reply #14 on:** October 08, 2010, 08:56:08 AM »

It ran maybe about 3-4 minutes total on lean conditions, under 2500 rpm before i put in the 40#. an RRFPR was considered but i didn't want to go that route running 90 psi of fuel in lines that were built for 45... already had a solid fuel line burst before. yes i could of done a little more research, however, the engine isn't supposed to see boost at idle (BPV) and run under normal conditions, ie idle with stock components. this isn't what quite happened. the aim of the start-up was to check idle, not drive the car.