My Fuel Injected 2180 shows low vacuum at cold start....Megasquirt controlled, turbo charged with less than 10 K on it.....

Once warm no problem with hot starts. It's a bitch when cold.....

Any suggestions?

You can't turbo a 914.

Joe Dada

In THIS case...ya can't turbo a Speedster.....

what do you mean by " a lot of vacum" ?

20kpa?

100KPa?

EDIT: I didn't read the post clearly. what do you have for a AAR/ FI selonoid?

I have a turbo gauge....when cold it shows -3 or 4 psi at idle. When warm 10+

What is the MAP reading in MT?

What does the AFR gauge say at startup?

Move to a hotter climate?

Can you post the datalogs?

How is your idle speed after a cold start? Is it really low? If so that could explain why you have less vacuum.

Go over to the shop talk forums, lots of guys with type 1 turbo know how in the forced induction forum.

I'm not sure exactly what your Mega Squirt is doing but you are lacking fuel at start up and warm up. Can you ask MS what regulates the warm up phase?

Megasquirt has a setting for priming pulse width and that is set pretty high already in our case. During idle we have 2.5msec pulse width give or take with descent A/F ratio. During cranking I went as high as 7 or 8. Maybe it is too much?

Still, the first two minutes the engine pulls less than 3 PSI vacuum during its shitty stumbly idle - a little more on decel. When I open and check the fast idle port that we rigged up I can feel a lot of pulsation. Once warmed up we get a descent 10 -11 PSI and the fast idle port when opened sucks a nice and even.....

Its doesnt suck, it blows.....hahaha
Seriously...its a blow through turbo...its gonna be real low till the air warms up..

R

what are your warm up enrichment (%) settings? and ASE settings? you could try bumping those values up too...

point taken but we had the same problem even with the turbo disconnected from the intake....

It could be that you have enough overlap that the Map Sensor is seeing a lot of variation. If so, it may be necessary to add a buffer in line. I was running with the WEB #73 cam which had some overlap and it took me quite a while to get the cold start even close. Even after adding a buffer chamber between the Map sensor and the plenum, there was still room for improvement.

THe MS site suggests a fuel filter as a buffer, but I wanted something adjustable, so I found a threaded fitting at the hardware store that had an inlet & outlet side, and the main body had a threaded cap. I was able to adjust the size of the buffer chamber by threading the cap in or out.

I suggest watching the Map sensor on your Megatune during cold start and see if it jumps back and forth more than +- 2. Mine started off going +- 5 and 6.

Good luck,

I think you guy's are talking about your turbo pressure! That is measured in PSI.

MS measures in vacum in KPa through the MAP sensor. It sounds to me you have these two things confused(just a guess). The tubo has nothing to do with what MS sees for a fire up/cold start sequence.

before you start the engine, let your 02 sensor go through it's cycle. fire up the engine only when you can get a AFR reading. You will be able to see if you are rich or lean at fire up.

From here you will be able to tell what area needs to be adjusted, i.e. ASE and /or WUE.

ALso, run a datalog at start up to see what your cranking pw's and cranking rpm's are, this will help you get them dialed in.

BTW, 2.4ms is a good pw at idle

This is why. You need to get the idle up. It's unhappy for some reason, it doesn't have enough fuel or air, the timing is off, or it's fouling a plug on start and running on 3. Those are just guesses. Don't trust the AFR meter for the first couple minutes either, it may read wrong if the sensor is cold or the car is misfiring, etc.

PS: This is one of the hardest things to get right with MS. I speak from experience.

Looking at that turbo setup it looks like the air does have to travel a long way to find engine vacuum. It looks very restricting. With no turbo piping I bet your throttle bodies would pull a decent vacuum at idle. The turbo probably impedes air at idle anyway since we know there is no boost.
So I have to reverse my original thought and say you don't have enough air and fuel at start up. I agree with Keyzer to turn up your idle at the throttle body.

Update for the night:

Static timing was off - my mess-up. We use an 8-pin GM HEI module triggered of the dizzy. Megasquirt is enabling limp-mode during cranking where only the static advance of the dizzy is used. It was set to something like 10 degrees ATDC (way too retarted, just like Mike ) Now it is around 0 degrees. The manual for a 1.8 says 7 degrees BTDC at idle with vacuum adcanve disconnected. Maye I have to bump it a little more.

The tach signal from the HEI module used by Megasquirt for timing control is very noisy. As a result once Megasquirt takes over timing the TDC mark starts to "bounce" around under a timing light. The Megasquirt website has shows that aftermarket HEI modules can be an issue and suggest a little modification to the optocouple circuit. I guess I need to do that little mod

The temperature sensor calibration for IAT and CHT was off and was corrected.

I switched from the two-point enrichment to a table-based enrichment and made sure to get fuel into the engine.

It finally started with some convincing. We'll see tomorrow when it's cold again how the enrichment is doing with the improved static timing.

Ingo

One word....VALVES!!!!!!!!!!!!

They were tighter than a virgen gnat's ass. Adjusted them and BOOM, instant vacuum at start up. Should have listened to myself when I said...self, check the baseline and work it up....

ARRRGHHHHH what a Pain in the ass.....

We all just assumed you had done this...
Butthole.
If we had suggested it, you would have beat on us, so thus you get less than obvious answers.

Always look for the simple shit first...hell, it ran for the last few years...what would have changed??

Did you sell that blue car yet?

Rich

I already admitted I was fucking stoopid....I have a fiend (spelled right) with a PhD in Chemistry that missed it too.....I printed that I fucked the pooch, what ELSE would you like me to print? That your sister thinks I'm a dead lay?

that's well known mike. old news.

Howz yer Sis?

We all make mistakes. The important thing is you figured it out before damage was done.

Remind me not to modify a post as to being stoopid and invite insults.....this is lame.....I need another beer....

What an idiot...

Thank you....

I already know my sister thinks you're a dead lay.



Don't stop there. This thread has enormous potential.

died last week. victim of boring sex.

k

dont whine...you keep posting in all sorts of threads in big ass bold letters...Im and Idjut...

Live and learn...

Rich

DUMBASS!

[i just had to chime in and join the ]

I'd like to thank the weenie wagger Eric for changing the subject of this thread...if it wasn't him, well, he's still got a short wagger.....

Why... I'm appauled. I would never...

Have a short weener or wag it or both?

Which IS it?

i think he's saying that Paul him.

RINGS AND VALVES AND TIMING??? GOOD LUCK

Confirmed .... Mikey is a peeker ... Eric, did he take his teeth out?

or


Wait a minute ...


maybe that's Mikey is a pecker!


Nope, wait ....




Nope, he's just a prick!

we can't let this get to far down the page..

we'll forget that Mike's pecker head dumbass

Well at least I know what Fuch's wheels are worth....inside joke....

your avatar is racist!!!!!

trying to keep the black man down!!

Ahhh,,,,it's clear and dark.....not black and white....

But thanks for playing the game.....

yer welcome