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Hesitations during a pull

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I had started the Megasquirt conversion to fix a problem that seemed to originate from the air flow meter where once the car was warmed up that after a long drive or on a climb the car would lose all power and choke it's way along.

Everytime I got a new AFM the problem was fixed for about 3 months then it would start again so I pulled out the AFM and put in a MSnS system. Took me about 3 months to get it installed and running but it works. The wideband is currently not installed since we are still playing with basic tuning but this has not fixed the problem at all. Fuel pump works great, it's an after market turbo pump and brand new.

 

Anyone have this problem or know what may be causing it?

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According to the Megamanual and some people here we were advised to get the engine running and tune it as best as we could without the wide band first then put it in when we got it going fairly well.

 

We'll check the fuel inlet screen and the injectors next, if that doesn't do it then we'll put in the WB and see if that does fix it.

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Everyone has their preferences, but I say install it and worse case it doesn't help you figure anything out. It has the potential to help with every part of the tuning that deals with air and fuel.

I agree - why would you want to do anything else? If you aren't looking at the engine's response to your tuning, you might as well be changing jets in a carb.

 

The problem you mentioned first could also be fuel tank venting (or lack thereof), btw. In other words, if the tank isn't venting, you could be creating a vacuum in the tank which would make it harder and harder to pull fuel from it the longer you drive. An easy test for this is to loosen the fuel tank cap and see if the problem goes away.

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According to the Megamanual and some people here we were advised to get the engine running and tune it as best as we could without the wide band first

 

I am aghast that the megamanual says that. Get it in and tune with it. I think the only thing they were trying to tell you with that (I hope so, anyway) is don't get carried away trying to nail each load cell perfectly until you have most of the map roughed in.

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Well we put the LC-1 WB in, wired it up according to the Innovtek manual and it does not even turn on.

Here's how the manual told us to wire the LC-1 (We have he blue box version)

 

Blue wire to ground

White wire to ground

Black wire of push button to ground

Black wire of LED to ground

(All 4 of those are soldered to the same ground)

 

Black wire of WB to the other black wire of the push button and the red wire of the LED

(Those 3 are soldered together)

 

Red wire of WB to 12v power source (We have it on the pink O2 wire of the MS ECU as the MS diagram said)

Brown wire of WB is wired to the fuel pump relay at pin 87 with a 10A fuse

Yellow wire is unsused and taped up

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Found out some of the colors were backward on the MS diagram and that the LED Innotek gave us was defective so now the WB works, well at least we were able to calibrate it so far. Here's how it is now set up:

 

Black wire of the WB into the red wire of the LED

Black wire of the LED into the black wire of the push button

Other black wire of the push button to ground

 

WB blue wire to ground

WB white wire to ground

WB brown wire to pink MS O2 wire (pin 23)

WB red wire into distributer relay for constant switched power (pin 87)

WB yellow wire still unused

 

Still have a slight problem with the ignition white wire with a red stripe having constant power instead of being switched. Added a cut-off switch to remedy the situation for now, might be permanent or temporary.

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Which pink wire are you referring to? I don't see it.

 

From the manual:

a. Red 12V supply (You can use the fuel pump power source)

b. Blue Heater Ground

c. White System Ground (should be grounded at the same place as wire above)

d. Yellow Analog out 1 (Pin 23)

e. Brown Analog out 2 (You can use this for an air/fuel gauge)

f. Black Calibration wire (Leave it disconnected as you only need to calibrate it once, make sure it is taped off as it has to be an open air calibration, and you don't want it to try recalibrating accidentally with the engine running.)

 

The unit takes about 30sec to warm up to operating temp. You also have to change the output to 10:1 = 0v and 20:1 = 5v or else the a/f will be off in megatune (using the Logworks application).

 

Mario

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The pink wire is pin 23 on the MS board. In the Innovatek manual it was saying that the analog 2 should go to an ECU and the analog 1 to a gauge and siince I have no gauge we put the brown wire to pin 23 (the pink wire) on the MS ecu. Should analog 1 go to pin 23?

 

We started the car just a few minutes ago to watch as many gauges as we could to see what went wrong when the car hesitated and we found the vaccuum pressure went negative right as the car did its thing. Tried this a few times and then the 5A fuse blew on one of the injector lines.

 

We also couldn't tell if the WB was working other than my a/f ratio was really messed up. I couldn't get the WB programmer to connect to the WB do I couldn't set those above mentioned values you said to enter.

 

At least we know it is the vaccuum line now but we arn't sure where to start. Any ideas? All the lines seem to be ok, maybe the head gasket or manifold?

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The 10:1 and 20:1 settings, were those to be entered in Logworks or the Lambda Programmer?

 

I could not get Logworks to run at all, for som odd reason it could not connect to the same port that I've been using for MS.

 

The programmer did work and there was a setting area under analog 2 where I could set it to 0v at 10.1 and 5v at 20.1 but as for 10:1 and 20:1 I did not see anywhere I could enter those values.

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In reality, it doesn't matter which output you use for what, as they are both programmable. The way they say in the manual is for if you have a stock ECU car that runs on a NBO2 and their fancy a/f gauge.

 

Anyways,

setting area under analog 2 where I could set it to 0v at 10.1 and 5v at 20.1

That's what you want.

 

You also need to reinstall MT if you haven't told it you'll be using the LC-1.

Mario

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My air-to-fuel is still messed up, probably since I have not taken the time to reinstall MT but that is not the main issue.

 

We have checked every vaccuum line on the car and capped them off one by one ans tested the car to see if it still hesitates and it does) and this is all the data we can find.

 

The engine idles at 700-800rpm with a vaccuum pressure of 19 in. Hg.

It hesitates at any RPM and any KPa but the higher the rpm goes the lower ourt vaccuum pressure gets until it goes negative around 4500 rpm. If the turbo happens to kick in the vaccuum has gone as low as -7 in. Hg but the car will not hesitate under boost only while driving up an incline or under any amount of pull.

When a hesitation does occur the vaccuum pressure goes all over the board.

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My air-to-fuel is still messed up, probably since I have not taken the time to reinstall MT but that is not the main issue.

 

We have checked every vaccuum line on the car and capped them off one by one ans tested the car to see if it still hesitates and it does) and this is all the data we can find.

 

The engine idles at 700-800rpm with a vaccuum pressure of 19 in. Hg.

It hesitates at any RPM and any KPa but the higher the rpm goes the lower ourt vaccuum pressure gets until it goes negative around 4500 rpm. If the turbo happens to kick in the vaccuum has gone as low as -7 in. Hg but the car will not hesitate under boost only while driving up an incline or under any amount of pull.

When a hesitation does occur the vaccuum pressure goes all over the board.

 

When you say "vacuum pressure -7inHg", do you mean that you are running ~3.5psi of boost? That's a really confusing way to refer to manifold pressure - too many negatives.

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No I didn't enter any boost values in, inches of mercury (in. Hg) is the value of the vaccuum pressure at that time. I don't think boost values can ever be negative.

 

Just wanted to make sure - you mentioned 19in of vacuum at idle (i.e. no minus sign) and then talked about it "going negative at 4500rpm" and as low as -7in when the turbo kicks in, which literally implies boost.

 

So if you aren't talking about boost, what do you mean by "vacuum going negative"?

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If you read up a few we thought that we might've had a vacuum leak that was causing the hesititations of the car but we could find no leaks. Is having negative values of vacuum pressure normal operation?

 

I know that vacuum pressure doesn't stay constant but I thought it had some parameters it pretty much always stayed between. The manual says it should be between 14.9 and 15.5 in. Hg at idle. Our is at 18.8-19.0 which isn't too bad and it jumps up to 24 when we let of the gas pedal rapidly. What we noticed though was that if we got her going, that the faster we got the rpms the lower our vacuum pressure went until around 4500 rpms (without the turbo engaged) the vacuum pressure would drop below 0 and start recording negative values and start choking and sputtering.

 

Whenever the turbo kicked in the vacuum pressure always went below 0 but the car never hesitated. (We keep blowing the 5A fuse going to one of the injector lines when we kick in the turbo and go past 4000rpm, which is annoying but that isn't my main problem).

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To disambiguate the situation, instead of saying negative vacuum and all of that, lets refer to it in relation to ambient pressure. Your idle is 18-19 inHg below ambient, which is good. You say in your most recent post the sputtering comes in when pressure passes through ambient and raises to pressures above ambient. For our purposes here, this can only happen when the turbo is making boost.

 

...the car will not hesitate under boost only while driving up an incline or under any amount of pull.

 

That is saying something else entirely. If you're not under boost (above ambient air pressure) then you're at 0 or below ambient air pressure. So, which is it?

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What do you mean, "Which is it?" I can keep the turbo from turning on and the pressure goes above "ambient." The vacuum gauge on MT, while on an incline, pressure goes above ambient w/o the turbo and the car sputters until we get pressure back to below ambience.

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I think your nomenclature is causing a lot of problems in the understanding of your situation and your understanding of people's suggestions.

Firstly, what kind of gauge are you watching? Are you talking about a mechanical gauge you have installed ini the dash, if so, is it one of these?

A) 3377.jpgB)3304-J.jpg C)4871_d.jpg

 

Or are you talking about one of the gauges in Megatune with your laptop connected. If so, what is the name of the gauge? "Engine Vacuum", "Engine Vac Boost", "Engine MAP", ...

 

Secondly... where, EXACTLY, is the vacuum gauge connected. If you are reading off of megatune, where did you connect the Megasquirt MAP vacuum hose on the engine? And if you are using a secondary mechanical vac/boost gauge, where, EXACTLY, is the signal line for that gauge connected on the engine/intake manifold, intake pipes, throttle body, whatever.

 

Thirdly, you talk about how at idle you are at 19in or so of vacuum, this is good. Then you say as you increase the rpms, up until 4500 or so, your vacuum reading (notice how I didn't say vacuum pressure, because that doesn't make sense since those or contradictory terms) goes down. It sounds like this is while you are driving, and when I picture it, I picture the vacuum gauge going from 19inHG down towards 0inHg, which is atmospheric/ambient. The throttle blade is a restriction which creates a vacuum in the intake manifold, as you open the TB to increase RPMS, whether driving or in neutral, you are removing the restriction and your vacuum will go down. (you won't have as much vacuum, ie the vacuum number will be lower, 19inHG -->> 0inHG). With a turbo, once you hit 0, the engine is no longer sucking air through the turbo, but the turbo is now pushing air into the manifold/engine. That is called boost/positive pressure/pressure above ambient. Once the turbo is forcing air into the engine, you don't say negative vacuum, you say boost.

I know you know all this stuff, but I'm trying to clarify the terms and names you are using for the different situations, since what you are saying is very confusing.

 

For example,

What we noticed though was that if we got her going, that the faster we got the rpms the lower our vacuum pressure went until around 4500 rpms (without the turbo engaged(a)) the vacuum pressure would drop below 0 and start recording negative values and start choking and sputtering(B).

 

Whenever the turbo kicked in the vacuum pressure always went below 0 but the car never hesitated. (We keep blowing the 5A fuse going to one of the injector lines when we kick in the turbo and go past 4000rpm, which is annoying but that isn't my main problem).

 

a)"without the turbo engaged" - did you remove the wastegate arm so the wastegate is always bypassing the turbo? or did you just not push the throttle down enough for the turbo to spool up?

B) if your vacuum records negative values, you are producing boost, so the turbo was engaged. If it was hesitating (choking/sputtering), you may have been really lean when you were in boost.

c) You should really figure out why you are blowing the injector fuses, check all you wiring, Ohm it out whatever. If you have it setup like we did with 3 fuses for the six injectors, you are losing fuel to 2 cylinders when that happens, that's very bad if you are under boost like you said. Make sure you have your PWM settings right, so you don't burn up your injectors.

 

Also, what are the AFRs when all this is happening, when you are explaining stuff, mention if you were at 13:1 or 19:1 or whatever. This is more valuable info than anything else.

 

As for your last post, that doesn't make any sense at all. What do you mean, "I can keep the turbo from turning on", to me this means you are keeping it out of boost, or keeping the MAP (manifold air pressure) below ambient, ie in vacuum. Then you say the pressure goes above ambient - this will not happen if the turbo is "off".

If the pressure goes above ambient, very easy to do on an incline with a turbo, your turbo is "on".

 

Dang, sorry for making this so long, but it didn't seem like this thread was making any progress in fixing your problem. Maybe you can post where you live and if anyone is local to you and has turbo experience, they might be willing to meet up and help you out.

 

If you have ANY questions about this post, make sure to ask for clarification, or you can PM me. If this is all stuff you know, sorry for the long explanation.

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It would be the engine vacuum gauge in the MT window which is hooked from MS directly to the manifold.

We never hit the throttle hard enough to generate any spool up yet the vacuum still drops below ambient, not much maybe -1 or -2.

 

We only have 2 fuses, 1 for every 3 injectors.

 

We reinstalled MT after hooking up the LC-1 WB as Mario had suggested yet the fuel pressure gauge and the AFR gauge in MT are still messed up. Fuel reads anywhere from -2 to -7.6 and the AFR never changes from 7.35 which I know is far too low.

The car idles better than perfect and has no problems if it isn't moving.

No Vacuum leaks, no fuel leaks, no open air hoses.

 

I'm central CA in the foothills if anyone is near there.

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We never hit the throttle hard enough to generate any spool up yet the vacuum still drops below ambient, not much maybe -1 or -2.

 

Yeah...that's the turbo creating a small amount of boost. At that rpm, even low throttle openings can allow the turbo to create boost.

 

As to your fuel pressure reading, do you have a fuel pressure sender hooked up?

 

Megatune isn't reading your wideband right because you haven't told it you've hooked it up yet. In Megatune, open File -> Configurator, then click Car 1 -> Settings -> Settings -> LAMBDA_SENSOR. Then choose the LC-1 and it should read correctly.

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