Hesitations during a pull

[himself]

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.

[himself]

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[boardkid280z]

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) C)

 

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(.

 

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?

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.

[himself]

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.

[X64v]

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.

[himself]

Ah ok, I did not know the turbo would make any power without properly spooling up.

 

Anyway, no fuel pressure sender hooked up but the LC-1 has already been selected yet the A/F gauge is still really messed up.

[mobythevan]

Yeah, it sounds like a few simple problems which become complex if you try to solve them all at once.

 

Like stated above:

 

1. Fix blowing fuses (If you can make a test run and not blow any fuses then that can be removed from the equation, no worry about injectors not being fired)

 

2. Fix the AFR gauge, recheck installation, conatact manufacturer, do whatever it takes to get that working.

 

3. Take a data log in megatune during your whole run, or at least climbing the hill where you have the problem (preferrably after the AFR is working so it will be in the log).

 

If it was me I would forget about vacuum, just look at the MAP reading in KPA. See what it is when the key is on, but the engine is not running, that is ambient pressure. Then anytime in the log that you go above the ambient KPA you are getting boost from the turbo. Ideally at sea level it would be 100kpa for ambient. And yes, your turbo or tuned port manifold if you have one can build a couple pounds of boost early on, especially loaded when climbing a hill of any sort. In my talon when I am way out of the spooling range, but climbing a hill, it will build like 2 pounds of boost and just set there for a while until I get up in rpms then it continues climbing to the wastegate setting.