boost fooler

[superpro86stang]

Ive read people are using a 10k pot to increase boost at cruising speed alittle but does anyone know what watt the pot should handle. Im trying to lower egt alittle at highway speed. My ecm is cutting all boost at 70mph and it is the ecm and not common problems with wastegate setup. My truck is a 98 f engine and I have gauges, exhaust, and air filter on it.
Any help appreciated
Thanks
Jeff

[TurboDiverArt]

Ive read people are using a 10k pot to increase boost at cruising speed alittle but does anyone know what watt the pot should handle. Im trying to lower egt alittle at highway speed. My ecm is cutting all boost at 70mph and it is the ecm and not common problems with wastegate setup. My truck is a 98 f engine and I have gauges, exhaust, and air filter on it.
Any help appreciated
Thanks
Jeff
Mine worked exactly the same way. I can't remember if when stock it was 70 or 75MPH but I think it's normal for the stock boost to cut out at high cruise speeds. I don't think you much need to worry about wattage on the POT; it's just a reference signal. I picked up one at Radio Shack and a two-pack of knobs. Like $7 all together.

Art.

[Robyn]

Well just for the record

After driving my new (new to me ) dually now for a few weeks I am absolutely in love with the Turbo master unit.

I personally would recommend going to a reprogramed ECM along with the turbo master.

I see about 5 PSI at 65 MPH under light throttle.
Once you start feeding the little beast the boost will climb right on up into the 12 range.
My EGT's are very nice at around 500 or so untill you really get on it then of course they head North

Trying to fool the computer in my opinion is probably not your best bang for the buck.
Also adding a larger exhaust system is a must if you really want to help the little creature under the hood. :D


Hope this helps

Robyn

[JohnC]

My ecm is cutting all boost at 70mph and it is the ecm and not common problems with wastegate setup.

If it truely cuts all boost, I suspect it is a problem with the wastegate control. The only time the PCM cuts all boost is when it is unable to limit boost to what it considers safe levels. the most common but not the only cause is a failing wastegate solenoid.

Put a scanner on it. If the wastegate solenoid duty cycle drops to zero then the PCM is having control issues...

[DennisG01]

Yes, boost should not cut out all together (unless you're off the throttle). I seem to remember about 3 to 5 psi at highway sppeds when I was stock.

[TurboDiverArt]

Yes, boost should not cut out all together (unless you're off the throttle). I seem to remember about 3 to 5 psi at highway sppeds when I was stock.
I definitely didn't get that when stock at 70-75MPH. With the fooler I would get about 2-3 psi of boost at 70-75 and 14-16 at WOT.

Art.

[DennisG01]

Hmmm. I could be wrong as it's been a while since I've been stock, but I know I was atleast 3psi at a steady cruise. Either way, though, boost should not cut out completely.

When your boost cuts out, do you also get increased black smoke? What happens if you stomp on the go pedal when the boost cuts?

[TurboDiverArt]

Hmmm. I could be wrong as it's been a while since I've been stock, but I know I was atleast 3psi at a steady cruise. Either way, though, boost should not cut out completely.

When your boost cuts out, do you also get increased black smoke? What happens if you stomp on the go pedal when the boost cuts?


For me I would have a little boost at 65-70 (2100-2300 RPM), definitely not 3psi. By 75 (2400 RPM) I would have none and I've got a digital boost gauge that reads to the 1/10 of a psi. If I gave it a little throttle I'd come right back into normal boost.

I thought I remember a while back reading that the stock program pulled boost out at higher RPM and speeds for cruise.

With the turbo master I've got 3-4 psi of boost anywhere above about 55 MPH.

Art

[superpro86stang]

Thanks for input, I do have a scanner and its cycleing the wastegate solenoid at 30% at highway speed and about 70% at idle. The boost is fine until you hit about 2200 rpm and it drops from 10psi or so to 0. I do have 4" open exhaust and aftermarket air filter. I can switch vacuum lines on wastegate solenoid to test the rest of the system and it will do better than 15psi at 70 that way but obviosly I cant run that all the time. I tried a 10k resistor inline in signal wire and it made no difference what so ever on baro or boost readings on scanner?
Thanks Jeff

[a5150nut]

Thanks for input, I do have a scanner and its cycleing the wastegate solenoid at 30% at highway speed and about 70% at idle. The boost is fine until you hit about 2200 rpm and it drops from 10psi or so to 0. I do have 4" open exhaust and aftermarket air filter. I can switch vacuum lines on wastegate solenoid to test the rest of the system and it will do better than 15psi at 70 that way but obviosly I cant run that all the time. I tried a 10k resistor inline in signal wire and it made no difference what so ever on baro or boost readings on scanner?
Thanks Jeff

IIRC. the risistor run across the two wires not in line. I made the same mistake hooking mine up. Kinda confused me for a little while. But then it doesn't take much any more................

[rjwest]

My experience with a 96 (OBD2)


If the PCM senses to much boost ( around 10-12 psi ) it will defuel,
loss of power, this condition is reset with a key off ( engine shut down).

With a Manuel waste gate controller, if the spring is to tight, this
over boost can occur ( defuel , ) and boost will be low untill engine restart .
That is where the boost fooler becomes usefull for the manuel wastegate,

For the stock vacuum controller, the boost fooler will make the PCM think less
boost is being made and keep waste gate closed longer, result, more boost
in all operating ranges..cooler egt

Note , with the manuel waste gate controller, an overboost usually
occured when up shifting on hard accelaration ( boost surge ) mostly on a 2-3 shift.

[JohnC]

The boost is fine until you hit about 2200 rpm and it drops from 10psi or so to 0.

What kind of load are we talking about? With stock programming 10 is pretty much the max you'll ever see, and then only for a moment. If you're seeing 10 psi sustained at less than full throttle, the PCM is probably having problems controlling the boost and dropping the wastegate. Any codes set?

[superpro86stang]

No codes set and without load it will spike to 15psi and hold steady at 10psi while accelerating and below 2200rpm. At cruising speed the boost drops off completly and at 70mph it will not boost at all even floor boarded. At 70mph the wastegate solenoid stays at 30% all the time even accelerating or pulling.
My egts are high but if I could get maybe 5psi constant cruising boost the egt drops to about 600. I cut the green wire on the sensor and installed a 10K resistor but it made no difference in boost.
Thanks
Jeff

[rjwest]

I cut the sense wire, installed a 10k pot
1 lead to the cut senser wire that goes to the sense unit
1 lead to ground

the center tap ( varible ) goes to the green wire that goes into the harness.

The PCM now sees a percentage of the sensor output...

about 3k to 7k split(to start ), the 7k being the ground side.


You may be getting a DEFUEL set in the PCM, No codes readable...
just cuts back fuel which cuts back boost.

[DmaxMaverick]

I'd suspect you have a failing PCM, or an aftermarket PCM that's not quite right. You should not be seeing 10+ PSI sustained boost, and certainly never 15 PSI. If the WG modulation holds at 30%, and boost falls off, it is defueling, so either it is seeing something you're not, or it's failing. 10 PSI is enough boost to cause the PCM to defuel, and 15 PSI will cause limp mode.

How's the WG linkage movement? It could be hanging under load, then dumping at enough pressure, then not recovering. Interesting though, with no codes. This points back to a failing PCM, or an aftermarket masking the parameters that cause [normal] defueling and DTC's.

[superpro86stang]

The only time it will hold 10psi is accelerating but normal cruising at say 55mph is between 2 and 5psi. When at higher speeds say 70mph is about 2400rpm it will not boost at all. The pcm has no aftermarket decals on it but the fuel rate goes as high as 84mm which ive heard is too high for a factory pcm.
The truck runs great except on the highway above 65mph when it will not boost at all. It will still hit 84mm of fuel at 70 and wide open but no boost at all. My egt will climb very quickly on the highway because the engine has no air. If I give wastegate direct vacuum and run 70mph with sustained boost at 5 psi the egt is about 650 which is where I would like to see it. Without boost unloaded Im seeing 800 just cruising.
Thanks
Jeff

[Scooby]

Before I changed to Mr Heath's 6.5 control systems, mine would cut out boost when I set the cruise control at highway speeds. I was not pulling anything with the truck at that time, but I do remember boost going from between 5 or 10 depending on highway speed when using the pedal, to 0 once cruise was set. I cant say enough about the difference in the truck once the Turbomaster and "enhanced" ECM were added. I think Volkswagen calls it farfignugen, or something like that.

[Robyn]

I like those fignugen things, they are so good with a cup of coffee :D

In all fairlness I would go to a turbo master and mess around with it until you have it just right and the puter is not screaming at you.

[JohnC]

I suspect you have an aftermarket PCM that is masking the wastegate code. In addition, you have either a failing wastegate solenoid and/or a sticky wastegate. Even though it is not setting the code it is reducing fuel and boost in response to not being able to control manifold pressure.

That's the only story I can come up with that fits all the observations.

[superpro86stang]

Thanks for the help, I will probly try a solenoid first and see what happens. The turbomaster sounds good I just dont want any codes.
Jeff

[Scooby]

THe Turbomaster wont give you any codes if you dont set the boost too high. I ran mine for almost a year with just the Turbomaster (and gauges). Then when I switched computers the truck came alive.

[rjwest]

A Defuel for over boost will not set a visable code,
The PCM go's to defuel mode until ign is shut off.
Or a reset is commanded to the PCM via a Tech2 or any software that can clear codes.

The symptoms of a defuel are NO power. and naturally, no smoke