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Discussion Starter #1
Hello everyone ran into bit of a head scratcher hoping for some help. Recently i got a 90 gt non running an motor toast. I rebuilt a new motor put everything all back together stock an unfortunately ever since day one i have hit fuel cut in it. My boost is going to 15lbs an im having a hell of a time trying to have any control over the boost. I have tried 2 different manual boost controllers an even hooked it back up stock with the stock electric actuator still wants to spike.

So, i went an bought a chipped ecu with the probinator chip installed an cranked my one manual boost controller as tight as i could an I hit 9lbs in 2 no fuel cut an in 3rd gear jumps straight up to 12 an hit fuel cut. Now i understand that the fuel cut is only caused by the flap on the vaf being opened for to long an setting off the factory saftey over boost/ fuel cut. So i pretty much can not drive the car becuase it hits fuel cut non stop.

I have a brand new factory TB elbow thats not cracked nor is the other one that attaches to the Vaf. I have a smoke tester an ran it thru boost controller vaccum line an also straight off the turbo at 25psi. So i was trying to make sure to check the intake manifold, an the charge system. At first the stock egr was leaking smoke out fixed that an nothing else showed leaks. If I had a boost leak or any kind of leak wouldnt it show itself at 25 psi? Also i have tried a different Vaf an the car ran even worse. So im really scratching my head here. Cant find any leaks anywhere. Really cant control the boost an sure as hell cant figure out why that flap an the Vaf just gets pinned so easily. I have a 89 gt that is built with a chipped ecu an im running 8.5 or higher comp wiesco pistons an a gtx2867r at 10lbs an have never hit the factory fuel cut or have any issues running that setup so what the heck am i missing guys please help lol thanks
 

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Discussion Starter #2
I forgot to bring up the possibility of stock internal wastegate actuator? Could this be the cause of the problem in anyway shape or form? I just dont get what would cause this issue.
 

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I forgot to bring up the possibility of stock internal wastegate actuator? Could this be the cause of the problem in anyway shape or form? I just dont get what would cause this issue.
-Is timing set to factory 9*?

-If you bought a chip and still have boost cut you didn't get a good chip.

-In every test scenario you mention running a boost controller, run a piece of hose from the compressor housing nipple to the waste gate (no T's, no interruptions), If you still get boost over 7 or 8psi the wastegate is not opening far enough, say it's opening 20% max, as the gears increase so does the load on the engine and the amount of exhaust passing through the turbo. Therefore to maintain steady boost in all gears the waste gate flap must open more for every higher gear.

-Many factory boost hoses have an inline reducer in the wastegate hose, this doesn't change the pressure tho wastegate operates at but it does slow the speed at which it opens and closes. Make sure there is no reducer in the wastegate line.

-Is the turbo solenoid valve that sits between the boost source and wastegate hose (code 42) still inline with the wastegate hose? That solenoid valve is basically an adjustable boost controller, it runs as a T straight to the wastegate and a bleed of line operated by the solenoid valve that is controlled by the ECU, it opens in mid range RPM's and increases boost but stays closed at low rpm and high rpm. It also closes if the knock sensor gets activated, reduces boost and the ECU pulls timing. The amount of boost it bleeds of is adjustable by loosening the nut and adjusting the screw. It could have been readjusted allowing increased boost. And from my recollection of testing the return spring in the solenoid stays opened above 18psi, I double the springs and use one as a stage 3 boost controller adding 9psi when toggled on. If the single spring was to fail there would be nothing to resist the cup from moving under pressure and the bleed of solenoid valve would flow all the time.

-The wastegate flaps swing arm is a rectangular tab with pin welded to it, find a open end wrench the size of the rectangle (12-14mm) put it over the rectangle and pry the wrench to your left (passenger side), the wastegate flaps travel is limited by the actuator rod and the o2 housing, it's total movement (if up is 0degrees) is around 45 or 50 degrees to the left.

So if with the correct timing and a straight connection between the boost source and waste gate you get more than factory boost. The swing arm is seized or binding or the waste gate actuator bladder is leaking.

This is not an issue I have ever experienced, I have however experienced boost limitations caused by exhaust flow, with a clogged catolitic converter I couldn't get more than 12psi, on a bone stock 626gt with like new everything and a chip I couldn't get more than 15psi from the car, I actually blocked the wastegate hose off so it stayed shut, boosted 15psi in every gear all the time. Had the exhaust brake at the downpipe on an mx6GT without a chip, hit boost cut in 4th gear on slow spool with the boost controller shut.
So a really good flowing exhaust could cause boost spike on the stock turbo.

If all else fails, remove the lock clip that holds the waste gate actuator arm to the waste gate swing arm, move the swing arm to the left using a wrench or vice grips on the rod and remove the actuator arm hole from the swing arm pin. leave the swing arm to the left (passenger side), the waste gate is now fully opened, if you get instant boost and boost cut the car is magic or the waste gate hole is blocked/sealed. If it is not blocked than leave everything as is, install a bigger turbo and proper boost cut chip, increase fuel delivery and enjoy the magic engine.

Boost leaks have a different effect on things, say if you get boost cut a 9psi on a stock set-up you could have a boost leak between the turbo and intake valves, the amount of pressure the turbo has to make for the leak isn't seen on the gauge but will increase the amount of air drawn through the air flow meter causing boost cut at less than 12psi intake manifold pressure but well above 12psi turbo compressor pressure.

Finally the AFM, you say you have tried a second and also tried a 2nd ECU with similar or worse results, if you check the ws manual there are instructions to test the afm boost cut, I think you just put the key in the 3rd position and move the flap until the dash peeps, this happens at about 1/4 flap travel if it happens as soon as you start moving the flap their could be a wire issue between the ecu and AFM and a higher voltage is being sent back to the ecu than the flap position is at (or lower can remember if it's 0-5 v or 5-0v.
 

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Discussion Starter #4
-Is timing set to factory 9*?
Yes it is

-If you bought a chip and still have boost cut you didn't get a good chip.
Well bought it off a guy selling it thru eBay from canada he also sells just the chip an offered to purchase my other stock ecus from me. I contacted him over things an he thought i may have a boost leak between the turbo an the TB. The car does definitely pull harder with the chip ecu then tbe stock one. Because i did get a full pull in 2nd with both ecus, the chip one you are moving, the stock one was like shits in slow motion lol. Is suppose to be the probinator chip.

-In every test scenario you mention running a boost controller, run a piece of hose from the compressor housing nipple to the waste gate (no T's, no interruptions), If you still get boost over 7 or 8psi the wastegate is not opening far enough, say it's opening 20% max, as the gears increase so does the load on the engine and the amount of exhaust passing through the turbo. Therefore to maintain steady boost in all gears the waste gate flap must open more for every higher gear.
Running just a straight hose from wastegate to nipple on compressor an it shoots straight to 15 lbs.

-Many factory boost hoses have an inline reducer in the wastegate hose, this doesn't change the pressure tho wastegate operates at but it does slow the speed at which it opens and closes. Make sure there is no reducer in the wastegate line.
There is no reducer

-Is the turbo solenoid valve that sits between the boost source and wastegate hose (code 42) still inline with the wastegate hose? That solenoid valve is basically an adjustable boost controller, it runs as a T straight to the wastegate and a bleed of line operated by the solenoid valve that is controlled by the ECU, it opens in mid range RPM's and increases boost but stays closed at low rpm and high rpm. It also closes if the knock sensor gets activated, reduces boost and the ECU pulls timing. The amount of boost it bleeds of is adjustable by loosening the nut and adjusting the screw. It could have been readjusted allowing increased boost. And from my recollection of testing the return spring in the solenoid stays opened above 18psi, I double the springs and use one as a stage 3 boost controller adding 9psi when toggled on. If the single spring was to fail there would be nothing to resist the cup from moving under pressure and the bleed of solenoid valve would flow all the time.
No it is removed from the car just running a straight manual boost gauge from WG to nipple on compressor

-The wastegate flaps swing arm is a rectangular tab with pin welded to it, find a open end wrench the size of the rectangle (12-14mm) put it over the rectangle and pry the wrench to your left (passenger side), the wastegate flaps travel is limited by the actuator rod and the o2 housing, it's total movement (if up is 0degrees) is around 45 or 50 degrees to the left.
Without removing off the car very pain in the ass to try an reach in there an mess with.

So if with the correct timing and a straight connection between the boost source and waste gate you get more than factory boost. The swing arm is seized or binding or the waste gate actuator bladder is leaking.
I wouldnt be shocked if there was something wrong with the actual arm seized. The car came from canada is rusty an sat for over a year plus broken. I saved her.
This is not an issue I have ever experienced, I have however experienced boost limitations caused by exhaust flow, with a clogged catolitic converter I couldn't get more than 12psi, on a bone stock 626gt with like new everything and a chip I couldn't get more than 15psi from the car, I actually blocked the wastegate hose off so it stayed shut, boosted 15psi in every gear all the time. Had the exhaust brake at the downpipe on an mx6GT without a chip, hit boost cut in 4th gear on slow spool with the boost controller shut.
So a really good flowing exhaust could cause boost spike on the stock turbo.

If all else fails, remove the lock clip that holds the waste gate actuator arm to the waste gate swing arm, move the swing arm to the left using a wrench or vice grips on the rod and remove the actuator arm hole from the swing arm pin. leave the swing arm to the left (passenger side), the waste gate is now fully opened, if you get instant boost and boost cut the car is magic or the waste gate hole is blocked/sealed. If it is not blocked than leave everything as is, install a bigger turbo and proper boost cut chip, increase fuel delivery and enjoy the magic engine.
If I take the turbo back off i will check this out for sure since i have 2 other stock turbos to check out an compare to or swap with.
Boost leaks have a different effect on things, say if you get boost cut a 9psi on a stock set-up you could have a boost leak between the turbo and intake valves, the amount of pressure the turbo has to make for the leak isn't seen on the gauge but will increase the amount of air drawn through the air flow meter causing boost cut at less than 12psi intake manifold pressure but well above 12psi turbo compressor pressure.

Finally the AFM, you say you have tried a second and also tried a 2nd ECU with similar or worse results, if you check the ws manual there are instructions to test the afm boost cut, I think you just put the key in the 3rd position and move the flap until the dash peeps, this happens at about 1/4 flap travel if it happens as soon as you start moving the flap their could be a wire issue between the ecu and AFM and a higher voltage is being sent back to the ecu than the flap position is at (or lower can remember if it's 0-5 v or 5-0v.
Will try an see about this.

Can a 88-89 ecu work with a 90-92 the only difference I have seen is the middle an end plug are swapped on the ecu? Was wanting to try my ecu from my 89 with a forsure good chip ecu in the 90 an see what happens. Thanks for the help as always carnage.
 

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Barney that is the hardest reply to read ever.
When you quoted my post you will notice the [quote username at the begging and quote] the the end,
Like this:
[ QUOTE="Barney, post: 2653890, member: 94622"] quoted words [/QUOTE ]
I left spaces at the beginning and end so it would appear.
Just copy and past the quote brackets before and after each sentence or paragraph you want to quote and reply bellow it, and repeat for the next one... Erase those you aren't commenting on.

Everything I suggested can be done with the turbo on the car, checking the wastegate swing arm, moving it, disconnecting it and checking the wastegate hole the flap covers, Undo the 5 x 17mm nuts holding the o2 housing to the turbine housing and pry it to the left until it touches the dip stick bracket, you can now see the wastegate flap and hole, move the swing arm using a wrench and see if it blocked.

As far as the chipped ecu you shouldn't notice any difference in performance over the factory ecu at matching boost. The only thing the probinator chip should do is remove boost cut. There may be a tiny timing difference over stock, the Zombie chip added more timing and at 12psi vs the factory chip at 12psi the difference was barely noticeable.

No it is removed from the car just running a straight manual boost gauge from WG to nipple on compressor
WTF? you mean manual boost controller. You should take boost gauge readings from the intake manifold.
I will assume manual boost controller. Why is it still their, bypass it and see if it's the problem.
Is it a turbo smart style boost controller with a bead and spring? If so throw it out or sell it on ebay, they are junk they cause boost spike and dips, deliver different higher boost rates when slow spooling 3rd 4th or 5th, deliver different boost rates in colder weather....

----------------------------------------------------------------------------------------------------------------------------------------------------------

Once you sort this boost problem out, do yourself a favor and set-up a good working boost control system, it cost less than the turbo smart boost controller costs.

-Block the nipple on the compressor housing.
-Weld or thread a nipple to the intecooler hard pipe before throttle body, use 1/4" id host, connect a short piece of hose to the nipple on the charge pipe.
-Install a reducer in that short piece of hose.
-Put a T on the other end of the short piece of hose.
-Run one side of the T to the wastegate actuator.
-Run the other side of the T into the dash (use the rubber grommet below the clutch master).
-Get a 1/8" needle valve similar to this one:

This one is under 10$ at amazon.
A valve with a dial knob that turns from closed to opened gradually like water tap.

-Connect the hose running into the dash to the in side of the valve.
-Run more hose from the out side of the valve and back into the engine bay.
-Get a reduction T with two ports the same size as the PCV hose that connects to the elbow after the AFM (1/2" or 3/8" or whatever the hose is) and 1 port that is 1/4" and connect the needle valve out hose to the PCV T.
-Remove the Needle valve Knob (Held with allen key bolt or scew), remove the compression stem nut.
-Find two thin fender washers that fit over the threads the compression nut goes on.
-Remove the plastic plug in the dash that above the hood release leaver.
-Put on washer on the valve body and put the threads and needle stem through the hole in the dash (so the point towards the seat). Put the other washer over the threads and put the compression nut back on and tighten until the valve is snug to the dash and you can still turn the stem (May require more washers on the back side of the dash ).
-Put the knob back in the valve and tighten it up.

This would be the set up " _ " is 1/4" or 6mm hose:

Hardpipe Nipple_____in hose reducer______T 1/4"______________Wastegate actuator.
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I__________In Dash Needle Valve______PVC Hose T

How this works.
1- The boost at the compressor housing is higher than the boost at the throttle body. By moving the wastegate boost source, the wastegate is more accurately regulated to match actual intake boost.
2- The reduces before the first T help slow the wastegate movement and increase the needle valve control over boost (less knob movement per psi)
3- The needle valve simply bleeds of a percentage of air that is supplied to the waste gate.
4- The air coming out of the needle valve is basically a boost leak, by returning it to the metered air going to the turbo it is no longer a boost leak and because of the venturi effect the vacuum before the turbo will balance the pressure coming from the needle valve and keep it steady based on the intake air volume matching the boost air volume.
5- Because of 3- and 4- the percentage of air bled off by the needle valve stays constant with the varying volume of air at the same boost throughout the power band and gears. This means it holds even boost spool up to red line, setting 15psi in 3rd = 15psi in 1st,2nd,4th and 5th, slow spool in 4th on the highway or from a launch at the track you get the set boost, no spikes or dips in boost.
6- Having the dial in the dash allows you do dial in boost without pulling over and going under the hood and in cause cold weather of perfect humidity levels increase boost it can be instantly corrected instead of tolerated until you get the chance to pull over.

Reduction T:
 

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Discussion Starter #6
Will the 89 ecu work in the 1990 car? The only difference i see between the ecus are the middle plugs are different.
 

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Will the 89 ecu work in the 1990 car? The only difference i see between the ecus are the middle plugs are different.
Short answer is no.
The pin size and shape on both the plug and ECU are different between A and B specs.
Do the injectors have black plugs with metal clips A or grey plugs B?
Does the distributor harness plug have 6 wires (black plug)A or 4 wires (grey plug)B.

The Aspec chip will not run a Bspec car and vice versa. It will start the car and the engine will sputter, missfire, chug black smoke, wont rev or accelerate ...

Unless you got a production date 1990 car with Aspec (88-89) wiring and controls you cant run the Aspec chip or ECU.
 
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