[Lowerednjuiced]

For years I've been trying to figure out why my 1990 Mustang with a 2.3L turbo conversion sputters between 2200 to 4200 RPM.
The Specs: LA3, 35lb injectors, large vam, T5 5 speed, 4.10 rear gears, large aluminum radiator and big fans, fuel pressure regulator, discharge spark plug wires, 255LPH fuel pump, top mount intercooler with SSQV blow off valve mounted to the intercooler, stock intake, stock E6 Turbo exhaust manifold, Flowmaster muffler dumping through a 4" tip before the rear end, stock 1988 Turbo coupe turbo, manual adjustable boost controller, stock spark plugs, stock dizzy with TFI....

Everything has been changed out numerous times except for the pistons and head...
The engine has the standard flat top pistons and the original non-turbo cylinder head. I have Turbo Coupe pistons to install.
I have a heads from a 1987 and 1988 Turbo Coupe and I have some questions about both the heads.
Is there a difference in the size of the chambers?
Are the ports larger on the Turbo Coupe head?
Are the valves the same size?
When using roller rockers, which cam should I use - non-turbo, turbo or roller rocker camshaft?
Are the lobes of the camshafts different sizes?
Are the Turbo Coupe valve springs stronger than the non-turbo Mustang head's?

I'm asking all these questions about the head because the car is in Greece, I am in the Seattle area with the parts and shipping the head will cost around $300 when it's all stripped down of all the parts on and around it. Is it necessary to change the head?

Also, the large VAMs we tried seem to not even work at all. We wired them into the EGR valve's pins in the ECU and it's like the thing isn't even there.
We also need to know about the Boost Controller. There are 2 wires that go to the Boost Controller but where do they go? What pin #s on the ECU?
We've disected a couple ECUs trying to figure things out but it's so confusing!
Another thing i should add is that every ECU we try, LA2, LA3, LB2... gets HOT when the engine is running. wether it runs for 1 minute or 1 hour the thing is blazing! We have ECU cases fitted with fans to keep them cool but blowing hot air onto the passenger's legs isn't cool.

Sitting on the shop floor we can rev up the engine and it runs awesomely but when it's under load it gives us hell by popping through the exhaust, shaking violently and it makes me feel crappy every time I get in and try to enjoy the damn thing. Going up hills is horrid, I live in a village up the mountainside and my friends on thier 50cc mopeds always have to wait for my car to catch up.
Above 4200 RPM on flat ground i can punch it and the thing moves faster than any of our 5.0 Mustangs here.
I figure that at a certain RPM point the sensors cut out and the engine is on its own... maybe?

I have videos uploaded to Youtube of the car on the road. Search 'Mustang Turbo Greece' and my videos pop up under my user name lowerednjuiced
You can see what I go through while driving the car.

any help is much appreciated. I posted here in the forums in the past about these problems and tried the advice given but.... nada...

...michael

[OneOwner88LX]

I would get a digital volt meter and make sure the correct voltage is going back the the ECU from the VAM. I would also pull codes from the ECU. Make sure all your grounds are good.

I would go with the Gillis Boost Valve available from here:

www.boostvalve.com

This site has lots of good wiring and vacuum diagrams:

http://www.flemworld.com/slug/howto/8790T.html

[84turbo]

you should get the dished pistons in there that'll help to lower the compression and get the turbo head and cam on there the duration on the cam will help. Even with the 255 pump it sounds like you might be runnin a little lean check your ratio.

[Lowerednjuiced]

The voltage coming out of the VAM going towards the ECU should be between 0 - 5 volts... correct? The return voltage was reading 12.7 volts, the same voltage as the battery. 2 VAMs read that voltage, one is remanufactured, the other used but clean.

I should also add that when i took off the intercooler and ran the engine it did the same thing, sputtering between 2200 to 4200 rpm...

it's a bit hard to repair a car thats thousands of miles away. For the past 3 years i've been asking questions about how to fix it, then some people give me advice, i try it out and still the same results... but with the lack of internet access on the island in Greece it isn't possible for me to run to a computer and get the info, ask questions, collect more advice, try it again, fail, run back to a computer... nope, i ask my questions here, go to Greece to try to fix the car, fail at it, come back to the USA 2 months later all bummed out and then i wait a few months to ask questions again, then 10 months later i go back to Greece and start all over again...

The engine has been in and out of the engine bay so many times now that we can pull it in 3 minutes. We can have the entire car stripped of every nut and bolt then have it sitting on a forklift as a bare shell in about 2 hours.
Everything on, in and around this car has been removed. We even cut the cowl loose from the frame to reweld areas that had rusted away, the side rocker panels have been seperated, areas that i don't think any of you ever knew existed on these Mustangs, we have cleaned up and made new again.
This summer i plan on stripping the body of the paint down to bare metal for a one off paint job...
but when it's all done i would really like to get in it, turn the key and go wherever i want without worrying about a break down!

[Lowerednjuiced]

Not a rookie, not a rookie, not a rookie....

[Lowerednjuiced]

I still need to know the differences between the cylinder heads... and when I get the info i'll run down all the forums and help out other people...

[NavySVO]

Where in Greece? Hania (Crete) has internet cafes.

Ok, Let me see if I can be of some confusion, er, I mean help.

The cylinder head can either be the O or D port. Either one. Some people bicker about it, but in the end, it doesn't really matter. The TC head is the same as the most other TF applications.

Cam; use a turbo cam as valve overlap (Google it) is much narrower on the turbo application. You want one, I got one with roller followers I will sell you. PM me.

Valves are the same on a turbo head. Springs, dont know. I am betting it doesn't make a difference if you are not using a high lift cam, so you are fine.

If your EEC is getting hot, then you have things wired wrong and are probaly sending too much current to it.
The first thing wired wrong is your VAF meter. Attached is a troubleshooting sheet. You should not have 12 volts running through that return circuit at all. It should be 1/2 that. Read the sheet attached. Why would you wire the VAF meter into the EGR pins?
Also, there is a site where Stinger talks about turbo-swaps and wiring. PM Evintho for it or search here:
http://www.flemworld.com/slug/howto/8790T.html
http://www.stinger-performance.com/turboswap.html

Backfiring through the exhaust is usually a sign of running fat on fuel, or a fuel mapping problem which will definately occur if you have VAF meter or associated VAF meter wiring problems. Also, to verify you actually have a large VAF meter. It should measure 3-1/8" outside diameter.
Backfiring through the intake is usually a sign of grossly-incorrect cam timing.

In addition, when using a BOV with a VAF metering system, it can mess with the perfomance of the car because you are expelling air that has been accounted for by the signal sent to the EEC from the VAF meter.

[b_chandler]

Backfiring through the exhaust could also be caused by a bad coil or coil wire. Or the cam timing is off the opposite way that NavySVO described.

+1 on the ECU wiring. Stinger Performance has the ECU pinouts that nearly everyone is using for turbo swaps.
If the ECU is getting hot, something is wrong, and by no means should the VAM signal be sent to the EGR pins on the ECU.

As for the heads, I was always under the impression that the factory turbo heads had different exhaust valves than their N.A. counterparts The size is the same, but the alloy is different. I've been wrong before, so correct me again if I am. Also the exhaust seat was heat treated for severe duty. Having hardened seats installed in an oval-port head gets you around that. Just make sure they're installed properly, nothing sucks worse than having a seat come loose. I had it happen on a nitrous-fed small block in a Maverick I once owned.

[Lowerednjuiced]

Samos island, the last time i was there the internet service was being upgraded and new antennas started going up for it.

The Turbo head does have the O ports, the head on the engine in Greece is the D port.

The cam that's on the engine is the roller cam with roller followers. I have 3 other sets of those, 4 cams... i used to work for a junkyard and they gave me more than enough stuff than what i needed. they also gave me an 8 spark plug head and intake system but I won't ever figure out how to do that 8 plug coil pack mod.

The VAF, VAM, MAF... air flow sensor is the large one, i have a few of the smaller ones too, in fact i have a remanufactured smaller one on Ebay right now.

We wired in the VAF to the EGR wires because there's some instructions online that say that's where to wire it in!
Pins 26 and 43 sound familiar... is there a joker Camaro owner online trying to mess up mustang owners?
That would be crazy...
We have a 70mm MAF that we tried to wire in as well and that did nothing to help us either.

There's no backfire through the intake, just coming right out the bottom of the turbo. We ran it with the exhaust taken off to see if the exhaust pipe was too small.

Not having a BOV though... that would suck... but, maybe it's essential for the system... once the throttle plate closes the air has already entered the intake manifold, then through the valve into the combustion chamber which created the vacuum which activates the BOV helping to expell the air on the other side of the throttle plate so that the air trying to push its way into the engine doesn't ram open the throttle body. If I could say it in Greek it would make more sense to me because it was explained to me in Greek to begin with.

The auto technician in Greece, Aki, used to work in the world rally car series on the Fords and Subarus. He worked with Colin McRae... I guess McRae was a hands on guy and always worked on the cars alongside the techs.
The cool thing is, if I didn't buy the part I need, Aki can make it in the shop. They made the cold air intake, driveshaft loop, subframe connectors, strut tower brace and a frame brace between the transmission and engine.

But nobody in Greece has figured out why it sputters...

I'll try to find the notes I took last summer and see which website had the wire diagram to wire the VAF into the EGR wires and there should be a diagram showing which wires we plugged into.

...michael

[NavySVO]

Originally Posted by Lowerednjuiced

We have a 70mm MAF that we tried to wire in as well and that did nothing to help us either.

You can't just wire in a MAF and run it. You have to have a J3 chip for the EEC that can be tuned

Originally Posted by Lowerednjuiced

Not having a BOV though... that would suck... but, maybe it's essential for the system... once the throttle plate closes the air has already entered the intake manifold, then through the valve into the combustion chamber which created the vacuum which activates the BOV helping to expell the air on the other side of the throttle plate so that the air trying to push its way into the engine doesn't ram open the throttle body. If I could say it in Greek it would make more sense to me because it was explained to me in Greek to begin with.

Well, that is not what they are for. Sorry, don't mean to come off as rude.
The BOV is used to relieve back-pressure on the intake tract between the turbo and the throttle body during shifting or gas pedal lift to prevent a compressor stall (surge) which will damage the compressor wheel. It also allows the wheel to keep spinning and then allow it to spool up quicker.
You can get a Bypass Valve that will do the same thing, but it will recirculate the air vise purging it to the atmosphere.

[TOM RENZO]

Chandler is correct. The turbo valves are different than NA motors. And the seats are ductal hardened. Seat inserts are a must on turbo heads because just about all of them crack at the seats.