OK folks, need to get some insight here. This not your typical thread. I've been working on getting my car going for a few years now. Have some tuning help, but not clear why the car will not boost. By not boost, I mean it will never go over atmospheric either in Tunerstudio or on the Autometer mechanical boost gauge. I'm really running out of the drive to get this car going. It's causing a lot of pain and aggravation in my household. Wife would love to see it gone frankly. Some details...
It's a 93 Cobra with twin turbo built 347 and 5 speed and of course MS ECU. Specifically, I bought the MegaSquirt-II V3.57 plug and play and have full version of Tuner Studio and Mega Log Viewer installed on my laptop. I have been working with someone experienced with MS remotely over the past few years, but just seem to be having the same issue no matter what we do. I mean, I've literally done just about everything imaginable to this car to figure it out and it continues to run poorly. By that I mean, it lays over under load, misses and will not build boost at all. It starts up and idles steady aside from some slight miss here and there. I recently starting working with a tuner on this forum and some things have certainly improved, but it still will not build boost. Idle fuel pressure is around 42 psi. Off the top of my head, this is what I've been through...
* Engine was freshly built before install (has minimal test miles on it perhaps 10-20 miles at most over the last few years)
* Thought I washed the rings out after a number of attempted starts before determining fuel constant was way off for my injectors (I honestly thought that was pre-set in the tune since I gave them my injector size- thinking back to my days of running an AFM PMS, doh)
* Have since verified I have consistent cranking compression (120-130psi warm which seems lower than I'd expect but all cylinders are extremely close to one another) and low (<5%) leakdown. Cannot check a couple cylinders simply because it's impossible to feed the test hose into the spark plug holes, but can't believe it would result in no boost even IF they were both dead (which I can't believe or else I'd be pumping raw fuel out the exhaust)
* Thought maybe cam was retarded (FTI custom ground for my setup), but verified it's correctly installed straight up
* Correctly set crank timing using piston stop (was off a few degrees initially)
* Replaced spark plug wires (Livewires) although even though they're new if they lay too close to exhaust, they will arc (I've had to tie strap them away from the manifold)
* Replaced spark plugs (3-4 times now)
* Car has historically run rich since initial tune, but is much improved lately with new tuner
* Calibrated Wideband (twice)
* Smoke tested and boost leak tested entire induction path multiple times (there are no leaks)
* Turbos are clearly moving air - you can hear excess air being vented through the intakes at idle and if you pull the pipe off at the throttle body and rev the engine with your hand over the intercooler outlet it will blow your hand off
* Turbos definitely spool up - I can hear boost venting when throttle slams shut
* Blow off valve is not leaking - I removed it temporarily to verify
* Wired wastegates shut just to verify they were not opening for some reason and dumping boost. Double/triple checked they are fully closed.
* I have a Magnaflow catted X-pipe. I watched vacuum stay steady while free revving the engine around 2000 rpm to verify they are not clogged. I even pulled the factory O2 sensors once to let the exhaust leak there just to be sure.
* There is no PCV system on the car - PCV hole at rear of intake is plugged and I have two catches cans with a -12 line from each valve cover to each can
* There's no MAF of course as it's a speed density setup
* It makes 12 inches or so of vacuum at idle
I run 93 octane, no methanol.
* I just finished capping off one turbo inlet to the intercooler at a time to see if perhaps one turbo was bad and the good turbo was leaking boost through it. I did each side and no change.
* I ran the car without the intercooler outlet connected to the T-body... so the turbos were just blowing straight to the atmosphere and the engine was running in N/A mode. The car was noticeably slower when I test drove it. It's clear that the turbos are doing something.
It seems as if the engine cannot make use of the boost. When I lay into it, the boost gauge will go to essentially zero vacuum/zero boost and I can hear and feel the turbos working... the car wants to move quickly, but it starts to break up and feels like it's suffocating.
Some more details about the setup. Everything here was installed brand new aside from the turbo kit which is no longer available.
Engine: 347 Sportsman, 4340 rotating assy, TFS SFI balancer, 7 qt oil pan and HV pump with ARP shaft, FTI 185cc CNC Twisted Wedge heads with spring package to match custom FTI cam installed straight up, billet timing chain, all new lifters and correct length pushrods, ported and extrude honed upper/lower Holley Intake, Accufab 75mm TBody
Fuel System: In tank pick-up feeding -10 line to Aeromotive inline filter, -8 line to Y-block to -8 line to twin T-Rex pumps feeding billet fuel rails, billet Aeromotive regulator, -6 line back to tank. 72 lb low imped injectors
Ignition system: MSD digital 6AL, Screamin Deamon coil, Livewires, Summit billet distributor and the plugs are Autolite 3923's @ 0.035" - they were the recommended heat range and gap for this setup based on input from others running a similar combo with the same turbos.
Power adder: Used Incon 800TT Twin Turbo setup. Setup was removed in working order. Turbos spun freely before install. Have recently verified they still spin freely and are not crashing.
Exhaust: 2.5" Magnaflow x-pipe with high flow cats. 2.5" stainless catback with 2 chamber flowmasters.
Cooling System: Aluminum dual row radiator, Flex a lite electric fan/shroud, Weiand polished water pump, New T-stat (180F IIRC)
Trans/Driveline: MMR TKO 900, Spec Stg 3+ Clutch, Billet steel flywheel, FRP Aluminum driveshaft, Moser 31 spline 5 lug axles, Auburn Pro Diff, 3.55 gears, big brakes, etc
It's a 93 Cobra with twin turbo built 347 and 5 speed and of course MS ECU. Specifically, I bought the MegaSquirt-II V3.57 plug and play and have full version of Tuner Studio and Mega Log Viewer installed on my laptop. I have been working with someone experienced with MS remotely over the past few years, but just seem to be having the same issue no matter what we do. I mean, I've literally done just about everything imaginable to this car to figure it out and it continues to run poorly. By that I mean, it lays over under load, misses and will not build boost at all. It starts up and idles steady aside from some slight miss here and there. I recently starting working with a tuner on this forum and some things have certainly improved, but it still will not build boost. Idle fuel pressure is around 42 psi. Off the top of my head, this is what I've been through...
* Engine was freshly built before install (has minimal test miles on it perhaps 10-20 miles at most over the last few years)
* Thought I washed the rings out after a number of attempted starts before determining fuel constant was way off for my injectors (I honestly thought that was pre-set in the tune since I gave them my injector size- thinking back to my days of running an AFM PMS, doh)
* Have since verified I have consistent cranking compression (120-130psi warm which seems lower than I'd expect but all cylinders are extremely close to one another) and low (<5%) leakdown. Cannot check a couple cylinders simply because it's impossible to feed the test hose into the spark plug holes, but can't believe it would result in no boost even IF they were both dead (which I can't believe or else I'd be pumping raw fuel out the exhaust)
* Thought maybe cam was retarded (FTI custom ground for my setup), but verified it's correctly installed straight up
* Correctly set crank timing using piston stop (was off a few degrees initially)
* Replaced spark plug wires (Livewires) although even though they're new if they lay too close to exhaust, they will arc (I've had to tie strap them away from the manifold)
* Replaced spark plugs (3-4 times now)
* Car has historically run rich since initial tune, but is much improved lately with new tuner
* Calibrated Wideband (twice)
* Smoke tested and boost leak tested entire induction path multiple times (there are no leaks)
* Turbos are clearly moving air - you can hear excess air being vented through the intakes at idle and if you pull the pipe off at the throttle body and rev the engine with your hand over the intercooler outlet it will blow your hand off
* Turbos definitely spool up - I can hear boost venting when throttle slams shut
* Blow off valve is not leaking - I removed it temporarily to verify
* Wired wastegates shut just to verify they were not opening for some reason and dumping boost. Double/triple checked they are fully closed.
* I have a Magnaflow catted X-pipe. I watched vacuum stay steady while free revving the engine around 2000 rpm to verify they are not clogged. I even pulled the factory O2 sensors once to let the exhaust leak there just to be sure.
* There is no PCV system on the car - PCV hole at rear of intake is plugged and I have two catches cans with a -12 line from each valve cover to each can
* There's no MAF of course as it's a speed density setup
* It makes 12 inches or so of vacuum at idle
I run 93 octane, no methanol.
* I just finished capping off one turbo inlet to the intercooler at a time to see if perhaps one turbo was bad and the good turbo was leaking boost through it. I did each side and no change.
* I ran the car without the intercooler outlet connected to the T-body... so the turbos were just blowing straight to the atmosphere and the engine was running in N/A mode. The car was noticeably slower when I test drove it. It's clear that the turbos are doing something.
It seems as if the engine cannot make use of the boost. When I lay into it, the boost gauge will go to essentially zero vacuum/zero boost and I can hear and feel the turbos working... the car wants to move quickly, but it starts to break up and feels like it's suffocating.
Some more details about the setup. Everything here was installed brand new aside from the turbo kit which is no longer available.
Engine: 347 Sportsman, 4340 rotating assy, TFS SFI balancer, 7 qt oil pan and HV pump with ARP shaft, FTI 185cc CNC Twisted Wedge heads with spring package to match custom FTI cam installed straight up, billet timing chain, all new lifters and correct length pushrods, ported and extrude honed upper/lower Holley Intake, Accufab 75mm TBody
Fuel System: In tank pick-up feeding -10 line to Aeromotive inline filter, -8 line to Y-block to -8 line to twin T-Rex pumps feeding billet fuel rails, billet Aeromotive regulator, -6 line back to tank. 72 lb low imped injectors
Ignition system: MSD digital 6AL, Screamin Deamon coil, Livewires, Summit billet distributor and the plugs are Autolite 3923's @ 0.035" - they were the recommended heat range and gap for this setup based on input from others running a similar combo with the same turbos.
Power adder: Used Incon 800TT Twin Turbo setup. Setup was removed in working order. Turbos spun freely before install. Have recently verified they still spin freely and are not crashing.
Exhaust: 2.5" Magnaflow x-pipe with high flow cats. 2.5" stainless catback with 2 chamber flowmasters.
Cooling System: Aluminum dual row radiator, Flex a lite electric fan/shroud, Weiand polished water pump, New T-stat (180F IIRC)
Trans/Driveline: MMR TKO 900, Spec Stg 3+ Clutch, Billet steel flywheel, FRP Aluminum driveshaft, Moser 31 spline 5 lug axles, Auburn Pro Diff, 3.55 gears, big brakes, etc