North American Turbocoupe Organization



Vacuum leak after turbo gasket replacement??
John B Offline
Member
#1
So, I just got done putting the car back together after replacing the exhaust manifold gasket, turbo gasket, and sealing the downpipe connection. The car started up just fine but it's running like crap. I can't rev the car past 3000 rpms. I can hit the accelerator to the floor and it won't rev past 3000 rpms. The revving is very sluggish too; delayed from the time I hit the accelerator and for the car to respond. I think it's possibly a vacuum leak but I'm not sure where.

The previous owner put on a front mount IC set up and deleted some factory items. The factory boost solenoid is no longer used. There is a BOV on the charge pipe which has a single vac hose running to the vacuum tree. The turbo inlet has two nipples. One hose goes from one nipple to the pcm and the another vac hose goes to the vacuum tree and slips into another line going into the firewall (I'm assuming that this is the cruise control vac line).

Now, the interesting thing is, there is a silicone hose elbow coming off the compressor outlet into the first piece of IC piping. I noticed that when I was giving the car gas, this elbow was collapsing on itself once I let off. Basically the vacuum was causing it to collapse. This has never happened before... Could there be a hole/rip in this silicone elbow which would cause it to collapse like that and be the source of my problems? Is there such a thing as excessive or too much vacuum? I didn't touch anything else while doing this project. ALL settings were left exactly the same as before. Thanks for the help guys!
88 Turbo Coupe: Front mount intercooler, MGW short throw shifter, full coilover conversion, tubular control arms front and rear, svo front brakes, vacuum assist brake swap, manual steering swap, GT35R turbo with external gate, pimpx ecu, 60lb injectors, 3 core aluminum radiator, corbeau fixed back seats, and the list goes on.
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Pete D Offline
Administrator
#2
The hose coming off the compressor outlet should not collapse in on itself when the throttle is suddenly closed. Either it is incorrectly installed or the hose walls are soft and weak. See if it can be adjusted for more stability. If it cannot be done, don't spend a lot of time on it, get a new elbow.

Are you saying you put a new gasket between the exh. manifold and the cylinder head? The turbo engines don't use a gasket there but the N/A engines do. Gaskets there on the turbo cars tend to bun out with time.

Air or vacuum leaks are often the IC hoses off location or improperly clamped. Same with the VAM to turbo inlet hose at the back of the VAM. Make sure the inside of the hose and the VAM are free of oil when you connect the hose.

Check that stuff and let us know where it stands.
Pete Dunham


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John B Offline
Member
#3
Thank you Pete; I know from the factory that the turbo 2.3's didn't have exhaust manifold gaskets but the previous owner put one on. I'm not sure what the reason was; maybe there's some slight warpage but I replaced it for now. So, after some trouble shooting and going through my checklist again, I realized that I never removed the shop towel that I placed in turbo compressor inlet... I plugged all the holes when I was doing bench work to stop anything from getting in. Luckily, it just spun in the compressor inlet and didn't catch on anything or get sucked through. Took it out and the car is running fine now. So lesson learned; double check all piping for obstructions haha
88 Turbo Coupe: Front mount intercooler, MGW short throw shifter, full coilover conversion, tubular control arms front and rear, svo front brakes, vacuum assist brake swap, manual steering swap, GT35R turbo with external gate, pimpx ecu, 60lb injectors, 3 core aluminum radiator, corbeau fixed back seats, and the list goes on.
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Pete D Offline
Administrator
#4
One of my step sons had a TC for awhile. He called me one day and said "Dad, I don't have any turbo, no boost". He lived a good distance away but said he could get it over to me. Sure enough, no boost. What a dog! We took the inlet track apart and there was a shop towel in the turbo inlet. It did no damage and removing it got things normal again. He swore up and down that he had no idea how it got in there??
Pete Dunham


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Jeff K Offline
Administrator
#5
We have all done silly stupid things like that in the past (at least I have). V
Jeff Korn

88 Turbo Coupe: Intake and exhaust mods, T3 turbo at 24 psi, forced air IC, water injection, BPV, Ranger cam, subframes, etc., etc.
86 Tbird 5.0 (original owner): intake, exhaust, valvetrain mods, 100 HP N2O, ignition, gears, suspension, etc., etc.
05 Taurus SEL Duratec daily driver
04 Taurus Duratec (wifes car)
02 Pontiac Grand Prix GT
95 Taurus GL Vulcan winter beater
67 Honda 450 Super Sport - completely customized
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John B Offline
Member
#6
Pete D Wrote:One of my step sons had a TC for awhile. He called me one day and said "Dad, I don't have any turbo, no boost". He lived a good distance away but said he could get it over to me. Sure enough, no boost. What a dog! We took the inlet track apart and there was a shop towel in the turbo inlet. It did no damage and removing it got things normal again. He swore up and down that he had no idea how it got in there??

Sounds exactly like my situation and I think he knew how it got there.. Haha
88 Turbo Coupe: Front mount intercooler, MGW short throw shifter, full coilover conversion, tubular control arms front and rear, svo front brakes, vacuum assist brake swap, manual steering swap, GT35R turbo with external gate, pimpx ecu, 60lb injectors, 3 core aluminum radiator, corbeau fixed back seats, and the list goes on.
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