18psi and no power - GN and T-Type Performance Enthusiasts (GNTTYPE) Forums

383mazda · #1 12-07-2011, 11:13 PM

Short story-
Had the car out the other day and blew the silicone off the TB in 4th gear at 25psi. Loud pop, but car limped home (idled fine... so nothing too bad happened I hope). Put all the hoses back on, played with the WG to keep boost down, now it will stop at 18psi under WOT but feels competely gutless. No obvious leaks anywhere I can find, idles and drives nice...

Long story-
Just did a chinese "GT67" turbo upgrade (with garrett piston rings and a GRW ball bearing, so it's good). I'm using the same WG that was on the TA49 turbo along with RJC's valve. At half throttle I'd hit 25+ psi at rpm and could "feather" it to 30psi very easily, I was never able to do a full WOT but it felt very very strong at 25psi. Blew the hose off and decided I would take the RJC valve off to see where my WG was set to get my boost under control. I can get 18psi now at WOT but the car is way down on power. it doesn't stumble or anything, it just feels like the car weighs 10,000lbs

Supporting mods: siemons 60lb injectors, FPR, Alky kit, RJC power plate, chip (forgot who's at the moment), fuel pump of course...
At WOT my scan master reads 800 on the mV's and no knock at all. Seems like all the fast ingredients are there but it's just not pulling at all???

383mazda · #2 12-10-2011, 09:18 PM

Well, what are the symptoms of a "slightly" blown head gasket? I have a few bubbles in the radiator - but I drove it 200+ miles the other day to get it diagnosed. It never overheated once (although the water temp warning light on the dash is on? SM shows 168 degrees though).

The car feels like someone stuck a rag in the intake pipes somewhere. The pop off did result in a huge chunk of hood insulation being blown / ripped off over the coil pack - I guess it couldn't hurt to pull the plenum of and take a look and see if sucked anything in?

charlief1 · #3 12-10-2011, 10:31 PM

Quote:

Originally Posted by 383mazda

Well, what are the symptoms of a "slightly" blown head gasket? I have a few bubbles in the radiator - but I drove it 200+ miles the other day to get it diagnosed. It never overheated once (although the water temp warning light on the dash is on? SM shows 168 degrees though).

The car feels like someone stuck a rag in the intake pipes somewhere. The pop off did result in a huge chunk of hood insulation being blown / ripped off over the coil pack - I guess it couldn't hurt to pull the plenum of and take a look and see if sucked anything in?

LOL Either this is Bob or his boy.

Saw the car a couple of days ago in person and it's very possible to blow a head gasket and still drive it. Fill the radiator up first all the way and then start it up and drive until warm. See if it blow fluid out into the puke tank. Call me if you need to.

BTW, found the control arms for the F-85 yesterday for just under $500 shipped. Remember, my board name at hotmail to send me an email.

chrisjkruse · #4 12-11-2011, 10:17 AM

hmm.. if not the head gasket...timing chain maybe?

383mazda · #5 12-11-2011, 07:53 PM

Hi CharlieF1 - I'm Bob's son Brandon. I wish I could have gone down to meet you the other day. We (my dad and I) were about to buy the head gasket leak ditector kit from O'Rielly's but it was $50 so we passed for now. I'll check the puke tank as I know I topped off the radiator the other day to drive it into town (when I first discovered the pack of power...)

Timing chain should be "new." This is a swapped motor with 40k miles on it as of last year and I'm pretty sure my dad did a timing chain before the motor got put in.

charlief1 · #6 12-11-2011, 08:05 PM

LOL Well I'm sorry you didn't get the chance to come visit. Maybe next time.

You can get the head gasket lead detector from AZ as a loan a tool but you have to buy the fluid. You return the tool when you're done with it and can keep the fluid fr future use. Since it has bubbles in it when you run it make sure the radiator is full and run it again. It may not over heat but see if it starts blowing fluid into the tank. If it does then I'd put money on the head gasket.

Did you try changing the coil pack yet to see if the miss is gone?

383mazda · #7 12-11-2011, 08:10 PM

Forgot about AZ loan a tool deal, I grab one tomorrow. Did you guys pull any plugs? That coil pack is 9 years old, but it doesn't have more than 10k miles on it... That miss by the way is brand new, started after the "blow out."

charlief1 · #8 12-11-2011, 08:22 PM

Didn't pull any plugs but I did pull the wires off the coil pack. #6 didn't seem to have a reaction so I'd say that's the most likely area for the blown gasket. There wasn't any spark jumping from the terminals off the #6 so try changing the coil first and see if the miss goes away. One of the guys I know in NY just had this happen to him about a month ago. Same exact issue. It was #6 as well.