PT61 "shut off" after 10 PSI during WOT

[Lunkan]

Hi!
I just got my new PT61 today, which I happily installed. When I took it out for testing, I had to tune up the alky to get rid of some knocks. First it worked ok, but I didn´t do any WOT runs.

After a while, I was doing like 40 and hit the pedal, and as fast as the boost whent past 10 PSI it just shut off. When I took the foot off the pedal, the car ran fine again. So I tested with mild acceleration, and it spooled up fine, so I tried a WOT from 0. Just the same, when the boost past 10, it just shut off again.

When I came back to my house, I pushed the test-button and the engine almost died. That has never happend before.

/Andreas, confused

 

[Razor]

Hows the transmission.

Check to make sure the hoses leaving the turbo and IC are all on correctly. You may be partially blowing a hose off. Also check your MAF to assure it doesnt have any issue.

Bad turbos dont cuase the engine to shut off. they burn oil or dont build boost.

It also may be chip related, try another chip just in case. You shouldnt need alky at 10 PSI boost. If the chip cures the condition, reset the computer by unplugging its power and waiting a while, then re-plug it back in.

Look at all your vacuum hoses, give another quick inspection.

I worked on a car that didnt build past 12 PSI and it was a bad coil pack assembly. No matter what the boost was set.. as soon as it hit 12.. would sputter(run bad) with lots of KR.

 

[jmidolo]

Make sure you put your gound back on that turbo housing bracket that attaches to the block...sounds like it maybe either loose, badly fitting or something..

 

[Lunkan]

The first thing I did, was check all the hoses. First off I noticed the vacuum hose to MAP-sensor had jumped, so I cut it (was bend) and reinstalled it in a better position. Never jumped off again.

The hoses and orifice from WG solenoid are new.

As for boost, it builds like 20 PSI if I don´t go hard on the pedal. If I give it half throttle and slowly go to WOT, it will peak at 25 PSI and fall out to 20. But if I hit it WOT in a sudden, it takes off hard and cuts off when the boost passes 10.

Well, the car doesn´t really die, it just feels like it. It takes off hard, but just loose the power when the boost passes 10 PSI. Hard to explain, but I never had this issue with my TA49 or the stock (used it last weekend when I got my car back from the shop).

 

[Lunkan]

A friend in Sweden asked me if it could be the methanol cutting the spark when it comes to sudden. I had to turn up the alky, as I had some KR. But I never thought this could be an issue. Now it´s 00.10 here in Sweden, so I can´t check until "tomorrow".

Thanks,
/Andreas, tired

 

[Lunkan]

Originally posted by Razor
Hows the transmission.

Check to make sure the hoses leaving the turbo and IC are all on correctly. You may be partially blowing a hose off. Also check your MAF to assure it doesnt have any issue.

Ohh, I forgot to mention. I got the car back from the shop a week ago. I had the transmission rebuilt for a second time (first time was during winter), the direct clutch was gone.

The MAF is a brand new LT1 with translator. It worked fine with the stock turbo (which I used when I drove the car from the shop last weekend).

/Andreas

 

[jmidolo]

Originally posted by Lunkan
Ohh, I forgot to mention. I got the car back from the shop a week ago. I had the transmission rebuilt for a second time (first time was during winter), the direct clutch was gone.

The MAF is a brand new LT1 with translator. It worked fine with the stock turbo (which I used when I drove the car from the shop last weekend).

/Andreas

OK, in addition to the ground on the block on the turbo bracket..check the ground that goes on the top bellhousing bolt...

 

[Lunkan]

Originally posted by jmidolo
OK, in addition to the ground on the block on the turbo bracket..check the ground that goes on the top bellhousing bolt...

I´m sorry, but now I´m going to sound as an idiot. But what´s where´s the bellhousing bolt? I know most english terms, but this one I don´t.

/Andreas

 

[jmidolo]

Originally posted by Lunkan
I´m sorry, but now I´m going to sound as an idiot. But what´s where´s the bellhousing bolt? I know most english terms, but this one I don´t.

/Andreas

Bolts the transmission to the engine block. Check the top 2 bolts, behind the coil pack. You can get at them from the bottom w/a long ass extension or from the top w/the Coil pack removed. theres' a grounding strap that goes onto one of them.

 

[bruce]

Might be out of fuel, bad TPS, amongst other things.

With the new turbo the motor might be needing more fuel. If you slowly get on it the fuel pump can kinda keep up, but at high sudden demand runs out so quick that the motor quits.

What shape is the fuel pump?, more then 3 years old, no hot wire kit, etc..

 

[Razor]

Its like this, if you have a problem.. last thing you want to do is throw boost at the motor. Extend the rod on the WG and bring the boost down until things run as should.

We also think your running new spark plugs gapped to .030-.032 not .035. So check this as well.

get it running without alcohol at 14-16 PSI cleanly.. then up the boost.

Also one thing, did you get an adjutable chip from Eric? The early ones have a glitch. I dont know if your chip may have this issue. Just an FYI. And did Eric burn a chip with a translator in mind?

If your running 50lb inj, get Danny to lend you a chip?

Joe, there are no ground straps on the bellhousing bolts. They all go to the rear bolts on the intake manifold. Except for the battery ground which goes to the front of the passenger cylinder head. Good call tho on grounds.

 

[Lunkan]

Originally posted by jmidolo
Bolts the transmission to the engine block. Check the top 2 bolts, behind the coil pack. You can get at them from the bottom w/a long ass extension or from the top w/the Coil pack removed. theres' a grounding strap that goes onto one of them.

I checked the all groundings when I reinstalled the transmission last weekend. The one on the firewall was loose, but that was a week ago.

Originally posted by bruce
Might be out of fuel, bad TPS, amongst other things.

With the new turbo the motor might be needing more fuel. If you slowly get on it the fuel pump can kinda keep up, but at high sudden demand runs out so quick that the motor quits.

What shape is the fuel pump?, more then 3 years old, no hot wire kit, etc..

The car is full of gasoline, and the TPS gives correct readings when using the pedal (checked with Tlink).

I haven´t checked the FP though, but I have an Autometer A/F guage that reads rich. The Walbro is like 2-3 years old, never run with a hot-wire. I got the hot-wire, along with the car, in an un-opened bag, and when I where to install it, one wire in the connector was broken.

Originally posted by Razor
Its like this, if you have a problem.. last thing you want to do is throw boost at the motor. Extend the rod on the WG and bring the boost down until things run as should.

We also think your running new spark plugs gapped to .030-.032 not .035. So check this as well.

get it running without alcohol at 14-16 PSI cleanly.. then up the boost.

Also one thing, did you get an adjutable chip from Eric? The early ones have a glitch. I dont know if your chip may have this issue. Just an FYI. And did Eric burn a chip with a translator in mind?

If your running 50lb inj, get Danny to lend you a chip?

Joe, there are no ground straps on the bellhousing bolts. They all go to the rear bolts on the intake manifold. Except for the battery ground which goes to the front of the passenger cylinder head. Good call tho on grounds.

I´m on the rod as soon as I quit work (hopefully the weather is ok). As for plugs, I´ve run them like 90 miles. I didn´t have a .035 , so I had to measure it with two smaller ones. Maybe they´re not gapped right then. At least, they´re not less than .030

As for the chip, I did´nt remember to check. Do I have to remove the labels and check for a certain chip-type, or is there another way to see? I did tell Eric I had the translator.

With Danny, do You mean Daniel in Gothenburg? If so, he only runs stock injectors. But I do have 5 more chips. Emission, 92 and 108 from Erric and 2 thrashers.

Thank You all for taking the time
/Andreas

 

[Lunkan]

I turned down the boost to 17 PSI and turned off the alky, and everything worked as it should. But it did record lots of knocks (didn´t scan, but nock guage whent from 2 green up to red). When turning the alky on (lowered the initial first), the readings disappeared.

But now I blew the header gasket AGAIN, and I don´t have anything to fix it with.

 

[jmidolo]

Originally posted by Razor
Its like this, if you have a problem.. last thing you want to do is throw boost at the motor. Extend the rod on the WG and bring the boost down until things run as should.

We also think your running new spark plugs gapped to .030-.032 not .035. So check this as well.

get it running without alcohol at 14-16 PSI cleanly.. then up the boost.

Also one thing, did you get an adjutable chip from Eric? The early ones have a glitch. I dont know if your chip may have this issue. Just an FYI. And did Eric burn a chip with a translator in mind?

If your running 50lb inj, get Danny to lend you a chip?

Joe, there are no ground straps on the bellhousing bolts. They all go to the rear bolts on the intake manifold. Except for the battery ground which goes to the front of the passenger cylinder head. Good call tho on grounds.

Doug brings up some good points that sometimes get overlooked..get the baseline set first then up the boost.

Doug, maybe not in your 'tranny held in by a seatbelt' car there isn't a ground..but in the 3 cars I've owned and pulled trannies from..there's been a strap on them. You are correct about them being on the head, but there's also one that goes on the drivers side top bellhousing bolt....

Joe

 

[Lunkan]

It wasn´t the header gasket that was gone, it was the x-over that cracked. Well, that´s easier to fix than the gaskets. We have a realy good shop nearby that can mandrel bend stainless up to 4", so they will fix me a new one tomorrow.

 

[sholdwick]

Grounding straps

Not to step one this thread, but all 4 of my cars have had grounding straps going to the tranny bolts.

 

[sholdwick]

Grounding straps

Not to step one this thread, but all 4 of my cars have had grounding straps going to the tranny bolts.