car jerking at 2800 rpm and preventing turbo from start

[ozalkl]

hi guys,

I just did the timing belt, water pump, complete fluid flush, changed the coolant etc on my car yesterday, and on the way driving her home, i noticed the car jerks and its like cuts when it hits 2800 rpm preventing the turbo from kicking off, my mechanic told me that there was a cut in one of the coolant pipes at the back of the engine and it was terminated and another hose was connected to the turbo, so he canceled that old pipe as it was leaking coolant, the funny part is that the car was boosting fine when i was driving her to the workshop and now she dose not boost.

can anyone clarify for me how dose the turbo connects to the coolant and how is the pipe connections for the coolant?

I will post some pics today when i get back from work

[gtrjon]

is it like a rev limiter at 2800 rpm or can you accelerate past it? when your ecu goes into limp mode it should be right around 2500-3000 and than you would not be able to rev past that point.

[ozalkl]

I cant go past that rpm, here is some shot of the pipe i was talking about:


that pipe was terminated and its connected to a another pipe which goes under the intake, i had not figured why is it cut, thats y i hope you guys can guide me through the pic.

another shot



here is the engine shot

[gtrjon]

yea so your in limp mode my gtr used to do it randomly never figured it out i pulled my motor to build it hopefully ill figure it out during this process. someone have more info regarding the cut pipe?

[craftz]

That's a coolant line going to the engine side of the chra on the turbo. Your mechanic probably picked up another feed but I don't understand why your not leaking coolant from the open line. Any more info on what he did.

[ozalkl]

If he didn't connect the pipe, could be the reason that the car in limb mode?

[gtrjon]

If he didn't connect the pipe, could be the reason that the car in limb mode?

i dont believe so i am pretty sure limb mode has to be related to electrical.

[fletch27]

Double check you maf plugs they'll cause that

[ozalkl]

I was tracing the wiring etc to see if anything was not proper and i saw that the MAF plugs were off as in not hoocked to the socket, so i plugin that socket and I tried to start the car, but now she is not willing to start, the starter clicks and tries to turn the crank but the car is not getting started, its -10 now and the car is parked on my drive way, it was -30 yesterday and the day before.

anyone know how to diagnose whats the problem, is it just because its cold weather that preventing the engine starting, or something gone wrong somewhere

[S13_MPH]

Anything related to the performance of your engine that goes off (weird), will be recognized by your ECU. The turbo is not controled or regulated by your ECU, and neither is the coolant. But what if the line that your mechanic plumbed in is not a coolant line, and your turbo is not performing the way it should, and your running that turbo without water cooling. It still has oil cooling but there is still a small chance that you a running your turbo dry.

Also I used to have terrible intercooling piping, and i would always blow my couplings off at high boost. Then my car would run just like how you are describing. When the intake pressure goes into boost rather then vacume my engine would stall out and would run rough aroun 3000.

I would go over all intercooling piping and make sure all the pipes are secure, and there are no cracks. Give it a good look over. If you have an intercooling leak a hard start when its cold, or a hard start period, is a good indication that intercooling pipes are leaking.

Or.....

B/C you changed you timimg belt maybe one of the cam gears slipped or moved when you put you new belt on, and your only a couple of degrees retarded or advanced, and if your timming is off at boost it creates knocks or pings. Your ECU would notice that and it could potentilly put your car in limp mode.

Hopes this helps

Mike

[BenOswald]

it is your coil packs, 99.99% sure change em all, maybe if you have a friend with some working ones borrow his to make sure before you go buying new ones..

[jim_uk]

try checking your MAF sensor and wiring, becos if these are faulty it could cause it too not rev above 2800/3000rpm

[S13_MPH]

It could be the coil packs, but 99.99 percent sure???? I dont know. I would look at the stuff you and the mechanic touched first. Or else you could put yourself further down the rabbit hole of troubleshooting. I've been down that road. It sucks.

[Skym]

Coilpacks can make engine run on 5 cylinders and is very sluggish. It would be noticeable, as engine would still rev but miss throughout when reving engine. Coilpack failure is due to wrong heat range or gap on sparkplugs. In some cases they fail due to age / heat, but they should be changed every 100,000kms as part of routine maintenance.

From what I understand, when you unplug MAF, stock ECU uses a default value for MAF and engine can be started but shouldn't rev above 2800rpm or so due to revlimiter. Also get MAF error code that needs to be cleared via removing cables from battery (or at least the negative cable), pressing brakes to drain any left over charge, reattaching cables or negative cable.

If it's cold outside, engine runs very rich on cold startup tables (ECU) and engine is harder to start. If have airleaks, makes it even harder again to start. What you do is crank engine longer, so pistons pump more and suck more air into engine to combat the rich mixture and then let key go. Or if really bad, use throttle to crack open throttlebody to allow more air into engine while cranking engine.

Sometimes can be harder to cold start a engine due to oil you use, as it's way too thick and engine has to struggle against the thick oil to start. A 5w weight oil should be used if in a cold climate.

[ozalkl]

I cant do anything at this moment, as the weather been insane and not on the skyline side, its been -25 on average for the past 2 weeks since i parked her on my drive way and been snowing since then, will wait till march 14 as the weather will be nearing +0 or at least its nice to work and troubleshoot the problem.

but as i said earlier, i found out that my mechanic didnt connect the MAF plug, so i connected that and there where it all happen that the engine wont start, and currently when I open the key i can see the HICAS light lit up too.

I need to really troubleshoot why the car is not starting