low power

[SHEARER_TSI]

Ok, so I am going to look at a 1G on thursday. The car had jumped time and the current owner had a new head put on it. He said the car feels low on power. He said the car is in time and has no boos leaks at all. So I am wondering what do yo guys feel are some common things I should check for. He said the car does not smoke at all so i think the turbo is ok. Could the waste gate be stuck open?

 

[Tyeler18]

We're having similiar problems on one of our 1g's. Skipped time (no bent valves), did headgasket/timing belt. Timing both mechanical/electrical is dead on, 2 little boost leaks from the jpipe and throttle body gasket which we're waiting on fixing (still holds boost well on a BLT), yet still has little power and horrible spool time.

We believe his fuel pump is dying/clogged filter because we're logging 52% IDC's at 20lbs on a 16g and stock fuel system.

 

[SHEARER_TSI]

Hmm interesting. This car is bone stock and has 80K miles on it. Maybe it is the fuel pump.

 

[Tyeler18]

Hmm interesting. This car is bone stock and has 80K miles on it. Maybe it is the fuel pump.

This was bone stock with 77k, we removed the emissions crap and put my spare s16g on it while his 14b gets upgraded, but other than that she's bone stock.

 

[red1993gsallmt]

Do a copression test, if that looks fine do a leak down test

 

[SHEARER_TSI]

And if those come back okay?

 

[red1993gsallmt]

And if those come back okay?

Then its incorrect fuel, timing or boost. Stick to the basics, was the plate with the crank timing mark installed correctlly, seen that put on backwards. Is it making target boost?

 

[SHEARER_TSI]

No clue I have not seen it yet. It has a stock boost gauge if you can call it that. They guy said it does not fall on its face just seems like it does not run like it should.

 

[JusMX141]

Base timing is off, or CAS is 180* out.

 

[red1993gsallmt]

wow do 4g63s even run at 180* out? Ive never done that, only done it with v8s with a distributer and shot a nice flame out of the carb. That dont run 180* out. Justin,did you see my hx40 timeslip?

 

[SHEARER_TSI]

I was thinking that since the autos have less power than the 5 speeds could it just feel slow to someone who is used to the 5 speeds?

 

[turboglenn]

They will run with the CAS 180* out, there's 2 signals for the cam (or "home")signal to tell the ECU that the next even upcoming is either cylinder #1 or #3 they are of different sizes though and can throw some things off (on my system i get rid of the # 3 homessignal but it's not astock DSMlink'ed ECU) these 2 "homes" are different lenghts of duration which doesn't matter except it puts the rising and falling edges in different relation to the upcoming cylinder that the ECU 'thinks" it's coming up on, thus throwing off how well the engine runs, but being that the 4 main triggers are still in perfect time the basic events can take place, they just get thrown off by the incorrect homes

basically with DSMlink you can be running 180* out and almost tune around it, that's why there's an option to "invert CAS" signal on the DSMlink because depending on the year and what ever other reasons there were changes to the coil firing that changed which coil was for 1-4 and what was for 2-3

it's really quite simple, there's 4 triggers (one for each cylinder) that occur 70* BTDC of each cylinder to give the ECU time tothink and output a signal for injectors and ignition to happen at it's given time BTDC.

My best guess would be that the timing belt was installed looking correct but is actually off time.. it's so easy to do it's not even funny,there's a note on how to correct it by rotating the exhaust cama half tooth forward and then securing the belt to the intake cam and rocking the gears "back" a little and then aligning the crank mark.. without doing it this way almost everytime the exhaust cam will be off a tooth retarded... you can tell if this is the case by aligning the cam marks perfectly and seeing if the crank mark is dead on 0* or at TDC.. if it's a few degrees off on the timing mark at the crank,or if the mark on the crank disk isn't perfetly centered to it's mark on the front cover then your timing is off (timing as in crank/cams mechanically not ignition timing) I've seen it done a ton of times and even myself have had it go together off and p[eople on this forum and others will lookat a pic and say that the timing "looks fine" butin all actuality it's not.. the crank can be past or before the mark's perfect center and the engine will run and nothing will hit, but depending on what side of the mark you're off to (past or before) you'll either gain spool or loose spool as well as gain midrange(loosetop end) or lose all bottomend and just rev out good in the very top.. whenever some one says there's a loss of power after a t-belt job this is the first thing i suspect and mainly after just the last 2-3 years of inspecting this i've found it's often off base more often than it's done correctly, and this is simply because the books say nothing about this error in setting the timing and if it weren't for the VFAQ tech note about it in their instructions i wouldn't have caught on to this as soon as i did either. double check this, I'll put a round of beers (one 6 pack ) on it being "not perfectly on" and being your issue

 

[supravw]

I don't know about 2g cars but all the 1gs I've had would not run with the cas 180* out. It will try to start and might run for a second but not possible to drive. So you can take that one off the possible reasons list.

 

[SHEARER_TSI]

I have been in cars that were off by a tooth and they run like shit. The way this guy describes it is it just doesn't seem right not like whoa wtf? know what I mean.

 

[turboglenn]

I don't know about 2g cars but all the 1gs I've had would not run with the cas 180* out. It will try to start and might run for a second but not possible to drive. So you can take that one off the possible reasons list.

I think it's mainly a DSMlink thing..aftermarket ECU's that are stand alone will run at 180* out but not correctly, nevertried it on a stock ECU with something like just an AFC or similar on it..but yea usually they will just pop and spit and act like they almost want to fire up with the CAS 180* out