No Power... Tried more things... Any Ideas?

CodingParadox

New member
So, posted here before, but I've since tried a few things and eliminated others.

Basic symptoms:
* No low end power at all... WOT doesn't do anything until higher RPMs and even then not much. Once it starts boosting, I get a fair amount of power, but nothing like what I should be getting.
* 3000 RPM-ish and 5500 RPM-ish create a really weird vibration harmonic where if i hold it near those RPMs, it hums and vibrates strongly until I move above or below that area (+/- 200RPM or so.)
* Ticking noise when I give it more gas. It can hold RPMs in place with no ticking, but when I give it more gas you can hear the ticking. Hence, it might be exhaust, it might be valve tick, but at idle and holding an RPM in place, no tick can be heard, leading me to believe it wouldn't be valve tick.

Things we've tried:
* Re-did timing from scratch a few times. Incredibly carefully set TDC on the crankshaft pulley, then TDC on the two cams, attached belt. Felt same exact as before. Took the belt off the cams, rotated crankshaft 360 degrees (same thing as cams by 180) and put it back on. Absolutely no difference.
* Pulled ignition wires off one at a time and tried running the car to see if a single cylinder was busted (ran on 3 cylinders each time, different removed wire each time.) Each time, the car idled far worse, and had way more trouble revving. No one cylinder had any greater effect than another.

Possible ideas:
* Is there anything else to do with the timing? Could valve clearance possibly be causing this? Stuck valves or anything like that? Could the TDC nubs on the cams under the valve cover be wrong or something? Anything we should try with timing like moving the cams 90 degrees different or anything like that? Moving it one tooth off from what looks right maybe?
* The car was sitting around for something like 18 months before running again. What could go wrong like that?
* The gas was crappy. The tank was nearly empty, and when I filled it up with new 92 gas and drove around for another 5-10 minutes, it got noticeably better. Could the fuel filter possibly be clogged or something due to the crappy gas or something? Should I flush the tank from scratch to eliminate all remnants? Would having 80% new gas and 20% old gas in there possibly be causing this? What if the old gas was 87?
* I put in NGK Iridium spark plugs, at the gap level they came at, and switched to ignition wires from the MR2 3S-GTE I have lying around. Could the iridiums possibly be doing anything bad or possibly the other ignition wires? I can't imagine they would, but I'm getting desperate for ideas at this point. I haven't tried switching to the old plugs or wires yet, but I'm considering it. It just doesn't seem like it could have anything to do with it.

*desperate*
 

Stubble

Active member
No low end power: you seem to be focusing on timing, so I assume you've done distributor cap and rotor, and the wire from the igniter to the distributor, in addition to your plug-and-wire change. Wires are in correct firing order? Check your grounds to the igniter (remove, clean and scrape, and reattach). Check other grounds as you see fit (maybe fuel injector solenoid).

Pull off your exhaust mid-pipe and catalytic converter to see if it is plugged. This is a common problem. Solution: gut cat.

Valve clearance: checking is not too difficult; adjusting is more work. Pull off the valve cover and use feeler gauges to measure the clearance. You will also see if a valve is 'stuck' although I'm sure this isn't the case. While valve cover is off, use a micrometer to measure the cam lobes (I'm not sure if you will have the clearance to do this or not without removing the camshafts). The correct dimensions and clearances are in the BGB or a chilton's.

Obviously there are no engine codes?
 
If car runs normally when not under boost then I would
consider either a bad turbo or plugged exhaust (ask MofoParrot
about effects of a plugged primary and secondary cat converter)
Make sure your noise is not the turbo wheel. If your turbo is
shot it could be the cause of both problems. Check how much
play the turbo has (try to move impeller wheel back and forth,
and up and down, if the wheel touchs the housing get a new
turbo quick)
 

CodingParadox

New member
I'm getting two engine codes: 4-1 and 5-4.

One of those is TPS... I tried replacing the TPS and still got the code, so I don't know. I checked the TPS with an ohmmeter and I got proper resistance, so I don't know what's up with that.
The other is intercooler water level. That can easily be fixed when I get around to it.

Quite the contrary - the car actually pulls fairly well when it's boosting. That's the only time there's ever any power. Up around 4-5k RPM with WOT and the turbo spools, then I'm getting fairly good power. It's the low end that I have _nothing_. I literally have to ride the shit out of the clutch with WOT to get going from a stop without stalling. Yes, it's that bad.
 

Stubble

Active member
OK, I found your other post.

Did you verify the wiring from the TPS to the ECU? I'm not sure if you get the 41 code if the resistance is off - my BGB says if there is a short or open circuit.

Is there anyone you can borrow an ECU from to try a test drive? Good power at boost but no power off boost sounds like a sensor/fuel control problem.

Is the AFM working properly? Is it sticking shut at low air flow, but then slamming open under boost/high mass flow?

I don't have an ST165, but does it go into a limp mode if it has the low IC water level code? I suspect that this code would just keep the the turbo VSV from allowing overboost, so this wouldn't be your problem. Anyone with an ST165 that can help here? :shrug:

You could try the shotgun approach and test every sensor and actuator/solenoid in the engine bay. Some are hard to get to, such as the ones under the intake manifold.
 

Rallly

New member
CodingParadox":1ffciwdk said:
So, posted here before, but I've since tried a few things and eliminated others.

Basic symptoms:
* No low end power at all... WOT doesn't do anything until higher RPMs and even then not much. Once it starts boosting, I get a fair amount of power, but nothing like what I should be getting.
* 3000 RPM-ish and 5500 RPM-ish create a really weird vibration harmonic where if i hold it near those RPMs, it hums and vibrates strongly until I move above or below that area (+/- 200RPM or so.)
* Ticking noise when I give it more gas. It can hold RPMs in place with no ticking, but when I give it more gas you can hear the ticking. Hence, it might be exhaust, it might be valve tick, but at idle and holding an RPM in place, no tick can be heard, leading me to believe it wouldn't be valve tick.

Things we've tried:
* Re-did timing from scratch a few times. Incredibly carefully set TDC on the crankshaft pulley, then TDC on the two cams, attached belt. Felt same exact as before. Took the belt off the cams, rotated crankshaft 360 degrees (same thing as cams by 180) and put it back on. Absolutely no difference.
* Pulled ignition wires off one at a time and tried running the car to see if a single cylinder was busted (ran on 3 cylinders each time, different removed wire each time.) Each time, the car idled far worse, and had way more trouble revving. No one cylinder had any greater effect than another.

Possible ideas:
* Is there anything else to do with the timing? Could valve clearance possibly be causing this? Stuck valves or anything like that? Could the TDC nubs on the cams under the valve cover be wrong or something? Anything we should try with timing like moving the cams 90 degrees different or anything like that? Moving it one tooth off from what looks right maybe?
* The car was sitting around for something like 18 months before running again. What could go wrong like that?
* The gas was crappy. The tank was nearly empty, and when I filled it up with new 92 gas and drove around for another 5-10 minutes, it got noticeably better. Could the fuel filter possibly be clogged or something due to the crappy gas or something? Should I flush the tank from scratch to eliminate all remnants? Would having 80% new gas and 20% old gas in there possibly be causing this? What if the old gas was 87?
* I put in NGK Iridium spark plugs, at the gap level they came at, and switched to ignition wires from the MR2 3S-GTE I have lying around. Could the iridiums possibly be doing anything bad or possibly the other ignition wires? I can't imagine they would, but I'm getting desperate for ideas at this point. I haven't tried switching to the old plugs or wires yet, but I'm considering it. It just doesn't seem like it could have anything to do with it.

*desperate*



Did you figure this out?
 

CodingParadox

New member
Not really. I think it might have been something to do with the knock sensor going nuts, as it felt like a major timing pull. Changing the oil a couple times made it somewhat better, but that block ended up being cracked, so that's likely a contributor. There was no single smoking gun -- I ended up selling that car off after the motor gave up the ghost and got a 185.
 

Rallly

New member
CodingParadox":y3ph754t said:
Not really. I think it might have been something to do with the knock sensor going nuts, as it felt like a major timing pull. Changing the oil a couple times made it somewhat better, but that block ended up being cracked, so that's likely a contributor. There was no single smoking gun -- I ended up selling that car off after the motor gave up the ghost and got a 185.

My bad, I thought it was a n st185 giving you the issues.
 
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