Zeroing in on problem...and it's mechanical? Maybe.

[JessN16]

For the past 3 months -- and for about a year prior to this car sitting up for 2 years -- I'd been having a running/driveability problem with the car. It was hesitating under boost at low RPM, such as if you were to engage 5th gear at 50 mph going up a slight hill, and accelerate. The bottom end of the torque curve felt choppy.

 

The problem has just gotten worse since I got the car running again. It's the same story nearly every time -- car is great for the first 3-5 minutes after it's cranked, when everything is cold, then it gets worse the warmer the engine gets.

 

This past week, the problem got so bad it was almost stalling. I was having so many electrical issues, I felt that's what it must have been. Well, I finally got the electrical taken care of, and the problem was still there. And now I think it's mechanical.

 

For one thing, I have a lifter making a ton of noise. It's an Alabama head, non-JV, and it's always been a little noisy. But now it's a da*n sewing machine. But what is going on really feels like ... like I just don't have a turbo connected to the car. The turbo in this car is a 16G, and it was built and installed back around 2002.

 

However, if the turbo is bad, it's hiding it well. The car is not burning oil, and is not leaking oil. After a few spirited runs tonight, though, I noticed the hot side of the turbo glowing a little. The car has no pre-cat, but does have a main cat. But the cat was not glowing, and there's no rotten egg smell.

 

The car is also running a little rich at almost all times, according to the A/F meter. I know my mileage sucks all of a sudden, and that didn't use to happen to this car. The car is not running hot, and there are no signs of a head gasket failure.

 

One thing did help a little tonight, but not much: Plugging up the BOV.

 

Things I haven't checked: The TPS, and the codes. I'm stopping by Radio Shack in the next couple of days to get a 12V LED. I suspect the 02 sensor is probably in need of replacement.

 

But those loud lifters have me thinking this could be a mechanical problem.

 

Jess

[JAinsworth]

Jess, iirc, the cts is 2 individual wires on your car. If they are hooked up backwards (on the opposite terminals) you will have this issue. Try reversing them and see how the car performs.

Jimmy

[AutoBodyGod]

Remove the cam tower and remove the rocker shafts in order and clean the rocker shafts. After cleaning the rocker shafts, blow them out with a high pressure air hose and reinstall the assembly back in the order you removed them from.

[JessN16]

Remove the cam tower and remove the rocker shafts in order and clean the rocker shafts. After cleaning the rocker shafts, blow them out with a high pressure air hose and reinstall the assembly back in the order you removed them from.

 

AutoBodyGod,

 

I'm sure the head needs it, but any kind of motor work is WAY above my comfort zone as a shadetree StarQuest owner. What you suggest will have to wait awhile, I'm afraid.

 

Jimmy, you're right, my CTS is two individual wires. I may flip them tomorrow and go for a spin and see what I get.

 

Jess

[Shelby]

noisey lifter mean 2 things 1 your lifter thats makeing noise is no longer any good,, 2 you may have an oil suppy problem to the lifters,, you need to make sure the head has the right size'd oil passages and that you are useing the right rocker arm shafts

 

finding a bad (colapse'd lifter ) is easy remove the valve cover and check each rocker arm with cam lobe down,, if the rocker arm can be move'd up and down the lifter is bad ,,you will need to colapse all lifers when you reinstall the assy,,

[Edde]

If the 02 has more than 50k on it it's due. I'll just point out that a lot of cars, boats, and bikes out there are having FUEL issues from methanol and whatever. Filters and chemicals and clean injectors. Even if a filter isn't old it'll stop when junk or gel gets into it. When the car is cold (in warm up mode) it can get just enough gas thru a clogged injector to make it seem to run but when the ECU takes over it can't compensate enough so it runs like crap. Milleage goes in the toilet.

 

Also do you have a dist pickup coil that's in spec? 1150 or so ohms - whatever is in the fsm. I just recall the ignitor change.

[JessN16]

Update from tonight...

 

Swapped the wires on the CTS, took it for a spin, no change.

 

It's definitely temperature-related. And I'm in a good position to know pretty much exactly what temp is causing the problem: A few years ago, Grant (pure_insanity) and I installed a new radiator and changed the factory fan system out, installing aftermarket Zirgo fans. For the primary fan, we wired it to come on with a temp sensor at 180. For the secondary fan, we put in a variable control, so I could make it come on at whatever temperature I needed it. It's currently set between 190-195, and I wired up status lights on my dashboard so I could see precisely when it kicked in.

 

Well, the problems come right before the secondary (195) fan kicks in. Starts running like crap all through the powerband, but worse on boost when the engine is loaded up, as described before.

 

I made my last run tonight very late, when air temps had cooled into the upper 70s. I could never get the car to warm above 195, so the problems only came in very faintly. But earlier in the evening, when the air was still warm and the car could get a good heat in it, it ran like utter crap.

 

And, the warmer the engine gets, the louder those lifters get. When engine temp is below 195, I barely hear the lifter.

 

So something is happening here that is directly tied to a temperature of 195 degrees F. Either the TPS is having a resistance issue, 195 just happens to be when the lifters can't get a good oil supply/start failing, or an injector starts going downhill at that temp. Or maybe the CTS is just flat-out bad no matter how it's wired.

 

I'll be checking codes in the next day or two and that should give more info. But I'm encouraged that I'm getting good work done here in regards to eliminating possibilities.

 

Jess

[psu_Crash]

Are you 100% sure it's lifter tick you are hearing? A leaky gasket or crack anywhere on the exhaust manifold/turbo will make a loud ticking sound. And a crack could open up more as it warms up.

Also wondering if you have done a boost leak test? I assume you haven't, you should

 

fyi there is really no such thing as a "12V LED" All LEDs are about 1.5-3 volts, depending on size and color. It's the resistor in series with the LED that determines what supply voltage may be used.

[vbrad511]

If this all started when you reworked your fans I'd tend to think that's where your problem is. Sounds to me like wherever you've tapped the power for your variable controller is eating into juice that's needed somewhere else. Either disconnect that variable controller, or find another power supply and ground for it and see what it does.

[Indiana]

I thought this was mentioned before but you might check it again. The CTS has two wires and one is the sensor power and the other is the ECUs sensor ground so that the ECU sees this resistance change all the time. The temp. gauge sending unit also has two terminals but its second pole goes to ground only after the coolant is hot because that is a switch not a resistor and its for an automatic tranny car to not be able to go into overdrive when the coolant is cold and so that your automatic air conditioner isn't going to blast cold air in your face in the winter and how that works to change modes is in the service manual. There is a resistance reading for the ECU to see on both of these two completely different sensors for the temperature gauge to read something since one in the harness uses the ECU for the ground and the other gets its ground from being screwed into the intake. The ECU will get a false CTS reading from the temp. gauge unit if its plugged into it by mistake since its goes to the body ground. The resistance read from these are two different range scales and can't be swapped it causes the gauge to read wrong and the CTS reading back to the ECU to be wrong. Make sure the CTS which has the molded oval end has the plug from your harness with the BLACK wire in it. This should be at the top of the FAQ if its not already in there somewhere its so easy and common to have these two plugs wrong.

 

http://www.b2600turbo.com/images/ECICTS.jpg

 

 

[Shelby]

ECu is runing in open loop all the time,, eather 02 sensor or CTS circirt open or ground'd,,

but how does the rad get to 195f if the fan sensor is set to turn on at 180f ,

you want the big fan to come on at aprox 180f and the small fan to back it up at 195 f ,, if the cooling system is up to par the small fan will almost never kick on ,,you have a 192f-195f thermostat in the engine,, i'd swap that for a 180f one

[JAinsworth]

Jess, swapping the two wires on the cts should have made a difference. With no difference I tend to believe it is bad. I'll send you a good one to swap out.

[JessN16]

Are you 100% sure it's lifter tick you are hearing? A leaky gasket or crack anywhere on the exhaust manifold/turbo will make a loud ticking sound.

 

I've had those other things (gasket, bad manifolds, etc.). This is definitely a lifter. We installed this head nearly six years ago and it was a little noisy from the start. There are some good aspects of this lifter -- if you're a half-quart low on oil, it gets loud. I guess I don't even need to use a dipstick anymore. Sounds like someone hitting a piece of pot metal with a small ball hammer when it starts making racket. Let the engine get warm enough or the oil lower than that, and at least one other lifter gets into the party, too.

 

Jess

[JessN16]

If this all started when you reworked your fans I'd tend to think that's where your problem is. Sounds to me like wherever you've tapped the power for your variable controller is eating into juice that's needed somewhere else. Either disconnect that variable controller, or find another power supply and ground for it and see what it does.

 

It didn't start when we re-did the fans. The fans and radiator were done about seven years ago, at the same time we did the BSE on this car. These running/driving problems started about two years ago. Then, the car quit running for other reasons and it stayed parked until earlier this year. We fixed those other electrical problems, but the crappy running condition is still with us.

 

Jess

[JessN16]

ECu is runing in open loop all the time,, eather 02 sensor or CTS circirt open or ground'd,,

but how does the rad get to 195f if the fan sensor is set to turn on at 180f ,

you want the big fan to come on at aprox 180f and the small fan to back it up at 195 f ,, if the cooling system is up to par the small fan will almost never kick on ,,you have a 192f-195f thermostat in the engine,, i'd swap that for a 180f one

 

Beats me, Shelby. This car has always run a little warm. And it's already got a 180 t-stat.

 

Jess

[BOOSTED88tsi]

Never mind, read to fast. Edited August 20, 2010 by BOOSTED88tsi

[JessN16]

Did a lot more testing with it today and now I'm not sure that I don't have an exhaust leak. I definitely have at least one and as many as three ticking lifters. One is ticking all the time. The other two come and go, and when they're all three singing together, it's hard to hear anything else.

 

But I heard what sounded like a big exhaust leak this morning after a 30-mile trip, and it showed up again after the return trip. I got out, popped the hood, let the car cool down a little and the leak seemed to go away.

 

However, I also have more information from the A/F gauge that supports an electrical problem: On a completely cold motor, my A/F readings are very precise. There is only one or two LEDs lit up at any given time. But when the car gets very warm, and the running/driving problems begin to show up, the A/F gauge goes somewhat nuts, with five or six LEDs lit up at the same time, and everything is very erratic.

 

So here's where we're at in terms of what I think is causing this:

 

1) CTS

2) Lifter set

3) Exhaust leak?

4) TPS

5) Bad 02 sensor

 

At this point, I'm going to swap in a new CTS, check my codes and that's about as far as I can go. I need more experienced ears to listen to the noises it's making before I go tearing down the hot side of the motor looking for a leak.

 

Jess

[Shelby]

most reman heads come with mechanical rockers,, have you ever look'd at the rocker shafts,,to make sure they are the right shafts and the shaft is not broken into , and if the shafts are the right ones were they ever clean'd out

 

and once more you need to get hold of a digital volt ohm meter and learn to use it ,, it takes the guess work out of testing sensors

[JessN16]

most reman heads come with mechanical rockers,, have you ever look'd at the rocker shafts,,to make sure they are the right shafts and the shaft is not broken into , and if the shafts are the right ones were they ever clean'd out

 

and once more you need to get hold of a digital volt ohm meter and learn to use it ,, it takes the guess work out of testing sensors

 

Shelby,

 

You'll be happy to know that I do, indeed, own an ohm meter now. Exactly how to use it, well, that's another story. But I do have one.

 

Jess

[C300]

If your Fuel Air Ratio has been Rich for along time your Catalytic converter could simply be plugged. Sounds like the air is trying its best to get out... Anyway, It's simple enuff to check. Just disconect the down pipe from the exhaust, wire it up, and go for a spin. Oh, and avoid Johnny Law , C300