Engine sputters on throttle when in gear

[myotis1134]

Hey guys - this is starting to be a trend that I’m getting tired of...

Was driving home from Anchorage when the car began sputtering and died.

I was going 55-60 mph, and had down-shifted into 4th, going around a curve, when I heard a bang (I think), and the engine began sputtering when I gave it throttle. Check engine light came on, but I was in a ****** place to pull over so I kept driving. When I gave just enough throttle to maintain speed - maybe 65-75%, there was no sputter. When I gave throttle beyond that - to accelerate- the engine sputtered pretty bad.

Im currently off the road - waiting for a tow. I’ve had the opportunity to look over the engine, but nothing obvious has jumped out at me. When I first popped the hood, a little smoke or steam was coming up from near the AC compressor. I cracked the radiator cap, and coolant spewed all over the alternator, but when I checked the oil it barely registered on the dipstick.

I’m parked about 1/4 miles from the local store in Cooper Landing, so I walked over to get some oil and beer. I put a quart of oil in, and read 100% on the dipstick, so I wasn’t THAT low to begin with.

I don’t have anything to jump the error code terminal with, but my code-scanner is coming out here with the tow. I see no leakage under the car - aside from where I dumped the coolant, and a spot under the steering rack (checked the steering fluid reservoir- level is good).

I’ll tear into it when I get it home and read the code(s), just looking for potential insight at the moment.

Thanks in advance.

p.s. The car died when I let off the throttle, but would come back to life when I’d jump the clutch, and stay running as I feathered it.

 

[myotis1134]

Just started it up, and it idles ok, but when I give it throttle the engine gets super choppy, and the check engine light comes on. Guess I’m gonna wait for that tow...

 

[myotis1134]

OK - got it home and pulled the codes:

in order

111 - Control system OK

121 - Closed throttle voltage higher or lower than expected

123 - Throttle position sensor above maximum voltage

173 - HEGO (HO2S) sensor fault/rich

177 - HEGO (HO2S) sensor fault/always rich

214 - Cylinder identification circuit failure

542 - Fuel pump secondary circuit fault

The last two are new...

 

[zoomlater]

542 is set when your engine dies/stalls. You can ignore it.

214 is the cam position sensor code. Did you change this when you did your servicing? Sensors can be bad out of the box. My car bucked/missed when this sensor started going out. You can try disconnecting it to see if that sensor is the problem. It will take three or so tries to start the car as the engine is guessing. See if it runs after that. You still have a TPS issue.

Did you clear all the codes after the last time so you are only seeing newly set codes.

 

[myotis1134]

@zoomlater - Yes cam position sensor came with the 120k kit, and no I didn't reset the codes.

Here's my current theory:
The car started and ran fine when I loaded it into the trailer, and when moving it out, and all my fluids appear to have intact levels.
The codes all seem to point toward the TPS, and the symptoms I observed while driving could have been caused by a combination of a bad TPS and a partially-to-mostly clogged/blocked catalytic converter.
There could be bad O2 sensor connector wiring somewhere, which is causing the running rich code, and contributing to the increasing amount of carbon being washed out of the combustion areas and deposited in the catalytic converter.

 

[rubydist]

The tps is very important on these engines, so that needs fixed right away for it to run correctly. I have seen both the sensors and the wiring harness be bad on that circuit, but the codes you have seem to suggest the tps itself is the issue.

If you have not changed the oxy sensors lately, I would change both while I was working on it.

Is the tach acting strangely? I would be tempted to ignore the cam sensor code at first and get it running correctly, then see if that code comes back before tearing into that one.

 

[myotis1134]

New TPS is ordered but won't get here until Monday. O2 sensors are both new - replaced them during the 120k last month.

Cleared the old codes a few hours ago, and took it for a spin around the neighborhood to see if I could generate fresh ones specific to this issue. I did run into almost the same symptoms, but was able to keep the engine running. The car died several times with the key on, so I got a 542, but before that I got

214 - Cylinder identification circuit failure

I suppose I'll wait until the new tps comes in, swap it out, clear the codes and try again.

I didn't notice the tach doing anything weird while out driving around. The weird thing is that for the majority of the drive, I wasn't getting a coolant temp on the gauge, but after the engine started acting up the gauge began to register a temp.

 

[rubydist]

The temp gauge for the instrument panel is completely separate from any of the engine control stuff - all it does is make the gauge show the coolant temperature, so that part is a coincidence.

 

[BaySHO Performance]

The replacement TPS may help, but it definitely looks like you have a cam sensor problem as well for the 214 to come back. Run your finger along the bottom of it to see if it's wet with oil indicating a bad cam seal which would compromise the sensor.

Camshaft Sensor (Duralast) F134 $37 Autozone
Cam Seal (1 National) 1213N $9 O'Reilly

 

[myotis1134]

New TPS installed - way better throttle response, and the vehicle ran fine until it warmed up and I parked it at the store. Had trouble starting up, lots of hesitation when under throttle, and pulled 2 codes when I got home:

214 - Cylinder identification circuit failure
542 - died with key on

Also getting smoke from around the belt system. Guess I'll get in there and take a look at the cam/crank sensors.

 

[BaySHO Performance]

my bet is that the seal behind the cam sensor has failed, and oil is dripping on to the cat causing the smoke.

 

[myotis1134]

Cam sensor looks good. Clean and dry inside the cap.




What are the odds that this whole mess could be caused by a partial or completely clogged catalytic converter?

 

[luigisho]

50/50. with all those electronic codes I'm not sure about that. The cam looks squeaky clean. So where does the CID circuit run? That would be my next thought. But if you have a quick exhaust check, to get that off the table, then go ahead and let's see where that goes.

 

[BaySHO Performance]

You might want to replace the sensor anyway.

 

[rubydist]

The code for the cylinder id means that either the cam sensor is bad or the circuit to the cam sensor is bad. Since it seems to work fine while cold but after a heat soak it has issues, it is more likely that it is the sensor that is bad. I would replace that first thing.

 

[myotis1134]

Is the rear exhaust manifold seriously unable to come off without removing the head?

 

[BaySHO Performance]

Is the rear exhaust manifold seriously unable to come off without removing the head?

On an MTX, correct. There isn't enough room between it and the firewall for the manifold to clear the studs. I guess if one had a reason to remove the head and manifold, the studs and nuts could be replaced with bolts. That might overcome the problem.

However, the ATX engine sits 2" further forward to make room for the transmission. I'm in the process of removing the rear manifold to replace a couple of speedo cover O rings that are leaking and compromising the VSS. The AC accumulator at the back (at the front on an MTX) may get in the way. I'll know by the end of the day if it's possible.

 

[BaySHO Performance]

I can now confirm that the rear exhaust manifold can be removed with the cylinder head still in situ on an ATX.

 

[myotis1134]

Decided against pulling the heads. Dropped the Y-pipe and cut open the cats to see how they looked inside, but couldn't tell one way or another - which probably means they were not clogged.

I'm guessing that when a catalytic converter is plugged with crap - it's fairly obvious from an internal visual inspection what the problem is.

Cut and ground the cat chamber away from the pipes (total pain in the ass). Gonna reinstall the individual parts, take some measurements, and go pick up some exhaust pipe to bridge the gaps.

I'd much rather pick up the shosource re-engineered y-pipe, but can't afford it at this time, so the MacGyver method it is. Besides, this way I get to adjust the angle of the front oxygen sensor a couple degrees - it interferes with my steering fluid line at the stock orientation.

 

[BaySHO Performance]

I use a USB borescope attached to my phone for, among other things, looking at the cats close up. And if a cat is blown, chances are that a piece gets stuck in the cat back, creating lots of back pressure with a very noticeable loss of power.