j30 major issues. Advice needed.

[wellyman]

Hey all:

Here's the background on this 94 j30. Had an injector fail. Replaced and quickly found that the lower seal of the injector was not seated properly in the fuel rail. Fuel from the rail flowed into the #4 cylinder, and hydro-locked. Completely pulled off the Intake plenum and fuel rail assembly, and reseated and rechecked, and reinstalled. Before I started it back up again after the hydrolock, I pulled all plugs, drained oil and changed filter and oil, and made sure all liquid was out. I knew I probably had some liquid gas flow into the exhaust manifold thru the valves. I did have gas get into the upper plenum and when I was removing the plenum after the hydrolock, there was fuel that came out of the passenger side slave trottlebody. All this not good, I know. Well after reinstall, it started, running very rough and smoking excessively, as I expected after the hydrolock. The smoke disappeared after idling for 10 min or so. The car ran aweful, and I drove it for 100 miles or so out of necessity for transportation. Very Very bad spark knock was present with engine load. Well after many many hours of testing, which I hope to clarify with everyone's help here will follow. After testing the rotating assembly, and checking compression, I think that mechanically speaking it's ok. Luckily the hydrolock didn't break anything. My problem is electronic in nature, so it seems. I hooked up a timing light, and saw that it was reading about 38 BTC, and would climb to 44 or so at which time the motor would stumble, and the timing would retard to about 20, smooth out, and would jump back up to 38 again, slowly start advancing again, stumble....

Seeing that the spec for timing is 15 BTC, I decided to adjust the timing via the camshaft position sensor. There's only a small range of adjustment that can be done before it's maxed out, but I retarded the timing all I could with it. The timing became 22 or so BTC, and stayed steady. It began running much better, and the stumble is almost gone. Spark knock is still present, but less. So somethings advancing timing too much or something's not retarding timing enough. Here's where I need help. Any ideas what I should do would be greatly appreciated. The book is next to useless, and I've been to the library and have been testing sensors to try to figure out what's happening.

From the sensors I've tested, 2 seem to be suspect. Knock sensor doesn't seem to have continuity to ground as it says it should in the manual. But from what I've read on it Knock sensor shouldn't cause the car to run horrible and underpowered, nor influence advanced timing. I have all the numbers and info if someone knows what it should really be.
The other sensor is the TPS/closed position sensor. The tps resistor seems to test fine, but closed position sensor circuit seems to be faulty, or I'm not reading the info correctly. According to the manual, there should be continuity between the two terminals on the sensor on throttle closed, and open when slightly open to fully open. On my test, the circuit is open at closed, and continuity is present when trottle is at about 1/2 trottle to fully open. Almost opposite.

I'm hoping someone can make sense of all of this, and give direction as to how to confirm what is causing such exteme timing advance. I know that my adjusting the camshaft position sensor is just masking a bigger problem, but I don't know how to diagnose what that problem is. Can a knock sensor cause timing to advance to where the car is running sooo bad, or can the closed position thing be major. The car is old, and has 120 k on it, but it ran pretty good before all this happened. Compression numbers were great on all 6 cyl. Damn near ready to take it to infiniti, but would love to save some money and time. Really hoping some guru's here and shed some light.

Thanks all in advance.
Jeff

[sparkeykev]

Originally Posted by wellyman

Hey all:

Here's the background on this 94 j30. Had an injector fail. Replaced and quickly found that the lower seal of the injector was not seated properly in the fuel rail. Fuel from the rail flowed into the #4 cylinder, and hydro-locked. Completely pulled off the Intake plenum and fuel rail assembly, and reseated and rechecked, and reinstalled. Before I started it back up again after the hydrolock, I pulled all plugs, drained oil and changed filter and oil, and made sure all liquid was out. I knew I probably had some liquid gas flow into the exhaust manifold thru the valves. I did have gas get into the upper plenum and when I was removing the plenum after the hydrolock, there was fuel that came out of the passenger side slave trottlebody. All this not good, I know. Well after reinstall, it started, running very rough and smoking excessively, as I expected after the hydrolock. The smoke disappeared after idling for 10 min or so. The car ran aweful, and I drove it for 100 miles or so out of necessity for transportation. Very Very bad spark knock was present with engine load. Well after many many hours of testing, which I hope to clarify with everyone's help here will follow. After testing the rotating assembly, and checking compression, I think that mechanically speaking it's ok. Luckily the hydrolock didn't break anything. My problem is electronic in nature, so it seems. I hooked up a timing light, and saw that it was reading about 38 BTC, and would climb to 44 or so at which time the motor would stumble, and the timing would retard to about 20, smooth out, and would jump back up to 38 again, slowly start advancing again, stumble....

Seeing that the spec for timing is 15 BTC, I decided to adjust the timing via the camshaft position sensor. There's only a small range of adjustment that can be done before it's maxed out, but I retarded the timing all I could with it. The timing became 22 or so BTC, and stayed steady. It began running much better, and the stumble is almost gone. Spark knock is still present, but less. So somethings advancing timing too much or something's not retarding timing enough. Here's where I need help. Any ideas what I should do would be greatly appreciated. The book is next to useless, and I've been to the library and have been testing sensors to try to figure out what's happening.

From the sensors I've tested, 2 seem to be suspect. Knock sensor doesn't seem to have continuity to ground as it says it should in the manual. But from what I've read on it Knock sensor shouldn't cause the car to run horrible and underpowered, nor influence advanced timing. I have all the numbers and info if someone knows what it should really be.
The other sensor is the TPS/closed position sensor. The tps resistor seems to test fine, but closed position sensor circuit seems to be faulty, or I'm not reading the info correctly. According to the manual, there should be continuity between the two terminals on the sensor on throttle closed, and open when slightly open to fully open. On my test, the circuit is open at closed, and continuity is present when trottle is at about 1/2 trottle to fully open. Almost opposite.

I'm hoping someone can make sense of all of this, and give direction as to how to confirm what is causing such exteme timing advance. I know that my adjusting the camshaft position sensor is just masking a bigger problem, but I don't know how to diagnose what that problem is. Can a knock sensor cause timing to advance to where the car is running sooo bad, or can the closed position thing be major. The car is old, and has 120 k on it, but it ran pretty good before all this happened. Compression numbers were great on all 6 cyl. Damn near ready to take it to infiniti, but would love to save some money and time. Really hoping some guru's here and shed some light.

Thanks all in advance.
Jeff

Have you checked for codes this place will tell you hoe to do that
http://www.auto-diagnostic-codes.com/

it may point you in the right direction

[Bob24]

Originally Posted by wellyman

Hey all:

Here's the background on this 94 j30. Had an injector fail. Replaced and quickly found that the lower seal of the injector was not seated properly in the fuel rail. Fuel from the rail flowed into the #4 cylinder, and hydro-locked. Completely pulled off the Intake plenum and fuel rail assembly, and reseated and rechecked, and reinstalled. Before I started it back up again after the hydrolock, I pulled all plugs, drained oil and changed filter and oil, and made sure all liquid was out. I knew I probably had some liquid gas flow into the exhaust manifold thru the valves. I did have gas get into the upper plenum and when I was removing the plenum after the hydrolock, there was fuel that came out of the passenger side slave trottlebody. All this not good, I know. Well after reinstall, it started, running very rough and smoking excessively, as I expected after the hydrolock. The smoke disappeared after idling for 10 min or so. The car ran aweful, and I drove it for 100 miles or so out of necessity for transportation. Very Very bad spark knock was present with engine load. Well after many many hours of testing, which I hope to clarify with everyone's help here will follow. After testing the rotating assembly, and checking compression, I think that mechanically speaking it's ok. Luckily the hydrolock didn't break anything. My problem is electronic in nature, so it seems. I hooked up a timing light, and saw that it was reading about 38 BTC, and would climb to 44 or so at which time the motor would stumble, and the timing would retard to about 20, smooth out, and would jump back up to 38 again, slowly start advancing again, stumble....

Seeing that the spec for timing is 15 BTC, I decided to adjust the timing via the camshaft position sensor. There's only a small range of adjustment that can be done before it's maxed out, but I retarded the timing all I could with it. The timing became 22 or so BTC, and stayed steady. It began running much better, and the stumble is almost gone. Spark knock is still present, but less. So somethings advancing timing too much or something's not retarding timing enough. Here's where I need help. Any ideas what I should do would be greatly appreciated. The book is next to useless, and I've been to the library and have been testing sensors to try to figure out what's happening.

From the sensors I've tested, 2 seem to be suspect. Knock sensor doesn't seem to have continuity to ground as it says it should in the manual. But from what I've read on it Knock sensor shouldn't cause the car to run horrible and underpowered, nor influence advanced timing. I have all the numbers and info if someone knows what it should really be.
The other sensor is the TPS/closed position sensor. The tps resistor seems to test fine, but closed position sensor circuit seems to be faulty, or I'm not reading the info correctly. According to the manual, there should be continuity between the two terminals on the sensor on throttle closed, and open when slightly open to fully open. On my test, the circuit is open at closed, and continuity is present when trottle is at about 1/2 trottle to fully open. Almost opposite.

I'm hoping someone can make sense of all of this, and give direction as to how to confirm what is causing such exteme timing advance. I know that my adjusting the camshaft position sensor is just masking a bigger problem, but I don't know how to diagnose what that problem is. Can a knock sensor cause timing to advance to where the car is running sooo bad, or can the closed position thing be major. The car is old, and has 120 k on it, but it ran pretty good before all this happened. Compression numbers were great on all 6 cyl. Damn near ready to take it to infiniti, but would love to save some money and time. Really hoping some guru's here and shed some light.

Thanks all in advance.
Jeff

I having a similar problem. Car will start sometimes and then the next it won't. I have changed the entire steering column including the ignition module, thought that was the problem. I was wrong still doing it does anyone think it could be the security system?