When we bought the car last week it had a surging idle and it would bog down when you hit the gas from a stop. After 20 yards or so it would "catch up" and drive just fine.

I got the codes off the box.
Peg #2: 221,122
Peg #6: 143

We reset the codes so they were 111 and drove it around for 10 minutes and got these codes:
Peg #2: 232
Peg #6: 143

So it looks like O2 sensor for #2 and the knock sensor for #6. Now I also noticed that the exhaust pipe is missing a bolt where it connects to the exhaust manifold. I don't know yet if someone broke a bolt in there but I feel some threads. What is the bolt size that goes in there? Looks like a stud with a nut.

Would the missing bolt have any effect on the codes above?

Should I just bite the bullet with the O2 sensor?

Would replacing the O2 Sensor "fix" the knock sensor? Or should I just replace both at the same time?

This is a non-turbo car and looks like it has the Regina system, with the coil on the shock tower.

Thanks!
Harold

 

is exhaust gas blowing out where that stud is broken? you'd probably see evidence of fresh soot around it. if not, then just keep an eye on it, if it IS blowing out, then its probably also sucking air in, and that throws your O2 sensor off, which makes your engine run funny.

if the knock sensor is going off when it shouldn't, then the ignition retards to be safe but this means much less power and efficiency.

 

So far there is no soot around the missing bolt area.

So regardless of the O2 sensor I should replace the knock sensor then?

 

143 says its a O2 sensor WIRING issue, not just a tired sensor. the wires are, I believe, up on the firewall on the right side, above/behind the exhaust header. IIRC (been a while since i looked at a 7/9 o2 sensor, so this is from memory of my daughter's 240 sensor I did recently), there's 2 connectors, a 2-wire connector for the heater, and a 1-wire connector for the actual o2 signal.

IIRC< Regina uses a different sensor than Bosch (I may be wrong here, never had a Regina car)

reginal fuel injection doesn't use a 'mass air flow' meter, this is pretty distinctive. the big distinction on regina REX ignition is a SQUARE coil with an integrated power module. but there are some cars that have bosch EZK ignition with regina fuel injection so combinations of the two are possible.

 

Code 1-4-3 in the ignition system (EZK 116) is due to missing signal from the knock sensor as 940driver states. Reading up on the code it states symptoms are "Poor acceleration, low power, high fuel cons". I would check the wiring to the knock sensor and make sure it isn't broken. Also check the connector. If all is ok, replacement may be in order.

Regarding the missing nut, it very well can be causing the 2-3-2 or any oxygen sensor code. As Pierce stated, any exhaust leaks upstream of the O2 sensor also let in oxygen which is sensed by the computer as a lean condition. The ECU will try to enrich the mixture to compensate.

 

Took a few days but I got to work on the car again and here is what I found...

Wires from the O2 Sensor look brand new. There is connectivity from the knock sensor end of the wire to the connection on the firewall. Which I think is connected to the third wire of the OS sensor.

The missing nut on the front cylinder's exhaust manifold is a broken stud. Looks like I need to remove the exhaust manifold to try and get the stud out of the head. Is that a simple remove the manifold and put in a new gasket and bolt it back on job? Not counting the removal of the stuck stud of course, just the manifold itself. hahaha We cleaned the engine up and there is no soot around the broken stud since running it for several days.

The knock sensor looks newish but I can't tell for sure. Connector looks to be really good shape.

The muffler was leaking on the up wind side of the tailpipe. Tightened the clamp down. Sounds better but didn't change anything else.

 

removing an old exhaust manifold is nearly always an exercise in extreme frustration and best avoided until its completely unavoidable.

 

Can a Bosche O2 sensor be put on a Regina setup? Looking at AutoZone's site the one we have looks like the one they mention for bosche ignition while a different is specific for Regina.

 

To add to the symptoms she now says that it will occasionally die when she has stopped at an intersection.

 

I ordered a knock sensor but in the mean time I took the old one off and cleaned it up. It was definitely over-torqued. We put it back on and connected all the wires and I fired it up and took off down the road like a rocket. No problems with any hesitation! I turned around in a driveway and came back to the house. Put it in park so my daughter could get in and go to work. She gave it gas to go and boom, hesitation was back again. No clue what that is telling me.

 

I've replaced the knock sensor and there was no change. Just replaced the O2 sensor and still no improvement. 232 code came back as soon as I went around the block. I found a wire that was wrapped in some electricAl tape that goes from the firewall to the top of the transmission. Could that be a player here?

 

that sounds like the CPS, crank position sensor, at least if its going right on top of where the transmission meets the engine, at the back of the head on the exhaust side.

thats a PRIME candidate for failures, although usually a CPS failure results in total stalls and/or no-start conditions.