Close to giving up...can't find the misfire!

[SpeedAgent]

This stands out to me. Why was the engine orignally at 9 degrees and had to be bumped back to 3, I'd double check timing following the FSM and make sure it is within spec. And if it's not adjust it so it is, and if it runs worse than something is going on there.

This I'm not quite sure of. The engine came out of a parting out vehicle, so the details are scant, but it was at 9 degrees when it was pulled and as the mechanic was tuning up everything once installed he said it didn't run well at 9 degrees, so he set it back to 3. So, you guys are right, if it wasn't right at 9 when that's how it was when it came out then something else was going on.

I'm going to start on this tomorrow and also look into the IAC issue mentioned in another response. Thanks guys!

 

[leonard_nemoy]

Well, I checked and greased the temp sensor connection, checked and greased the possible fuel pump power connection, and double checked the injector connection order. I can't reach all of the connections to each injector, but the ones I could reach were not corroded and were snapped on. Fired it up and within minutes it was stumbling again.

Should I;

A- get a timing light and check timing

B- buy a new temp sensor because this could easily be the problem

C- I can't think of anything more

Instead of just replacing the temp sensor you can actually check it with a multimeter.
Coolant Temperature Sensor Test

 

[Mudder]

To go back on what I said, 3 degrees is the factory setting in the 1fz. It was probably advanced to 9 because many people have advanced the timing to 7 to get the engine to have now power. I'd verify it really is at 3 degrees.

 

[SpeedAgent]

What do you guys think of this possibly being related to a blocked Cat? The converter is likely original, so would have 235k miles on it and a blown HG would not have helped it's health. Can a blocked Cat cause these types of issues?

 

[Zjohnsonua]

Unlikely. Have you checked the already suggested items?

 

[SpeedAgent]

I have not had time to look at it since yesterday, but i'm making a list and will be going 1 by 1 until it smooths out.

 

[Proven]

My original posted question - you got this engine dressed? (all electrical from the donor vehicle) or undressed? (a bare block without any wiring connected to it) If it came dressed, you got the original ECU and all control modules with it? or did you strip your old block and "re-dress" the motor with your existing electrics.

Uncontrolled variables make diagnostics impossible without baselines being established. You'll need a timing light to set the timing for a start. We are assuming that timing is static, but it is not in this case. Other things like engine grounds and connector pins being fully locked/seated is another variable.

I had 1 pin loose on my MAF (mass air flow sensor) in another truck that caused all sorts of havoc. When I gently tugged on that pin it locked into place and all the problems went away. With that, there was a code thanks to OBD2.

I've googled your codes and everything I read points to either a bad ECU or a wiring harness issue which could have been caused by installation or existed prior on the donor...we don't know because the truck is Frankenstein.

Since the timing is very suspect, I would do that first. It is a bit of a process to set the timing correctly.
I found this on mud, but there are likely others: How To: Adjust or Advance Timing

 

[SpeedAgent]

Thanks for the continued help guys. I'm trying to keep up with the experiments each day, but life is getting in the way. However, I just did the cat temp test and here are my results; laser reading on pipe forward of cat- 277F and the reading on the pipe post-cat- 216F. I got the readings on the respective pipes equal distance from the front and the back. I let the car idle for about 10-15 minutes before taking the readings. Also, I didn't get any smoke but the exhaust is very strong. Not gas or coolant smell, but noxious fumes.

To me, it seems like my cat is at the end of its life. Thoughts?

 

[SpeedAgent]

My original posted question - you got this engine dressed? (all electrical from the donor vehicle) or undressed? (a bare block without any wiring connected to it) If it came dressed, you got the original ECU and all control modules with it? or did you strip your old block and "re-dress" the motor with your existing electrics.

Uncontrolled variables make diagnostics impossible without baselines being established. You'll need a timing light to set the timing for a start. We are assuming that timing is static, but it is not in this case. Other things like engine grounds and connector pins being fully locked/seated is another variable.

I had 1 pin loose on my MAF (mass air flow sensor) in another truck that caused all sorts of havoc. When I gently tugged on that pin it locked into place and all the problems went away. With that, there was a code thanks to OBD2.

I've googled your codes and everything I read points to either a bad ECU or a wiring harness issue which could have been caused by installation or existed prior on the donor...we don't know because the truck is Frankenstein.

Since the timing is very suspect, I would do that first. It is a bit of a process to set the timing correctly.
I found this on mud, but there are likely others: How To: Adjust or Advance Timing

This is on my list for tomorrow!

 

[mudgudgeon]

What do you guys think of this possibly being related to a blocked Cat? The converter is likely original, so would have 235k miles on it and a blown HG would not have helped it's health. Can a blocked Cat cause these types of issues?

I've had a couple of different vehicles with clogged cats cause a misfire, and seen it with buddies cars too.
I would keep pursuing the little things first such as bad wiring, timing etc. Or eliminate the cat and see if there's a change.

 

[Zjohnsonua]

Temp measurements via emissivity (laser thermometers) are completely dependent on surface conditions (i.e. slight amounts of dust can completely wreck a measurement) and materials and may vary widely (which is why good laser thermometers have so many adjustments to try and allow for all these variables). I'm not saying the cat test is not valuable as converters do fail, but I don't think it's the best direction to pursue at the moment based on your symptoms.

There is lots of good input already provided by several folks. If you'll knock out some of those checks you're likely to make some progress and get more input.

 

[Whiphub]

This is on my list for tomorrow!

Any luck?

 

[SpeedAgent]

Any luck?

None yet. It's to the point I can't drive it. I am waiting on the new cat coming tomorrow. With any luck that may fix/help my problem enough to at least drive it some.

 

[BILT4ME]

PARTS CANNON!

 

[LandLocked93]

From the cheap seats...
...does your dizzy have oil inside it? Is the insulation of the wires inside the dizzy in tact or coming apart?

From one of your posts, SpeedAgent, you mentioned you checked the injectors and cranked the truck. The truck ran fine for a few then returned to stumbling. That seems to point to, as others have mentioned, a possible injector with a penchant for intermittent operation.