Last few weeks the transam has been running a bit lumpy. One morning in particular it took afew minutes to "clear" then ran smoothly.
So it's been getting worse till last weekend when it ran so bad I had to check out the diagnostics.
I got the codes 13 & 44 which means the oxy sensor which I replaced. Now, the car won't start at all. There are no error codes being reported, I've checked all plugs, put on new ht leads,distributor cap & rotor arm, checked timing etc. Getting fuel to the carburettor & a spark too.
Has anyone had a problem like this before? Any help would be appreciated.

 

Whether or not it's throwing codes doesn't really matter when it comes to a no-start situation.

3 main things are required to start an engine:

-Fuel/air mixture
-Spark
-Compression

Just because you're getting fuel TO the carb, doesn't always mean fuel is getting THROUGH the carb. Make sure when you crack the throttle that fuel is getting squirted.

Are there any noises associated with this no start? Grinding, whirring, clicking, buzzing, anything?

 

I agree with Stekman in that you may be getting fuel to the carb, but the carb might not be able to do right with it....

the first thing i would do if i were you is take some carb cleaner and just shoot it down the jets to clean it out... you can also use starting fluid to do this, it's about the same stuff anyways (and will not hurt your car by running it with some in there on start up)

I'm assuming that what you were saying is that it will start up, but when you start it up it will idle very rough before it smooths out, and then recently it has just stopped smoothing out.

You may also wish to check your TPS, clean that off too, I think that carb cleaner can be used for that as well. I dont think it has anything to do with your O2 sensors, because it sounds like it's a open loop problem, where the engine doesnt read the O2's yet, so it cannot be the O2 sensors.

 

Another thing you may want to clarify: when, in relation to replacing all those parts, did the no-start occurance begin?

 

I finally got to the bottom of the problem. It turned out to be faulty spark plugs. Now I know I said I got a spark, which I did. I have a test tool which goes between the ht lead & plug, & it showed the spark. However, a friend of mine had got me a set of cross referenced plugs 6 weeks ago. Obviously they must have been the wrong heat range & failed after the oxy sensor gave up, running really lean. This was why I assumed the plugs would not have been at fault. I had my old plugs in the shed so thought "what the heck, nothing to lose" and how right I was.

Everything now running smoothly.