No start condition, cosidering clogged cats,

http://forums.corvetteforum.com/show....php?t=1466770

Unhooked EGR tubes (suggestion from another member) and I
got a positive response almost like it wanted to fire. Is this enough
of a pressure relief in the event of clogged cats or should I drop the
exhaust from the manifolds to eliminate any doubt? Just curious,
what kind of pressure should I get at the exhaust tips while cranking?
This is a lame question but i dont feel much of anything back there
while Mama cranks the engine for me?

 

clogged cat's won't stop it from starting. It will keep it from running well, but it won't keep it from starting.

What about fuel pressure? Spark? any codes? Coil? ICM? Wires?

 

Makes sense bogus but Im running out of ideas.


-Was getting Code16 (bad Opti)
-Brand new MSD Opti (Getting spark at all cyls.)
-Quadruple checked plug wires
-New Plugs
-Brand new Ford injectors 24#
-NOID test: Pulses at all injectors
-New fuel filter
-Siphoned and replaced fuel
-Fuel pressure:43lbs (will hold all day)
-New ICM & Coil
-Swaped ECM with a known working ECM
-Snap-On scanner shows no faults or codes
-VATS disabled
-Cranks But no start, Will sputter out the intake
only after cranking. Never a reaction while cranking?
-MSD Tech says: "If your getting spark the Opti
is not defective."

 

Retro and bogus for what it is worth I have seen plugged exhaust keep an engine from starting. It is not common and must be an extreme restriction but it does happen. The suggestion to open the EGR was a good one and if it seemed to make a difference I'd try dropping the exhaust, after all it costs nothing but your time.
If that doesn't succeed, something else worth trying would be to remove the plugs and squirt a small amount of engine oil in each cylinder (similar to running a wet compression test) with the plugs still out disable the ignition to prevent a fire and crank the engine briefly to distribute the oil, then reinstall the plugs, enable the ignition and try to start. Cylinder walls can get washed of oil after extensive cranking and lack compression. Again this costs nothing but your time.
I didn't read the entire first post so forgive me if this has been covered but how about the timing chain? Good luck.

 

A completely blocked exhaust component will cause a no start situation. Kind of like, if someone put a potato in the exhaust pipe/muffler. If you feel some pressure out of the mufflers, it's probably not a blocked cat. You can also try and hit the cats with a block of wood or rubber hammer and listen for a rattle. Not sure what type of presssure you should get from the exhaust tips, but toptech made a good statement.

 

Test your injectors, I had the same problem so I replaced my cat with a hi flow, but it turned out I had two bad injectors.

 

WOW! I no absolutely nothing about Optis, I have had experience with clogged cats though on a couple cars, and I've not experienced a no start condition. Not to say it's not possible though! A couple things though, First I thought I read on one of the forum posts that you can have spark on an opti equiped car....but it's possible for the spark to be to weak for a start....maybe someone will comment on that.
Second, I've been wrenching for over 45 years, and I know the first thing I'd do, since it really sounds like a timing issue..at least to me. I'd pull the valve cover on the drivers side,pull the #1 plug, rotate the engine until both valves were closed and then check to see where the rotor was pointing..I actually have used a drinking straw inserted in #1 and rocked the engine to make sure I was as close to TDC as possible.

You know, when we run into problems after we've worked on something we need to double, triple check what we've done. I actually did a port job on a friends old ford, put it back together and...to make it short (chevy minded) I put all the plug wires in a clockwise rotation on the dist. it ran like poop, when the light came on, I finally realized the at least old fords the rotator turned counter clockwise. Duh.

Just trying to help here. Seems like thoughs with Opti experience agree that it can't be installed 180 out....but God, I'd have to check it just to be 100% positive, since you've put in so many new parts. BTW, is this a new or rebuilt Opti?

 

I am with rick on this one.... I wonder if the opti was installed 180 out... I know that's impossible with Gen II optis, but I think it can be done with Gen I (I will have to search to confirm my fuzzy memory).

I agree, drop the exhaust, prove us all wrong!!!

I guess it is possible, but if the cats are SO clogged, then would they rattle? I mean, they would have to melt into a plug of goo to do that... it would be exceptionally rare.

 

It would be rare for that to happen, IMO. As you know with these cars, anything is possible.

RetroTA, I see where you mentioin you have steady fuel pressure, signal to the injectors, spark, but didn't see where you confirmed getting air. As Rick stated, make sure your in time and the wires are on the right cylinders.

 

I don't recall off hand if the cats on the no start cars did rattle and will be the first to admit it is a rare condition but made the suggestion since this seems like an unusual circumstance and it is something to try that costs nothing. The washed cylinders phenomenon is a similarly rare occurance, but sometimes happens to add to the confusion. Often the original problem has already been fixed (no fuel, spark etc.) but lost compression keeps the engine from starting, again it costs nothing to try. Lots of other great suggestions flying too, hang in there Retro, you'll get it to light yet!

 

sounds like mixed up plug wires.. but drop the exhaust and take a peek.. its easy on the LT1 cars.. three bolts at each maniold, two botlts at two different handers along the way back and two bolts at the mufflers (one each side) and the thing drops as one whole unit!!

after that I would recommend a trip to the local chevy dealer on a flatbed and let them worry about diagnostics..

 

One of the cats pulled off my car had a huge chunk rattling around in there. It was too big to fit to out in either direction. I'll have to take some pics if I can get it out. Good luck fixing whatever is wrong.

 

Bogus - I KNOW you're going to hate this one, but I'm posting it for info. My 200,000 beater 1993 Camaro melted the cat into a big glass marble last week. Yes, it definitly rattles, but it still runs just fine. Lost a mpg or two, but no other big change. That being said, Yeah, I agree one could still cause a no start condition, it's just not a very common occurance. And yes, I'm going to fix it, the rattle's driving me nuts! . I know where a fairly low mile one is in a junkyard, just can't get there till this weekend.

 

Thanks All! Any input you offer is appriciated. Will keep Ya posted.

 

they don't last forever! And you are making effort to fix it... so be it!

 

It would be easier to get a Gen II opti 180* out, than a Gen I. A Gen I would literally have to be beat on, to be 180* out.

 

If all the new parts are installed properly, my guess would be ECM problem.

 

Dropped exhaust, No start. I swapped my ECM from a car that
runs and no start? Had a Chevy mechanic check it out and his
best guess is a defective MSD Opti! He said at the dealer thats
where he would start. Is there a way I can check the timing
of the Cam/Crank while I have it apart? Im thinking I can check
the solid spline on the Opti drive pin to the arrow on the crank hub?
Both at noon on a factory LT1?

 

Wow, that will be bad news if it turns out to be the problem, not the first post indicating there may be problems. No doubt DYNASPARK wil smile! I would sure have reservations at this point. Keep us informed and good luck Retro.

 

Will Do, Top Tech