James94LT1

My car has a new style opti that has a few hundred if that miles on it. I installed it when I did the head cam change. I now have no spark and just replaced the ignition module, they said my old one tested bad. The new one made no differnece. So I've been trying to figure this out.

I have the Vaccum hooked up to the front of the LT4 intake for the Opti, I never properly ran the other tube to get fresh air anywhere and I capped it off. Complete shot in the dark here but could this kill an opti if it was getting no air coming in but sucked out???

Thanks for any help!!!

ericcer

So you replaced the ICM. How about the coil?

bogus

the high pressure is from the intake tube... the low pressure is from the intake hookup.

I guess it is possible that too much moisture was sucked in without being properly filtered or pulled all the way through...

James94LT1

I haven't replaced the coil, thats next, it is only a few moths old itself, but
I am not ruling it out.

There shouldn't be any way to get moisture in, that line is blocked off by a vaccum cap. Could this create some kind of vapor lock or something is what
I am wondering.

James94LT1

Anyone?!?!? Or am I the only dumb a@# that has done this? :lol:

JasonL

I think one of the local Z28 guys did the same thing, plugged the inlet hose (gosh knows why). While in theory it shouldn't kill the opti, it ran like crap until he uncapped the hose. Try uncapping it and see what happens...

John Row

Yes, you could have crunched the opti. I've heard that the vacuum is enough to colapse the distributor area. You might get by with just replacing the cap and rotor.

I think what happens is that the cap presses on the rotor till it either strips the screws or breaks the plastic and the rotor no longer spins.

Just for grins, see if it threw any codes.

Good Luck.


[Modified by John Row, 12:12 AM 11/20/2002]

merrick

It may have been condensation in the opti. Or more likely, the vacuum in the opti can cause random arcing. Low air density under vacuum reduces the insulating properties of the air.

James94LT1

Thanks guys... I am thinking the same thing. I can't believe I killed a new opti on accident! With everything that has gone on with the head/cam swap I just overlooked this part. Oh well Live and Learn Right?

I am going to take the new ICM and have it tested this friday just to make sure nothing is shorting it out causing the problem. If its good, then I'll order a new opti. Looks like I now have plans for thansgiving weekend :crazy:

It will be interesting to see the insides of this opti also.

John, I have a cable on the way so I can run scans with datamaster. Would I be able to see any codes with it even though the car won't start. Before it died I never saw a check engine light or anything.

Thanks Again Guys!

JasonL

I don't understand why you're going to order a new opti if you haven't tried unplugging the hose first. Takes minutes as opposed to hours... :confused:

James94LT1

JasonL,

I get to go home Thurday Night, I am on the road for my job right now. I am
going to forsure give that a shot first! :yesnod:

James

John Row

Yes, you can pull codes without it running. Use a paperclip to short pins 4 & 12 on the ALDL. Here's how.
www.c4vettes.com/codes.htm

It will quickly display the codes in the speedometer, so be ready with a pencil and paper. Then you can use the keys on the right side of the instrument panel to manually page through everything.


[Modified by John Row, 1:27 PM 11/20/2002]

ZR_Don

On my previous Vette, I replaced the Opti. The new one lasted about 3 months and started mis-firing and throwing codes. Turns out the New Opti went bad too. Luckily for me, the servicing dealer coverd the replacement and labor of the opti. Keep your receipts!

Hope this helps! :chevy

James94LT1

Thanks John... I'll check it out!!!

AquaMetallic94LT1

Yup, been there, done that. The face of the cap will come down on the rotor and grind it to bits. A new $200 cap and rotor will fix it.

The stock vent harness for the vented opti has a special check valve that limits the vacuum in the distributor in case the vent line gets plugged. I recommend getting the harness. Put the vent line in to the air inlet duct after the MAF (if you have one) and before the throttle body.

Lone Ranger

Also, where the vacuum line comes off the intake underneath the throttlebody, it can get a kink in the line where it has to make about a 60 - 90 degree turn right after coming off te intake. Usually a good idea to make sure it's not kinked.