gimpsy

Well while trying to troubleshoot a bad idle today with the engine warmed up I decided to drive down and fill up the tank with some new gas just to see if that could be the problem. When I backed out of the driveway a loud clacking noise starting coming out of the engine so I drove it right back in the garage and popped the hood. After listening I traced it down with a screwdriver to the Opti, when I put the screwdriver on the block behind the opti i just here normal noises and when I am on the plastic body of the opti I here the clacking loud and clear. I don't here it on the water pump or anything else on the front of the engine.

Has anyone had any experience with this sound and an opti? I just replaced this with a Delphi unit in Dec. and the problem I was trying to fix with replacing the unit hadn't improved so that is why the troubleshooting and I haven't driven 50 miles on the car since I changed this.

Art

Nowhere Man

behind the opti is the timing chain. that would make a clacking sound.

gimpsy

Nowhere I would agree with you but I went back out and listened again, with the screwdriver on the timing chain cover there is very faint clacking, but on the opti housing it is real loud and you can sort of feel it. I think something is hitting inside the cover no idea why it just started out of the blue like that though. The engine idle is going up and down also and struggling to idle. I will be pulling it apart tomorrow.

Art

Klondike

Since the car does run, You obviously have the Opti timed correctly. My guess would be the cap either isn't seated straight or the fresh air vent hose has a kink or pinched closed. That would allow the vacuum from the intake side of your vent to the opti to apply full manifold vacuum to it instead of just a breeze through it. Vacuum inside the opti will suck the top of the cap down to where the rotor will contact the cap contacts and can even collapse the cap and brake it. Disconnect your vent/vacuum line from the manifold side and see of the noise goes away. You might get lucky and not have to open it up again.

Nowhere Man

I have a junk opti laying around I want to take apart. But never did. So I don't know what's inside to make noise. I am impressed you were able to get a screw driver down there to listen.

Nowhere Man

That is if he has a 95-96

gimpsy

Klondike,

Gave it a look and no obstruction I pulled the hose off the manifold and started up and clack is still there. The engine had a hart time starting like the timing is starting to get off now, I hooked up my vacuum pump to the hose and it will pull a little vacuum but it drains down quick. I think something isn't right with the opti. Summit is where I purchased it and they said they would send a new one no charge so at least there is some good news with that.

And yes it is a 95 I thought it says that in my tag line but I will check why it doesn't.



Art

Klondike

I feel your pain man. I'm on my third opti myself. The 2nd one was an expensive one that wasn't worth a hoot from the start and while I chased the problem, (it can't be my brand new opti!) it got progressively worse till it finally chugged to a stop. Keep us informed as to what you find. Everybody has an Opti story.
At least they didn't install them inside the bell housing!

Nowhere Man

I replaced my original at 110k when the water pump went. The second one worked great until a coolant hose busted and washed the opti. Then that replacemt went bad and had to be replaced.

RUU

Sounds like the rotor may have come loose. Lots of people take the cap off their new opti and Locktite the rotor screws before installing.

gimpsy

This is really my third one, after I swapped my tranny out I noticed this odd little miss and had it diagnosed to the opti. I purchased a 99.00 one and installed it, I guess I got it in wrong and when I tried to start the car it wouldn't and I ruined the cheap one because I messed up the bearing. I wasn't too upset because it was the 99.00 one so I purchased the better Delphi unit because I didn't want to take the car apart again and everything was fine except for the odd miss wasn't fixed my mechanic friend said the new opti was probably bad again, I didn't buy it though. I really haven't driven it much since then and I had just purchased data master to try and see what the engine was doing to fix the miss when this came up today I think it might just be bad luck but I will know more when I take it apart. I thought I had the bad idle nailed yesterday when I found an O2 sensor that I had not installed tight in the exhaust after swapping the tranny.( it was just loose setting in the hole) My bad I guess I was in a hurry or something you live and learn with this stuff.

Art

helphos

What he said! I've heard of people having this problem within months of replacing their Opti. The cure is going in and applying a little loctite on the rotor screws. That is, take the rotor out, apply loctite to the threads and put it back in, nice and snug.

I've done it on the two that I've replaced. It's too much work to not take five minutes and cross that possible problem off the list!

auggy

Can you believe that GM was putting ancient tech in the later years of the C4 by still using a rotor and a cap. At least they did away with gapping the points. When I had to deal with a rotor and a cap, I would clean the contact points every few months and notice an improvement in performance. You can not even do that on the opti. What loctite color do you use on the rotor ? medium or high strength?

Klondike

I used the BLUE on mine, just cause I had it handy. I think the high strength RED would probably be OK too, because you really don't plan on going back in those darn things anyway. If I have to go that far, it would probably be to replace the whole thing.

gimpsy

I am getting good at pulling this apart took 1.5 hr.

The opti is bad and I need to go to the store and get a tool to open it up but it feels like the rotor came off when I hold it up side down it won't turn and when I hold it the way it sets on the engine it barely turns and bangs around in there. Oh well Summit will send me a new one and I will install I hope that this fixes all my problems with the bad idle also.

Art

Patsgarage

Which hose went bad and soaked the Opti ? I blew a lower rad hose and am trying to figure out if it could have soaked mine. Thanks.

gimpsy

I got the E torx so that I could pull the cover off and this is what I found. Honestly I have no idea how the car was running given the fact that the little arm the sends the spark out to the spark plug wires was broken completely off. At any rate the 2 screws that hold the rotor on were nice and tight so I would say it looks to me like the vacuum went up and sucked the top down onto it. How could that have happened? I was fiddling with the vacuum hoses the day before this happened, taking them off and on looking for what I was concerned was a vacuum leak, I also replaced the pcv valve and the EGR valve. I would think anything I did there could have only decreased the vacuum. The hose coming out connecting to the intake was nice and loose. I would like to avoid this happening again if I can..

Art










This one is the first picture taken when I pulled the top off remember the engine was running until the moment I turned it off to remove Opti.. I did turn the shaft when I got it off but it wouldn't turn unless I held it up like on the engine.

Nowhere Man

The bypass hose from the "T" in the upper raditor hoses to the water pump. Before that I replaced all three raditor hoses for preventative maintenance. And that hose I could not find at the time.

Bandit's C4

Dang! Internal Shrapnel...

Paul Workman

Do I see traces of coolant on the bottom of the cap???