Sounds like the DIY smoke machine is the way to go. A perfect side project. I am sure I will find a few lines that will need to be replaced on this 92. The PO hold me they replaced the Opti, well that was 1/2 true they replaced the top cover. The picture explains why I got the famous H64. Interestingly enough the new cap was being hit by the rotor. Not sure if the bearing went bad as well or wasn't seated 100% to the base. Either way it's getting replaced. The PO also said they changed the water pump, also kind of true. They didn't but the $5 gaskets and used RVT, also didn't do a good job torquing the bolts. The one bolt was pretty much finger tight. A blessing the Opti code happened. I would have had a major coolant leak in short order.

 

Mac, I agree ,I ran a carfax on my c6. Only showed maintenance visits. Did not show any of the major repairs it had.. More worrisome, it didn't mention ant of THE FOUR ACCIDENTS i had. Even though the frame was never damaged,they were accidents and should be reported. CARFAX is a FRAUD. You cannot rule out problematic histories 100% It only helps if something happens to be mentioned.

 

I would not throw away that opti. I can be corrected by the experts but that looks like an original mitisibusi sensor. You would be better off sending that to the optidoctor to be rebuilt. If you really want one from China I think the optidoctor will buy that for $80.00. Dan

 

You can send him pictures at:
optisparksolutions@gmail.com to see what he says. His name is Brad. Dan

 

Been following this thread. The real story here is that this Vette has been rescued by the right guy.
What an interesting thread.
Looking forward to some pictures of the car.

 

 

The new Opti is in with the new plugs and wires. She's fired up like a champ, all the codes are gone for now. Life is good! Got the new coolant in after two water flushes just in time before the temperature dropped into the teen's. Now I need a few good days of rain to clear the roads and take it out for a drive.

 

I tried emailing Dan, no response. I am happy to sell the old Opti and if it keeps a C4 on the road great. Better than throwing it out. Maybe he's busy with the holidays.

 

Good luck with your adventure of owning a C4 hope nothing else shows up. And when you have spare time maybe you can get my Vette running again.
Dave 2

 

Thank you! Your's will get fixed. Tonights task was fixing a broken antenna mast cable. The suggestion to go through the license plate holder to the taillights is a great suggestion. I had the motor out, removed the broken cable and back together in 45 mins. No need to pull the tire. I was listening to the radio while I cleaned up. It's the recommended way to do it for a mast replacement. I will say one key to getting the old mast out is a quick sharp tug. Don't pull hard with even pressure it will just bend the bracket.

 

Question for the group, well two actually.

1. The bolster switches didn't work both Passenger and Driver side. I had the seat base off to work on something else (see question #2) and I figured what the heck. I saw a Youtube that they are easy to clean. I pulled both and they both had heavily oxidized copper contacts. Very green, I cleaned them off and everything works fine now. Any ideas while they would get so oxidized? Great zero $ fix, just time and a few curse words getting the seat base latch over the plastic retainer.

2. I fixed the lumbar air pump diaphragm with the bike inner tube trick, another zero $ fix. Easy to do. Question do you really feel the lumber air bags pump up or is this a gimmick? Either way I have to look into it more, air is going in just not pressuring. Not sure if it is a bad release valve or blown air bladders.

Thank you for reading, I am curious about why the switches would get like they did.

 

I think it's fairly common for the switches to get corroded. Did this same cleanup on my son's 1990 with inoperable controls and the switch internals looked like this:



My thinking about cause is that failed weatherstripping allowed for excessive water incursion. Also, the fact that they were gummed up suggests that maybe the initially had some dieletric grease coating in there as well?

 

Thank you, I guess its a common issue, 30+ years. I also have a small amount of parasitic battery draw, after cleaning these switches I wonder if it will stop. I know they are hot switches and don't need the key in the ignition to work. I will take the battery off the tender for a week and see. I also have a driver side door hatch switch that doesn't work. I have seen a few different threads for the issue. My center console and Passenger side switches work find, so I think it is the switch itself but I will get a meter on it and see what nets out. On to the next fixing adventure. Side note I did get the car out today, the road are clear of salt after the recent rain. All my fixes seem to have work. I have good power and no codes. I feel a little flutter at a constant speed but my feeling is that is injector related from sitting so long and not running. I will have to watch and I get more miles under my belt.

My biggest monster is the reverse gear which I think has failed. Not sure I am ready to tackle that monster alone. Bill Z. has confirmed what I believe is to be true the gear is gone. Maybe happened when the PO trailered it. On the ride home and I didn't know this the PO x2 had hose clamped the reverse lock out in the up position. I tapped reverse at about 60 just for a quick second and it might have done it in. If that's all it took I think the trans had a flaw and it is bitter sweet I found it but good that I did now before I am out and about and have it fail. The next fixing mountain awaits.....

 

I was messing around with the transmission tonight. The PO had used a hose clamp to lock up the reverse lock out. I took off the hose clamp and the collar is very hard to move it is stiff and drags. A smooth pull but a hard pull like you are dragging something though grease. How easy is this collar supposed to move? I took the shift **** off and confirmed the rod does lift. I can get it into the position reserve should engage etc. Is that rod once the collar is off, supposed to be able to be pulled out. I am trying to figure out what is going on here. I am sure it's nothing to do with the reverse gear issue. Would the wrong kind of transmission fluid cause something like that to happen. I assume the box is separated from the main transmission housing, is it dry in there?

If anyone has any ideas I would be happy to listen.

Thank you

 

There have also been posts about CARFAX errors in the other direction. I can't give a specific but it was something about the original owner still had the car, it showed 2 accidents and the owner knew damn well they had not happened. A CARFAX report is OK as a cross-reference, using it as one of several sources, but don't rely on it as gospel.

 

Good evening All,

I have a question for the group. I have been working on an issue. I can't get the car over 4500 rpm. I can slowly work my way up to about 4500 then it slowly starves out to about 2500rpm. I will get a CEL, if I let off the gas and let the car recover the CEL goes off and I can repeat the process. When I got home I checked the codes and I got 4: H55 Lean Fuel Monitor. I have a fuel pressure gauge on the way. In the mean time I checked what I could. The FBR vacuum line is ok, holds vacuum. The PO had replaced the fuel pump and filter before I got the car. My question is on the injectors. Being the car sat for 7 years I know all kinds of junk can get in the tips. I did the ohms test and I do get a differential more then 0.5 ohms between them all. Attached is a picture of the results I am leaning to replacing them just because the car had sat for so long and she won't open up. If the fuel pressure checks out ok, would logic be it could be the injectors or a restricted cat? The car is better the colder it is, the more it heats up the more the issue shows. After a good heat soak I can only get up to 4000 rpm then less and less. I think it goes into a limp mode after a while and I can only get 2000 - 2500rpm and after it cools everything back to like before. I had changed the Opti with a Petris and its not been out in any moisture or rain. I did get an H15 code but I am pretty sure that was from when it stalled out as I was playing around after I couldn't get rpm. I will erase it and see if it comes back. I wanted to ask the group is that ohms reading in the normal range? I know it will not tell me the spray pattern of the injector just the general condition. I am leaning to change them just to rule out that issue and from some of the things I have read the 92 should be about 16 ohms with stock injectors. Any opinions would be helpful.
Thank you

 

This probably should have been a new thread, but since you're here....

If the car sat 7 years, I would start by draining the fuel tank and checking for crud, crap and sludge. There is a "sock" filter on the fuel pump, did PO change that? Also, if the sock has come off at some point, the inlet tube on the fuel pump can get packed with sediment. (Our '92 left us sitting under an overpass 30 miles east of Amarillo, in 102 degree heat! ) The fuel pressure gauge you said is on order. Don't just look at idle, tape it to your windshield and go for a drive, see what it says when the problem happens.

There is very good advice posted here frequently, "don't just throw parts at a problem, diagnose and pin it down".. That's true, and I agree. BUT - if it were my car, and it had been sitting 7 years, I would replace the fuel filter, the pump and the sock, and the gas, cleaning the tank in the process, just as a "good idea" regardless.

To clarify, go ahead and do your fuel pressure test first, to establish that info. But KNOWING your fuel delivery TO the engine is reliable will help your peace of mind. Let us know what you find.

PS - I do realize I didn't address your specific question re the injectors. Just thought the above is a real good starting spot.

 

One easy test is to let you car idle in the dark with the hood open. See if it is arcing anywhere. Then I'd check all your electrical connections. Clean them all.

 

I got the gauge a day early and I just had to use it. These are the results I got, and I know looking at the pressure loss with the car off isn't an official test but the pressure is going somewhere and I lost 10 psi in 1 hours time. My question is with this information and not being able to get the car to open up, does these lead toward an injector issue? I also checked the fuel pump sock and its easy enough to look at, it is clean and attached. Any advice is more than welcome. Other then the glowing red pre-cat syndrome is there any other good test for a clogged/restricted exhaust? The car does start in 1 -2 cranks and has good power in the low RPM range.


Thank you for the help

 

you do not have a stuck open injector.

if po “replaced” the fuel pump like he fixed the opti......

if you are leaning out (your code) you are starving for fuel. if you scanned the car, you should see the blms maxed at 160. This means the computer is adding as much extra fuel all the time by way of commanding the injectors to stay open longer. And it is still failing to keep stoich.

Can you tape the tester to the windshield (dont close hood all the way) and get the car to over 4000rpm. watch the pressure. does it fall off?

flow rates from pump may be fine at low rpm but at high rpm pump may fall on face.

brainstorming things that can affect a lean condition:
-plugged pump intake sock (been mentioned already)
-weak pump
- electrical current issue flowing to otherwise fine pump
- plugged fuel filter (if this, look inside tank....what plugged it)
- injectors having seizure at high rpms (im not knowledgeable on lt1 injectors but with predecessor L98 some multecs were garbage after exposure to ethanol, those usually show poor resistance)
- try your resistance again when engine is hot


gotta run im sure others will chime in with other ideas.