ForceFed

Here is a little background on the car:
93 CYM
39,400mi
completely stock except for Pettit grounding kit

Ok, in the last month or so, the car has been burning quite a bit of oil upon cold start up. It didnt do this all summer. I changed the plugs about 3000 mi ago and the old plugs were black and had a lot of carbon buildup on them. obviously fouled. I put a new set of plugs in and it ran better for a while. Now, 3000mi later, the plugs are starting to foul again. It would seem the car is running a little bit too rich. I'm also experiencing turbo issues. When the first turbo spools up in first and second, i get no hesitation. In third gear and above once the first turbo starts spooling up and hits around 3200-3800rpm the turbo seems as if it stops spooling and the power falls on its face, until the 4500rpm switchover, then all of a sudden the car takes off. NOW, when the car is having its first turbo issue, there seems to be an almost fluttering noise coming from under the hood as if the BOV is stuck open and the air is not quite making it to the intake manifold. I know the turbo is still holding boost, but its just not making it to the motor. Very strange. This has been going on for about 2 months now. Recently, the second turbo is having issues. Seems when the 2nd turbo comes on, there is an abundance of power from 4500- about 5500 then the power falls flat on its face. Then yesterday, out of nowhere, i got on it and it hit 4500-5500 with no power but after 5500 it came back alive with the power that it is supposed to have. I'm not 100% sure, but i get the feeling that its something electrical with the turbos, but i'm lost as to why my car is burning so much oil on start up and why its running so rich. Anyone else have a similiar experience or can tell me where to start looking? This is becoming highly annoying.

Darril

ForceFed

13 views and no replies, come one guys, some of you must have an idea or suggestion.

Darril

Viper jr

Sorry, wish I could help :/

ForceFed

bump

ForceFed

help? pretty please?

silver93

regarding your plugs - make sure you determine if they are "oil" fouled or carbon fouled. Rub it on the heel or your hand. if it leaves a mark, they are oil fouled. carbon fouling will not leave a mark on your hand.

are you sure this is a turbo situation. sounds like a fuel situatiion (3K hesitation, perhaps).

i am going through a similar thing int hat around 2800-3800 rpm, with any type of load, the car falls flat on its face during acceleration (a "lean", dead spot") then goes agian.

if you think thats the case there are several things to check, like -have you changed your fuel filter lately? there are other things to look at as well.

anyway, just some thoughts

Trexthe3rd

First step, install a boost and an A/F gauge.
By completely stock I assume you are saying you do not have a down pipe. Big no-no.
Depending on the combination of readings on the gauges there could be several reasons for what you are seeing. Get them installed and post the readings so we can help further.

ForceFed

Thank you guys for the response. There is a bit of urgency on my part to remedy the situation as the Corvette forum boys and i are setting up a light to light or 0-60 between my CYM and a bone stock C4/C5, and it has to happen within the next week or so as i'm taking the car off the road for winter soon.

Darril

ForceFed

Come on guys, the clock is ticking and i need some suggestions. Obviously, i cant get a boost guage and a AF installed in time for this race with the corvette. If any of you have experienced the troubles i am having, please post your remedy/ies. Please help me and my FD make a good showing. Thanks.

Darril

SanJoRX7

I agree with the fuel filter diagnosis. If it hasn't been changed in at most 30k, do it now. Could be clogged injectors not providing enough fuel, a fuel pump on its way out, etc. If you're running rich there's really only one way to find out and that's to install a diagnostic tool (Power FC and Commander, A/F gauge). Determine what the conditions are because as I'm sure you're aware, if you treat the symptom and not the problem, you'll end up spending lots of time and money on a frustrating problem that's not fixed yet. Do a little more recon on this and the boys from the forum can help (more informed == better decision).

Flybye

The fluttering noise, well, it could be a million things. My suggesion? Start diagnosing EVERYTHING. The actuators will need to be pressure tested, the one way valves will need to be pressure testes, the solenoids will need to be ohm tested, the BOVs will need to be pressure tested, etc. The fluttering could be any of the actuators not opening properly or even a solenoid malfunctioning. You need to diagnose the entire sequential system. First thing is to make sure you dont have any leaky vacuumn hoses.

The overly rich condition could also be several thngs. A stuck fuel pressure regulator, dirty injectors causing them to stick, or even a malfunctioning ignition system not causing full combustion to take place. I would start with testing fuel pressure then checking the ignition system. It IS also possible a sensor may be malfunctioning causing the ECU to constantly run the engine rich, but if this were the case, then I'm sure you would be getting a check engine light.

ForceFed

Thanks for the suggestions SanJosRx7 and Flybye. I just got a new set of plugs to put in. You should see the old ones as they are black as night and wet as well. But its a oily wet. I'm running NGK 7's in the leading and NGK 9's in the trailing. Are the 9's too cold of a plug? I got the 9's for the summer so the engine would run a little cooler, but maybe thats too cold of a plug for the engine.

Also, whats up with my car burning a lot of oil on startup lately?

Darril

SanJoRX7

Check it out: Start small and go big. If you can positively diagnose a problem with a bit item, then you're money, but if not then what you can do is start replacing the smaller, less expensive things that have a high tendency to fail (like the oil metering pump and sending units, pieces of ****). That way not only are you eliminating them from the equation, but for an older car, you're guaranteeing some extra reliability by putting brand new parts in (bonus, yes).

If this isn't the tack you like to take, then i'd side with flybye on this...start having some of that stuff tested to rule it out (like the injectors, and the ignition). Pretty much any way you look at it, unless you have a real rotary guru like Ivan (my saviour) around, you're gonna spend some coin on getting this odd problem fixed

Good luck

migamb

First of all without a boost gauge you can't tell what is going on just because it feels like it lost or gained power does not mean it did. Your first mod on a FD should be a boost gauge. This way you can t into it at different spots and see where the trouble is. I had Turbo issues and it took me over a month to fix with a boost gauge, without it I would still have the problem. Do yourself a favor get a boost gauge it won't take you more than 2 hours to install, also get a new fuel filter as these guys have said $25 from rx7.com. After the boost gauge you will see and be able to report what is happening like only 7 psi primary as an example.