Need Advice From The TPI Experts

Rock Doc · 09-09-04, 09:28 PM

On my 86 vert I just installed a K&N air filter. When I take off on a full throttle start the car launches really hard to about 25 or 30 MPH then it falls flat on its face for about a second catches it breath and goes on like nothing ever happened. This did not happen until after the filter change. Any advice as what to look for will be greatly appreciated.

Thanks, Rock Doc

vetteboy86 · 09-09-04, 10:51 PM

I dont see how the air fitler could cause this. As a matter of fact I dont think it can. However how much fuel do you have in the tank? This happens to me, if the tank is below or at a 1/4 it will starve itself of fuel from the hard acceleration. I would almost bet it is a fuel delivery problem.

Craig

Rock Doc · 09-09-04, 11:01 PM

Quote:

Originally Posted by vetteboy86

I dont see how the air fitler could cause this. As a matter of fact I dont think it can. However how much fuel do you have in the tank? This happens to me, if the tank is below or at a 1/4 it will starve itself of fuel from the hard acceleration. I would almost bet it is a fuel delivery problem.

Craig

It was definetly below 1/4 of a tank!! Never would have thought of that.

Thanks, Rock Doc (Kevin)

vetteboy86 · 09-09-04, 11:05 PM

Kevin,

Glad to help you out. I have been caught with my pants down so to speak next to a mustang. I just make sure if I get into a speed contest I have at least a half a tank.

By the way great choice of a vette

Craig

vette-dude · 09-22-04, 10:34 AM

Quote:

Originally Posted by vetteboy86

I dont see how the air fitler could cause this. As a matter of fact I dont think it can. However how much fuel do you have in the tank? This happens to me, if the tank is below or at a 1/4 it will starve itself of fuel from the hard acceleration. I would almost bet it is a fuel delivery problem.

Craig

91 Vette Vert, Auto, L98, 74,000 miles, all stock. Original everything except maintenance and tune up items.

So if you have a low tank of gas (1/4 or so) would my 91 Vette buck and kick and backfire in the mufflers because it is getting low fuel volume (sounds like leaning out to me)?? I am having this problem under hard acceleration and occasionally when the AC is on and engine is at idle in gear. Am changing the fuel filter today as a start. I feel I got a full tank of bad gas from a Sh--tz station as my Silverado began acting up the same day and way (filled both same day but different grade gas). I am now down to 1/4 tank in Vette and it has started this missfiring. I added a gas water drier to the gas when it was full but it never missfired under acceleration before. Fuel Pump is not noisy and I do not have a pressure gauge to check fuel pressure. Have done a search on this problem but did find alot of info but thought I would ask the question. I have gotten a SES light before when the engine goes from cold to warm (on a cold day) but it goes out after a restart and never shows up again till the next time it is driven on a cold day. Suspect that is the 02 sensor and it will get changed also. Ignition system is fairly recent but will pull plugs and read them and take a look at Dist. This is an L98 engine. Any help, Anyone?

Randy

Edmond · 09-22-04, 01:28 PM

Randy,

Check out those plugs and wires. Also check out the distributor. All those things are pretty inexpensive to change. I would also go for the PCV valve, which is probably less than $5.00. The O2 sensor change will instantly give you better throttle response; they're not expensive, somewhere in the $25.00 neighborhood.

vette-dude · 09-22-04, 02:35 PM

Thanks Edmond, that is kinda the direction I was going to go. Figured the fuel filter and a fresh full tank of Gas first, then the 02 sensor, plugs, wires, cap, and rotor. One thing at a time till I eliminate the sporadic miss. If that don't get it, I'll Be Back as the T-man said. Randy

vetteboy86 · 09-22-04, 10:45 PM

I would find out what code you have. Yes the first thing is get the bad gas out, and get fresh. O2 sensor is good idea, but before you go crazy get the code and let us know.

Craig

Edmond · 09-22-04, 11:34 PM

And while you're at it, change the oil and put on a good filter. A lot of people are using synthetic. If you go that route, I would recommend Mobil 1. Wal Mart sells the 5 quart containers for $20.00 and use a filter such as Delco, K&N, Mobil 1 or Purolator Pure One. Doing so will increase your gas mileage.

You should also run the gas tank to as close to empty as possible. Fill up with premium and use a couple bottles of Chevron Techron cleaner. It's in a black bottle. That is the best stuff that you can get.

Vettefan87 · 09-22-04, 11:42 PM

Quote:

Originally Posted by Edmond

...You should also run the gas tank to as close to empty as possible. Fill up with premium and use a couple bottles of Chevron Techron cleaner. It's in a black bottle. That is the best stuff that you can get.

Just to add a little bit. The K&N is a lot easier to take off it has a 1 inch hex on the bottom or something like that, that you can put a socket on and easily take it off. The Chevron stuff is the only safe thing we can run with our injectors, I have heard.

Justin

Edmond · 09-22-04, 11:46 PM

Quote:

Originally Posted by Vettefan87

Just to add a little bit. The K&N is a lot easier to take off it has a 1 inch hex on the bottom or something like that, that you can put a socket on and easily take it off. The Chevron stuff is the only safe thing we can run with our injectors, I have heard.

Justin

Yeah, forgot to mention the 1" hex. They're about $10.00 here at the local auto stores. I think Summit sells them for $8.99 but you'd have to buy them in bulk to save much. You can pretty much throw the oil filter wrench out.

vetteboy86 · 09-23-04, 04:44 PM

The guy at Auto Zone told me those filters are to be changed everyother oil change. I was like if your oil is dirty enough to be changed, why wouldn't you change the filter. What dumbasses, I would never go without changing the filter.

Craig

vette-dude · 09-23-04, 05:42 PM

Well I guess I hijacked this thread and my apologies but think I found the problem. Pulled the Distributor cap and it and the rotor were toast. ( Stock Delco Alum terminal cap.) Then pulled number 1 plug. It is an AC 5. It was gapped at .062 and is suppose to be .035 according to the owners manual. I think it is the wrong plug also as the correct plug number is a FR5LS. I noticed when I took the plug out it appears to be an angle plug head in this motor. It is all original--does anyone know if this is equipped with angle plug heads? They are alum. and all the plugs look to be on an angle so it I don't think it is cross threaded. Only pulled the one till I get new plugs tomorrow. I have heard of widen the gap on the plugs but .062 is a littl much for a stock ignition coil to fire I think. Maybe .045 would be better??? The plug was firing pretty cleanly though!! Also these plugs have washers and the head does not have a tapered seat. I hope this cures the high speed miss. Will let you all know for sure.

Randy

PS: New cap will have bronze terminals.