SiberianDVM

I could use some help figuring out what is wrong with my car: stock 3.2L motor 1984 Carrera, does have cat delete and Steve Wong chip, running 93 octane supposedly ethanol free pump gas, just filled up that morning.

On the track at VIR this weekend, on 2nd run session, at about lap 5, on uphill straight at WOT, between 5000 and 5500 RPM in 4th gear, 110mph or so, car had momentary loss of power, like it was hitting the RPM limiter. Also did it in a couple of other places on the track at WOT, then it would run smooth.

Temp was good, just about 1st lower white mark. Oil pressure and levels were good. Pulled spark plugs and they looked good, nice and tan, no corrosion or pitting.

Put it back together, and final run session of the first day was about the same.

Instead of getting worse the second day, it got slightly better: still hesitated after it was hot, but not as bad. And just uphill at WOT this time. Bad gas? Semi-clogged fuel filter, fuel pump going bad? I really don't know where to start, as it runs fine under normal conditions. Any help appreciated.

theiceman

hm interesting .. this one might be a bit tough .. do you have spare coil you could put in ? If it is only when hot i would doubt its bad gas .. could be fuel related though like a pump. Tough part is to determine if its electrical or gas .. you allmost need to hook up an analyser while driving ( LM1 ) to see if it goes lean as it misfires ... ( gas ) .. or super rich ( no spark ) .
The only reason i mention the coil is because it is easy to swap out and see , ( along with the DME of course) .

SiberianDVM

It's going to be really tough to diagnose if it only happens at WOT uphill at VIR, since that is 6 hours away.

Nope, no spare coil. I'll try looking back through POs maintenance records and see when electricals were last done.

theiceman

oh one other thing .. make sure you have the 2 wire CHT sensor .. could be going out on you , especially if its the single wire .. if it is the single wire should be changed anyway and would be a good place to satrt ..

SiberianDVM

Looking at POs maintenance records (good but by no means complete); fuel filter, distributor cap and rotor was replaced about 30k miles ago. Spark plugs were replaced right before I got it, only a few k miles, but most of them were on the track. No mention of spark plug wires or coil, but spark plug wires look old. Spark plugs are Autolite!! Really?

I don't might replacing some semi-consumables like the plugs, plug wires, distributor cap and rotor, fuel fliter, maybe the coil.

Since this is a track car, should I go to a higher capacity ignition system? I want to keep in within E stock PCA rules.

Spark plug recommendations?
Spark plug wire recommendations?

theiceman

its not going to be the wires.. but sounds like it needs some of that maintanace stuff anyway ..

SARGEPUG

Did you do anything to the gas (additives, top off w/ different gas, etc) before the "better" 2nd day? Was it @ some rogue station or one you know, trust and moves a lot of premium? I filled up once w/ bad gas (93 octane / Mobil). Car sputtered off the bottom / lacked normal power and would sometimes slightly backfire between shifts, during aggressive driving. Took additives and a couple more good tanks of gas to pass, but did get progressively better during that process.

SiberianDVM

Didn't use any additives, 1st or 2nd (better) day. Didn't run enough laps to need to add gas between day 1 and 2.

On the drive up, I stopped at my normal station to fill up with "ethanol free" 93 octane. This gas is about 40 cents higher per gallon than other stations in the area charge for their E10 92 octane premium. But, it is a local chain, Greg's Gas, that just about has the local market cornered on ethanol free gasoline.

rusnak

Is there a Greg's Gas near Ron's Trannys?

It sounds like you have a fuel starvation problem. What was the fuel level at the time? You'd need a fairly full tank to cover the swirlpot, and even then, it might be emptying out faster than fuel can get back in.

SARGEPUG

I stay away from small "chains" like the plague. Also, I don't seek out ethanol free and thankfully have no issues. Even though I went to a Mobil that had bad gas. If I fill up one of the Porsches at home base, I go to a Shell that is always crowded, hence moves a lot of gas. It also moves a lot of premium. That Shell has actually knocked the Mobil down that gave me the issue. It's new, has 20 pumps, huge store, etc. Compared to the old Mobil across the street w/ 8 pumps and pathetic store. If I'm at my house out East, I go to a Mobil there that is same as the Shell at home.
Also the fact that in these times, you are going to a station that is .40 higher for premium that others, could be an issue. It's tough enough to move premium in a bad economy, but a double premium can be real trouble!

SiberianDVM

You never know who or what you are going to see at Greg's Gas.

Had a full tank. Just filled up that morning on the way to the track.

Tell me more about this swirl pot, which sounds a lot like something you would find in a French whorehouse. Is it something that I should clean, replace, or just ignore?

SiberianDVM

Greg's Gas used to be known here as Smiley Stations, as their emblem was a big yellow smiley face. They are a huge local chain. This area is very near a pipeline and 2 terminals, like less than 2 miles, so gas prices are pretty low, and people drive to this area to fill up, so they pump tons of gas. This morning regular E85 was $3.16, mid was $3.26, premium E85 was $3.46, and ethanol free 93 was $3.89.

Plus they sell fried chicken from my chicken plant.

SiberianDVM

Oh man, that thing looks like a PIA to change, but I'll put it on the list.

rusnak

I just thought of something else. There is a screen or something at the bottom of the tank that filters out gunk. It might be clogged?

You can unscrew the fuel sender and pull it up and out to get a good look inside your fuel tank. Other than that, there is a fuel check valve at the fuel pump outlet, and the fuel filter.

If your fuel pressure is good, then chances are the above items should be ok.

theiceman

it is a pita

you need a socket with a cut out in it for the wire

you can jumper out the sensor with a paper clip after it starts happening and do a few runs. if that fixes it you have your answer. if it doesn't, remove paper clip and move on.