Is my charge temp too high?

[BlueByYou]

Hello everybody. I am hoping you guys can help me diagnose what feels like fuel cut off under higher acceleration.

I just got the car less than a month ago. My first Cobra. Some basic info.

2003 - Car is from Texas. Now in South Florida.

Gen 1 – 2.3 Whipple rebuilt with straight cut gears at about 18lbs on a 3” pulley. 600HP

Afco dual fan heat exchanger (some bent fins but nothing crazy)

IC and radiator expansion tanks

170 thermostat

When I first start the car and start driving, acceleration is peppy and strong. After about 20 or 30 mins of driving around, it feels slightly sluggish at tip in. A lot of traffic lights so a decent amount of waiting at lights. Just got an Aeroforce Interceptor and today was first drive with it connected. Engine temp was between 180 and 200. Intake temps were averaging 90 degrees. Charge temps slowly creeped up and eventually got to 150. While at that charge temp and rolling into some boost the car bucked something serious. Felt like the fuel was cutting out. As SOON as I let off the accelerator, the cars responds and will drive fine as long as I don’t get into higher boost. The car did the same thing when I first got it but I didn’t have the Interceptor to check numbers. I checked IC pump and it works. Did jumper method to test operation. Expansion tank is full of coolant. Can that charge temp cause the bucking? Once the car cools down for about 30mins, it doesn’t do it.

Could it be that IC pump is starting to fail? Can high humidity be a culprit? Any suggestions on what I can look at? Thank you for any help.

 

[01yellercobra]

90 degree inlet temps is pretty good. Although I'd guess your watching IAT1 temps. Which is the outside temp. I think you need to look at Charge Temps on the Aeroforce.

I'd be watching voltage and fuel pump duty cycle. If there isn't a wideband in the car I would get one soon.

 

[BlueByYou]

The 90 degrees was the intake air temp. The 150 was the charge temp.
What numbers should I be looking for in voltage and fuel pump duty cycle?
There is a wideband gauge but it's not hooked up. Gotta do that.

 

[olympic]

150 charge temp isn't too bad just idling around in traffic. It will drop down once you open the throttle and move some air through the engine. High charge temps can make the car feel a little sluggish though. As stated above, keep an eye on battery voltage. A weak alternator can work fine when it's cool but drop the voltage when it gets hot.

 

[olympic]

The 90 degrees was the intake air temp. The 150 was the charge temp.
What numbers should I be looking for in voltage and fuel pump duty cycle?
There is a wideband gauge but it's not hooked up. Gotta do that.

Voltage should stay well above 13v during normal driving and no lower than 12.5v under WOT. Fuel pump duty cycle ranges from 0 to 0.5 (you have to double the number to get % because there are 2 fuel pumps.) There is no ideal number, you just don't want to see the pumps maxing out.

 

[hotcobra03]

Think 40 above outside would be normal 130 driving


I would assume a quick spike would be expected when nailing it.

Who’s to say how high of a spike is normal

Have you replaced fuel filter
Another area to cause buck

Plugs. And gap of plugs

A lot to look over

 

[BlueByYou]

Think 40 above outside would be normal 130 driving


I would assume a quick spike would be expected when nailing it.

Who’s to say how high of a spike is normal

Have you replaced fuel filter
Another area to cause buck

Plugs. And gap of plugs

A lot to look over

I've had the car less than a month so I havent gotten too deep into it like the fuel filter but I can certainly check those.
Problem is when the car is cooler, it pulls hard with no bucking at all. Once temp goes up is when it starts doing it only at higher RPMs.

 

[c6zhombre]

There is a wideband gauge but it's not hooked up. Gotta do that.

Pretty much stop driving the car. If you have to drive it.....totally avoid WOT pulls until you have the WB functioning. That's the first order of business. Next, get a partial pull datalog with the wideband reading....say a 2k to 5k pull. Review the data. Be prepared to get a retune if necessary and possibly some fuel related parts if the data shows an obvious issue. Plugs and fuel filter never a bad idea to change.

You're IAT2 (charge temp) is not out of whack at all being in the 150s in south florida. By 150 the tune should be pulling multiple degrees of timing as a safety measure....and it naturally will feel sluggish. Bucking on the other hand sounds bad. If you're intercooler pump was out....you'd see 170 IAT2s very fast.

Never buy one of these car without a compression test....and even if that's good, be ready to get a retune once you purchase because there are tons of idiot tuners out there. Bad tunes and/or combination of poor fuel related parts will lead to a catastrophic engine failure.

 

[03' White Snake]

Also could be the PPRV if you are feeling a bucking during shifts or High in the RPM let off and get back on it.

 

[BlueByYou]

Pretty much stop driving the car. If you have to drive it.....totally avoid WOT pulls until you have the WB functioning. That's the first order of business. Next, get a partial pull datalog with the wideband reading....say a 2k to 5k pull. Review the data. Be prepared to get a retune if necessary and possibly some fuel related parts if the data shows an obvious issue. Plugs and fuel filter never a bad idea to change.

You're IAT2 (charge temp) is not out of whack at all being in the 150s in south florida. By 150 the tune should be pulling multiple degrees of timing as a safety measure....and it naturally will feel sluggish. Bucking on the other hand sounds bad. If you're intercooler pump was out....you'd see 170 IAT2s very fast.

Never buy one of these car without a compression test....and even if that's good, be ready to get a retune once you purchase because there are tons of idiot tuners out there. Bad tunes and/or combination of poor fuel related parts will lead to a catastrophic engine failure.

Thank you for your input.
I had thought to get it re tuned or at least checked out first to adjust if any, for South Florida altitude and humidity.
Never done any kind of data logging before so gotta learn to do that. Car came with SCT X3 tuner.
According to paperwork that came with the car, it was last dyno tuned in December of 2019 at Heidman Racing Dynamics in Houston, TX. Unfortunately, the graph doesn't show A/F.

 

[c6zhombre]

Thank you for your input.
I had thought to get it re tuned or at least checked out first to adjust if any, for South Florida altitude and humidity.
Never done any kind of data logging before so gotta learn to do that. Car came with SCT X3 tuner.
According to paperwork that came with the car, it was last dyno tuned in December of 2019 at Heidman Racing Dynamics in Houston, TX. Unfortunately, the graph doesn't show A/F.

That's actually a reputable company, so I'd think it was a safe tune when it left the shop. However, crap happens and you could have any of the before mentioned issues stated in this thread. Parts wear out and fail. That's the reason you want the WB working all day and every day to nip something in the bud. Learn the datalog process it's not too difficult. Plenty of threads on it for an sct x3. The WB and datalog should help you diagnose this pretty quickly. Post the highlights of the data once you get it and people in this forum will help you bird dog the issue. Hopefully, it's something simple like the alternator and you don't need to drop the fuel tank.

 

[BlueByYou]

Thanks for all the replies. I appreciate all the information. Turns out what I thought was a WB (not hooked up) was just a A/F gauge with no WB capability. Looks like Aeroforce sells a Wideband Air/Fuel sensor kit to hook up to the interceptor. Time to do some homework and collect some data.