need some advise on TPI not running well when warm

[CMACDONALD1]

Hey guys i have a 1968 chevrolet that has a tuned port in it that i did not install but when it gets warm it starts to stumble at about 2800 RPM and progressivly worse with RPM. my last trip out with it i drove it down the hwy and when it got up to tempurature it progressivly lost power untill it finally would not even run so i pulled over to the side of the road let it cool off and away i went again. My guess is that i have a fuel pump problem as it seems to be a bit noisy at times. any help or advise would be greatly appreciated. Thanks in advance.

[mclairmo]

Computer uses many sensors to determine fuel supply and ignition advance. The coolant temp sensor may be faulty and causing problems. Or maybe an air temp sensor? A faulty knock sensor will also do the same thing. Obtain a TPI manual and troubleshoot those sensors with a volt meter or just replace them. Noisy electric fuel pumps are normal.

[dimkapdx]

Although not installed in a Chevy truck, I recently dropped a built TPI out of a Vette into a FJ40 (pics below).

Have you tried to read the codes? As an example on my truck, there were some problems, but the check engine light wasn't on. Turns out that the check engine light was improperly hooked up, and the computer spit out a LOT of codes when I read them with a scan tool. Addressing all the codes one at a time got it running just fine.

From everything you are describing, it sounds like it may be Air Temp Sensor either on the bottom of the plenum or top of manifold towards the rear (by distributor).

[tk-mpl]

If you have a data link connector, see if you can get any codes out of it. If you can read the O2 sensors see if it is leaning out when it gets hot. My guess is fuel pump also. If you have no power on accel chances are you don't have fuel pressure. If you can get a fuel pressure gauge on it to either rule it out or verify it.
Trevor.

[CMACDONALD1]

thanks guys for the help. I decided to put the truck on jack stands and have a look at the external pump that was installed and right beside the pump was the fuel filter so i got to thinking maybe I should start there and what ya know I pulled it out and put a new one in and BINGO!!! I have never had a fuel filter plug off like that before but I just thinking worst case. I'am glad it was something simple. Thanks again guys for all of your help there is a tonne of knowledge on this site. here is a pic of my truck also.

[tk-mpl]

hopefully it didn't burn the pump out. Most of the time when I have changed a fuel filter that was plugged enough to cause a driveability concern it takes the pump out. The one time it was still on the hoist and the pump most of free spun after I put the new filter one and it burned the pump out. The bad thing was I upsold the filter from a service. It still had the original eqipment stamp on it. The customer thought it was our fault and didn't want to pay for the pump. I just told them, better to happen here the on the hi-way..
Trevor.