Recommend an ECM to replace my 8747?

[EagleMark]

All that fuel line has to do is hit a hot piece of metal and POOF! Vapor lock.

You could also be on the verge of needing a fuel filter? Many times I've seen them work fine but the reduced flow would cause data to change...

Revving motor to 3000 RPM also increases fuel flow by raising voltage just a little to pump. This would circulate all excess fuel back to return and cool things off.

I think you have some sort of hot fuel issue?

[dpilot83]

You could also be on the verge of needing a fuel filter? Many times I've seen them work fine but the reduced flow would cause data to change...

Is there any way for the fuel filter to be plugged if your pressure at the back of the throttle body is staying up? I do not have my remote electrical gauge hooked up so I don't know what the fuel pressure is doing under load, but I'm also not having any problems with it not running right under load, it's just during idle. During idle, even when it dies or when there is a hard start/no start situation the fuel pressure is always good (usually about 13 PSI).

[gregs78cam]

I recently had an issue with my truck's tbi conversion. The fuel lines had gotten too close to the exhaust and it was having boiling fuel issues. It would run fine until it got warm, it would always do it, but when it did it would stumble when you got to about 30%TPS. Idle was just fine though.

The other issue I ran into recently was on a buddy's truck, where the fuel pump was not making enough pressure at any state other than idle. The thing that tipped me off was that when in closed loop it was pegging max lean.

These are just my two recent discoveries with TBI. Were your injectors replaced with the TBI rebuild? Is their power wire corroded? getting hot? not able to carry enough current? Could this be combination of issues, i.e. injectors that get flakey at low pulsewidths, such as hot idle?

A datalog might reveal some interesting trends.

[dpilot83]

I think the vapor lock theory is losing traction after today. I used it a fair amount today. One time I drove about 15 miles, stopped for 15 to 20 min to eat and then started it again and it had a tough time starting. Outside air temp was 64 degrees F (18C) at that time. Lots of cloud cover here today.

The next example was more significant I thought though. I stopped to help my wife clean the church after another 20 mile drive. When I stopped I immediately opened the good to help it cool down faster. We probably spent 15-20 min finishing the cleaning of the church. We decided to go eat afterwards so. I started my pickup to park t more out of the way in the parking lot. It started fine and I ran it for maybe 1 minute changing parking spots. I did not open the good this time because I figured it would not have warmed up much. We spent probably 30-40 minutes eating and came back to get the pickup. It barely started again and ran really rough until I got it revved to 3000 RPM.

So whatever it is, I think it's getting worse. I'm quite puzzled that twice today it appeared to break the heat related rule. So far in the past it has only done it when it was 80+ degrees outside and it had been idling awhile.

Not so today.

i need to go ahead and get everything that I need to start logging data. I'll probably just order tonight.