My4x4FJ40
Open 6 days a week
where in Tenn are you, I have a Tech1 GM scanner that will give you all your running data values on your sensors live feed out.
lee
lee
Chevy 350 with new TBI in FJ40 problem... (1 Viewer)
- Thread starter ledbellyhead
- Start date
This site may earn a commission from merchant affiliate
links, including eBay, Amazon, Skimlinks, and others.
I don't recognize the injector numbers and a quick search didn't turn up any info. That doesn't mean they're wrong. Maybe purchased from GM as replacements rather than original ones. 305 injectors won't deliver as much fuel as the ECM thinks, so it would run lean everywhere. When cold the ECM adds extra fuel because of poor atomization and reduces it as it warms up. That might explain why it runs worse when warm since it can't benefit from the extra fuel. BTW, with fuel injection you don't want to run it hard or wide open until certain that the fueling is ok. Too lean and the combustion temps go way up and begin to melt things.
The original broadcast code is ATKX but it doesn't matter if the chip has been replaced or reprogrammed. I'd give tbichips.com a call. HOT7747 must be their designation and they may recognize the injector p/n. It's not a bad idea to get an ALDL logging system of some sort. You'll be able to tell much more about how the engine is running and gather data to send in if new programming is eventually needed.
The original broadcast code is ATKX but it doesn't matter if the chip has been replaced or reprogrammed. I'd give tbichips.com a call. HOT7747 must be their designation and they may recognize the injector p/n. It's not a bad idea to get an ALDL logging system of some sort. You'll be able to tell much more about how the engine is running and gather data to send in if new programming is eventually needed.
- Thread starter
- #24
I'm in Lenoir City, Close to Knoxville, if your not close don't worry about it, I've never heard of Unicoi, unless that's Union County, I am thinking of building a cable and I have already downloaded the program, looks pretty neat...
I'm gonna call TBI Chips today and hopefully figure something out, I had hoped that it was a number that he serialized with and would know how he programmed it, but it appears to be a common number that he uses, it is the same on ebay where he sells them.
I've not been running it hard, it won't hardly run... Definately not been on the driveway since change. I would have expected some serious backfire if it were bad lean. I havn't heard any afterfire at all, but it does sound kind of like an old junk car that has that weird exhaust sound like it is very mild afterfire. But when warm and I stomp the throttle, it has a very vacuumed sound, but doesn't rev., I have to let off to get it to go increase and slowly bring it up to increase RPM. I guess I need to quit doing that... but I have to, to see if it has changed or gotten better.
Thanks again for everyones help !
I'm gonna call TBI Chips today and hopefully figure something out, I had hoped that it was a number that he serialized with and would know how he programmed it, but it appears to be a common number that he uses, it is the same on ebay where he sells them.
I've not been running it hard, it won't hardly run... Definately not been on the driveway since change. I would have expected some serious backfire if it were bad lean. I havn't heard any afterfire at all, but it does sound kind of like an old junk car that has that weird exhaust sound like it is very mild afterfire. But when warm and I stomp the throttle, it has a very vacuumed sound, but doesn't rev., I have to let off to get it to go increase and slowly bring it up to increase RPM. I guess I need to quit doing that... but I have to, to see if it has changed or gotten better.
Thanks again for everyones help !
- Thread starter
- #25
Got you man, looks beautiful in Unicoi from the pics, definately too far for either one of us to drive without planning a weekend trip with the wife or something... But thank you for the idea.
- Thread starter
- #26
New 350 injectors, runs a little better, but when she gets warm, same thing. I talked with Brian, he said to pull the valve covers and get the head numbers, take a vacuum reading at intake manifold, and mail the chip to him... another 50-150$... This is no simple install.
- Thread starter
- #27
Alright, just an update, I made a video of it and got Brian at TBI chips to watch it, his first comments were that the MAP was probably not reading right, he figured out that the back port line I had hooked to it, J which is where the Vacuum schematic I had from the internet had it going was reading wrong... I moved it to the intake port, not even on the TB and the thing runs like it is brand new... What a pain in the but, I owe him, he cought it right off... Thank you all for you help. This TBI kicks but compared to the old holley and quadrajets that I had...
Have you logged enough miles to to compare the TBI mpg?
- Thread starter
- #29
Just filled her up, it did take noticeably longer to get close to E, the power and reliability is already worth it compared to the carbs I had, I'll let you know what I get. I had to take some time enjoying the new engine, stomping it at every light before checking mileage. It has been an excellent learning experience.
