I'm not sure about this ^ issues. I do know that a mechanic got the jeep runninig great for about 5-6 days and it went back to normal stalling out and ruff idleing. how do you check these ^ possible issues?
Also, FYI - Jeep has ~100,000 miles, New Water pump, oil pump, Radiator, Distributer cap, Etc. Etc. I had an issue with the engine over heating and I finally replaced my exhaust system. The muffler was rusted out. After all that it seems to not over heat.
I would like to know more about the GM Throttle Body Injection system. It was my understanding that an injection system cost $1,500-$1,000. If there is one that is less, then I'm interested. Also, will this work on a Nuttered System? If not, then I can splice back together if need be.
Wannabejeeper asked earlier in thread, so I sent him the following PM
I didn't want to hijack the thread so I figured I would send you a pm. I used what is commonly referred to on the forum as a junkyard tbi. Essentially I put together a throttle body injection system using the parts from a gm mid 80's to early 90's 4.3L V6 engine (literally 10s of millions of them out there). I scavenged the ecm, wiring harness, throttle body, knock sensor control and some relays. I purchased a fuel pump, gm ignition module, knock sensor, speed sensor used the map sensor off my own jeep. I rebuilt the throttle body and cleaned it up, modified my distributor so the ecm could control my spark, modified the wiring harness to remove the wires not needed and shorten up those that were too long and installed everything. It runs great. I've chosen for now not to get a custom chip tuned for my engine as the run tables look pretty good and I'm happy with the performance. I followed a few how to guides on the web to put it all together. Howell sells a kit using the same throttle body, injectors, sensor and ecm, but doesn't use spark control in their kit and charges $1400 for it. I spent about $400 and have a system that controls both spark and fuel.
Howell and others make a good product and market their services. What you get from buying their kit is a single source, stickers and testing from EPA if needed (California folks have to have that) and some product service for questions during and after install.
What you don't get is a system that controls both SPARK and FUEL. Howell, for whatever reason, does not use the spark control feature in the ecm and does fuel only. If you have an aftermarket distributor and currently have issues with timing, you will have the same issues when you put on the Howell system. I venture to guess that most folks who throw on a carburetor don't go through the steps necessary to set their timing correctly, as setting timing is not simply advance at idle it involves spark over the entire power curve (which has to be coordinated with fuel delivery), something most never bother to address.
If you put together a system yourself you will use the identical items Howell uses for the ECM, wiring harness, sensors, throttle body, fuel pump, and injectors. You can, if you choose, add on a knock sensor and velocity speed sensor to give you better control, and of course you should take advantage of the ECM's ability to control spark timing which means you will add an ignition module controlled through the ECM. If you do that, you will have a better system than you would get for one third the cost from of the kit from Howell.
If you want to pursue doing a tbi install send me a pm. It isn't all that complicated and there are substantial resources already out there to guide you step by step.
First of all, Thanks to Mr. Berniebikes for all his help! the 4.3 TBI seems to be a possible route to take. There is one question that popped up while reading the 4.3 TBI conversion. If I may be rebuilding my motor in the near future, would a 4.0L head conversion be a better choice than the 4.3, or would it be much more expensive and complicated?
The 4.0 head conversion will add about 35 hp to the 4.2. While you may experience some performance gains (probably in the range of +5%) from also converting to MPFI, the conversion will require the head, intake and exhaust manifolds, bell housing if you don't have the Ax-15, Flywheel for the CPS (or alternatively fitting a CPS ont he front balancer with a conversion kit), new tank mounted fuel pump and fuel lines (to take the higher pressure required) fuel rails and associated sensors. IMO, MPFI is better since you get a measured fuel distribution to each cylinder with separate injectors. I also believe the conversion is much more involved and will require you to drop the transmission and fuel tank in addition to replacing the head, header, intake manifold, fuel lines, pump and other stuff. MPFI conversion is definitely much more expensive. You will have to weigh if the incremental gain is worth the work to you. I weighed the alternatives and thought about it for a while and decided that essentially a bolt on TBI system that would give me 90 to 95% of what MPFI would give was the best route for me. If I had been in possession of a donor 4.0 with all it's pieces, I probably would have decided differently!
Yesterday I completed the Carter Easy Fix by Terry Howe (Randy Peterson). It took me 30 minutes to complete and it worked great. I would recommend to everyone at least try if you have Carter Problems. It seems to be a temporary fix, so thanks to Mr. Berniebikes, I think I may plan on the 4.3L TBI conversion in the near future.