That's where my next issue came into play. Remaining parts came in for the rad hoses and I spent my weeknights finishing the mounts for the rad shroud and getting the hose hooked up. Once I had that all done I got my timing light out and started up the truck. Radiator installed, shroud work good with the modifications and all hoses are leak free. Now to get this thing timed and test drive through the weekend before Ure!
Yeah, that didn't happen
Issue #1. I can't get the truck to idle when cold to even get it up to operating temp. After fiddling with things for a while I tested the IAC by hooking the diagnostic connector up and listening to it click. I just happened to look down into the TBI and saw that it was closed, which it should be when it is on. But then when I disconnected the cable it wouldn't open back up. Took it out of the TBI and thankfully the one from the 2.8TBI is identical and I was able to swap that in to get the truck to at least idle.
Issue #2. Even with the IAC fixed I still seemed to have a terrible idle. I could get the truck to idle cold but only if I advanced the timing to like 24* BTDC
With that in mind I started researching the TPS. I orginally removed it to see if the 2.8TBI TPS could be swapped on but when I found out it couldn't I just reinstalled it. I remembered the 2.8TBI TPS is adjustable, so I figured maybe I didn't have the one on the 4.3TBI adjusted correctly. Found one of Geoff's posts on the 4X4 site that stated the spec should be .54 volts with the throttle closed so I measured mine at a .42 volts closed and proceeded to adjust. Well the 4.3TBI TPS is not adjustable. The holes are not slotted like the 2.8TBI TPS but I removed it and filed the one hole to allow for adjustment to the .54 volts. At this point the truck was hot and it would at least run hot, granted it idled at about 1500RPM
so after adjusting the TPS I restarted it and it seemed to be running good. Got the idle down with the timing connector disconnected and set the timing at 13* BTDC as it seemed to idle best here and pulled it outside for the night to let it cool down and try it again in the morning.
Issue #3. Saturday morning came and I needed to be at the gym to coach a class by 6:30am. Jumped in the truck and started it up and it would barely run. Said screw it and started driving it thinking once it got hot it would run ok. Well my new radiator set-up works amazing! I couldn't get the truck up to operating temp for the trip and it just never had power and ran like absolute crap. When I got to the gym I read some more posts and tried a few more items, like disconnecting the EGR soleniod but alas it still wouldn't idle and then I noticed it also wouldn't rev above 3500 RPM. After coaching I babied it home and pulled out my fuel pressure gauge. Started up the truck and the pressure built up super slow and when I would step on the gas it would drop to 7PSI before the hitting what felt like a rev limiter. Ok, fuel issue. But I've already replaced 2 crappy aftermarket fuel pumps in this with a factory one (remember I have the GM pump in this for the GM tank I made) so I was really hoping it wasn't the pump again. Unhooked the line before the fuel filter and test with the gauge again and wala, steady pressure the hole time! Dang fuel filter was plugged up
Worst part was I had a replacement filter hanging in the garage that I had painted to be installed prior to the trip and just hadn't done it yet! So installed the new fuel filter and adjusted the timing again to 14* BTDC. Runs like a beast. I can't believe the power it has now! Like able to chirp the 31's power!
My only remaining issue now is a stalling issue when coming to a stop light. Happens more when it is cold. I ran the fuel tank just about empty and filled up with some Exxon Supreme 100% non ethanol fuel today and that seems to have helped so I am leaning towards the knock sensor adjusting timing on me. When I installed this motor I used the 2.8l knock sensor and doing some research tonight it looks like the 3.4l has a different part number so I ordered one to see if that helps. If not I will go back to fine tuning the timing some more but for now it will get me to Ure this weekend!
Back to the radiator. For anyone that is interested it is a 3 core all aluminum radiator from a 67 mustang. All in all I have about $300 in it with the metal for the mounts and the silicon hoses but the nice thing is if I ever need another it is available, unlike if I had a custom one made. And the capacity is much greater. Over the weekend when it was in the 60's here in NC I couldn't get it above 180* and even today I with it back in the 80's I sat in traffic due to some road closures and it never got hotter than 180ish. Used to get over 200* just sitting idling before! Real test will be this weekend I guess.
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