Thanks for all the hard work to get answers as to what works and still is legal. Very informative to us guys in California who have to go threw smog inspection.
There is a reset for the IAC. It requires the base timing be set to 0 and then also idle speed adjusted as well. The adjustment might be on one of the GM forums. When the IAC is removed it affects the idle as that is what the IAC is mainly for, idle air control. One more thing, the EGR valve can be a big issue as the spring gets weak and starts letting exhaust gasses in at the wrong time. The hose going to the MAP sensor if old can look like swiss cheese. I hope that all helps.
Great job. I enjoyed these videos. No smog for my '89 in Texas but I still want it to run as clean as possible after I replace the 350 with a fresh long block and perform a few minor mods similar to yours. I will refer back to these videos.
I rebuilt my 1992 GMC K1500 throttle body in the past and just did it again, taking my time machining sure the regulator sits flat. Made sure perfectly clean with Berrymans carb cleaner. My truck has known to have a tachometer jump up down erratically. On first cold start the engine pulsates. The intake was redone 7 times, because the technicians were using silicone which fuel depletes leaving a big air gap. I changed to an Edelbrock but began thinking maybe the OBD1 computer did not like that. Also I did not use Fel-Pro Gaskets but GM OEM gaskets, I contacted Fel-Pro that said we do not make gaskets for this year of truck. After the last throttle body rebuild engine sounds at its best, but I know I am not out of the woods. I replaced all sensors, MAP, EGR Sensor and EGR, O2 Sensor, Both Heat Sensors, new distributor, 5 different Air Idle Control modules with all ACDelco sensors. 10 years ago had a new Cat installed but has been running extremely rich for years could have messed that up. I changed the wires with 8.1 MM and new plugs several times. I now added a fuel injector spacer and intake deck spacer, feels faster but this small pulse issue when starting, spiking tach. I did the Hypertech chip 22 years ago, ran better faster no issues then. Went back to the original Intake manifold, please help.
@@GibsonGarage tried putting the original chip in same thing. These chips use 160 thermostat, I tried a 180 no better. I began thinking bad ground added a second 6 gauge ground to the block, just a tad better. Got another new distributor forth new coil. Just keep buying parts. One of the biggest changes I discovered it had a knock sensor so after 31 years put that new in its by the starter. It’s hot here got a new 4 core aluminum radiator, first radiator was manufactured messed up put antifreeze in the oil took it out had a radiator shop test it proved it was made wrong.
I’ve gone to several mechanic shops they state they have no experience and no equipment for an obd1 computer. So I bought a by directional scanner that works on both obd1 and 2 didn’t help or show me and diag reads. I tried doing everything I know before going to ABC automotive my last shot at fixing the pulsating idle and tach spiking up and down. The owner worked for GM at the time of the designing of these trucks, but will cost money.
Here’s a video of the spiking tach. Then after it gets warm the idle goes way too low. When running better at times the idle goes to normal. I put in 3 TPI seniors adjusting the purple wire as close to 5 Vic as I could get it. Simply got the truck way better than it has been in years running so close to perfect but yet it will run just a tad.
do you have the stock fuel regulator spring in your tbi are you running with your timing at 0 because for some reason my truck wont run with my timing at 0
I have a 95 Silverado that's mostly stock except custom chip to delete EGR, 180° stat, and a exhaust cutout bypassing cat(when I'm on the track ;)) Why are you running a 160° thermostat is that what your PROM chip tuned for? Glad you got your numbers down. You could move to Texas where your truck is no longer emission tested after 24 years of age ^_^
BTW get yourself a electronic exhaust cutout I think you would enjoy it....your pickup coil on your distributor could cause the rough idle better to replace the whole distributor. Have you considered a ODB1 to USB cable to have a live display of stats / data logging.
get the 160 out a 180-195 will lower your emissions. provide better mpg and power. this isnt a carbed setup. zero reason for a 160. just shooting yourself in the foot. with the chip... if they added alot of timing then try the 180 it may rattle a bit with the 195. but also why the cold plugs? should be 44s or 45s i wouldnt run that cold of a plug unless i was spraying a 150 or 200 shot. again. shooting yourself in your own nutz with those cd plugs and 160 thermostat
hey i got 1990 k5 blazer tbi i rebuild my engine with a few up grades nothing big 3704 edelbrock intake headers 3' pipes rings and heads pretty mush stock i up graded my torque converter to a 2000 to 2400 stall..410 gears i got 35x12 15inch tires on it... have a xtreme energy cam hydraulic flat tappet 4374/444 lift 206/212 duration 112 degrees it the next step up from stock i thought it would run with my computer with out messing around with the chip but i were wrone my buddy help me build it he no more about the high performance racing stuff..this have been a nightmare for me .this is my second chip he made when i frist put the engine in with the factory chip the engine sound good but it didnt have no power like it shouild and would not idle the engine would surge up and down and cut off the frist chip it got alittle better where it did shut off but the pow and acceleration speed wasnt there i can take off from a start and get into it and when i get about 45mph or about 2000 rpm i start to lose power no fuel it gradually picks up speed slowly ..the guy that did the chip said thats a good thing because there more room to turn the fuel up but i have to change the regulator spring in the tbi so im waiting for the other chip hopefully i should be good ..i really wanted a bigger cam because i want to hear it...but i was on a budget with my money ..if i would have none i were better off with the holley sniper EFI...BY NEXT SUMMER IF EVERY GO OKAY IM GONNA GO THAT ROUTE AND PUT A BIGGER CAM IN THERE THAT WHAT I REALLY WANT IM NOT SATISFIED WITH THE SOUND AT ALL..
The 160-degree thermostat came with the hyper chip it's to avoid spark knock when changing the timing colder spark plugs seemed to help also. And the thicker aluminum radiator helps hold that temperature when the factory one isn't designed to run that cold
