88 350 TBI- rewire or carb?

[Willie_Rae]

I'm new to this forum, I have a 88 K2500 silverado with the 350 TBI. A few years ago, the motor was having trouble so a mechanic did a bunch of rigging to the TBI system. It was rigged to run, many sensors/necessary stuff is either unplugged, or rigged to run. It ran OK but it was awful on gas, not a lot of power, you could definitely tell it was not running like it should.

The motor was rebuilt not many miles ago. Bored .30 over, flat-top pistons, and supposedly a small cam but I'm not so sure if it has an aftermarket cam in it (no lope at all).

The timing was so advanced premium gas was a must and after that it could use a booster as well. I tried to set the base timing as it should be, and the motor bucks every time I spin it over, slowly stripping out the new ring gear. I have been told to swap from TBI to a Holley 600 4 barrel/HEI dizzy but I would rather spend the money and correctly wire the TBI for the reliability (cold weather starting, MPG, etc) than do the carb swap seeing all the parts and rigging necessary to do said swap.

If it would be better I am willing to carb swap but it seems to me it would be better to rewire the stock TBI and regain the reliability of the TBI system and not have lights on in the dash (pet peeve) than it would be to swap to a carburetor setup. The only reason I'm considering this is for the ease of cam choice, being the computer doesn't have to accept it so I could go as big as I wanted, no worries.

Any ideas on what causes the bucking? We set the timing and as long as the dizzy wasn't tightened down, it wouldn't buck. But when it was tightened, it started to buck and strip the gear. I need this fixed ASAP, seeing as this is my only mud/trail truck.

 

[DerekTheGreat]

Personally, I'd find a way to get the TBI system running properly. It's a major boner kill when I see someone has slapped a carb in place where a perfectly good fuel injection set up lived, especially on something that is daily driven. I know to these old timers nothing unleashes more bald eagles than slapping a carb on but you can't beat the reliability of EFI.. Where did you take it to have that done so others can avoid that same shop? Haha.

There isn't much to the system and chances are they simply disconnected or cut wires. Give us some pics of the engine bay and stuff around the TBI unit so we can see what's going on.

Well, when you set the timing how are you doing it, with a light and the spout connector unplugged? That's how it needs to be done, there is a connector which lives on the passenger side firewall, it will be tan with a black stripe.

Also, if they put a new gear on the dizzy it might not be the right one, I know with Ford stuff if you don't put the right metal combination together it will eat the gear.

 

[Willie_Rae]

After talking with my dad, he said the TBI is completely shot (everything will need to be rewired and new sensors etc.) I'll have to go with a carb sadly or spend much more money to have someone revive the TBI. To me it's just not worth the trouble of redoing it. Call me whatever you want, but I'm gonna go with what is easiest to get done and to me seems more reliable. Plus this will allow for a big cam!

Forgot to mention that the gear I mentioned is the flywheel gear, not the dizzy!

And the guy who rigged this TBI is no longer with us. He passed recently

 

[magimerlin]

Tbi is very simple.. wiring is rather simple to it to. 4 wires(2 each) to the injectors, 1 plug is tps, and 1 plug is iac. Very simple and simple wiring set up.

So 60-80 in 2 sensors. And a bit of your time to do a quick rewire, or go to the junkyard and grab a new harness and toss it in. Still cheaper then a carb set up. And with a carb set up you still need to wire in a tps sensor somehow so that the transmission gets the load percentage info so it knows when to shift.

Sent from my SAMSUNG-SM-G891A using Tapatalk

 

[DerekTheGreat]

What magi said (again). They're not complicated, it's just the old timers giving you advice are saying they are. If they didn't switch the intake out then I wouldn't be surprised if the sensors are still there, just cut & capped. Visit a junkyard, grab what you need including a spare TBI unit, rebuild that with the $20 kit & even put new injectors in it if you want. Then, no matter what the temp is outside, bump the key & go, never foul plugs or wash out cylinder walls again.