TBI 4.3 V6 - 1988 Chevy K1500

[john1320]

Anyone here own or work on these?
I have a few questions on specific areas, like air/ fuel and computer.

We just upgraded to the Edelbrock TBI mainifold and an open spacer.

Finally got it to start and idle, but you have to keep the throttle cracked a bit until she reaches temp. Gives immediate ck engine light when the idle smoothes out, right after initial start.

Please no flaming- my Tona died right after I tore the mani off my truck.

[mpgmike]

Do you know how to check for codes? That'll probably take you right to the problem. If it ran fine before, check for vacuum leaks and damaged connectors to your sensors.

Mike

[xtrempickup]

I had one the same year and same motor. Checking codes on these you need a scanner i think. +1 for vacuum leaks, those plastic lines suck also see if maybe you didnt put it back together the right way with the lines. i sold mine this year with 175K miles original motor, 2nd trans and completely stock with 4x4. still got 2K for it

[89Waredaytona]

to check codes, get a jumper/paper clip. and jump the last 2 terminals on the DLC connector under the dash. as you look at it, i believe its the 2 that are above one another to the far right. a vac leak, a mis-adjusted TPS, plugged AIS, normal GM stuff...

[john1320]

No vacuum leaks- that leaves sensor codes only. I love the divide & conquer method!
I hated the old plastic lines and front PCV feed.
Only three lines total now. (EGR/MAP/EVAP)

Crap! I forgot to mention I installed a JET AFPR before final assembly of top-end.
Can I tune with an A/F gauge, or is there a cheap in-line guage to read pressure?

[john1320]

Quote:

Originally Posted by xtrempickup I had one the same year and same motor. Checking codes on these you need a scanner i think. +1 for vacuum leaks, those plastic lines suck also see if maybe you didnt put it back together the right way with the lines. i sold mine this year with 175K miles original motor, 2nd trans and completely stock with 4x4. still got 2K for it

Mine only has one flaw- rusted out bottom-rear cab corners. (fist sized)
I cleaned em up a bit, and a local shop said companies sell weld-in pieces now.
It's an old power company truck- thus explaining the V-6 powered 4X4.
In all fairness, she is only 20-30HP shy of the 305TBI and 50-60 less than the 350.

I can see that better A/F from all my mods will up my towing ability to that of the 305. Is there a sturdier tranny, or will this one stand up to towing indefinately?
Mods- K&N filter, new 2.5" exaust with new cat and Flowmaster- side exit.
Tuned up spark and fuel, and rebuilt the TBI unit.

[black86glhs]

#1....the trans should be no problem...it can handle it. #2....I would be looking at the AFPR. Try adjusting it either way and see if it runs better. If not, it sounds like the base idle speed is not set correctly.

[xtrempickup]

Cab corners are really cheap also, I had on corner fixed before it got bad, my bed arches above the wheels started rotting this past year. The trans can take towing, I towed like 6 cars home with that truck, but uphill, its terribly underpowered and that was with a tow dolly and a daytona on the back.The motor is the solid part of that truck, thats a 4bolt main 4.3L, my father who was a mechanic for 25yrs said that motor will go indefinately and that motor was in tow trucks, whether thats true or not, i've never seen one in a tow truck in that time period

[john1320]

Awsome!
Will be tuning AFPR with a new A/F meter wedsday.

[mpgmike]

FWIW, I think stock pressure is around 12 psi at idle.

Mike

[john1320]

That's right.
Just out of curiousity, what would you do to these heads for more MPG?
Maybee nothing at all?

[john1320]

It's ALIVE!!


Drove the truck this afternoon after some tweeking on timing and fuel.
Still have more fine tuning to do Saturday with the a/f meter I picked up.

I now have quik throttle response and a cooler running temps.
As for power & tq, we won't know for a week. I plan on putting it on the dyno to see what those three mods have done. (INT, EX, SPACER)
I'm just happy knowing I can tow with confidence.
Damn it's good to be on the road again!

[john1320]

WOW!
Pulls hard now, despite those 33s!

Found bad injector, explaining some issues.

sucks they have to be so expensive...

Now back to the Dodge...

[EvilcowRoland]

Congrats man. You need to bring that monster by sometime and you can see Mark's new ride sitting in my garage.

[john1320]

Seems the newfound power and two "spirited" runs have poped a HG.
Damn that right foot!

It was running funny two weeks after we had it straight- thought it was that right side injector.

Alumiseal helped a bit, but now my oil is foamed.
I'm going to give it one more oil change since I was slow on the sealant,
maybee it will hold two more weeks...