More TBI issues

Ricky B

Ricky B

Wiiide Open
Joined
Mar 20, 2005
Location
LKN - Tha Dirty Mo (Mooresville, NC)
For those of you who were at the BDOR event you might have heard the truck but the k5 is runnin really bad off idle (tbi 350) have a hard time starting it and then after a while it will start and idle perfectly but then you put it in gear and off idle it splutters and wants to die but as soon as you get it above a certain rpm (not sure what exact rpm but its not too much) it runs perfectly fine, just doesnt like off idle throttling.

Any tips/tricks? Already did the seafoam flush.

Thanks
 
what year?

Igniton Check
condition of plugs?
condition of wires?
condition of cap and rotor?
Is it getting good blue spark at the plug?

Fuel check?
Look at the injectors are they spraying evenly?
check fuel pressure?

Are there codes?

Check map sensor with voltmeter.
check TPS with Voltmeter?

Hook up a vacum guage?
Vacuum test inadequate, go to a compression test.

If you check all these things i am sure you will find it.
 
I was sure that truck was running a Holley carb.
If it's TBI then you have some work to do.
Have you ever looked at how the spray pattern is in the throttle body? It should be a fine cone spray down into the manifold with a little throttle. Sounds like you're dripping/pouring fuel all into the intake.
If so you'll have to rebuild your injectors. Not a big deal, look at Google. Also check wires plugs , etc., as stated before. After that you can start checking for codes.
Good luck,
RQ
 
its a 85 and somebody swapped the Feul injection onto it and there are wires laying frikin everywhere so I was just happy I got it running at all in time for the Big Daddy Event, we were having some serious shorting issues that week before

(can anyone say Holy sh** Fire! Fire! Unhook the battery!)

yea . . . . apparently I can :shaking:

Actually about the spray pattern, if you look into the TB it basically pours gas out the line likes its taking a leak after watching a movie and drinking a big gulp, I figured that wasn't right but if its supposed to be a fine spray then thats the problem.

I guess we'll check out the injector rebuild then go through all the other common replacement stuff. As far as codes though I don't think I could really use those as a guide cause with the way the dang thing is frikin wired I'm surprised it works, lol.
 
if the wiring is really that screwed up, pay the money and get a tbi conversion harness from painless. it costs money, but how many gas fires can you afford?
 
laptop --> winaldl & start checking things.. find out which ecm is in there..

but cover the basics. ignition, plugs, wires,

stick a fuel pressure guage on there.. need hold a solid 10(min) to do anything. And if the engine has had any work/cams headers etc done on it you will need to do some chip tuning..
 
Yep, Check fuel pressure, filter, is the gas old?
You can rebuild those injectors. It should be a fine cone spray pattern.
Any wire splices should be soldered and shrink wrapped, NOT crimped. Howell has a wealth of info and a good product for a wiring harness also.
RQ
 
Ricky, if you decide to get a harness, I have a Howell TBI harness for sale, along with a whole bunch of other TBI stuff. I had it on my 84 truck when I ditched the carb. Very easy to wire in.
 
i heard that thing running at the show and it sounded to me like it was an ignition problem. Maybe piss poor timing or the igniton coil/module breaking down.

IIRC if your knock sensor wire is grounded, or laying against metal after the burn, it will retard the hell out of your timing and make the computer controlled timing go haywire.
 
TBI setups have to have a stored memory it takes a redicilous amoutn of starts to get it to quit but make sure ur battery does not go dead or unhook it every time u do u will have this problem I have been through it on my 87 truck
best fix ........... :driver:
 
so basically it could be one of a hundred problems . . .

stupid electrical crap :shaking:

I guess We'll just have to start goin through things one at a time and see which ones make it run better

As far as the random wiring I went through and at least got everything taped off and tight b4 the big daddy event, still needs some more lovin but for the most part the random wires have been taken care of.

I bet its injector related though cause it looks nothing like a fine spray when it comes out, that and a new feul filter will probably be the first things that I mess with.
 
greg slade said:
i heard that thing running at the show and it sounded to me like it was an ignition problem. Maybe piss poor timing or the igniton coil/module breaking down.
Click to expand...

My old roomate had an 87 Blazer with the TBI setup, and the ignition module was taking a dump and acting like that.
 
My TBI 350 acted exactly that way. I chased what I thought was electrical gremlins for a while then changed the fuel filter. Let's just say there was a little backpressure with the old filter and with the new one in place all was good again.
 
Your poor fuel stream says do the injectors FIRST. One thing at a time. This is, of course, assuming your pump is good, pressure is good, filters are clean, etc..

I've also experienced a shitty TBI ignition module.. it ran like crap across the board.
 
:stupid:
You KNOW you have weak stream fuel.
Start at the tank come forward.
1) Check pickup/pump
2) Fuel Filter
3) Injector

Then determin if you need to dive into electrical.
I have also had TBI module issues, but you KNOW you have fuel delivery issues. With todays shit for gas, a new fuel filter never hurts, so I would probably (in all honesty) do that first
 
jrraw23 said:
Yea the feul pump was just replaced so its good, .
Click to expand...

Never, ever, ever assume that the new part is good. That will bite you in the ass. (As it has with me, more than once)
 
This is one of those few cases where I'd suggest going from (very crude) efi to carb. You had a holley for sale a while back...why not use it? Far less wiring.
 
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