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Old 05-31-2018, 03:06 PM   #1
Raptor0206
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Who''s the TBI master?

Whos the TBI master on here? This damn k5 I bought is giving me the blues! 1987 k5 with a 350 all stock. When I bought it it had been sitting for a long time. Prior owner swore it ran but couldn't get it to start. Anyways I bought it replaced the batter and battery cables. No fuel to the injectors so checked power at pump and found the pump to be bad. Threw in a new complete sender and fuel filter and it fired up....had a constant pop out the exhaust here and there. But ran. Got it warm and shut it off and it wouldn't restart. Acted like a dead battery or overheated starter. Next day started fine but hand a stumble. I wrote it off as bad gas. Ordered a new tank and installed that a few weeks later the old gas turned my new sender into a rusty mess but still worked. Still had a miss after that found the injectors to be dripping. Installed new injectors and fuel pressure regulater. Now ran much better but still had same issue. Then I did a tune up new plugs, wires, cap and rotor. No change. Figured it's running rich with some black smoke after you get on it. Replaced the map sensor helped a lot still got the heat soak. Last step I adjusted the timing back to 0 (brown wire unhooked) hooked it back up and runs like crap. With my timing light it was at about 30-32 degrees timing before. I noticed when I first started with the timing light I had a strong constant flash but at the end it was intermediate. Now the truck runs like crap. What would you guys go with next? New ecu? New spark control? New distrubtor? Coil? New o2? (O2 does look new) New egr? also I checked for vacuum leaks and replaced some of the lines along with the plastic lines.
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Old 06-01-2018, 06:08 PM   #2
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Re: Who''s the TBI master?

This reply is going to sound... poor. But if it were me, its what I'd be doing. I'd tally up everything it may cost to get that old 350 working good, and compare the price to an LS swap. If its half the cost, go with the LS swap. I've come to the point where I hate chasing my tail on these old worn out motors. We go round and round on my own square, friend's squares, my friend's mustangs, camaros. I'm getting to the point where its tiresome to try and fix a gutless (by today's standards) old motor that may die some other death soon enough anyway once its running well enough. And that already burns a bit of oil.

I may have a different stance if you'd owned the truck for the last 5 or 10 years and had a great idea of what kind of shape it was really in, and had already done a lot of work on it and had a real good feel for the truck. Someone who just bought one and its having engine trouble? Skip spending all that time and money on fixing up an engine that is low on power and probably low on how much life it has left anyway before it will need a rebuild. Someone else has likely already gotten the best years out of that engine. Back in the 80's and 90s. Just my .02
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Old 06-01-2018, 06:15 PM   #3
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Re: Who''s the TBI master?

Quote:
Originally Posted by bennylava View Post
This reply is going to sound... poor. But if it were me, its what I'd be doing. I'd tally up everything it may cost to get that old 350 working good, and compare the price to an LS swap. If its half the cost, go with the LS swap. I've come to the point where I hate chasing my tail on these old worn out motors. We go round and round on my own square, friend's squares, my friend's mustangs, camaros. I'm getting to the point where its tiresome to try and fix a gutless (by today's standards) old motor that may die some other death soon enough anyway once its running well enough. And that already burns a bit of oil.

I may have a different stance if you'd owned the truck for the last 5 or 10 years and had a great idea of what kind of shape it was really in, and had already done a lot of work on it and had a real good feel for the truck. Someone who just bought one and its having engine trouble? Skip spending all that time and money on fixing up an engine that is low on power and probably low on how much life it has left anyway before it will need a rebuild. Someone else has likely already gotten the best years out of that engine. Back in the 80's and 90s. Just my .02
I completely understand where you are coming from. The issue is we are doing a frame off 66 c10 build with an LS swap. This truck has a strong 350 in it that ran good for a hour lol. I could LS swap it but I want to get this motor running strong and use it while I complete the 66.
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Old 06-01-2018, 10:35 PM   #4
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Re: Who''s the TBI master?

go to

https://www.thirdgen.org/forums/tbi/
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Old 06-02-2018, 09:41 AM   #5
cadillac_al
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Re: Who''s the TBI master?

No check engine light? any codes? It might just be the ECM.
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Old 06-04-2018, 10:41 PM   #6
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Thumbs up Re: Who''s the TBI master?

I'd check the Fuel Pressure Regulator and spring if you have black smoke that's usually an indication of a faulty FPR.
Good Luck.
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Old 06-04-2018, 11:33 PM   #7
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Re: Who''s the TBI master?

Maybe change the Fuel filter again if you did not already.
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Old 06-06-2018, 10:40 PM   #8
andyh1956
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Re: Who''s the TBI master?

OK do this 1st & report back. Out on the intake manifold the ground cable & two smaller cables bolt down. Take the two smaller ground wires & cut the ring off back to good wire & install new rings. Then with everthing clean bolt all three of them down to the manifold using the SAME fastener. Use a pair of star washers in there also.
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Old 06-07-2018, 11:48 AM   #9
Bluestep
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Re: Who''s the TBI master?

Pull the distributor cap and rotor, inspect the magnet on the reluctor (right below rotor). They sometimes crack where the rivets go through. This gives a weak or intermittent spark and faulty information to the ecm, which controls the fuel injectors. You can replace it as a unit with the shaft or replace the distributor.
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Old 06-07-2018, 09:04 PM   #10
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Re: Who''s the TBI master?

Quote:
Originally Posted by Bluestep View Post
Pull the distributor cap and rotor, inspect the magnet on the reluctor (right below rotor). They sometimes crack where the rivets go through. This gives a weak or intermittent spark and faulty information to the ecm, which controls the fuel injectors. You can replace it as a unit with the shaft or replace the distributor.
This is what I'm leaning towards as well.

OP - I am having the exact same problem (runs well, occasional popping, weak/intermittent spark). I just bought a OEM distributor to replace the Chinese one that's in there, thinking it has to be something with this.

Will update once I figured it out.
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Old 06-08-2018, 07:46 AM   #11
cadillac_al
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Re: Who''s the TBI master?

The on board diagnostics can't pick up these problems? I guess it does become a guessing game.
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Old 06-08-2018, 08:19 AM   #12
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Re: Who''s the TBI master?

IMO the BEST forum member here to answer these questions is "Hatzie"

Email him or send a message, I'm sure he will post it here or contact you.
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Old 06-08-2018, 05:41 PM   #13
Jake Wade
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Re: Who''s the TBI master?

Distributors and Fuel pumps are the two main problem areas with these trucks.
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Old 06-11-2018, 04:21 PM   #14
bennylava
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Re: Who''s the TBI master?

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Originally Posted by Jake Wade View Post
Distributors and Fuel pumps are the two main problem areas with these trucks.
+1 on the fuel pumps. I've replaced both in my 87. And now, Several years later, one of them has died again. The pump that died might have 12k miles on it.

Is there some kind of "upgraded" fuel pump that won't die so easy? For a stock engine though.
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Old 06-14-2018, 08:07 AM   #15
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Re: Who''s the TBI master?

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Originally Posted by bennylava View Post
+1 on the fuel pumps. I've replaced both in my 87. And now, Several years later, one of them has died again. The pump that died might have 12k miles on it.

Is there some kind of "upgraded" fuel pump that won't die so easy? For a stock engine though.
Wonder if ethanol in the fuel now causes this or cheap Chinese parts.
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