Strippertech
Registered Member
And I did swap over all of the tbi to the vortec
CK5
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TBI egr chip
- Thread starter Strippertech
- Start date
gmbellew
Registered Member
did you swap the TBI and it's sensors to the vortec engine intake manifold, and are using the TBI coolant temp sensor and O2 sensor? if so, you just need some tuner help and potentially more fuel pressure.
Strippertech
Registered Member
Yes that’s all stock parts.
gmbellew
Registered Member
then you need a tuner to burn a new PROM or something like EBL Flash II and do it yourself.
Two other Vortec quirks come to mind.
What intake did you end up running? I know there were some Vortec adapting intakes made that had a port mismatch. It's been years, but never know.
Another is the thermostat bypass. If the Jimmy doesn't have a valve on the heater core inlet, not a problem (I think that was only Suburbans...could be wrong), but if there is, need to run a bypass as GM did. The bypass isn't going to affect what you mention as issues, but something to consider if you haven't.
What intake did you end up running? I know there were some Vortec adapting intakes made that had a port mismatch. It's been years, but never know.
Another is the thermostat bypass. If the Jimmy doesn't have a valve on the heater core inlet, not a problem (I think that was only Suburbans...could be wrong), but if there is, need to run a bypass as GM did. The bypass isn't going to affect what you mention as issues, but something to consider if you haven't.
Sometimes even stock TBI engines benefit from a little more fuel pressure. You're sort of increasing the flow rating (lbs/hr), but also the spray pattern. Definitely measure what you have to start. The pump could be old and the regulator spring could also have weakened.
I am sorry but someone has to say it.
Why go backwards with TBI on a vortec engine?
Vortec is more power, smoother, better fuel economy and easier to adjust to changes.
I understand if you went carburetor because you didn't want electronics, but you still have electronics with TBI.
Why go backwards with TBI on a vortec engine?
Vortec is more power, smoother, better fuel economy and easier to adjust to changes.
I understand if you went carburetor because you didn't want electronics, but you still have electronics with TBI.
To be fair, never driven a Vortec truck, so smoother idle could be a benefit. Sequential injections benefit is apparently all on the low end of the RPM scale, so I'd guess it possible to feel that. But in terms of power, the L31 over LO5 is almost all due to the heads, roller cam, and half a point in compression.
LO5 is 210hp on a good day, while the L31 is 255? 25hp for the Vortec heads in any testing you'll see, leaving 20 for a roller cam and compression bump. I honestly don't think there is much HP left on the table from discarding the Vortecs injection setup. Which to be honest, seemed fairly problematic as-built compared to TBI anyway.
While there could be some loss of power with a TBI unit on the L31 long block, I wouldn't let it keep me up at night. There is a not insignificant amount of mechanical and electrical complexity with Vortec that a TBI swap eliminates.
I have both a suburban with the 350 TBI and one with the vortec 350, and although both have never given me trouble, I would not want to Frankenstein any if them, the vortec is now going in a 92 truck and it's going in complete.
It works why mess with it
If it works, great, but crank sensors fail, and the original Vortec poppet injection was failure prone enough that kits were available to get rid of it. Having a buddy that had the Vortec injector problems, it definitely happens/happened.
I can't recall any inherent TBI problems that aren't simply related to age vs. failures due to design, which can't be said for the Vortec.
From what I understand, the 88-98 trucks were the same body style. As such, almost everything would be plug and play I would expect.
The OP on the other hand, going between two body styles, would have to rewire his entire truck and STILL have to adapt things like fuse panel, PCM mounting, fuel system, emissions, and accessories to get it to work. In his case, swapping the intake and paying someone to tune the ECM is a whole lot less work, cheaper, and less likely to be problematic than the other route.
In the end he still ends up making more power with a more refined engine than he started with.
Those poppet spider units were troublesome. The updated units were much better. Not sure for how long, all the units I change never came back, excfor distributor issues. Most went longer then I was assigned to the maintenance, @10 years.
Tbi trucks, it was alternators , injectors, tbi base gaskets, and distributors.
Tbi trucks, it was alternators , injectors, tbi base gaskets, and distributors.
