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howdy, I have an 87 LG4, and I'm not really interested in playing with the CC Q-jet, I prefer fuel injection to carbs any day, and have been considering swapping a TBI harness and ECM in place of the CC q-jet parts.
Obviously because the LG4 doesn't have swirl port heads, the tune will probably be drastically different than the L03 tune, so I would probably need a chip burned, has anyone done a swap like this? I'm really looking more for drivability, and reliability more than power.
I would like your thoughts, I have some of the parts here already, in fact, I have a whole TBI 350 I can rob parts off of. again, I'm not really after performance, if I want performance, I'll drop my 5.3 in it and go.
The tune will not work fine. Been there and done that. RBobs tune he developed and includes with his EBL works very well on LG4 or similar 305s with 80s heads like 416s, 601s or 081s. The older heads need a lot more timing and fuel to make less power.
The 1987 LG4 is a 1987 peanut cam LB9 with carb induction instead of TPI. So his TBI swap will be a L03 with LB9 TPI heads. Surely this has been done before.
Tell us. How will the tunes "not work fine" manifest?
Biggest problem is advance curve followed by too little fuel. I robbed the timing advance table out of a LF3 305 that I used with my TBI swapped LE9 with 081 heads on it. That engine also ran best with 350 injectors and needed the 350 injector data, the BPWC set correctly for a 305 running 350 injectors and the VE tables tuned to correct the fueling. Finally I had to add a ton of AE to prevent the engine from falling on its face with a frequent lean backfire when the throttle was opened.
Soooooooo...How will the tunes "not work fine" manifest? Behind the wheel, I'm talking.
You're taking the parts and tune for a 170 hp, 0-4400 RPM, 5L engine, and putting them onto a ~170hp, 0-4400 RPM, 5L engine. I mean, the difference in those engines' needs must be astounding! I want to hear about all these drivability issues that are about to ensue!
Soooooooo...How will the tunes "not work fine" manifest? Behind the wheel, I'm talking.
You're taking the parts and tune for a 170 hp, 0-4400 RPM, 5L engine, and putting them onto a ~170hp, 0-4400 RPM, 5L engine. I mean, the difference in those engines' needs must be astounding! I want to hear about all these drivability issues that are about to ensue!
Difference is in the drastic difference in cylinder heads. The burn rate and fueling needed are drastically different. The engine will surge, run lean, no low-end torque and in general run terribly until it is tuned. Same thing happens when you try to run a smog era 350 under the 350 TBI system in a truck as well. I tuned one locally years ago in a 1990 R1500 Suburban that had a basic Goodwrench smog era 350 put in place of the L05. It drove horribly on the stock TBI tuning.
The cylinder heads would case massive differences in mixture quality, I was planning on a tune either way, but hoping someone had something off the shelf that I could drop into a stock computer cheap, I'd rather not buy an EBL for the car, as future plans will probably be some other engine requiring a more advanced ECM, most likely an LS, but I haven't made much progress with that plan yet.
The engine will surge, run lean, no low-end torque and in general run terribly until it is tuned.
Cool thanks for finally answering the question. Now I know where you're coming from, and that it's BS. The engine will run fine. The difference between the two is meaningless as it relates to the air/fuel delivery systems. I have done what the OP is proposing (and I've done way, way "worse"), on a 350 APU. No surging. No "no low end tq", didn't run lean, and it generally ran pretty good. "pretty good"= as good as the carb, but with a brainless starting procedure.
Originally Posted by Fast355
The burn rate and fueling needed are drastically different.
Hyperbole. "Drastically", huh? Drastically? Those TBI 170 hp engines must get some drastically better fuel economy than the other 170 hp engines! It's the 50 mpg cylinder head!! Uh oh...I can already hear the van-economy stories coming.
You sound like the tools on the Subie forums; "You installed a oil catch can w/o a TUNE!? You need a tune!" "Turbo-back? You need a tune!" "Air filter? You need a tone!! It'll never work!!" It'll work.
OP, go for it. It'll work, and work fine. Could you tune it to be better? Of course -you can tune stock to be better, but it'll WORK, just fine.
Last edited by Tom 400 CFI; 05-08-2024 at 09:39 AM.
Cool thanks for finally answering the question. Now I know where you're coming from, and that it's BS. The engine will run fine. The difference between the two is meaningless as it relates to the air/fuel delivery systems. I have done what the OP is proposing (and I've done way, way "worse"), on a 350 APU. No surging. No "no low end tq", didn't run lean, and it generally ran pretty good. "pretty good"= as good as the carb, but with a brainless starting procedure.
Hyperbole. "Drastically", huh? Drastically? Those TBI 170 hp engines must get some drastically better fuel economy than the other 170 hp engines! It's the 50 mpg cylinder head!! Uh oh...I can already hear the van-economy stories coming.
You sound like the tools on the Subie forums; "You installed a oil catch can w/o a TUNE!? You need a tune!" "Turbo-back? You need a tune!" "Air filter? You need a tone!! It'll never work!!" It'll work.
OP, go for it. It'll work, and work fine. Could you tune it to be better? Of course -you can tune stock to be better, but it'll WORK, just fine.
It will not work just fine despite what you claim. I have had to tune every TBI setup not running swirl ports so that it would run 1/2 way decent. They are more drivable setting the initial timing to 8-10* rather than TDC and bumping the fuel pressure up to ~14-16 psi, but they are still not correct.
"Had to tune" is just as subjective as "it works fine". Nothing wrong with bumping base timing and adding some FP, if it gets acceptable results, and that will -if it's even needed. I mean, I got a 400CID to run low 13's on a stock 170hp 305 tune/ECM. This swap will work.
Just b/c you couldn't do it, doesn't mean that it won't work. It'll work.
Ive seen L31s, L05s, and L98s running TBI on the factory L03 tune and seemingly they ran ok with bumps in timing and FP. Im sure a tune would help you but inot entirely necessary by any means
"Had to tune" is just as subjective as "it works fine". Nothing wrong with bumping base timing and adding some FP, if it gets acceptable results, and that will -if it's even needed. I mean, I got a 400CID to run low 13's on a stock 170hp 305 tune/ECM. This swap will work.
Just b/c you couldn't do it, doesn't mean that it won't work. It'll work.
Personally I cannot stand driving things that are obviously out of tune. The fuel trims will help mask tuning issues to a small extent, but having an engine that has lean or rich flat spots, a surging idle, runs excessively rich or lean on a cold start in open loop, etc is not something I want to experience from an EFI vehicle. If I wanted that kind of drivability I would put a carburetor on it.
Ive seen L31s, L05s, and L98s running TBI on the factory L03 tune and seemingly they ran ok with bumps in timing and FP. Im sure a tune would help you but inot entirely necessary by any means
I have run a TPI Vortec head 383 on a stock 1995 L05 350 TBI tune. It fired right up, ran and drove quite well once it warmed up and went into closed loop, but it was far from running right.
years ago,i got engine from '88 caprice: LG4 with quadrajet and #187 swirl port heads-87 LG4 is not swirl port ?
The 87 I had came with 081s, a roller cam and had a flat top piston short block. It also came with the somewhat common early roller block issue of having a small water jacket crack in the lifter valley area.
Personally I cannot stand driving things that are obviously out of tune....but having an engine that has lean or rich flat spots, a surging idle, runs excessively rich or lean on a cold start in open loop, etc is not something I want to experience from an EFI vehicle. If I wanted that kind of drivability I would put a carburetor on it.
Same here. This made-up story sound terrible!
What's that got to do with the price of bread? Ditto on the Vortec TPI story. Saaaaay Whaaa? Hey LOOK!!....a SQUIRREL!!
What's that got to do with the price of bread? Ditto on the Vortec TPI story. Saaaaay Whaaa? Hey LOOK!!....a SQUIRREL!!
It is not a made up story by any means. I put the TBI setup on a 305 I built using 081 heads and it ran like poop. Advanced the timing 6-10* and put 350 injectors in it. Ran better but did not run right until the ECM was tuned. RBob put TBI on his LG4 Elcamino and tuned a file for it when testing the EBL. His non-swirl port head calibration for that LG4 that he actually includes as a base tune file with the system is very different than a swirl port head. It actually ran said engine I built very well with minimal changes.
You really think you know it all and seriously do not. the TBI PCM run TPI is a perfect example of it will run down the road but was far from being in a good state of tune.
There are guys that have swapped 350s in place of 4.3Ls and driven them down the road with the stock 4.3L V6 ECM a few even with the stock 4.3L injectors in place. Does not mean that 350 is even close to running right either.
Had to go back into data from 2 decades ago on my ancient Dell laptop that I have had since 2004. This is how bad the fueling can be off using non-swirl port heads on a swirl port head based tune. This was a TBI system from a 350 on a stock LE9 305 bored 0.040" over, stock compression ratio flat tops to replace the OE flat top pistons in that engine and the factory 929' spec 194/203 cam with 081 heads in place of the 601s using a 305 chip with the timing bumped up a bit. I went with the 081 heads because they had the bolt holes to run the later serpentine setup. The system was hitting both upper and lower BLM limits on fuel trim adjustment. With the 305 injectors and 305 chip it would not even pull itself down the street it was so lean at lower rpm under throttle. The only time it ran well was in power enrichment on the stock 305 chip and injectors, the rest of the time it was lean running, backfiring, surging disaster that liked to stall often.
Blah, blah, blah...irrelevant blah.......It never ends. A broken, skipping record of bullsh!t.
Originally Posted by Fast355
You really think you know it all and seriously do not.
Right back atcha buddy! The only difference here? While I DON'T "know everything", I know that this CAN be done, b/c I've done it. You simply cry that it "can't" b/c ya can't see the forest for the trees. Ya got your head so far up a van's azz, worried about BLM, INT, fuel trims, timing curves....on two 170hp 5.0L turds!!! They're just old dog crap engines, it'll work "better than good enough" for the OP, and better than the carb.
OP asked if it'd work. It'll work, and do so w/out any of the BFS drivability issues that you claimed from other, irrelevant, convoluted, made up, cherry picked stories.
OP, It'll work.
Last edited by Tom 400 CFI; 05-09-2024 at 10:05 AM.
Blah, blah, blah...irrelevant blah.......It never ends. A broken, skipping record of bullsh!t.
Right back atcha buddy! The only difference here? While I DON'T "know everything", I know that this CAN be done, b/c I've done it. You simply cry that it "can't" b/c ya can't see the forest for the trees. Ya got your head so far up a van's azz, worried about BLM, INT, fuel trims, timing curves....on two 170hp 5.0L turds!!! They're just old dog crap engines, it'll work "better than good enough" for the OP, and better than the carb.
OP asked if it'd work. It'll work, and do so w/out any of the BFS drivability issues that you claimed from other, irrelevant, convoluted, made up, cherry picked stories.
OP, It'll work.
When he gets it together and it runs like crap, I will tell you that I told you so and offer tuning help to make it right. I am not cherry picking anything however you are with your sole crossfire 400 example that you claim ran so well. The old Goodwrench smog era 350 ran the same way under a TBI system as my old 305 ran. It ran about well enough to know that it was not happy running. I fixed that one too. I have fixed enough of these tuning them over the years I know what works and does not work well.
I also find it funny, that old turd made over 200 whp and 270 wtq after tuning it. Stock tune it made 178 whp and like 240 wtq. The torque curve was much smoother and it was no longer so lean under load that it had obvious seat of the pants drivability issues.
TBI has a reputation for being finicky with engine changes, which it very much is and that all revolves around the tuning being wrong. Guys get fed up with the drivability issues and dump the TBI for a carb. I see it all the time in the GMT400 world.
Gentleman play nice. The truth is probably in the middle and each opinion is just at the opposite end of what one is willing to tolerate. That part is subjective in nature, so to the OP, you'll probably have something that runs, but is not perfect. How far away from perfect is it? Probably somewhere in between both extremes.
Gentleman play nice. The truth is probably in the middle and each opinion is just at the opposite end of what one is willing to tolerate. That part is subjective in nature, so to the OP, you'll probably have something that runs, but is not perfect. How far away from perfect is it? Probably somewhere in between both extremes.
Didn't you put a L31 or LT1 cam in your L03 years ago on the stock chip?
.
Last edited by ShiftyCapone; 05-09-2024 at 01:40 PM.
Didn't you put a L31 or LT1 cam in your L03 years ago on the stock chip?
.
I did. 081 heads and an LT1 cam. Car idled and was driveable but ran like poo. I scrapped the combo before I bought the EBL stuff. With the stock cam I bet it would have been bareable, but not optimal. Probably close what OP will experience
I did. 081 heads and an LT1 cam. Car idled and was driveable but ran like poo. I scrapped the combo before I bought the EBL stuff. With the stock cam I bet it would have been bareable, but not optimal. Probably close what OP will experience
Which is my whole point. Runs well enough to drive around but also tell you it is way out of tune. Weren't you also the one that wrote CHP magazine on their Mission 305 build? I remember someone from this TBI boards questions getting answered by CHP and they admitted it ran absolutely terrible that is until the next update where IIRC Tom Bishop at Turbo City actually tuned it with 350 injectors in it and more fuel pressure. Traxion Performance also built a L03 car in the late 80s using L98 heads and a custom ground cam on the stock L03 bottom end. They had to customize a prom chip to run that combination correctly as well. I think I still have the magazine article writeups on that as well.
The truth is probably in the middle and each opinion is just at the opposite end of what one is willing to tolerate. That part is subjective in nature, so to the OP, you'll probably have something that runs, but is not perfect. How far away from perfect is it? Probably somewhere in between both extremes.
EXACTLY.
Someone, "gets it". Note that my point wasn't "perfect". It was...."It will work". Nothing is perfect...OEM tune ain't perfect.
Traxion Performance also built a L03 car in the late 80s using L98 heads and a custom ground cam on the stock L03 bottom end. They had to customize a prom chip to run that combination correctly as well. I think I still have the magazine article writeups on that as well.
TBI has a reputation for being finicky with engine changes,
Must be like those Subaru's with oil catch cans I mentioned earlier, eh? They "need" tunes too.
I sensed some sarcasm about my 400. Do you want to talk about that engine and it's drivability? I'm happy to share how some metrics with you. I know it wasn't perfect.....I think that you lost the forest for the trees on that one, too, though. The point about the 400 wasn't that it was a model of driveability perfection (though it was damned awesome). The point was that if you can take that thing, and migrate 95 CID from stock, pick up 20mph in the 1/4 with associated mods to do that, with no ECM tune....and get fantastic drivability to boot.....THEN, it becomes obvious that you can swap from one 5L, 170 horse engine, to another, 5L 170 horse engine, and it will work. If the OP needs to bump pressure and base timing, do it. Tell the OP that so he can move forward.
Last edited by Tom 400 CFI; 05-09-2024 at 05:02 PM.
Which is my whole point. Runs well enough to drive around but also tell you it is way out of tune. Weren't you also the one that wrote CHP magazine on their Mission 305 build? I remember someone from this TBI boards questions getting answered by CHP and they admitted it ran absolutely terrible that is until the next update where IIRC Tom Bishop at Turbo City actually tuned it with 350 injectors in it and more fuel pressure. Traxion Performance also built a L03 car in the late 80s using L98 heads and a custom ground cam on the stock L03 bottom end. They had to customize a prom chip to run that combination correctly as well. I think I still have the magazine article writeups on that as well.
Wow, your memory is better than mine . That indeed was me who pushed back. It was so long ago I'm going from memory which is dangerous. Since OP is retaining the stock cam it will be less optimal than if he had a cam as well but we all know how limited the stock tunes are on these cars . I think we're all saying the same thing .
Wow, your memory is better than mine . That indeed was me who pushed back. It was so long ago I'm going from memory which is dangerous. Since OP is retaining the stock cam it will be less optimal than if he had a cam as well but we all know how limited the stock tunes are on these cars . I think we're all saying the same thing .
The C3 ECMs also do not store any long term fuel trim data after the key is cycled unlike the P4s. With the fueling being as off as the BLM data shows it to be it takes a while for the slow processor speed of the C3 to adjust everytime it gets to the various BLM cells. The P4s such as the 7427' are much better in that regard and tolerate changes better on stock tuning. I could tell the difference with the P4 right away compared to the old C3 even before I tuned the P4.
Gentleman play nice. The truth is probably in the middle and each opinion is just at the opposite end of what one is willing to tolerate. That part is subjective in nature, so to the OP, you'll probably have something that runs, but is not perfect. How far away from perfect is it? Probably somewhere in between both extremes.
yeah, it's what I was more or less expecting, I've honestly ignored most of the bickering here, because you're right, it's very subjective.
for now, I'm trying to get the stock carb stuff working more or less like stock. At this point, I'm not going to spend the money for an EBL, as good as a part that it is, I would rather put the money towards the 5.3 I have in the garage.
yeah, it's what I was more or less expecting, I've honestly ignored most of the bickering here, because you're right, it's very subjective.
for now, I'm trying to get the stock carb stuff working more or less like stock. At this point, I'm not going to spend the money for an EBL, as good as a part that it is, I would rather put the money towards the 5.3 I have in the garage.
Honestly unless you need to pass an emissions test. You would be time and money ahead grabbing a decent non CCC Q-Jet to put a carb kit into and mechanical HEI from a late 70s or early 80s truck or van. Good replacement electronics are nearly unobtainable for the CCC Q-Jet stuff now, the setup tools for the carbs have been discontinued for decades and rarely obtainable and it will drive you crazy trying to make one run correctly without being able to scan the OBD1 computers datastream. With a 5.3L swap in the plans, to me it would make the most sense to just pull off what is not working well, simplify it to a basic non-computetized setup and spend minimal money on it. I converted an early 80s Elcamino to the mechanical stuff about 10 years ago because the previous owner had already mostly desmogged it and hacked up the CCC harness. The carb was junk and the distributor was not advancing the timing. The car itself was pretty much a rust bucket and owner just needed a year or two more out of it to get to and from work. It ran a lot better replacing the failed CCC components and hacked up CCC setup with the mechanical equivalent that were properly functioning. Had a lot more power with an actual advance curve and nearly doubled the fuel mileage compared to the CCC Q-Jet running in full rich mode all the time.
05-07-2024, 07:01 AM
It's the 50 mpg cylinder head!! 
Uh oh...I can already hear the van-economy stories coming. 
