Trucker82

So I just got done installing a twin turbo setup. I added a 190L walbro Fuel Pump, 60lb injectors, new fuel regulator, and sent the PCM to Late Model Throttle in Milwaukee. Starting the engine and idle the engine smells a little rich. But when I floor it the engine will only rev to 3500 RPMs and sound almost like its hitting a rev limiter and my Air/fuel gauge reads a lean 10. When I drive it and floor the accelerator it acts like im only giving it 1/4 throttle. The engine idles a little funny with the RPMs going up and down from 500 to 700 when warm. Cold it idles just fine. Also, I did no cam change and most of the stock sensors were left untouched or reinstalled.

So I tried to eliminate the usual suspects, rechecked for obstruction in the turbo piping, hoses tight, ect ect. Also, When I sent the PCM to LMT i told them I was eliminating the MAF, but then I later reconsidered and installed a new LS7 MAF but the engine does the same disconnected or plugged in. When driving I see its boosting up to 6-8 lbs.

Also, several times I started the engine warm while doing my checks of everything, and when I first start the engine it will hit 5000 RPMs no problem, but it immediately goes back to the sluggish behavior.

So WTH?? Any suggestions? I left the truck at the mechanic to look over but if there is something I can do myself I will do it for sure....Thanks for the help

JoeNova

Couple things.

1. A 190 LPH fuel pump is only good to ~400whp or so.
2. Idle 'smells' rich? What does wideband say.
3. AFR gauge reading 10 isn't lean. Its pegged rich. It will have major trouble accelerating if it is that rich.
4. Did you tell them you were getting an LS7 MAF or were they still under the impression you were removing it?

Trucker82

Couple things.

1. A 190 LPH fuel pump is only good to ~400whp or so.
2. Idle 'smells' rich? What does wideband say.
3. AFR gauge reading 10 isn't lean. Its pegged rich. It will have major trouble accelerating if it is that rich.
4. Did you tell them you were getting an LS7 MAF or were they still under the impression you were removing it?

Im sorry but I dont know what whp is? Wheel Horse Power?

At Idle Wide Band fluctuates between 14 and 16 then drops to 10 floored/behaving irratic.

I orriginally told them I would delet. they sent me back the PCM. And then later talked me into getting the LS7 MAF which is installed now.

Thank you for the responce and help!

Sales2@Texas-speed

iTrader: (5)

14-16 afr is fine for idle and cruising speeds. When you get on it and it goes to 10, your car is running way to rich. Most widebands only go as low as 10, so you are probably worse than that. You need to get it fixed. WOT you should see between 11.0 -11.7 ish while in boost. I feel like that is optimal for both detonation reasons and max power.

You have a fuel issue here, go back to the tuner and see if they can fix you up.

Dominic

JoeNova

Yes, wheel horse power. A single 190 lph pump isn't enough for a turbo setup. Its really not even enough for a decent N/A setup.

If you asked them to delete MAF, they disabled it. Your LS7 MAF is likely not doing anything.

Deeohgie69

iTrader: (3)

So did you just send your pcm to them or did you take the car to them to tune it? If you just sent them the pcm then I'm guessing they only put a base tune on it so you could drive it there for them to fully tune it.

I sent mine to my tuner to do a base tune on mine when I went from my na to boosted setup. I would imagine that your tuner put a rev limit, boost limit, and mph limit on it until he actually had the car to tune it. At least that's what mine did and I would think that any reputable tuner would do so the customer wouldn't blow the motor up. It sounds like he has it pig rich so it wouldn't detonate and take the motor out to me.

If you didn't have to take it back for a final tune and you did mail them the pcm for the full tune, then I would go elsewhere. I'm actually surprised that the tuner didn't tell you that pump wasn't enough for your boosted setup tbh. If you still have to take it back for the full tune, then I sure wouldn't be going into boost and wot.

Trucker82

Yes They said they would do a base tune. But my thoughts of a base tune must be different from the tuner's. I called them today and asked if this is what they did and all the guy would say is that they gave it a base tune. Before and after they didnt mension that the base tune was disabling.....geeze! My mechanic told me to stop scratching my head and get the truck over to them. I really hope this engine behavior is because of the tune because I have looked all over and cant find a thing wrong.

Also, according to an artical I read in Super Chevy mag, the calculation for finding fuel needs I come out to 55GPH. Which is 5 G's short I know but for my setup, I plan to have the rev limiter set at 5500, I kept the stock Cam for drivabillity, and still tow my boat to the river. Im 40, not 20 and dont plan on driving like a street squirrel. Well maybe a little but no racing and probably a few burnies here and there.

I was hopeing that someone here might have had the same issue and know what to do. But Of course I really appreciate all your feedback. Thank you.

JoeNova

A 190 lph fuel pump isn't going to be enough. Period. You already know your pump is too small. Now you have zero safety margin. One boost spike and you could scatter your engine everywhere.

Deeohgie69

iTrader: (3)

The base tune answers your question. No tuner with any knowledge or respect for his customers is going to put a base tune on a turbo setup without safeguards. That's just bad business and will ruin a reputation.

He isn't going to allow the car to read full rpms at wot because he doesn't want it to go lean. And without the car in front of him, he's not going to just guess and hope it's good to go. They can do that for na bolt on cars and mild cam setups with being pretty close, but it will still be on the safe side. Turbo setup is a different animal though.

I would be money that the tune is your problem, which is good because it would have taken your engine out going wot. That fuel pump isn't big enough at all! If you would have been able to reach wot at max rpms, it would have starved for fuel, went way too lean and detonation would have taken out minimum a piston... And that's a best case scenario.

If you already paid for a base tune, then I would take the car to them and let them finish tuning it. That way you'll know if it's anything else. But my suspicion is that they don't really know alot about it if he didn't tell you that your pump isn't big enough for your build. My tuner wanted to know everything I did to my engine as far as mods, what transmission, the exact injectors, fuel pump, and the exact 3 bar map sensor I had.

Start with the tuner and go from there, but I don't understand why he wouldn't tell you that he put a rev limiter and such on it when you asked.

mOtOrHeAd MiKe

iTrader: (8)

Brian, you are going blow yourself up!

Deeohgie69

iTrader: (3)

Bump

Just wondering if your mechanic found anything or it was the tune?

Trucker82

Okay, so I contacted the tuner and they said yes! They put a base tune. I told them everything I was putting on the truck, so they knew, and thats why the truck runs so poorly. The tuners communication skills are typical of a young adult male....Details left out, partial explainations, impatience, ect. Ect.

Man, I had a preminition the tune would be limited but I didnt think it would be near disabling. But the in the end you guys are right. I probably would have gotten on it to test it out, and the results could have been dynamiting.

So thanks JoeNova for the reality-check on the fuel pump. I looked into upgrading the OEM style pump, and long story short, an engineer at Walbro reccomended I get a voltage booster for the pump I have now. They said a 255lph is on a 6-7 week back order for my silverado setup and even if I went to a 255, the dynamics on the top end still could produce less than desirable numbers for a turbo demand. He also said that their testing has shown that 17-18 volts at short intervals has shown almost no additional ware on parts....Wow so...okay from the mouth of the author-i-tie.

So Recap. The tune was the Problem. Im shipping my truck there on Monday for the final tune and Dyno. And I bought an MSD voltage booster to dial in the fuel curve.

I will post the dyno results if anyone is interested.....And a big THANK YOU FOR ALL WHO PARTICIPATED IN THIS THREAD!

Deeohgie69

iTrader: (3)

Hey no problem man, just glad to see you have it figured out

You should be ok driving the truck to them to do the final tune since they put a base tune on it. But I would not get it tuned until you have that fuel pump! If you do, then he won't be able to tune it to make the power it should because it will be starving for fuel. Then you will have to take it back for a retune once you get it installed so he can tune it to get all you can out of your setup. But if he is a decent tuner, then he should tell you not to bring it in until you have enough pump to run it.

How much power are you going to be making out of your setup? I would also check into a hotwire kit for your fuel pump if it were me. I would also step up to the Walbro 400 pump rather than the 255.

Trucker82

The 400 must be an exteral? I assume that because I asked if they offer a bigger pump with the intank fitment for my silverado and they said no. If I were to do the 400 I think I would just scrap the whole stock fuel system and go with all PTFE and AN fittings. Mmm unlesss I need to go there I will probaby wait until rebuild time.

The MSD box just got installed yesterday but I will plug it into the laptop tomorrow before I haul it over there. So thanks for that about getting it done first or having to go back when it is final. I did think of that, thats why I overnighted the MSD voltage booster from summit.

I am hoping to be in the 500-550 HP range on 14lbs boost max. I have ten psi springs installed but also have 7 lbs springs too. I also has the turbo smart boost T so I can double the spring rating on boost with the turn of the dial.

I put new head gaskets and ARP head bolts on an all stock LS1. I also put the Amsoil bypass filter so I can filter the oil down to 1 micron pulling some of the soot out of the oil and Tripling the size of the stock filter. I added an Earls oil cooler in front with a Mr. Gasket fan on the oil cool and Radiator. I added a new oil pump, all new cooling components, all new Silicone hoses, AN fittings and PTFE hose for all the external Oil lines and covered them with DEI fire Shield since they run close to the Turbos. I had the rear end totally rebuilt with a detroit locker and factory 4.10 gears. I put a new Centerforce clutch on a resurfaced fly wheel. I had the NV3500 Trans checked out and they said it was stellar for only having 100k miles. Not worried about putting HP on the trans because it was already rated a 3/4 ton trans from the factory. I also put new Billstien Remote cylinder Shocks all around, and will put Energy's poly bushings on soon.

Man its been so much more work than I thought it would be. And I swear the truck fought me every step of the way.
I sould be able to achieve 550 on 14lds boost you think?.

Deeohgie69

iTrader: (3)

This is a stock ls1?

If so, then 14psi of boost will blow it, but you won't need to push that much anyways. Bone stock ls1's have been pushed to well more than 700rwhp, but they usually don't stay together very long. 550rwhp is about the max you want to push one. For longevity I would stay around 500rwhp. The higher the miles the better off you'll be on it, but you can easily make 550rwhp depending on your turbo setup and turbo's you're running. I made 529rwhp on my bone stock ls1 on 9psi and 11 deg timing with a tc78 on my huron kit. So you can make 500 to the wheels easily, but if you're only talking 500 at the crank, then depending on your turbo's, you may be over that with a 5lb spring. I'd put your 7lb spring in it if I were you.

You can put a Walbro 400 in out stock basket with just a little trimming and I believe I read where some people didn't need to do anything. I guess I can't speak for your truck one though, but I would think you could fit it in there too. There's a write up where people are running twin pumps on fbody cars.

I would honestly hold off on the tune until you can make sure that your setup is ready for what you're going to be doing with it and your tuner isn't going to be pushing a lot of boost through your stock ls1. What heads are you running? Heads will affect your compression ratio and how much boost you can run through it. Meth injection will help achieve 550rwhp and live longer too. But you aren't going to have any issues making 500rwhp with a stock ls1 on low boost.

It seems like the more this thread goes on, the more you let out about your build. I would just go over everything on your build and make sure that it's setup right. I'd make sure you don't need anything else for it before you take it to the tuner. What pusher fans are you running to cool your setup? He'll shut the tune down if it starts overheating on him or if he has any mechanical issues.

I'm honestly not comfortable with the competence of the tuner you are using from the info that has been given on here. I communicated with my tuner about my entire build and made sure that everything sounded right to him and if I needed to change anything that may cause issues. Communication is a must and no matter how good the build is, it is only as good as the tuner. They can make or break a build and I would be worried that he hasn't stressed any concerns about the fueling, the kind of boost you mentioned running through a stock ls1, what heads, or anything about it. He seems unconcerned about all of it by what you've told us.

This whole thing sounds like a disaster to me man. I'm just trying to help you with the little bit of knowledge I have, which isn't much. But I do know that it's no fun when things go bad

Hope you didn't take any offense to any of this man. Just research and make sure everything is in check.

Trucker82

No offence taken! I posted everything on the engine and truck. I had thought about changing to the 7lbs but thought that may not be enough. If I can achieve 500 with the 10lb spring then there will be no need to dial up the boost-t. Honestly, I not a racer or young anymore. I have raced circle track and gotten that out of my blood. So I wont be flogging it every day or proving anything to my friends. I have the discipline to keep things where they should be in livable range. I really just want to Make the truck fun to drive and have the extra oomf while pulling my boat. However I have a target HP in mind and thats where I want to be. Thats also the reason I didnt put a cam and valve train or beefed the bottom end. I also have it on my list to the tuner to keep the rev limiter at 5500. Im pretty sure that LS1 should live at 10-14 as long as I never spin it past 5500 RPM. Shoot it probably wont see over 4000 unless im passing or climbing a hill. I do like the occasional burnie but I live in Wisconsin so I can have just as much fun in the snow whithout high RPMs. If you have any concerns I am happy to hear them! I really do want to keep the engine together and any feedback is appreciated ever if it is a reality check. I got thick skin....But never the less, I chose Turbos because they are quiter, you dont need a radical cam making drivabillity a certainty, and The LS1 is a stout engine. It does boggle my mind how many additional components are required to make the whole system work. Geeze, there is a lot to be said for simplicity and the old 5.7. But there is just so many more benifits of the LS7.

I remember back in the day when the only thing you could do was add a chip, and you were limited to that tune being acceptable. With so many people being computer savy and the millennial hackers, people finnally figured out the GM brain and how to make adjustments. Well its about time I say. I graduated SAM in 98 and built engines for a couple years before I moved on. The capabilities of the LS1 continue to amaze me. But there is still so much I dont know. I feel like a kid again excited to learn something new. I love this forum and how commited everyone is here to sharing information. Man growing up nobody would share info unless you in the biz or in school. But thats another story.

Deeohgie69

iTrader: (3)

I think anything over 12psi you are playing with fire. Everything I've seen on stock ls1's that they are usually between 8-10psi with no issues. What turbo's are you using?

JoeNova

I would get that stock pump out of there in a hurry. No voltage booster.

You can get a 340 lph pump from Racetronix for around $100. That's a good sized pump that you won't have to upgrade lines to run, and it'll supply enough fuel to give you a little bit of headroom.

JoeNova

Depends on the year. A 97-98 LS1, it would be playing with fire.
Anything after that, you're good to 650whp on a good tune without any issues. It doesn't matter if its 4 PSI or 20 PSI, its power/torque that trashes the rods, not boost.

Deeohgie69

iTrader: (3)

Everything I've seen and the tuners I've talked to said they don't want to push them over 12lbs or 550rwhp if you want it to last a long time. I've seen where people on here have gone over 550 and some live a few pulls... Some live a couple years. But the ones that live are usually the ones that aren't beat on regular. The percentage of ones in the 650rwhp+ isn't very high.

I'm in no way trying to start an argument, but I can't see a stock ls1 holding 20lbs of boost for very long. I'd say reliably, meaning drive it how you want and lasting, would be 12psi max unless you are throwing different heads to lower compression and recapping the rings.

Like I said, I could be wrong and maybe some people get away with it. Just the general population I've seen are within the 8-12psi range. I personally wouldn't feel comfortable doing it and I feel the guy that tuned my car is pretty knowledgeable on these things. My buddies ls1 lived for about 7 months on 15lbs so I knit can be done. His was a higher mileage ls1, but to me that's not longevity.