2doorrocket

Hello, While I'm a fan of using search, I've only found one other somewhat, and somewhat by a long shot, similar to my cars scenario. My vehicle has an issue where it goes into engine power reduced every time I hit 125+ mph. So far the car is a month and a half old, they removed my supercharger to replace a fuel pressure regulator and said that is going to fix it, I asked them to replace the fuel pumps they didn't.

I also have an issue with the car starting in the mornings and sometimes in the afternoon cold or warm. I push engine start and it takes a little while to start, I can count to 5 before it finally turns over and starts.

The vehicle did it again, ever since I got the vehicle back from them, I now have a foul smell coming from the AC, and I still have the same problem where it goes into limp mode / engine power reduced.

Tonight my radio was stuck on radio ID and none of the buttons worked on screen and off. Does anyone on the forums really know what it really entails to replace the fuel pressure regulator, did this heavy handed wrench monkey break something in the process of removing the supercharger? Does anyone know anything about this?

3 Z06ZR1

Lets see your car so we know your not still racing hot wheels!

2doorrocket

Wow your response was exceptionally helpful you ****ing degenerate, if you were resourceful enough you'd google my username and connect the dots with my Instagram.

DFW_Z06

The start-up delay is common on a cold start. Something to do with building pressure with DI engines.

09Z06pj

Some are very helpful around here and others... well, it is what it is.

Hope you get your car straightened out sooner rather than later.

Z06Vert

Boys, boys... lets not fall to this level!

I do think that your trying to self diagnose the issue and telling the service dept. that you want the fuel pump replaced under warranty is a waste of time. Are you a GM certified tech? If your not happy with the way things are being done at your Chevy dealership you need to find another dealership.

Good luck with your problems...

2doorrocket

Being a GM Certified Tech doesn't mean much, I have had a few cars that it's purely been the dealers fault it ended up getting bought back. There isn't much more involved in this system. It's either the pressure regulator or the high pressure fuel pump, since they replaced one and not the other and it still has the problem I'm betting on the other side of it. I mean the car is telling you that fuel pressure is low, and its having a misfire at that speed.

Z06Vert

Yeah I agree with you that being a certified tech often doesn't mean much... just puts them on the other side of the service dept. Unfortunately GM won't really listen to you... just the service department.

Service advisors, your communications middle man between you and whoever is working on your car, is another issue. It seems every time I pull in the service department they come running, tripping over each other to help me. I believe they get paid on commission for the work they write. I always have to tell them "I'm here to see Bob... I want to talk to Bob. They reply... "Every body wants to see Bob". He's a retired mechanic and really knows his stuff and he's the most ask for service advisor in the place. Sometimes I wonder what it takes to get a job as a service advisor? A pretty smile, high heels and a hot dress?... just kidding ladies, LOL. Used to be they were retired mechanics and had experience needed to somewhat diagnose problems before being sent to the mechanics... not anymore. Only thing needed is a heartbeat and ability to fog a mirror.

You really can't take them out for a ride down the road at 125mph, or I guess you could but I would have a hard time doing that here where I live, LOL.

Really though, if you feel you are not getting the service you expect you need to find another dealership. I know here in SoCal dealerships are very close to one another but for warranty issues you don't have much choice.

Good luck...

2doorrocket

Well... So much for that lol... I'm glad it stores all its codes and details, including the speeds. We will come to a resolution soon, since it is the 3rd time its done it, and no one cares about my fuel pump hypothesis I'll just let them buy it back.

Z06Vert

Yup... 3rd time and still no fix it's a lemon... at least here in CA.

NSC5

As you found from the search function DI engines will have a short delay at start while pressurizing the fuel rails HOWEVER I remember reading about another Z06 with the initial symptom of longer than usual cranking which was later followed by an oil leak due to fuel in the oil raising the oil level well beyond normal. In this case the high pressure pump had a small leak and since it is within the engine the fuel ends up in the oil. So if your cranking prior to firing time is truly longer than normal for a DI engine then keep an eye on your oil level, aroma, and pressure until this problem is resolved.

2doorrocket

Yeah but I've never seen this, not on my Viper, Hellcat, Grand Cherokee, ZL1 or anything, it really takes a while to start.

NSC5

That is what I thought from your original post and I am leaning towards the extended cranking time as being another symptom. Unlike running at 125 MPH cranking time is something the dealer technician can experience firsthand. But if I were you I would check the oil now just to make sure you don't have seepage from the high pressure system because oil diluted by gasoline isn't a desirable long term lubrication fluid.

foreverfuelie

All important comparisons except, as has been pointed out, the LT series engines are DI (direct injected). The Viper, Hellcat, Grand Cherokee, ZL1's are not. The fuel pressure needed to supply direct injection in LT's is brought to final pressure by a camshaft lobe driven mechanical pump. The engine must crank to operate the pump and "cold starts" require additional cranking due to "bleed back" of pressure in the secondary side. All LT4's seem to "suffer" this issue.

davepl

One thing to keep in mind is that it's not an emissions issue, because the injectors aren't firing.

In the old port injection, engines were required to fire in some ungodly short amount of time, like 1/3 of a revolution. But that's so that you don't waste fuel. If you're holding back the injectors, other than battery life and customer experience there's no downside to a few extra seconds of cranking, as it's not dumping fuel in while doing it - just building pressure behind the injectors.

I have an EFI ZZ502 that takes a while to crank because it needs both cam and crank positions, and I think it takes a full rev to get, but that's a different issue. This is just to build pressure, and it's not doing anything else in the meantime.

Your Viper, Hellcat, Grand Cherokee, ZL1, Enzo, and Cosby Supersnake aren't Direct Injection, so they don't have the secondary pump that needs to build pressure - it's all done with the electric pump which can spin up before the engine actually cranks. Actually the Supersnake would have an old school mechanical pump but it has float bowls to store fuel, so different yet again.

thebishman

Have you checked the intercooler fluid level? There were some owners experiencing limp mode due to inadequately filled fluid reservoir.
Bish

Bill Dearborn

I wouldn't call it suffering any sort of an issue. A couple second longer crank time doesn't mean a thing if it is part of the design of the engine. Comparisons to other cars don't mean a thing because their design is different. The only way I can see it being an issue is if you are parked in a canyon when a flash flood warning comes and the car takes a couple of seconds longer to start. Seconds count then but how often does that happen? Probably stand a better chance of being involved in a Buffalo Stampede on Wall Street in NY City.

Bill

jcthorne

Normal for the LT DI engines. Other manufactures DI engines do not have this problem.

Bill Dearborn

The loss of power at 125 mph may or may not be a fuel pressure issue. There are a ton of things that could cause that. What gear does happen in, 3, 4, 5, 6, 7??? Are you wide open throttle or part throttle? In the higher gears you can run 125 without a lot of throttle opening. It only takes 75 HP to maintain a constant 125 in a Corvette on level ground so at that power level you aren't requesting a lot of fuel. If you are wide open throttle and accelerating in 4th and you get a power reduction it might be right after you shift from 3rd to 4th. In that case it could be due to wheel slip when the shift occurs and you are seeing traction control cut in. Turn off traction control and active handling and see if it happens then.

Bill

Bigdog9586

Count to five is to long. I just started mine Monday for first time since first week of November and was actually shocked how quick it started.