Engine problems?

[h3towel]

Good afternoon everyone. I need some help diagnosing a problem I'm having with my car. Up until two weeks ago, she was driving great. Went to a car meet up on 8/30 to have some breakfast with some friends and as I was leaving, someone decided to race me. I let him know that it was a bad idea on his part. After that, I went to my parents for a bit and then back home. My wife and I decided to go grab lunch about 30 minutes from the house, and I stopped to get gas on the way. When we were leaving lunch, my problems started. The car didn't want to stay on, but once I got her on the interstate, she seemed just fine. When I got off, I had to constantly rev the engine to keep her from dying and would have to give it quite a bit of gas when leaving a full stop. I thought that my little race earlier in the day may have messed up the AFR targets in my fitech goefi 600hp, so I reset the learning. After that, she idled in my driveway for about 25 minutes with no issues. I took it to breakfast last Saturday and she was a little sluggish, but I just chalked it up to the first drive after resetting my learning. Drove to work yesterday and on the way home, I had some slight idling issues, but no big deal. Today I was doing a charity ride and about 45 minutes into the ride, my car did not want to run. I tried resetting the learning again, but no dice. I had to get it towed home. Now I'm wondering if I got some bad gas from 8/30 since that's when the problems started. Could that be an issue or maybe a clogged fuel filter? Hopefully it's not my TBI, but if it is, what does everyone recommend? I called a place to have my car tuned a while back and was told that they don't tune fitech since they aren't very good and don't hold a tune. I'm running a 347 that I got from Mike Forte. Any help would be greatly appreciated

[gbranham]

Sorry you're having trouble. Hopefully you can get it sorted out. I'll say what most folks are thinking...upgrade to Sniper 2 (good), ProFlo4 (better), or Terminator X (best).

Greg

[JMD]

I would address the easiest things first: fuel filter, check a couple spark plugs, look for vacuum leaks in hoses or under throttle body, check your bolts (intake, exhaust) and see if there's anything obviously loose. Can you read the sensors with a handheld or phone app or laptop? See what they're telling you. If you think it's the fuel maybe drain it out and replace? How about your O2 sensor? If it went bad it could cause a whole bunch of problems. Could you load a good tune then run it open loop and see if that makes a difference?

Just some thoughts...

[h3towel]

Thanks for all the great ideas. I hadn't thought of have of these. Is there any way to check the o2 sensor? Unfortunately, I don't have a good tune saved.

[h3towel]

Any thoughts on the edelbrock pro flo 4 systems?

[gbranham]

I have ProFlo4. Its awesome. When I build another, l'll use it again. I like that its a fuel injector system, as opposed to a throttle body injection system like Sniper 2. It has fuel injectors for each cylinder, mounted in an Edelbrock intake manifold designed specifically for ProFlo4. True turnkey system with no tuning required.

[BornWestUSA]

What is your ignition timing doing while this is going on?

How strong is the spark??

Fuel or ignition problems can cause what you are describing.

[JMD]

What is your ignition timing doing while this is going on?

How strong is the spark??

Fuel or ignition problems can cause what you are describing.

Good point. How old are your plug wires? Give them a close visual inspection, look for melting or cracking. How about your distributor? Does your computer control your spark or do you have a traditional distributor? Pull the cap off and take a look at the metal contact points. If they look melted or deformed that's a good clue there's an issue.

You would need to be able to read the O2 output. Do you have a way to monitor the engine sensors? The Sniper systems have a 3.5" touchscreen handheld that is used for that, as well as a tuning program where you can use a laptop to read and adjust everything.

The Sniper 2 is a great budget oriented throttle body injection system, but the ProFlo is multi port fuel injection which has some advantages over throttle body systems. I picked the Sniper because it looks just like a carb and I wanted the old school look and don't intent to push the engine to the edge. If I were racing or wanted something more modern looking and performing, the ProFlo would be a good option. I just can't stand the look of fuel rails cluttering up the engine bay in my roadster. ;)

[CDXXVII]

Check for exhaust leaks. Maybe you stressed your exhaust manifold gasket.

I got rid of me Edelbrock system and installed the Holley Terminator X Stealth TBI. My MK4 is running better than ever.

[cadtdi]

sounds like you might have gotten some bad gas since your issues started after a fill up.

[OSU Cowboy]

To me - what you are describing has happened to me before in my 347 carb'd MK3.1. Was running great, filled the tank, and then problems. We finally made it to a small town with an auto parts store, and I bought some "heet" that absorbs water out of the gas. It's pretty much alcohol really. I didn't do this with any sort of "octane boost" in mind, but just to see really if "water-in-the-gas" was the issue. Turns out - it was. Now, I routinely add a bottle of that to every fill up, as you never know when it will pop up again. It's not that expensive at well less than the cost of 1 gallon of gas. I'd urge you to try this as it has the potential of being an extremely easy "fix" vs. some of the other paths you might be considering.

DP

[OSU Cowboy]

Oh yeah - before anyone weighs in with the idea that the ethanol gas blends we unfortunately have to suffer through across this fruited plain which would or might absorb water on their own - where I live in Central Oklahoma 100% gas without ethanol is widely available, and I use that 100% gas in all of my vehicles as I don't like corn in my gas.

[OSU Cowboy]

That one time I had the problem, it was ethanol gas as my only choice in that particular small town.

[h3towel]

219742
I siphoned about 5 gallons out and the gas is pretty yellow in color. I feel like this is the wrong color. Should I drop the tank and empty it out, or could I just put fresh gas in and let it mix?

[Sharris2]

If it's yellow in color, you gotbad gas! Siphon it all out, put in fresh gas and replace the fuel filter. You should be good to go after that. It may take a few minutes to run all of the bad gas in your fuel lines out when running.

[h3towel]

Is there a special trick to siphoning all the gas out? I put a hose in and siphoned until I was pulling air. I turned the ignition on and still had over a half or a tank. Should I just drop the tank and empty it that way?

[gbranham]

Either your siphon hose wasn't all the way down in the tank, or your fuel gauge isn't calibrated properly. . I'd try a longer siphon hose first before I'd pull the tank. Or remove your fuel level sender and siphon from there.

Greg

[h3towel]

A friend of mine smelled the gas and said it didn't smell bad and thinks that there is some kind of obstruction in the line. He recommended pulling the TBI and cleaning it.
I want to call BS on this since I have just over 4k miles on my car and have never experienced this issue before. Any thoughts?

[gbranham]

We can armchair quarterback this all day, but you're going to have to dig in systematically to figure it out. Air, fuel, spark, at the right time. Any one of those fails or is compromised, and you'll have driveability issues. Start with your fuel delivery from end to end to make sure its flowing at the PSI you expect. If that looks good, I'd move on to ignition.

[tnt_motorsports]

Agree with Greg 100%.

If you think the fuel is ok put it in your mower and see if it runs. I'd pull your fuel filter and check it as well. Then start the process Greg suggested.

[cob427sc]

You should be able to siphon the majority of the gas out, then open the fuel line somewhere and run the pump until nothing comes out. Remeber, the water will be in the bottom of the tank as it will seperate from the gas. A can of dry gas will help eliminate any minor amounts in the fuel lines. I would recommend disconnecting the fuel line near the engine and run the pump until you see new fresh gas, then connect up.

[ProfessorB]

Sorry you're having trouble. Hopefully you can get it sorted out. I'll say what most folks are thinking...upgrade to Sniper 2 (good), ProFlo4 (better), or Terminator X (best).

Greg

And I'll say what NOBODY is thinking: 750 cfm Holley carb. :)
.
But as I read thru the comments yes...it could be anything but more likely to be fuel or fuel system rather than ignition. And in that category, most likely to be bad gas. That's what I would eliminate first.

[Mike.Bray]

And I'll say what NOBODY is thinking: 750 cfm Holley carb. :)

Very true, why would ANYONE be thinking of a Holley carb?

[cv2065]

Very true, why would ANYONE be thinking of a Holley carb?

What...another EFI issue....? :p

[ProfessorB]

Very true, why would ANYONE be thinking of a Holley carb?
.
Well, he could be like me....An F.O.G. (I know that the O.G. stands for Old Guy. And I THINK that the F stands for fantastic or fabulous....but I'm not exactly sure)

[Mike.Bray]

.
Well, he could be like me....An F.O.G. (I know that the O.G. stands for Old Guy. And I THINK that the F stands for fantastic or fabulous....but I'm not exactly sure)

I'm an F.O.G. also but I'm still going back to the 1800's and getting gas on my hands with every adjustment:rolleyes:

219976

[CraigS]

A thought although I may be too late. I recently got gas in 2 cans. One can got standard regular for the lawn tractor. The other got no-ethanol for the chain saw since it sits longer between uses. Both were absolutely clear. Put a pint of that gas in a clear glass jar and let it sit overnight. If you see layers it's trash.

[MB750]

A friend of mine smelled the gas and said it didn't smell bad and thinks that there is some kind of obstruction in the line. He recommended pulling the TBI and cleaning it.
I want to call BS on this since I have just over 4k miles on my car and have never experienced this issue before. Any thoughts?

Did you accidentally put diesel in your car?

[h3towel]

Update time. I'm 99.9% sure I had water in the gas I got before my problem started. I put some heet in it and just drove it for about 45 minutes this morning and let it idle for about 15 minutes after. It did shut down at the end of the idle, but started right up again. It was running a little sluggish, but put fresh gas in it once the tank was only 1/8 full. After about 5 minutes, she picked right up and was running fine. I'm still planning on switching my fitech goefi 600 with a holley terminator x stealth. Thanks for the help everyone. Also, according to google, exxon premium gas is yellow in color.

[Mike.Bray]

You will like that Terminator X a lot better than the Fitech. Worlds of difference.