Engine Sputtering after 351W swap(EFI)
 

Hello, I need some serious help. I just did a 351w swap in my 87 Mustang GT. I have 30lb injectors with a 75mm MAF sensor that is calibrated for them. I also have BBK 75mm throttle body and a Aeromotive adjustable fuel regulator. Now when I take off, the engine starts sputtering but when I engage the clutch I revs up fine but soon as start disengage the clutch again to take off the engine starts sputtering again and blowing black smoke out the back. My whole ignition system is MSD. I do have a stock fuel pump which is soon to be replaced, but I don't think thats the problem. I have lots of other mods that I have done to the engine, but I don't think thats relavent to the problem. Please help! Thanks.

Well if the block had been recently rebuilt, you are supposed to put about 300-500 miles on it before driving it like a race car. if you had driven it hard without it wearing in, you could be leaking oil thru the valves, past the piston ring's ect. which would account for all the black smoke.

If you havent been driving it like a madman, I'd just take it easy on the engine for a few days, also make the rebuilders aware of whats going on, mabey they have some thought's or suggestions on it, and just see if it starts clearing up any.

Which ECM are you using?

The computer is the A9L.

yo blue, ignore what fritz said, he doesnt have a clue and listen very carefully to whatever PKRWUD has to say. HE DA MAN!!!!

Lmao... Ooook, might not be his trouble, but ask anyone who's built an engine if it need's a break in period. Then ask if hard driving on a freshly rebuilt engine might not result in black smoke .

what color does oil burn?
and what color indicates a rich condition?

And how many times have you heard someone say "Oh , theres tons of black smoke coming out of my car" Only to find its just a dark greyish blue.

but that doesnt cover the sputtering. Think of the big picture, and its quite apparent that you dont know enough to help this guy. Let the pro's like PKRWUD help him. No one likes to read ignorance.

Well honestly, it sounded to me like the sputtering might have been related to the stock fuel pump not providing enough pressure for anything more than an idle condition and I was waiting to see what he had to say once he replaced it.

But enough of this petty B.S. if you actualy have anything to add insofar as trying to help solve this guy's problem then please do so.

i gave him the best advice possible, to not to listen to you.....and listen to PKRWUD. You were making assumptions first that shouldnt of been made.

I did'nt simply say "Dude, you fried your engine from hard driving", I had said IF he had been driving it hard and the engine had been recently rebuilt Therefore, if he had'nt, there would be no need for concern or focus on my post. I was merely giving him a possibility to reflect on, and a valid one at that.

Do you have the vacuum line hooked up to the fuel pressure regulator correctly? If not, you will run richer as your vacuum increases. Fuel pressure needs to drop as vacuum increases and vice versa.

Have you run any injector cleaners, octane boost, or other harsh chemicals other than gasoline through your fuel system? Some fuel pressure regulators may be sensitive to certain alcohols and the diaphragm will deteriorate causing fuel to leak into the intake manifold.

A stock fuel pump is no where near being capable of supporting a 351 with 30# injectors. You would need at least a 155lph pump. I would not try to open it up with that small of a pump, but I don't think it's the cause of your problem, as you have already stated.

You may want to share your cam specs, too.

Ok guys, fritz does have a valid point about engine break-in period. Thanks, fritz.

But the smoke is definately black. As for the vaccum line for the fuel pressure regulator, there are two ports under the upper intake(Trickflow). I don't remember off hand which one I connected them to, but I don't it matters since they both lead into the same port, or does it?

The cam thats in there is a truck cam, 444 lift. That will change as soon as I get new heads for it. I didn't add any kind of additives to the fuel and every component on the engine is new.

I also thought maybe that the plug gap might be wrong too, I have them gapped to 045. They were gapped to 080!

Thanks guys for all the input!

The FPR just needs unregulated vacuum which it sounds like you gave it.

Maybe you should go to a dyno with a wide band O2 sensor and see what your air/fuel ratio is running at. You may also want to hook up a fuel pressure gauge to watch what it does when you're driving.

You should probably have your gap at about .060 or thereabouts, especially with a high output ignition. If you're running platinums, it should be even more.

What heads are you running and what do you plan to get?

One other thought. You have a 180 degree or greater thermostat installed, right? If not, your computer may be stuck in open loop mode if it never gets up to normal operating temperature.

Trying to find a dyno out here in Germany is kind of hard. I am running the stock heads that the long block came with, but I plan to replace them with Trickflow Tristed Wedge heads. Will plug gap that is off by 015 make that much difference?

Thanks

Yes, I am running a 195 thermostat.

just a thought, but did you check your codes.

Codes?