engine vibration

[1990LTD]

I got my Ford running for the first time since December, and before that it hadn't run in about a year. During that year I did the intake/cam/injector/ecu swap. Before that year it was filled with fresh gas and Seafoam.

What has been done:

- cam from 94-95 cobra, cleaned up the stock lifters and replaced a bad one
- 19lb injectors
- mk vii computer
- ported ho lower intake, throttle body/egr spacer

also stuck a new cap/rotor on with new plugs and my 9mm frpp wires


I just dropped in a battery and fired it up, it runs a little bit rough. has a steady vibration/miss between say 900-1200, smooths right out and sounds like it's running great then starts chugging again when you get up past 1900 RPM. It also runs pretty hot, I can feel the exhaust heat through the floor where I could not previously.

The gas is a year and a half old. I've almost burned through the stuff that's in there and the car seems to run slightly better.

I haven't had a timing light near the car, I just got it to where it seemed to start and run well.

I plan to burn through the old gas and set the timing, do those sound like they could cause a vibration like I described? I used a torque wrench on everything when I was putting the valvetrain back together.

[gadget73]

is the ignition firing order correct? Not the same on an HO.

Sounds like its running lean. Maybe a bad injector, clogged filter, something along those lines. Pull the plugs and have a look. If you have a dud injector, I'd expect one to look different.

[1990LTD]

yeah, firing order is 351w now. 13726548 IIRC


thanks! i'll pull the plugs and have a peek at them soon.

[1990LTD]

If I play my cards right I can get a pop out of the exhaust after I blip the throttle. Gotta hold the revs steady above 1k, let off and then stab the throttle and it will sometimes pop.


I have no converters, so there's no combustion happening in there.

[GM_Guy]

Overly rich? Do you get a whiff of raw fuel at the exhaust?

Distributor stabbed correctly? I never knew this about fords until I read it relatively recently, but unlike a chevy, distributor position matters because the toothed wheel has one odd sized tooth to let the computer identify #1 cylinder and if its out it can affect how the car runs. Something to look into.

Alex.

[1990LTD]

Yup, dizzy is stabbed correctly AFAIK. It was one tooth off and wouldn't run so we re-stabbed it and it ran.


I DO indeed get a whiff of fuel out of the exhaust and I can get it to pop out the exhaust (not the intake) when I stab the throttle wide open for a second, let it get up near redline and let off.

[sly]

My Lincoln with its 302HO likes to idle rough in gear with the AC running, but I bumped the idle up a dink to be at 700 instead of 650 and it works well with that setup. It's still rough from time to time, but only when stopped and loaded. It may also have to do with the fact I'm running 15 degrees (or so) instead of 10 as well.

[1990LTD]

Cool, thanks.


This weekend I'm gonna pull some plugs and see what they look like, and likely pull the upper intake to re-torque the LIM bolts...but I don't really feel like doing that. At all.

[1990LTD]

Just had to check again because I was doubting myself 13726548.


Unplugged injectors 5-8 on the drivers side and all of them seemed to cause the exact same RPM drop.

[mitymerc]

Yup, dizzy is stabbed correctly AFAIK. It was one tooth off and wouldn't run so we re-stabbed it and it

It will run a tooth or two off, also if initial timing is too far advanced or retarded it will run super hot, ask me how I know LOL

[1990LTD]

lol, good to know. it looks like it's stabbed in there properly, comparing it to the pics on sbftech.com

[1990LTD]

ran through the old gas and put some new stuff in, runs smoother. not perfect but better...progress is being made.

[sly]

STP fuel system cleaner?

[1990LTD]

one of these things is not like the other...one of these things had a stuck open injector throwing fuel at it

[1990LTD]

also, those plugs were put in a few months ago. the rust is of no concern.