View Full Version : My gremlins are growing fewer...

04-27-2009, 03:41 PM
Recently, I have been trying to solve some driveability issues on my '90 5-speed. I hydrolocked the motor last November, picked up a motor from another forum member, Andrew in Macon. Did the swap, everything was unicorns and rainbows. Then, couple months ago, I started having some very abrupt hiccups at part throttle, like someone was cycling the key, and this was accompanied by a distinct loss of power, though I could still get 10-11psi of boost. Replaced the DIS, coil, plugs and built custom Accel spiral-core Superstock wires with the proper terminals for the Ford coil pack. Hiccups have gone away, power seems to be back, but now, she hunts for idle, rocking back and forth between 600-900rpm, and seems to sputter above 4200rpm. Replaced the IAC - no change. Crank ~~~. sensor is less than 6 months old, cam sensor is within specs, and firing order is correct. The exorcist around here doesn't deal with cars.

04-27-2009, 03:44 PM
Have you checked fuel pressure at the rail? Not that I can solve my own SC problems but that's what I would check next.

04-27-2009, 03:53 PM
Have you done vacuum leak checking yet?

04-27-2009, 03:55 PM
I've been starting to suspect a fuel pressure problem, and have been planning to install a fuel pressure guage indash. I already have a buttload of guages in my shop, but the fuel pressure guage I have will only read up to 15psi. Need a bigger swing than that, eh?
Do you think that a failing fuel pump may even cause the idle hunting? Idle to 4200rpm, she runs great.

04-27-2009, 03:59 PM
Have you done vacuum leak checking yet?

Not yet, I didn't suspect that, since I do have about 20 INHg @ idle, and hit 11psi of boost on the stock pulley, with a mildly ported sc and CAI.

05-03-2009, 11:24 AM
Still having the idle hunting problem, but it doesn't seem to do it until I have driven for about 20 minutes, or so. Still have the mild power loss above 4000rpm.

05-03-2009, 11:27 AM
A buddy at the local Ford dealership gave me a few used coil packs, but switching back and forth between them doesn't seem to change anything. I have ordered an Accel Supercoil replacement, but I don't feel it will do much except look pretty. Can this be fuel pressure related?

05-03-2009, 12:19 PM
You must check the fuel pressure under load, it could be dropping off under load indicating a faulty fuel pump.
Also check your fuel filter, if it's old then it could be plugged up.
Do you have any codes?

05-03-2009, 04:35 PM
Codes I pulled were for a coil failure, secondary misfire and no tach signal to EEC. I have since replaced the coil, DIS and plugs and wires. I have not had another code come up. I am thinking about installing an indash fuel pressure guage. Will an A/F meter work, or is that too vague?

05-06-2009, 12:22 AM
Any ideas, guys? I'm seeking wisdom here, y'all....

05-06-2009, 10:48 AM
Could you be having an intermittent fault in the ignition switch? It has happened to others.

05-06-2009, 11:06 AM
Codes I pulled were for a ...misfire and no tach signal to EEC.

you said that the cam sensor is 'within specs'...i can honestly say that through all the years owning an sc and the many cam sensors changed, i have never 'seen' what makes a cam sensor faulty...it just goes bad...so if you have the slightest uncertainty, i'd change that too. They go for pretty cheap and the symptoms for a bad cam sensor seem to vary alot. good luck!

05-07-2009, 03:11 PM
Cam sensor? I guess I might as well try that, Lord knows, I've replaced everything else...

05-07-2009, 03:13 PM
Could you be having an intermittent fault in the ignition switch? It has happened to others.

The miss is only at just above 4000rpm.

05-07-2009, 08:34 PM
What gap do you have on the plugs and what kind of wires are you using?

05-16-2009, 11:06 AM
Not 100% sure on the gapping, my buddy, a service manager @ Ford, gapped them for me when I picked them up. And I am using Accel Super stock spiral-core wires.