sqeeek

So I’ve had this thing for 9 months and I’m so fed up with it that I swear on my life I’ll buy a case of beer for whoever comes up with the solution.

Here’s the whole story so far:

Bought a half-finished 88 ranger 86 SVO swap last summer. By half-finished I mean that it never ran properly and looks like it was wired and plumbed by Helen Keller. To make a long story short, at the moment it starts and idles fine, but then:

- Mash pedal when parked = bad sputter, won’t rev all the way
- Slowly rev when parked = sputter until higher RPM, then will rev fine as long as you don’t let it drop below 3k rpm
- Mash pedal while driving = sputters for a second and then cuts fuel, like hitting a brick wall

In general, feels like it misfires and has very bad throttle response. Turbo never passes about 9psi. Very lacking in power. Sometimes cuts timing and goes into a weird ‘limp mode’ style thing where timing feels severely retarded. Sometimes has a very slight random misfire at idle. Sometimes has wandering idle, but not often.

Here’s what I know so far:
- TPS is set to .94v at idle and has good sweep
- VAM has correct sweep, have tried two VAM’s
- Motorcraft plugs gapped to .032
- Disconnected EGR vacuum line, no change
- Wastegate is running on manifold pressure, no boost control
- Inline fuel pump was replaced by former owner, haven’t checked what brand but looks new
- Fuel pressure is 34psi at idle, 40psi with vacuum disconnected, rises to ~42ish at 9psi.
- Head gasket was supposedly replaced by former owner, have yet to check compression
- Manifold has a small crack
- Remanufactured LA2, tried another with no change
- Relatively new cap/rotor
- Timing at 10* BTDC spout-out

The best I ever saw it run was when I ran it with no VAM, ran rich but like a rocket until the computer got scared and retarded timing. Flooring it still felt like hitting a wall.

What should I check next? I have $300 to blow and all Saturday to work on it. I will make videos, sacrifice goats, whatever helps.

And I’m not kidding – first person to point me in the direction that fixes the damn thing gets enough beer to knock out a Russian.

Chromeshadow

I'd start by checking these. Here are tips for checking the vaccum/intake manifold leak
http://www.secondchancegarage.com/public/186.cfm

sqeeek

Awesome site, thank you. Vacuum gauge shows 18psi steady at idle, but there are still a couple of vacuum hoses that might have a leak. I'll get those replaced and do a compression test tomorrow. (also just to clarify, exhaust manifold is the one with a small crack, intake is fine)

It also crossed my mind that cam timing could be off, I'll check that while I have the plugs out for the compression test.

Another thing I've been wondering - do those fuel pressure number look okay? I've googled extensively but have seen everything from 45-60 under boost called 'normal'.

CPTCO

What heat range spark plugs are in it? When I went FI my kit called for colder plugs. But ill be darned if I could ever get it to run properly. Went back to a stock heat range spark plug and haven't looked back since. I was having very similar problems.
Roush's theory was that my elevation was throwing things off.