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View Full Version : 84 svo runs out of power



Larry kelly
08-24-2009, 01:26 PM
My 84 svo runs up to about 3000rpm in 1st and 2nd gear and then runs out of power.It's running very lean and seams to break-up.New plugs.wires good fuel pressure. Help :confused: Larry

bigbsvo
08-25-2009, 08:32 AM
First off, what do you mean by good fuel pressure. Can you be more specific?

You need to put a fuel pressure guage on it, run the guage up under the wiper arm so that the guage can be read from inside while you drive it, and when your under boost it should increase to 50psi.

On the 84 and early 85 they had a dual pump set up, one in the tank and one exteral pump, you may have one going out. But, lets not go there until we see some numbers, please.

Also, what kind of wires and plugs did you install? Motorcraft, right? Motorcraft on a stock set up works well.

Bryan

Larry kelly
08-25-2009, 07:24 PM
It has motorcraft plugs wires have been checked and work fine,don't appear to be ford. I'll check fuel pressure under boost and let you know. thanks for advice Larry

Larry kelly
08-30-2009, 11:15 AM
I took the car to a friend who's an instructor at the local tech school.He said fuel pressure started at 40 at idle and almost got to 50 where started to shutter and break-up. it's got him miffed too. Larry

NotBud
08-30-2009, 03:15 PM
How are you determining that it is running lean? Wide-band sensor?

Your description points to either fuel pressure dropping off under load or ignition failure (coil, secondary wires, plugs, grounds). If I were to hazard a guess I'd say the high-pressure fuel pump is failing. They don't live as long as we'd like on the 84 models.

A further method for testing is to see how long it takes for the power to recover when it starts sputtering. When it's sputtering, if you reduce throttle say 25% how long does it take to recover? If it's ignition related then it will recover instantly - as soon as the compression load decreases. If it's a fuel flow problem it will take a few seconds to recover - time for the fuel flow (pressure) to return.

Kendal Coker
08-30-2009, 05:29 PM
It has motorcraft plugs wires have been checked and work fine,don't appear to be ford. I'll check fuel pressure under boost and let you know. thanks for advice Larry

If you did not change wires when you changed plugs the wires are your problem. They get so hot that you cannot get them off and back on without damage. I have had this happen. Doesnt miss under normal driving but will at higher rpm. I also would not spend the extra money for motorcraft wires. Get the 2 year warranty ones form the parts store and get new ones everytime you change plugs.

Larry kelly
09-04-2009, 12:07 PM
Ok guys sorry I was so late replying.One of the plug wires was broken at the boot so replaced them all,but I can't check it because in the process I found out the exhaust manifold is cracked strait through I'm having hard time finding E3 or E6 is a header the way to go any suggestions? Hey guys thanks for the help. Larry

Jim D.
09-04-2009, 12:58 PM
Going to a header can open a can of worms.

I have a ported E6 manifold -- shouldn't be too hard to find a stock manifold if you keep your eye open on eBay, and I'm sure someone will pop in with a recommendation.

You can try contacting http://performancepartsinc.com if you don't see it on their website.

http://www.forced4.com/ does have a header.

Any 1987-88 Turbo Coupe would have the same manifold. I have one I'll sell you if you come take the car with it!

Larry kelly
09-04-2009, 01:45 PM
performance charged and refunded me ,when they realized they sold the last one this morning.coupe sounds good but oyur along way from so. georgia

NotBud
09-05-2009, 10:49 AM
If you did not change wires when you changed plugs the wires are your problem. They get so hot that you cannot get them off and back on without damage. Get a tube of that high-temp silicone di-electric lube from your trusty Ford dealer and some long q-tips. Then liberally coat the inside of each plug boot before pushing it over the spark plug. This totally solves the sticking problem and you will stop damaging the wires upon disassembly.

And you could also stop using those crappy fiber-resistance type of wires and switch to a solid wire core. No more broken cable problems either (still use the silicone lube though).