xafalcon

I've just bought a 5 speed EA S-pac with MPEFI 3.9 engine. Never owned a six before just V8's, so I've got no experience to draw on. Can anyone suggest a likely cause for a flat spot just off idle? If I open the throttle very very slowly there is no problem. If I open it very fast, again no problem. If I drive normally, the engine tries to die when I take off from a standing start. I can get around the problem by keeping revs above about 1500 when I take off from a standing start, or alternatively by letting the engine bog down then give it full gas until it gets past the flat spot. The engine runs well above about 1500, and idles perfectly. It's just a problem at part throttle. Any ideas??

Thanks in advance for any suggestions.

Cheers
Tris

AUII_Forte

Does it miss or anything or just has no power?

You could try checking the timing to see if it's retarded. Also check your leads, dizzy cap etc etc.

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mongrelEB

Might be worth running a voltmeter over the TPS?

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Pacemaker headers + 2.5" exhaust
EF Fairmont interior
MP3 player
Lowered King springs
5 speed manual
EF motor

Newest mod: EF Ghia wiring loom and dash

BoZZa17

mine does the same thing!!!
but mine misses around the 1200 mark (well i think its missing) (car goes shakey)
i have no idea wtf it is
but ive just lived with it until now when someone else has mentioned it!!!

Troutman

Mine is pretty similar, I always thought it was normal. I'm sure if you played around with different cams etc it would be different.

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Jack Travis, E-Series Acting President

1989 Ford Fairmont Ghia turbo/GL replica (underway)
1994 Eunos 800M
1990 Ford Laser S

xafalcon

Checked the timing tonight - and it gets a little weird.... I shorted the W/R wire by the brake booster to ground, and the idle speed dropped to almost zero??? I though it was supposed to rise to about 1500?? Timing was set at 16 BTDC. I stopped the engine and using a torch I had a look at the balancer. There is a small loop of rubber hanging out the back of the balancer. I'll check the timing marks are still true with my modified spark plug this Sunday. Perhaps the outer ring of the balancer has spun a little? Anyone know if they are neutral balance or do they have a counterweight like a windsor or clevo?

Which way does the distributor rotor spin? Or asking a different question, which way should the distributor body be turned to advance timing?

There is no idle surge so I'm guessing TPS voltage is about correct. My 5.0 needs 0.9V at idle. Is this the same for the 3.9 MPEFI?

The engine runs fine (almost perfectly) otherwise. It has no power, but the throttle cable outer is broken so it only gets about 1/4 gas. I'm also used to my 5.0 EB, so this engine is down on capacity as well. Gets reasonable gas milage. It does have a rich idle with a little black smoke out the tailpipe, but I'm in the countryside so it doesn't get to idle in traffic at all.

Thanks for any further replies. Hopefully I'll get to the bottom of this and post my findings.

Cheers
Tris