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1985 Gc Fe-Lacking Power Down Low


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Hi all,

 

Most likely a common question, but the old GC 626, lacks power down low, but not on the the open road at higher speeds.

 

No Cat Convertor on this model, and is the Carby model.

 

There is a leak in the exhaust , but on inspection at a muffler shop has been given the all clear tailpipe up to the firewall so to speak.

 

Fella said that it could be a split somewhere that seals once hot?

 

Timing has been checked, there is no pinging sound but a little backfire when cold only.

 

Can someone suggest a checklist to narrow down the cause.

 

Much appreciated,

 

Regards,

 

Anthony

 

 

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The leak in the exhaust is possibly the manifold gasket to the head or to the engine pipe, check in those places, also if the engine is missing the exhaust pipe hanger below the oil filter then you may need to look for broken exhaust studs, they are a bit undersized on the FE/F2 series of engines and an unsecured exhaust helps them break alot sooner.

 

With regards to power, The non turbo motor was never a real power house below about 2500rpm, but backfiring tells me something is still not right. It could be the valve timing is a bit off, check to make sure the camshaft and crankshaft alignment marks are correct, i.e at TDC on #1 the cam mark should be lined up at "A". If its a tooth off it can make a huge difference to where the torque is developed.

 

Also check the health of the park plug wires/dizzy cap/rotor & coil lead. failure of these components can lead to missfiring, lack of power etc, and on a car of this age if the components are originals they probably need replacing and if they're not they could be some shonky aftermarket alternative which has a short life.

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Thanks very much for the information.

 

Are there any handy hints on locating manifold?stud leaks?

 

Should i try another dizzy to compare?

 

Most components have been changed with Mazda parts, bar the timing belt which I dn't think has ever been changed.

 

Can you suggest a good source for OME parts?

 

Regards,

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  • 4 months later...

Thanks very much for the information.

 

Are there any handy hints on locating manifold?stud leaks?

 

Should i try another dizzy to compare?

 

Most components have been changed with Mazda parts, bar the timing belt which I dn't think has ever been changed.

 

Can you suggest a good source for OME parts?

 

Regards,

 

I only just saw this for some reason. Chief has given a good background, that missing hanger can cause issues. In my case the studs were fine but the flex caused a small tear to develop at the front of the first resonator. Another cause of backfiring noise is worn exhaust valves. Do you know their condition?

 

Timing belt replacement interval is 100,000KM on the FE, but being a non interference design if it breaks no terminal damage - just a whole lot of inconvenience and nasty in the middle of a freeway!

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