2ltr pinto efi misfire and loss of power when hot

[Lee Raybould 0]

hi guys

I have a problem with my 2ltr pinto efi. It runs, starts and drives as it should when cold, but as soon as it gets a little temperature in it it looses power and pops fire  down the exhaust. Ive swoped all the usual culprits ie plugs, leads , distributar cap, rotar arm, fuel filter, checked timing changed fuel (as it stood for many years) have i missed something silly. As i drive it out the garage its on full power, turn it around and almost have to push it back in. could it posibly a coil breaking doown. has anyone experienced the same problem, any advise welcome.

[kevin the chicken 249]

My first thought was coil. Had it on a tractor once, an old ferguson. It took me a while to realise that the miss fire was less noticeable when the tractor was turned so that the wind was blowing on it! It would be worth trying a different one to rule it out.

[richyb66 1,160]

Coolant temp sensor?

[lotusseven7 2]

Mine was a coil issue breaking down when Hot, had new coil fitted runs like dream now.

[IanS 56]

Tappet gaps to small?

Valves warm up and get longer and no longer close properly.

Worth checking but a long shot.

[nicko 163]

On a pinto EFi there's a valve type thing (can't remember its name) on the inlet plenum. When left it can start to stick and give symptoms similar to yours, it needs removing and cleaning with carb cleaner.

Worth a try as it's an easy fix (It's held on with 2 nuts/bolts and has a wiring plug connected to it)

HTH

Nick

 

[Lee Raybould 0]

40 minutes ago, nicko said:

On a pinto EFi there's a valve type thing (can't remember its name) on the inlet plenum. When left it can start to stick and give symptoms similar to yours, it needs removing and cleaning with carb cleaner.

Worth a try as it's an easy fix (It's held on with 2 nuts/bolts and has a wiring plug connected to it)

HTH

Nick

 

Thanks. Have looked at this it seems to be opening when the cars running which I believe it should. But the symptoms still there. Will take it off anyway and clean thanks for the advice. 

[Lee Raybould 0]

10 hours ago, IanS said:

Tappet gaps to small?

Valves warm up and get longer and no longer close properly.

Worth checking but a long shot.

Thanks will check them after I've changed coil. Thanks again for the advice. 

[Lee Raybould 0]

12 hours ago, lotusseven7 said:

Mine was a coil issue breaking down when Hot, had new coil fitted runs like dream now.

Cheers going to change it and see what happens. 

[Lee Raybould 0]

13 hours ago, kevin the chicken said:

My first thought was coil. Had it on a tractor once, an old ferguson. It took me a while to realise that the miss fire was less noticeable when the tractor was turned so that the wind was blowing on it! It would be worth trying a different one to rule it out.

Cheers

[Lee Raybould 0]

13 hours ago, richyb66 said:

Coolant temp sensor?

I'll have a look. Cheers. 

[theduck 852]

Quick test for coolant sensor, onnce the engine is warm and showing the symptoms described, unplug the sensor and short the pins of the connector with something like a 2kohm resistor, that will emulate the signal from the sensor when the engine is hot.

[blue 48]

I doubt it’s coolant temp but worth checking if only to eliminate but popping and banging in exhaust is generally unburnt fuel in exhaust. 
Coolant would cause rich running but not unburnt so start on ign side of things.  Plugs coil etc. Don’t be fooled into thinking it’s as car warms it could just be something breaking down after a few mins of running not changing as coolant warms 

[theduck 852]

4 hours ago, blue said:

I doubt it’s coolant temp but worth checking if only to eliminate but popping and banging in exhaust is generally unburnt fuel in exhaust. 
Coolant would cause rich running but not unburnt so start on ign side of things.  Plugs coil etc. Don’t be fooled into thinking it’s as car warms it could just be something breaking down after a few mins of running not changing as coolant warms 

In my experience Pinto EFI ECU adds a LOT of fuel when it thinks the engine is cold, enough to cause incomplete combustion, loss of power, and unburnt fuel i the exhaust.  It could also cause fouling of the plugs which make the whole thing worse.

[Jez Morton 128]

I had a issue on my pinto efi, kept getting high tick over changed everything checked everything. It was the coolant temp sensor. Probably the cheapest part to change, but I had to buy long 25mm socket to get it out.