Pinto Misfire & temperatures

[davidimurray]

Pinto Misfire & temperatures

I've got my Pinto running now. It's an 1800 fitted with ZX6R carbs - jets are standard, needles are 1 below middle groove and idle screws are 3 turns out. This is all running with a Megajolt - timing has been set and checked and the map I have is one of the 'standard' base maps doing the rounds.

When the car is sat idling (it currently idles at about 1050 RPM) every 10/20 seconds I get a pop from the exhaust. You can hear it on this video here at 15 and 35 seconds - http://www.youtube.com/watch?v=6JVmMO2R4WY

If you watch the video further, when I raise the revs at about 40s second up until 48 seconds you can hear quite a few pops but they don't seem consistent. In the rest of the video I raise the revs further and the pops seems to decrease but there are lots coming off the throttle.

Has anyone got any suggestions on what could be causing this? An initial though I had could be air leaks into the exhaust?

Second question is about temperatures. Let the car get up to full temp. I've got a digidash and that shows that the engine fan comes on at about 105C and turns off at 98C. The fan switch is rated at about 75C so I am guessing this is just a function of the position of the fan switch against the temp sensor in the head. Does this seem like a normal sort of operating temp for a Pinto? If I hold the engine at 3500rpm for a few minutes, with the fan on the temperature sits happily at 101C so it would seem that the cooling system works.

Thanks in advance for your help.

Cheers

Dave

[twinturbo]

Did you have it running on the Pierburg Beforhand?

Do you still have the Pierburg to test with against the Jolt?

Has the Cam Timing been checked?

Cheers

TT

[deezee]

Sadly there is seemingly no solid settings for carbs to get the engine to run perfectly. From experience your going to need to check for air leaks (A common causes of exhaust popping), balance the carbs, do a compression test and fit a wideband lambda to the exhaust. Unless you can see what's going on in the engine, your going to struggle to tune the car. Popping can be caused by lean conditions in your engine. Which you have no way of knowing without a wideband.

[baz-r]

you might still be able to get a colourtune that may help see whats going on with the mixture

[mark]

Air leaks are quite common when people are doing the bike carb thing and the syptoms are exactly as you describe

My old cvh install did a similar thing until i got the manifold skimmed

Try using a blow lamp unlit on full, aim the gas around all the flanges and joints at idle and see if the engine picks up

If it does then its an easy fix, if not could be carb settings

[baz-r]

Originally Posted by mark

Air leaks are quite common when people are doing the bike carb thing and the syptoms are exactly as you describe

My cvh install did a similar thing until i got the manifold skimmed

Try using a blow lamp unlit on full, aim the gas around all the flanges and joints at idle and see if the engine picks up

If it does then its an easy fix, if not could be carb settings

or use wd40 to get in the gaps