HELP! Tach problems

[fat_85_civic]

Hey guys my car is having some problems and im hoping someone might know what’s wrong.

Firstly once my car is warmed up it will idle normally and fairly smooth but I have a SAFC in my car and it will just randomly say like 1500rpm for a split second before gong back to normal. I sure it’s not the tach wiring as it has only recently started happening. My normal tach doesnt show anything because it only jumps for a second. And when i put it on the graph mode i can see it jump every 5 or so seconds but the engine speed isnt changing. And if i hold it at say 2000 it will do the same thing but with bigger jumps and more frequently.

Im thinking it may be my igniter because a while ago when my car would get hot it would die and the tach would go crazy going up and down. To fix it I just put in an old igniter I had and now im thinking its going to do the same thing again.

Also when i let off the throttle and slowly coast as the revs drop below 2500RPM's the digital tach does the same thing but worse. on trhe graph mode it is just a constant zigzag when it should be smooth.

This also makes me think it is the ignoter or coil as why is it only doing it below 2500RPM.

Also when im accelerating with really light throttle from around 3000-4000 it has a slight hesitation which could be the igniter too couldn’t it?

Hoope fully someone will have some ideas

Also i want to buta new bosch coil but had a look today and the re is a few different models, does any one know where the find out which one need?

I have a 86 integra engine (D16A3) incase that helps.

THanks
Luke

[fat_85_civic]

bump....

[EuroDude]

Slight hesitation at mid-high revs may indicate a spark problem, so test the resistance of the spark leads, make sure the spark plugs are in good condition (check the colour of the contacts, they should be a slight brown colour) or replace them if you havent replaced them for a while. Also check for water in the Spark plug holes, and replace the Dizzy Cap with a new one (cheap). Hopefully its not a Dizzy igniter or coil problem, as that can be quite expensive.

As for the idle problems, check the usual suspects, such as the IACV screen, FITV Valve, and give the throttle body a clean. You may wanna try some fuel injector cleaner additive, and make sure the alternator and battery are working ok using a multimeter - should be 14v when the engine is running.