Tach jumps while cranking

[Xulfiqar]

Its kinda strange,

When I crank the engine the tach would jump - like be somewhere like 1 or 2 thousand rpm - and as soon as the engine fires, it sounds like trying to crank an idling engine.

Any ideas anyone - I already pulled the starter and built it myself, - its A spec brand spanking new Mitsuba 1.4Kw type.

[A20A1]

May be it's an ignition problem... I really don't know what to say.... sometimes my corolla will start and I can hear the starter whizz right after the motor starts. I have an Alt or battery connection problem. I have so much electrical nonsense going on... bleh, i wish i was driving the accord.

[shepherd79]

you just have to replace the started. get one from a junkyard or buy a new one.

[Civvy]

I've noticed on the past with some of my ex cars the needle has bounced fractionatly!! I'm sure if i look close enough to my car now, im sure it will jump fractionatly too. I've since always thought it was a common thing, and sometimes i've regarded it as another way to check the engine is firing when i'm in the middle of a breakdow! I'm intregued to know what is causing this on your car and that it has worsened, as its maybe an indication something has become faulty like the coil perhaps? or maybe something in the ignition low-tension circuit? Are your engine earths good?

[Xulfiqar]

Im gonna test the entire ignition circuit this weekend, coil, dizzy and ignitor, I mostly think that my starter solenoid is going bad.

[Civvy]

I dont c how your starter would affect the tach? ...its on a different circiut? Sorry if i am ignorant to this? I would check Low tension ignition circuit and then i'd check connections to the tach!!

[Xulfiqar]

Ok guys - it went all kinds of stupid like an hour ago - I turn the ignition on, and crank it - the tach spun till 7 grand for a split second and kind of killed my battery - I released the key immediately without the engine firing.

I restart - the tach hovers at 3 grand - starter sounds like a dead battery is cranking it - and it starts - but with an overstarting sound - (like trying to start a running engine) - Man I hate that.

I think the pulse generator wires are nearly broken - any guesses.

I work 6 days a week - so I only got sunday for repairs, which I usually do myself.

[carotman]

Well, I that will not really help you but might help you pinpoint some areas.

I had the same problem with my A20A. I replaced the battery, starter and igniter without luck. The car would basicaly start and hesitate while starting. The tach was jumping all the way to 7k..

when I swaped the B20A.. everything was good. I guess one of the engine grounds was bad because I used the same ignition setup (except the distributor itself)

Check every ground on the engine and try to clean them. That might solve your problem.

[Oyvind Ryeng]

I hear a busted distributor can cause a jumpy tach?

[Xulfiqar]

carotman - I think the pulse generator wires inside the distributor are nearly broken, due to age, that can cause erratic voltages to the coil - surging the coil full of current and in turn sending intermittent signals (noise) to the tach, that problem occured on my rolla - replaced the pulser - it was ok since then.

What I figure is that the huge current draw - tends to disengage the solenoid for a breif moment (causing teeth clash on the starter and flywheel)

[accordlxi2.0]

i had the same problem you're having, but the battery and alt is new.
i could keep cranking and when the starter was getting worse it would sound like a dead battery, but it was fine like shepard said it's more than likely the starter.

plus i notice on these car's that once the engine start's you could still hear the starter winding down.

[Xulfiqar]

I tested every item

Ignitor
Pulser
Coil
starter
alternator

according to the manual I downloaded from pauls site. eveythings A spec, I even cleaned the grounds - the problem is now less frequent but its still there. now Im pissed - what to do?

[Xulfiqar]

Man - my job sux - I was just deputed to some really weird places where internet was unknown - thats why the late response.

I tested the starting circuits - and have found that my ignition switch is faulty. Anyways - thanks a million to all of you.

[Hondacrazy]

Sounds like a bad ground.

[POS carb]

i think you have a bad ground or battery