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Discussion Starter #1 (Edited)
Hi all. I was looking at threads related to the symptoms I've been experiencing on my samu, but none of the mentioned solutions apply in my case.

I've replaced the ff on the samu:
- new carb vacuum hoses
- new spark plugs
- change oil
- timing belt & related bearings
- tune up
- cleaned out the fumes valve on carb
- new air cleaner

Symptoms/Problem:
When the engine is cold, the idle is low (400). When it warms up, it climbs up to normal (800-900). After 30mins-1hr of smooth driving, the samu would die out from take off. But the carb shoots up the rev before it dies out. Sometimes it dies out after take off, while in gear. It feels like it chokes when doing revs above or near 3000rpm just as I am preparing to change gears. When everything seems fine, I notice thick white smoke coming from the exhaust. But after a while, the smoke clears out.

We just cleaned the fumes intake vacuum valve yesterday which added more stability to the idling. The engine compression is totally alright.

Modifications:
- electronic fuel pump


What could be wrong or what could I do to solve the erratic behavior of the carb?
 

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Sometimes it dies out after take off, while in gear. It feels like it chokes when doing revs above or near 3000rpm just as I am preparing to change gears. When everything seems fine, I notice thick white smoke coming from the exhaust. But after a while, the smoke clears out.
Mine won't idle, but also dies like yours. Otherwise runs great. Mine generally dies after hitting a bump at a low throttle setting. If I am going fast enough, I can floor it and it will catch back after 4 or 5 seconds. If I am going slow, I have to crank it while holding it floored and it will usually fire back after 15-20 seconds of cranking, with smoke coming out of the exhaust.

I've not been able to figure it out, and am going to replace the carb, and send it back to the guy who rebuilt it to look at it.
 

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Discussion Starter #3
Hi vader! How long before it got to that state? Did you have the chance to own and observe the zook from a year ago compared to its present state?

I think I know what's wrong with our rigs... It's a very good chance it's the ignition coil.

Is your coil new? Mine is still running on the old one. Yours could be showing signs of inability to fire at variable power. And mine is slowly getting there by dying out on common rpm areas already. It would be great if someone could share any kind of experience they had with ignition coil breakdown.
 

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It stopped idling at random as soon as I filled the tank up after buying it. At some point it gave up and stopped idling altogether.

The random stalling started in February. I would have never guessed on the coil. I doubt it is new. Nothing on it except the engine and carb was new.

Coils are cheap. I'll throw one at it...
 

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Discussion Starter #5
Yes, sounds good. Pls do let me know if it improves after the coil change. Unfortunately, coils here are abt $100. Will see if I could borrow one for ellimination purposes. But it surely is a possible cause.

After the coil change, assuming the high tension wires, spark plugs, and distributor are ok, then it's the carb.
 

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I finally tracked my idle issue to a loose ECM to body ground.

I feel this was probably the same cause for the stalling at times. My theory is that, when I would hit a bump at low throttle settings, the feeback system would momentarily kick into action, seeing a rich mixture, and lean the mixture back to the point of stalling, or else the fuel cut solenoid was opening and the sudden presense of the idle circuit was flooding the engine with fuel.

There are two ECM grounds. One is on the intake manifold near the thermostat, and the other is on the firewall near the battery. Check both to make sure the fasteners are tight and the wiring and connector look good.

The locations are pictured in the manual located here;
http://suzukiinfo.com/sierra/1986-1988samuraifsm.zip
on page 5-30 and the procedure to check them from the ECM connector is on page 5-29 and 5-30.

Here is a procedure for setting idle(if you have a Hitachi carb);
http://suzukiinfo.com/sierra/idlespeedadjustment-hitachi.zip
 

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Hi vader! How long before it got to that state? Did you have the chance to own and observe the zook from a year ago compared to its present state?

I think I know what's wrong with our rigs... It's a very good chance it's the ignition coil.

Is your coil new? Mine is still running on the old one. Yours could be showing signs of inability to fire at variable power. And mine is slowly getting there by dying out on common rpm areas already. It would be great if someone could share any kind of experience they had with ignition coil breakdown.
when my coil died i was driving down the road and it just cut out then got it started but cut out again and would not start till i hit it with a hammer had to keep doing that till i got home
 

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Discussion Starter #8
Hey! Just got back from my trip.

Had the aisin original carb cleaned last week and it solved all my carb probs except for one... The idle up still gets stuck at high rpm when the lights or aircon is on. I figure it might be the spring assembly being too weak to push back the idle up, back to normal position after it engages. Will know tomorrow as i will be rejetting to smaller jets as well. I'm doing 11-12 km/L now without aircon. But ith the aircon on it's thrice as much the consumption! Woot!

Will make updates after the changes are tested tomorrow.
 
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