Problem with rough idle. Part 2... with minor repair

Rough idle has continue with worst way. Car jerking during idle and cruising. I suspect there is something wrong with spark plug firing system. Either spark plug cord, distributor or spark plug.

On my way back home, drop by to half cut shop to buy a set of spark plug cord. Also went to spare part shop to buy spark plug and fuel filter. Fuel filter was removed previously due to lean fuel inside combustion chamber. 

From Feroza HD engine workshop manual (can be download from HERE), NGK spark plug code is BKR6E11. 

What I have found from my engine if spark plug with differ code. It is BK5E, not BKR6E11.

Here is BKR6E-11 spark plug.

After replaced spark plug with cord, engine idle better than before. I also reset ecu to clear error code (it has error code 41, 42 and 43) for better performance and relearn. I will check ecu error code later to confirm if the is still error occur.

I also replace fuel filter as the old one already partial clogged. The filter is not 100% identical with original one, but as long it can be function as filter it is ok for me. Relay sitting beside fuel filter is for starter.

Then I also replace breather hose as old hose already cracked. First hose that is use is thick hose. It is multi purpose hose. Since the hose is too thick, it is hard to bend it like original hose. It look ugly, red color, thick and long hose.

So I replace with other hose, coil hose. I look better from my eye sight. Steel coil inside the hose will prevent the hose from kink at the bend section.

Problem with rough idle. Part 1...

On my new ride, it had a very bad idle. Even engine stalled 5 times per day. It's a very frustrating for me.

Then I started to seach for the culprit. First thing suspected is vacuum leaked.
After changed all the related vacuum hose, the idle still rough.

I bought a detomaso Throttle body although I know its not identical. But I still want try to mod to fit it. It's no luck. The TB can fit it nicely but idle still very bad due to different method of idle control. Then I decide to cleaned and put back original TB. Idle not very good after first start. Did a TPS swapped, and it seems idle bit ok. Drove it for 1 day and the problem came back. Now it really gave me headache.

I keep calm for a few days and start listing what is the possible culprit.
Here is the list.
1-vacuum leak
2-O2 sensor (replaced on 9 Jun 14 )
3-TPS adjustment
4-spark plug
5-spark plug cord
6-distributor adjustment
7-clogged fuel filter
8-weak fuel pump

So yesterday I made a decision to repair the cheapest solution first. What i did is
1-inspect spark plug. Whitish color. I guess a bit lean fuel.
2-removed fuel filter.
3-adjust TPS.
All those step did not cost any money.

After finish the steps above, started the engine and observed for idle. So far so good, idle are stable but a bit low rpm. Idle screw adjusted to compensate low rpm.

Today, drove it to work. Idle are steady and stable all the way. I hope the problem has been vanish.

I think TPS adjustment has solved the problem.

IMHO, no need to change TB assy, but try to adjust TPS according to manual. Most people will replace TB assy when they got rough idle problem. And problem solved. It is because new TB have good TPS alignment.


CONTINUE TO PART 2...