Engine running rough

[jonathan]

Hi my lada samara 1.3 1989 is running a bit rough, it runs fine but i have a manifold gasket leak i think because when i spray carb cleaner near the manifold it smooths out, also i have a leak between the brake booster and master cylinder how do i fix this ? Can i buy a seal only for it ? When i spray carb cleaner between the two engine smooths out also. There is a loud hiss noise from engine bay and brakes are a bit hard to press

Topic

[college man]

Cap off the brake booster line and see if the leak is detected or the problem goes away.
Also inspect that rubber line for cracks or splits. If the booster is at fault you will need a
new booster.

[jonathan]

[quote=”college man” post=180076]Cap off the brake booster line and see if the leak is detected or the problem goes away.
Also inspect that rubber line for cracks or splits. If the booster is at fault you will need a
new booster.[/quote]

Yesterday i removed the inlet manifold to servo vacuum hose and blocked the non return valve on the servo, it was still sucking air from between the booster and master, i can feel it with my hands

[jonathan]

Ok im stuck now. The engine is misfiring in cylinders 3 and 4. When i remove ht leads from them nothing happens, changed spark plugs with known good one, nothing happens, ht leads 1 and 2 have 12.4kohms and 3and 4 have 10kohms. Ignition coil have 1ohm resistance, spark plugs dont show plug fouling with oil or any other. Plugs are with a white tip all of them, also when im driving engine is still misfiring i can feel it hard to go up to speed

[jonathan]

Also distributor cap and rotor are new even the plugs and wires are new

[college man]

[quote=”jonnycilia” post=180088]Ok im stuck now. The engine is misfiring in cylinders 3 and 4. When i remove ht leads from them nothing happens, changed spark plugs with known good one, nothing happens, ht leads 1 and 2 have 12.4kohms and 3and 4 have 10kohms. Ignition coil have 1ohm resistance, spark plugs dont show plug fouling with oil or any other. Plugs are with a white tip all of them, also when im driving engine is still misfiring i can feel it hard to go up to speed[/quote]

10k sounds high for resistance.

[jonathan]

The wires are like 400 miles old. It is sparking if i unplug from the distributor cap and from the plug i can see the sparks. If the resistance is high how come 2 of them are working fine

[jonathan]

Ok today i tried a different test, i have read on the net that if you put your hand on the carburetor and it runs better its a vacuum leak, and i done it, it ran better and while i was holding my hand slightly on the carburetor i unplugged all of the spark plug wires one at a time and they all made the engine stumble so i think i can say that the problem is my intake manifold vacuum leak right ? Also when i spray carb cleaner on the intake gasket whete the 3 and 4 cylinders are it runs smooth

[jonathan]

Today i sprayed soapy water around where the spark plug meets the head and there was bubbles forming meaning there is a leak, its tightened all the way, also the engine is misfiring in cylinder 3 only the same one where bubbles formed

[Mike]

If you are losing compression past a spark plug, I don’t think the hand-on-the-carb thing would have improved the engine’s operation. Might just be coincidence that the soapy water is bubbling at that spot with engine heat.

[jonathan]

Yeah i thought that too, i dont believe its anything to do with engine compression it has only 24k miles on it

[jonathan]

Im believing that the intake manifold gasket is torn up or something where there is cylinder no.3 i can hear engine revs up when i spray carb cleaner, also there is a massive vacuum leak between the brake servo and booster which also hisses alot and when i spray carb clean engine revs up

[Author]

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