850 1995 Idling up and down Topic is solved

Post by **manovlov** » 04 Dec 2022, 08:59

On Tuesday, I drove 200 kilometers with the station wagon. No worries. But when I got back to the city, the idle speed started to go up and down, between 500 and 1300 rpm, just like that. I was able to bring the car back at the cost of over-consumption of gas. I deduced that this was due to the MAF.

In your opinion, this type of engine behavior, could it be the MAF, the cause of the failure? (I looked at it when I took out the air box, it is perfectly clean and no dirt on it, nor in the duct).

The spark plugs, the harness, the rotor, the finger are new. On the injection side, all the gaskets are new, and the injector filters have been changed. The PCV kit is new.

I think my vacuum system is good (I have to check it again).

But it could be an air intake...

Any idea what I should check?

Post by **misha** » 04 Dec 2022, 10:41

Disconnect Maf connector and see if the idle returns to normal.

Since you replaced PCV system recently...it could be that you have a vacuum leak somewhere.

Post by **manovlov** » 04 Dec 2022, 10:44

misha wrote: ↑04 Dec 2022, 10:41 Disconnect Maf connector and see if the idle returns to normal.

Since you replaced PCV system recently...it could be that you have a vacuum leak somewhere.

Hello Misha, yes, i agree.

850oldschool · Post by **850oldschool** » 04 Dec 2022, 10:53

I diagnosed my bad MAF by watching the graph of the output on my scan tool.

Many lower cost units have this capability.

Post by **manovlov** » 04 Dec 2022, 12:05

850oldschool wrote: ↑04 Dec 2022, 10:53 I diagnosed my bad MAF by watching the graph of the output on my scan tool.

Many lower cost units have this capability.

I don't think i can plug a scan tool on my 95.

850oldschool · Post by **850oldschool** » 04 Dec 2022, 12:48

My car is a 96.

Do you have the 16 pin connector under the coin holder next to the cigarette lighter?

Post by **misha** » 04 Dec 2022, 13:12

Jetronic management is obdI.

Post by **manovlov** » 05 Dec 2022, 08:01

850oldschool wrote: ↑04 Dec 2022, 12:48 My car is a 96.

Do you have the 16 pin connector under the coin holder next to the cigarette lighter?

Nope, i have this :

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Post by **manovlov** » 05 Dec 2022, 12:25

News.

MAF unpplug, the engine turns low(about 500/600/700 RPM) then stop.

Idling MAF plugged

MAF sensor itself

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Post by **misha** » 05 Dec 2022, 13:58

Do not unplug the connector while engine is running!

Remove connector,start the engine.

If the idle is stable and runs better with Maf unplugged than it is bad.

In your case....since you did a pcv job recently...i would check if there is a vacuum leak somewhere.

Pcv valve,intake manifold,vacuum tree,main big plastic hose from airbox to throttle body,fpr vacuum line.

Read the codes and post them here so we can see what's going on.

Did you plugged in a TPS sensor connector after pcv system replacement?