Erratic idle, stalling (Have read old topics :) )

[dagajsek]

Please help, I'm now officially lost and losing patience fast.

So B18FT engine inserted to R5, not exactly for racing reasons but for sunday driving car. There are no physical modifications to the engine, I used whole of original loom and the loom for dashboard with Volvo's dashboard. I just binned that black OBD box, because my version did not have any contacts on place where engine diagnosys should be. Other wires were cut to fit and resoldered.

So, when I started to use the engine, lets say half a year a go, It started fine, worked up to a nice idle on cold and hot coolant. First test drives came three months later. Of course, everybody tried the power of an engine and time by time I could hear idling going erratic (at that point not overly problematic). But still, engine worked, started up, was responsive (except for the really huge turbo hole, which is weird for T2).

Like in the fairytale last day of failureless work was on my wedding day (thank god or what?), the day after I hardly came home and it died on me on the driveway.

Now, with MAF plugged in, it starts quick, builds up 1200-1600 rpms, three seconds later falls to 1000 and then dies on some 700 revs with an awful noices that do not provide me with good feelings. With MAF disconnected, it starts, goes to steady 1300-1400 rpms and runs rich.

So firstly, checked the cylinder pressure, all good as they should be, It is a renewed engine.
Cleaned the sensor on gearbox.
Took out ICV, cleaned it, saw it has some problems moving and opened the winding part where there was some rust builup, got it back together, It should work (on test bench it certainly did and it did a full rotation, not a one third one before).
Took resistance measurement of temperature sensor, all good, connections to computers ok.
Binned the engine breather black foamy thing as it was not good anymore (but haven't ckecked it when building the engine so am not sure if it got bad now).
Replaced MAF with known good one.

Now some questions:
Firstly, how to test knock sensor and could it be the culprit for the problems caused?

Secondly, as I am not an electrician, how does that ICV even work. I saw somwhere it has two earthing poles and one positive. How can i test it even more? And what in the name of the lord can die in it to malfunction? It is a fairly simple device.
It is very weird that when engine is running without the MAF and I plug the MAF in the powerful hissing sound from the ICV is heard, as if computer shuts it close, and engine still tries to get air through some small hole but it is not sufficient and dies. The only way I can make engine somekind of work is to remove the hose from the throttle body and let air go through a small hole in the TB, blocking the hole with my finger resulted in sooty, black smoke coming from the tailpipe. When hose is on TB, the audible hissing occures both in the TB and on the ICV as mentioned before and car dies.

Thirdly, can there be somekind of problem with throttlebody itself? I tried to measure voltage (by help of VADIS files), but can see it misleaded me, I was measuring wrong pins. I won't be near the car for two weeks, so can not measure it again.

And lastly, how does a faulty lambda sensor cut into this story. I am not sure if it works, but will replace it either way. Just wanting to know.

Please help me with some clues, I've got no ideas aynmore.

Thanks,
Damjan, Slovenia

[pat480]

I had a similar problem some years ago on my non - turbo B18. Turned out to be the Engine Temperture Sensor. You mentioned you checked the resistance and it was in range but it might be still worth temporarily dissconnecting it and letting the CEM default settings take over. You could definitively rule out the Temp sensor if it is still idle-ing erratically...it may initially stall as the cold start will be wrong

[dagajsek]

Ok, another thing i've now put on the list to take a look at next time. Thanks for the tip, haven't tried that.

I now know how to test knock sensor, so that one will get some attention as well.

What do you think, is it possible to wire up that obd box even if it wasn't equipped with engine diagnosis? I am wondering if all LH2.4 units had option to do that or not.

[480_rocket]

Have you put a ignition timing light on it to check the spark timing? And the cam timing is OK?

Check fuel pressure. Check injectors resistance too.

No OBD port is possible. You should be able to hook an LED upto it though and get it to flash codes.

[dagajsek]

No, I haven't, i have no option of borrowing one.

Well, I haven't checked the injectors, but again, those got some service when I got the engine running (they were stuck at the moment) and were flawless.
Pressure is fine, have checked it, I run new 5bar inline pump.

That LED is kind of a mystery. After hooking up all the loom, I was left with two wires (going to LH and EZ), and of course have no idea of what they are supposed to do. And of course have no idea on how to use it. So if diag box has no connection to port 2, there is no way i can make it to tell me the possible trouble codes? And is LH 2.2 not 2.4, my mistake.