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My dream come true, but I need help.
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Munk



Joined: 14 Aug 2013
Posts: 23
Location: BC, Canada

PostPosted: Fri Feb 06, 2015 1:54 pm Post subject: Reply with quote

OK, so after months of waiting I have finally got my niva running... Almost.

So I pulled apart the engine to find the pistons had been obliterated and some deep horizontal corrosion lines on the cylinder walls where the rings had been sitting. I got the block rebored, replaced the pistons and rings with +0.8 sizes and put it all back together with new bearings, seals and love. I will upload some pics when I am at home.

Now my issue is that the engine hesitates when pressing the accelerator, it runs perfectly when cold but as soon as it goes closed loop the idle gets a little rough and it hesitates so bad I can't let out the clutch without stalling or peeling out. It will also hesitate while in neutral.
I checked the ignition grounding and vaccume hose to the map sensor and I can't see any issues. I don't remember having this problem before the rebuild but the engine was pretty *censored* so it's hard to tell.

The computer blinks 12 so I am guessing it is operating normally.
The tachometer also takes a while to start working, not sure if that is related..
Is there anything anyone can think that would be causing this?
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Munk



Joined: 14 Aug 2013
Posts: 23
Location: BC, Canada

PostPosted: Sat Feb 07, 2015 5:14 pm Post subject: Reply with quote

Today I fiddled with some wires and the field service diagnostic mode. After a pretty solid stall and some random code 15, 33 and 34 popping up I think I have managed to reduce the hesitation to the point that I can't tell if it is there. I still have to road test it to make sure but I am hopeful.
The one other thing I have noticed is this rather loud spastic relay firing behind the fuse box. It seems to be most active when I am testing for hesitation (tapping the throttle when it is around 1000rpm) and it causes the lights to dim and the tach jumps up to 2000rpm independent of the actual engine speed. Is this normal? I don't remember hearing this thing before and I can't figure out which one it is. It looks like there are 5 relays in that area, I can account for 4 of them. The ignition, starter, fuel pump/injector, and preheater relays. The fifth is a mystery. I cant imagine any of the known relays toggling like that as it would certainly cause an immediate stall.

Also, is it normal for the voltage to read 14.7V at the battery when running? It drops to 13.5V when that relay fires.

Can anyone shed some light on this?
Thanks
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baxter



Joined: 06 Feb 2007
Posts: 167
Location: New Zealand

PostPosted: Sat Feb 07, 2015 7:35 pm Post subject: Reply with quote

Message Gadgetboy (on this forum or lada.co.uk), if no one replies here - sounds right up his alley.
_________________
1990 Niva 1600, 2" lift
Baxter's Temple of Niva
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Munk



Joined: 14 Aug 2013
Posts: 23
Location: BC, Canada

PostPosted: Sun Feb 08, 2015 5:52 pm Post subject: Reply with quote

OK, so I think I identified the preheater relay and it seems to be pulsing. It is the one with the black connector right?

I keep getting random code 15 and 33/34 errors that go away after a minute.

I also noticed the engine is burning oil, I am guessing the rings still have to wear in.
Could this be causing problems with the o2 sensor, it would explain why the handling goes to crap when it goes closed loop.
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Munk



Joined: 14 Aug 2013
Posts: 23
Location: BC, Canada

PostPosted: Mon Feb 09, 2015 11:33 pm Post subject: Reply with quote

Just for the record I found out that my alternator was being driven by a bad belt. I replaced the belt and solved a battery charging problem I was having but the code 15, 34 errors and spastic preheater relay are still a thing..
The check engine light comes on and goes off periodically as I drive, I swear I have a bad ground somewhere.
I am on the verge of replacing the entire wiring harness, I was planning to do it anyway but just not so soon Sad
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GadgetBoy



Joined: 10 Jul 2008
Posts: 957
Location: Belfast, N. Ireland

PostPosted: Tue Feb 10, 2015 2:24 am Post subject: Reply with quote

You can't. The Engine Management runs on an entirely separate harness and it's no longer available.

15 is the CTS
34 is the MAP

The CTS is on the front end of the inlet manifold. The MAP is on the bulkhead. Both codes are indicating the value expected is too low. You can test the CTS is producing the correct resistances, see here:

http://www.lada.co.uk/forum/viewtopic.php?f=1&t=9987

Check the physical connection to the CTS. If there is any indication of dampness or moisture in the connector (oxide or purest green) replace the CTS. CTS's are known to start leaking internally after long idle periods especially if your coolant is old or the wrong concentration.

The MAP is a little more troublesome but the readings would indicate a vacuum leak. Check the MAP hose (again), the brake booster hose and all the mechanical connections and joints in the inlet tract. Even the tiniest vacuum leak will make a difference.

Check all the electrical connections in the ECU loom especially the large connectors into the ECU itself and the Coil Pack.

Don't worry about the manifold pre-heater relay for now, it's a red herring. It doesn't know what temperature it is because of the wayward CTS readings.
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GadgetBoy
'96 Niva 1.7i
Belfast, N. Ireland
http://www.ladaniva.co.uk
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