2 PROBLEMS, 1 RB

[Project13]

Background:

1988 S13 silvia. Originally auto ca18det, became manual ca18det. Now converted to rb20det (Manual)
The engine that has gone in is from a gts-t r32. I have put on a front facing plenum in order for the bonnet to shut. The engine was purchased from an importer and I haven't used it before.

Problem the first:

Car turns over and fires. Getting fuel and spark. It will hold a s*** idle if you keep it alive with the pedal. Cant hold idle by itself. Even when you use the throttle it is very lumpy. While keeping it alive with the throttle it will rev out, drop revs and die (unless you can catch it again with the throttle). You dont have much control over the revs going up. We've tried playing with the CAS and the IACV - no real noticeable improvements. We have tested an array of things and want to double check with you guys to see if anything else is worth checking. Any ideas on what could be causing this?

Note: If the Front facing plenum went on before the engine has started in this car, could it just require a good tune to get a decent idle and run better?

Problem the second:

A sparky that came and did some wiring did the runner so it is hard to ask him any questions.. but.. he has managed to wire the lights up so that the headlights and taillights are on a constant power. As soon as you connect battery, the lights are on. Doesnt matter if the ignition is off. We have unplugged the light switch, all interior fuses and relays, disconnected most plugs in the car, disconnected all fuses and relays in the engine fuse box.. believe it or not, the lights stayed on. With the exception of the ALTERNATOR fuse being out. The lights went off. Where the hell could these be wired to and why are they staying on??

PLEASE HELP ME!!

Thanks

[centralcoaster33]

For the wiring issues, you can revert back to the OEM wires with a little help from the diagrams in the FSM. Here's a link to that:
http://www.nicoclub.com/service-manual? ... /1989/1989
And some wiring diagrams for the early CA18DET link:
http://www.nicoclub.com/service-manual? ... %20CA18DET

For the stumble idle issues, I'm not sure. Make sure there are no vacuum leaks. That always blows the idle out of whack. Check timing with a light and set the IACV (start closed and work your way open as you go). TPS and MAF are what I look to on my car, but it's a newer S14 with KA24DE so I'm not sure about yours and hope others can chime in. You can always check our engine specific sub-forums and even the GTR sub-forums for similar issues, diagnoses and repair ideas.

[Project13]

Hi centralcoaster33. This is not the first time you've chipped in with some ideas for my issues so thankyou!

Have had a good look through wiring diagrams for the light problem. Also have a mate here who is an auto sparky and even he is a wee bit stumped at present. Testing stuff left right and centre and it makes no sense!! Driving us both nuts i think.

With the idle, I will try what you are suggesting today. I have checked for leaks and couldn't find any but no harm in another check. Have got the iacv right in and will start working our way out. Will move from there to maf tps etc. Also have checked these but will make double sure.

What are your thoughts on going to Front Facing Plenum before I had it running on the standard intake?
Bad move I'd say in hindsight but would be interested to get another opinion or two.
Could this make it run like a sack of sheet at idle? Or should it at least be able to hold its own?

Cheers again

[PapaSmurf2k3]

With the lights you could always just re-wire them to whatever switches and relays you need them to be yourself (using the FSM previously posted). Sometimes its better to just not even try to understand wtf the other guy was thinking

For the idle, I wouldn't think the plenum would matter, but if you can easily convert it back just to rule it out, it's probably worth doing.
If you can't find any vacuum leaks, I'd say try inducing one. Pull a vacuum line going to the fuel pressure regulator or something. It could be that the engine is just starving for air, or is running too damn rich. If it makes the problem worse, then you might be running too lean. Do you have control over your fuel pressure?

Performing these checks should tell you which direction you need to go.

[PapaSmurf2k3]

Lastly, have you confirmed valve and ignition timing? I'm not familiar with RB engines, but is the ignition timing easily adjustable?

[Project13]

Hi PapaSmurf,

I have got the idle sorta sorted now. Found that the mating surface between runners and plenum had an air leak and that a few wires (ecu and dash) we're wired up wrong.. New gasket and a bit of wiring and now thats on track. Sounds like it just needs to have the timing and tuning played with now

Still, I have no idea what the heck is going on with these park lights. I will look to re-wire if I cant solve it soon.. Just would prefer to save the hassle if possible. But I fully get where your coming from - Im digging for a needle in a haystack and it may be easier to just crack on to wiring them properly.. But first, I will try shed a bit more light on it and see if anyone here has any experience with similar issues or has any ideas on what might be going on.

As soon as it has the battery connected they are on (front and rear park lights) also the dash lights and the light in the heater control box do the same. The park lights brighten a little when you press the switch to turn them on and dim back a little when you turn them off... Please somebody correct me if I'm wrong here but there must be a circuit in this car that includes all of these lights and has been incorrectly wired to a constant power ?!
Head lights, High beams, fog lights, hazards and indicators all work normally. We have unplugged the light switch, all interior fuses and relays, disconnected most plugs in the car, disconnected all fuses and relays in the engine fuse box and it seems that only when the ALTERNATOR fuse is removed do they turn off.

ANY IDEAS ???

[centralcoaster33]

You can remove the appropriate relays and see if they've been "modified" to just be jumpers and always on. Wait, just re-read... you did that... It seems the jumpers may have been 'done up' in the wiring ball below the actual relays, since your pulling them out has no effect. You could look for a medium gauge wire that doesn't quit fit in with the rest of the wires and is crimped onto a few places by a shade tree mechanic. This work could have been done to the ignition switch wires in the steering column for Accessory 1 or 2. Get the FSM and look at the wiring diagram in the EC chapter. Find the common link between these odd light behaviors and look at those wires for a crimped on bridge somewhere.

[Project13]

Hey mate,

The majority of the loom is now unwrapped and we hadn't noticed anything yet. A lot of the wiring now looks a bit out of place due to RB wiring connected up to CA and some custom plugs... Makes it tricky to trace them and pick out the shady buggers.
As you say though, I will have a better look for a dodgy wire.

Final straw bro - re wire time after today. haha

Cheers for your continued help

[centralcoaster33]

Wiring is a PITA sometimes. This seems like one of those times! Best of luck.