E16SE ignition/fuelling problem

[MK999]

My E16SE has started showing some very odd ignition characteristics, firstly it is idling very low when warm, around 500-600ish rather than a more healthy 800-900 but it will sometimes idle perfectly fine when cold. It's also pinking, but never under load, it will pink on the overrun or when rolling along at around 2500 rpm, retarding ignition doesn't seem to change this at all.


Can't think what would cause it to idle lower than normal and pink but never under load! :confused:

Have checked all the ignition leads and they're all well pushed in etc, no visible air leaks on vacuum pipes etc (although there was one loose a while ago causing it to konk out when dropping back down to idle from higher revs and idle even lower than what is currently normal) Earths are all ok as these were checked at the same time as I had the air leak.

[Iain]

Low idle could be caused by the idle control valve (or is it called something slightly different on these engines? Just in front of the inlet and works off a pipe on the rubber inlet hose before the plenum I think?).

I've just looked up what causes pinking and a cause is underfueling (too much air) - this could be caused by the idle control valve sticking open?!

Just guessing to get the ball rolling :thumb:

[MK999]

Could be an air leak then, and if it is I know where, all the vac gubbings around the fuel reg are a little bit suspect, and the last air leak was caused by one pulling out so they obviously don't seal too well.

ICV has been blamed for problems a couple of times and always been something else so i'll leave that for now lol It is indeed called an ICV on these though and it does indeed work off a rubber hose just there, well remembered :thumb:

[MK999]

Checked for an air leak today, and can't find anything, seems it is running lean though as the plugs are slightly white. There's no sucking noises etc around the engine that would indicate an air leak, all hoses seem to be intact, would it be an idea to richen it on the screw on the AFM? If so which screw is it, the one that points towards the cambelt on the top with a round 'housing' type bit on it? and which way is richer lol

[Iain]

Surely if the ICV is sticking open it would let too much air in and weaken it, have you checked it's working properly yet?

[MK999]

That would be measured by the AFM and accounted for though surely? Suppose it's worth a go before anything else though, is there any way of checking it's working or just a case of yanking it out and attacking it with brake and clutch cleaner?

[chimp007_uk]

I wouldn't just start adjusting the fuelling, it might well be a a manifold gasket leak or the dizzy might be faulty and causing the erratic ignition timing.

a gasket leak can cause a tapping/rattley sound. I'd check everything before playing with fuelling especially when you have no way of monitoring the fuelling.

[Iain]

Hmm doesn't Haynes mentioned a method where you attach 12v feed to it and see if it slowly closes or something?

[MK999]

doubt it's dizzy, as the plugs are reading white, definitely running lean, just not sure why.

edit: I'll check the haynes for the above.

[MK999]

Found the haynes manual and can't see any movement in the ICV, guessing the best way to clean it is brake and clutch cleaner?

[MK999]

Managed to get it to a point where it seemed to be moving, and it now idles much nicer, but the pinking problem is still apparent. I advanced the ignition back to where it was before, and it hasn't made it any worse, so I don't think the timing is the problem. It will do it when coasting along or dropping the revs while sat still at about 2.5k.

[craig green]

Oddly the valve on the end of the inlet plenum is the 'coasting air valve'...

Did you lube the ICV (supplementary air device) after cleaning it out? The carb cleaner will have degreased it entirely.

[MK999]

I didn't, but I will do now. Coasting air valve much the same deal as the ICV, blast it with carb cleaner/compressor etc, or will it need replacing?

Also did spot the coasting air valve in the haynes, but as it's supposed to lean the mixture, I figured it wouldn't be causing the problem, as it's supposed to make it run leaner on coasting?

[craig green]

Its an odd problem. Theres not much that can go wrong on these engines.

[MK999]

Do they have a knock sensor? Wondering if that might be duff causing it to advance too far under certain conditions? Although if anything the ignition would be retarded when not under load? Will try blasting some cleaner/air down the coasting air valve.

Inlet gasket is brand new so I don't think it's that causing an air leak... could be the throttle body gasket though maybe, Might try and get a new one of those, although I was gonna do the butterfly at the same time as I did that. Think it's a cav 1.8 one that will replace it but I'm not sure if it's the full TB or just the butterfly.

[MK999]

Cleaned out the coasting air valve, and that didn't solve it. Also went for a suggestion by jimbob mcgrew that it could be the AFM sticking slightly causing it to run lean, so I took that off and found it rather mucky so cleaned all that up and it now responds much better when you put your foot down, but still pinks! Haven't had time to pull the plugs out as I have a couple things to do before work, but I'm assuming they're less white than they were now as the afm is opening up correctly and not running it lean on acceleration.

Only thing is this now points it back to being a timing issue, but it won't pink under 2k as you'd expect with timing advanced too far! Currently after setting the timing back to where it should be after trying it retarded to see if it affected it, when you pull it through the rev range at full throttle it will bog down a bit under load as you'd expect, up to 2k where it starts pinking, will pink through to 2.8-3k and then is fine. It will also pink when coasting around 2.5k, how much throttle you apply affects how much it will pink around that range, i.e foot off it will pink 2.2-2.8 and if you roll it along at constant speed only bang on 2.5k.

Will try retarding the ignition slightly again tomorrow, which may stop it doing it under load if i've set it back 1/2mm too far, but I doubt it will fix it under coasting :(

[Stuart]

crap idle/drive when warm is usually an EGR fault.

Not sure if your version of the 1.6 has it or not (it came in for the later ones)

[MK999]

Does have an EGR which I was going to sod off anyway eventually, but the crap idle I have put down to me messing about with the idle screw a while ago when the timing was mahiiiiiiles out, adjusted that back up and it seems to idle fine now.

Retarded the ignition slightly today and it reduced the problem a lot, it still does it when coasting though so I'm not entirely sure it's the problem, but the revs seem to drop too far when clutching to stop which was happening when it was slightly too far advanced before so I'll try it retarded slightly again see if that fixes it, it's also picked up power wise a lot. But it is now about 1mm out from the GM markings, so I'm not sure if it's solving the problem, or just covering up another one.

The engine is cammed, but this shouldn't really affect the ignition timing should it? Or would more fuel/air in the engine mean it ignites quicker and so the ignition timing needs retarding further than the standard markings to stop it pinking?

edit: It does actually pink a lot more and only drops idle too far when warm, How do I sod the EGR off? Blanking plate and unplug it/block all uneeded vac lines?

[gregs]

Had this on mine twice before , easy way to find out is on your octane module if its on 98 turn it to 95 then try it if that fixes it go get a new module and put it back to 98

[MK999]

Mine is definitely on 95 altho it's that old the number is really worn, is it worth getting a new one? Also it's yellow, is that the correct colour for an 89 E16SE? (Tensioner on cambelt and the vane type AFM if that helps anyone)

[gregs]

both on my gte and gsi are red. yer worth getting a new one!

[MK999]

GSi run 95/98 plugs? Looks like if I switch mine to 91 it's the same as red 95 according to the highly trustable top buzz site.

[jimbob-mcgrew]

damn mark, sounds like fun and games. have another look at that ICV cos when u manually put voltage thru it, it should smoothly flick fully open and then fully shut without juice (or vice-versa depending on my memory). mates one was seized shut on his and caused high slightly erratic idling, you have to be carefull freeing it up, not sure what the best method is, but we went in brutal styles with a screwdriver and chinked a few bits out of the leading slide edge, cained the hell out of it with wd40 afterwards and put it on and off electric to move it back and forth, it never seemed to move aswel as it shoulda done tho, it was gently catching at some point along its motion. if u cant fully fix it, prob worth investing in another. i doubt it will fix the pinking probs, but if u can eliminate all the bad bits it all helps. talkin of pinking and timing, i had loads of probs with mine and i messed around with the timing for ages, advanced, retarded, tooth in, tooth out, never made any difference to it really, it was only till i sorted the fueling out that the pinking stopped, must be the same with yours, but 2.5k is such a random spot for this to happen. i bet its something to do with the idle valve or in/out air/fuel sensors, me scratches head. probably got a hole bored down thru the centre of one of your pistons and the sparkplugs shooting a spark down into the oil in the sump and causing a temperal vortex at 2.5 grand lol

[MK999]

ICV seems to move very very slowly, do you have to put 12v on both pins, or does the haynes mean 1 pin positive one earth, then reverse it? Fueling should now be fine, but the ron plug will be causing some ignition issues, so i'll flip that round so it reads the same as red 95 and see what happens.

edit: those exhaust rubbers are yours if you want them btw, you seem to have signed out of msn.

[jimbob-mcgrew]

not sure how its supposed to move, but his was flicking back and forth prety damn quick, yeh we had live and earth on each pin. nice one for the rubbers :thumb:

[MK999]

Had a bit of a play with the ignition timing just now trying to get it back to where it was, only thing is when you set it back to just before it pinks under load, it pinks across a wider range further up, and is much more sluggish. It seems to run better with it more retarded, also it's not just under coasting that it will pink further up, it's a bit on/off but it will also do it when booting it. Plugs are still white after cleaning up the AFM, so it's running lean, idles fine when retarded to where it seems to prefer running but it will idle a bit off when you set it to just before it pinks under load... air leak? Or a mapping/fuelling problem?

edit: Also if you're coasting along and it's pinking, booting it doesn't stop it pinking, surely it should run richer for that split second under acceleration, so does that rule out the lean running causing the pinking?

[MK999]

More fiddling, checked all possible places for an air leak, no 'luck' on that. So I started wondering what could make it run lean, injectors... can't really test those. Pump, is an astra mk3 mpi and seems to run fine. AFM has been cleaned recently, fuel reg... now I'm not sure exactly how this works but I took the vac line off the top and it runs exactly the same as it does without, or it seems to sitting it on the drive and revving it by hand. Does this mean the fuel reg is funked and not increasing the fuel supply when needed?

I'm at a loss as to possible causes, and want to rule everything out before i go the easy route and say it's because the engine is breathing better and the fuelling needs increasing to match.. as it should manage on the AFM with so little modification surely? It only has cam, filter and exhaust.

[gregs]

you tried the octabe module yet???

[MK999]

changed to the same as a 95 red, doesn't effect fueling though.

[turbo-boy]

clean your injectors put a fuel gauge on the rail see wath pressure its it.and also do you hav a veriner pully for your hi lift cam?

[MK999]

No vernier pulley on it, Will look into refurbed injectors (it's a daily runner so i can't take them off and send them away for a week) and pressure guage is a good idea actually, would an inline one on the feed read correctly or do i need to tap it into the actual rail?

[MK999]

.

[MK999]

So today tried to get it running well enough to get me to combe/trax at the weekend and think I've managed that but it's still far from fixed... Put a new genuine cam belt on it as the powergrip ones I have got so far have stretched after a few weeks and gone loose? However apparently Gates make powergrip belts for GM so it's the same belt with a gm stamp on it ;/

Also fitted and adjustable FPR, which is supposedly set up to fuel a 1.8 cav, thought i'd try it and if it's worse off with it i'll switch it back, seemed to improve it but it's still pinking and now seems to be running rich to me? It's very hesitant at low rpm unless you feed the throttle in slowly, to the point where 1.5k in 5th flooring it takes 20s or so to get to 1.75k. However plugs seem to read ok, so wondering if it's worth fiddling with the timing again? It generally runs much better until you floor it at low rpm, but still pinks and plugs still read slightly lean, although it could be white residue from before

[craig green]

Explain how you are setting up the ignition timing.

[MK999]

Before the problem showed up it was just advanced until it pinked under load (floor it in 5th at low rpm) then brought back a bit, which set it bang on the marks on the dizzy.

Currently it's more retarded than that and pinking, and no amount of retarding it will stop it.

[craig green]

With all the pointers on the belt side lined up, where is the rotor arm pointing??

[Adam]

Are you SURE its actually pinking?

[MK999]

With all the pointers on the belt side lined up, where is the rotor arm pointing??

At the contact point for cylinder 1.



Are you SURE its actually pinking?

This is what I've been wondering recently, if it's just a rattle in the exhaust or something that sounds stupidly similar to pinking, is there any other way to tell, does it show on the plugs or anything like that?

[MK999]

Right after reading around a bit on different ways to diagnose it, the only thing I can possibly see to explain it is it's just an odd rattle that sounds uncannily similar to pinking... as running richer, running retarded ignition timing, and using 99 ron fuel, or 2 of the above combined at any one time, has not fixed/changed it. If it is pinking I'm totally lost as to why anyway.

On the plus side I wouldn't have spotted the lean running otherwise, or the way it runs quite unevenly across the cylinders (cleaned injectors required i think) and once I have the AFPR set to a sensible pressure the car will run much much better than before. The odd misfire has not reappeared since changing the belt/fpr so seems that has been fixed. All I can see to do now is drive it and if it goes bang I was obviously wrong about the odd rattle lol

Thanks for your help everyone that joined in.

[jimbob-mcgrew]

scrap it mate, she's done lol

[MK999]

Don't think I haven't considered getting rid lol I think it's all part of owning a nova