Mi16 (2.0L) Odd Ignition/ht Problem - 2 Cyls Sparking Only

[DrSarty 90 1 Cars]

Baffled!

 

My Miami's getting my attention again, and it runs - like it always has since installing the 11:1 Mi16 engine - but only sparking cyls 1 and 4.

 

I've swapped ignition coils (5 different coils in fact) to no avail. I've also tried this in combination with 2 different ignition amps, with always the same result.

 

The only thing I haven't tried is swapping the Crank Position/Angle Sensor (CPS/CAS), but that seems a last resort to me, but seeking advice. I've even swapped ECUs!

 

FYI, it's a decked 2.0 Mi iron block to give 11:1 CR with an Mi head, running a Catcams fast road cam. It uses a 3-row Mi16 ECU, so with amp and coil, dizzy and 5 HT leads on my loom, all freshly built. I've built several looms and all worked first time, and I've checked the loom and ignition circuit several times. I'm meticulous with looms (but still human of course), ensuring I got the coil and amp wiring spot on. The coil's well earthed too.

 

It also runs the Mi Air Flow Meter (AFM) on a GTI6 inlet. The aim was always to see what you could get out of an Mi 2.0 on limited spend and mostly standard components (only extras are the cam and 4-2-1 exhaust). 180bhp was anticipated.

 

What I don't get, is why it only sparks on 1 and 4; why not 2 and 3? The dizzy cap and rotor arm are both new, and I've checked the rotor arm and base plate are all true and it's good. Also, as it's only a single coil (i.e. not wasted spark), the ECU should be sending a single signal to the amp and coil which must work or it wouldn't run.

 

I thought it might be a poor coil, not recharging quick enough. Ignition amps I can only swap figuring they either work or they don't.

 

I'm rather stumped, and would appreciate some help here please. My last resort is to sp*nk up £600+ for an Emerald or similar ECU, ditch the dizzy and go for a coil pack. This way I'd lose the AFM too, but it'd cost, plus another £350 for mapping! Could it be the CAS? What about any type of bad earth somewhere?

Edited April 13, 2015 by DrSarty

[Kane 34]

In my experience a duff CAS would result in it not starting at all so I'm guessing it must be something else that's playing up.

[welshpug 1,627]

has to be the cap or leads if you get a spark at all IMO. if it was on a 2.0 loom and ecu then an amp going down would cause a pair of cylinders to fail, but not a single coil 1.9 system.

 

if you can get a spark tester inline on the king lead you can see how regular the spark is, I would imagine if you have a spark at all you will get a regular pattern.

 

How are you testing for a spark btw? have you tried new plugs? try swapping leads on the cap, see if the fault moves.

Tbh even if you do have 4 sparks, it'll never run great with that combination of 2.0 on 1.9 map AND a cam, an S40 is under £600 still, though you may have to wait a few weeks for a new batch to be manufactured. mapping was £300 last time I got it done.

[jackherer 543]

I agree, it's something on the HT side, either the dist. cap or the leads. Or maybe the plugs but that's unlikely.

[Tom Fenton 1,526]

Is it definitely no spark? Are those two injectors firing fuel in?

[DrSarty 90 1 Cars]

Hello peeps. Most I know, one I don't (Kane). Thanks for offering to help.

 

In no particular order:

> 3-row Mi16 ECU used based on recommendation from PeterT, who is well trusted on here

> the ECU also has a PeterT chip which I believe is designed for the 2.0Mi (it has a 2.0Mi16 label on it)

> I've also swapped out the PeterT chip back to OE - still no joy, just getting it to run on 4 (even badly)

> I'm checking HT spark pre-spark plug, so testing output from the dizzy

> I checked some time ago the leads by swapping them, but I'll try again - no difference at previous attempts, but perhaps I missed something

> I also swapped dizzy caps, rotor arms and arm baseplates, but happy to try again

> it could be 2 duff ignition amps; 1 was used, 1 x pattern. I do know pattern parts can be iffy. The new one isn't a Bosch

 

What I will try is using a circuit tester on continuity on each HT lead via the king lead (IN) then off each HT lead in turn by turning the engine by hand so the rotor arm meets each contact in the dizzy cap. I'll do this first with 1 known good HT lead to isolate to just the cap and arm combination.

 

Silly question perhaps, but can I test HT leads with continuity tester? I would've thought so, but just wondered if they needed much higher voltage to conduct. I suppose I could test without HT leads first.

Edited April 13, 2015 by DrSarty

[jackherer 543]

The rotor arm doesn't actually touch the dist. cap, the high voltage just sparks across the gap to the nearest post so you can't test it with a low voltage multimeter.

[DrSarty 90 1 Cars]

Hmmph. I should've figured that out shouldn't I Kieran, otherwise the contacts wouldn't very last long being swiped all the time?

 

I think I'll try a spark tester whatever that looks like, cranking the engine, injectors disconnected, one HT lead at a time, i.e. off coil (testing king lead and main HT feed to the dizzy), then with king lead fitted and off each dizzy output 1 to 4 using 1 known good HT lead.

 

If I get 5 sparks then, then I'll know it must be 2 of the HT leads (what was 2 & 3), but I doubt I will somehow.

 

If I only get sparks on 1 & 4 (testing one at a time), I'll then test 1 & 4 again with the other 3 leads, ideally ruling out 1 or more of the HT leads.

 

If I still get sparks on 1 & 4 only (using any HT lead), then I'll know that spark isn't getting to dizzy outputs 2 & 3 somehow. That could be the arm or cap. I can swap those (again) and retest all dizzy outputs, and if there's no change, it surely must be the feed from the coil (which is driven by the amp).

Edited April 13, 2015 by DrSarty

[Miles 331 1 Cars]

Silly point, the 2.0 system won't handle a AFM etc, or have I missed something

[Kane 34]

Just for info..

 

Upon cranking (and running), the CAS detects the point at which the engine is at around it's rotation using the flywheel teeth. At the appropriate time it sends a signal to the fuel pump and coil, possibly via the ecu, telling them to operate. So if your CAS is nackered you won't be seeing any power to the fuel pump or spark at the leads.

 

That's my limited understanding of it which obviously isn't your problem here but always useful to know as much info as possible.

 

Best of luck finding a solution

[jackherer 543]

Silly point, the 2.0 system won't handle a AFM etc, or have I missed something

 

It's running the 1.9 management, an idea you came up with originally IIRC?

[jackherer 543]

I think I'll try a spark tester whatever that looks like

 

How have you been testing for spark up to now?

[Miles 331 1 Cars]

'The ECU also has a PeterT chip which I believe is designed for the 2.0Mi (it has a 2.0Mi16 label on it)' Not knowing much about the internals would the 2.0 chip work in a 1.9 ECU?

[petert 555]

I'm a bit confused about which ECU and chip you actually have. What is the number on the ECU case? What is the written on the chip?

 

If it's a true 1.9L ECU and chip then it should work correctly with the 1.9L dizzy, amp etc.

 

If anything is 2.0L, then I doubt anything will work with a dizzy.

 

Glad to hear from you. I thought you'd given up on the world of Pugs. I still have a cam and a set of pistons here for you.

[DrSarty 90 1 Cars]

Thanks for the replies.

 

(Hi Pete. Been meaning to ask you to send the cam and pistons; I'll PM you.)

 

OK. Perhaps I've confused things a little so I'll clarify:

> 3-row Mi ECU part no. 0 261 200 355 (Bosch Motronic)

> Chip in ECU says '3 Row 7500' (which I believe is from PeterT), so I was confused with another chip I have

> I have previously swapped chips back to OE and still had the problem, but I will try again (although I tend to agree the issue seems HT side of things as the ECU is triggering the amp which in turn is triggering the coil)

> Tested spark using insulated pliers holding HT lead, on dizzy but off plug, with 1/2" socket extension inserted into HT lead and holding near cam cover bolt head to see spark whilst cranking

> ECU pins used as follows:

PIN 1 > ign amp (shielded wire), going to amp plug pin 6, and it appears from diagrams that ign amp pins 5 & 6 are linked (in the amp?)

PIN 2 > shield from wire on pin 1

 

I'm going to get an inline spark tester today now I've looked one up on YouTube and test each HT lead individually and off each of the 4 dizzy outputs. It seems a continuity test on HT leads doesn't work using the low voltage multimeter as I suspected.

 

If it's purely HT side, and IF it's not HT leads, then what could cause the dizzy to only send spark to contacts 1 and 4 in the cap? I'm clutching at straws here.

Edited April 14, 2015 by DrSarty

[petert 555]

That all checks out ok with the ECU & chip.

 

Two dud plugs? Put a timing gun on the lead from the coil to the dizzy. Crank and see if the pulses are regular. That will at least isolate it one way or the other.

[DrSarty 90 1 Cars]

It can't be plugs, as I was testing spark pre-plug, i.e. out of the HT lead from the dizzy.

 

I'll use the inline spark tester as advised on the coil <> dizzy cap link first to check spark regularity. I'll also be able to check all 5 HT leads, by connecting HT lead to coil, then attach the inline tester to the dizzy cap.

 

After that - using only good leads (which may be all 5!!) - I can test spark with the tester off each dizzy output 1-4.

 

Hopefully then I'll have isolated the problem. I really hope it's just 2 dodgy leads; but I could've sworn they were good, even new.

 

If no, then I'm completely stumped, and I'll have to review ECU > amp > coil wiring.

 

Rich

[petert 555]

It can't be plugs, as I was testing spark pre-plug, i.e. out of the HT lead from the dizzy.

I don't get this. If a plug is dead, then there will be nothing in the lead(s) if tested with a timing light. Swap plugs 2 and 3 with 1 and 4, then report back.

[jackherer 543]

I think he is jamming a socket extension into the lead and holding that near to the head and watching for a spark to jump:

 

> Tested spark using insulated pliers holding HT lead, on dizzy but off plug, with 1/2" socket extension inserted into HT lead and holding near cam cover bolt head to see spark whilst cranking

 

Possibly not the best method but it probably does rule out the plugs.

[welshpug 1,627]

better to use a plug not an extension, eliminate chances of poor contact

[jackherer 543]

I agree, when I've faced a similar problem I've taken all four plugs and clamped them with a jump lead croc clip, then grounded the other end of the jump lead. If everything is working you then see all four sparks in turn.

[DrSarty 90 1 Cars]

Well it might be messy but it works, and trying to crank the engine whilst balancing a spark plug and look for spark (without getting electricuted) ain't easy.

 

Now have a spark tester so will proceed as planned.

 

Also have replacement ECUs and OE/PeterT chips to revisit that avenue if necessary.

[DrSarty 90 1 Cars]

Okay. I think we're getting somewhere now, and whilst I believe I'm isolating where the issue lies, I'm still a little baffled.

 

My inline HT/ignition/park tester is fantastic. £7 well spent and I think helps anyone track down HT issues quickly, at least to narrow down where you need to look, i.e. bracketing.

 

Results:

> spark tester on original king lead between coil and dizzy = regular, strong spark (the bulb lights up clearly on regular 4-pulse spacings)

> repeated with all HT leads = same results

> the above means coil to dizzy is good and all leads are good. It also means amp and loom are both good.

> sticking with HT lead for cyl 1 (known good lead) with tester inline with cyl 1 spark plug and cyl 1 dizzy output (and king lead attached coil to dizzy i.e. where it should be) = regular, strong spark on regular 1 in 4-pulse spacing (compared to 1-2-3-4-1-2-3-4...)

> repeated for dizzy outputs for cyls 2-4 (still using same HT lead and cyl 1 spark plug) = cyl 4, same as cyl 1 i.e. regular, strong 1 in 4-pulse spark, BUT cyls 2 & 3 were both very weak sparks (same behaviour on each), also appearing to be 4-pulse spacings i.e. as per king lead only much, much weaker

 

This seems to indicate everything's fine up to the dizzy, but outputs to cyls 2 and 3 are very weak and also strange in regularity.

 

I've checked the rotor arm base, rotor arm, dizzy (white) base and cap all are true/flush to the side of the head and they were. Arm and arm base not loose or on the p1ss, and condition of arm and dizzy contacts seem fine.

 

Instead of uploading pictures, I've photo'd the arm and cap, put them in a document and attached that.

 

My thinking takes me that the cap's crap; maybe the arm too. Something in there isn't right. As you'll see in the pics, cyls 2 and 3 contacts are diagonal as are 1 and 4, i.e. it's not just the small or large contact pairs that aren't working. I was thinking perhaps the cap, arm or bases (base for cap and foot for arm) were somehow on the p1ss and the arm perhaps isn't rotating evenly to distribute HT spark from the centre pin to each contact in the dizzy cap , i.e. the arm contact is further away from some of the contacts when spinning and the spark's struggling to jump the gap. However that doesn't explain why the pulses seem to be more regular. It's like a constant dim sparkle/glow rather than the clear and bright single pulse shown in cyls 1 and 4.

 

Confuzzled...please help. All I can think of doing is getting a genuine Ducilier cap (which I don't think this is) and a genuine rotor arm from a main stealer and just swapping them out. I'm also thinking that perhaps the cap's getting screwed down too close to the head/dizzy baseplate, such that the rotor arm is getting close to the plastic below the contacts inside the cap. Thoughts?

Miami Cap & Arm 1 20150414 (Red).pdf

Edited April 14, 2015 by DrSarty

[jackherer 543]

Is the centre pin in the cap still moving freely against its spring?

 

It sounds like a faulty cap to me, how many caps have you tried and were they all new/known good?

[DrSarty 90 1 Cars]

Centre pin seems fine. Not sure I tried different caps TBH it was such a long time ago; but it looks like I'll have to. Might as well try rotor arms too - both OE items to be sure.

 

How can a dizzy cap be bad? It's not old, cracked/damaged and the contacts aren't worn.

Edited April 14, 2015 by DrSarty