Engine failure - swap compatibility?

[StanTheMan]

Ha ha Bruce ....

Mx 5 is alive

[Skifey]

While I think about it, have you tried hooking up a timing light to see where it is actually firing?

Nope, I've not bothered to yet because I was so certain of correct timing. What exactly will a timing light show?

Am I right in assuming this is a BP4W engine?

Nope, it's a 1994 BP engine that was swapped in when the previous owner had the car. Does this trigger plate you speak of exist on the BP?

Have you re-connected all electrical connections & earths? Checked fuses? Haven't disturbed crankshaft position sensor?

Well, here's the thing. Before I pulled the engine out of the car I drew a diagram of all the electrics in the engine bay so I couldn't forget where they went. I've reconnected everything so far as I'm aware but haven't checked fuses. I HAVE DEFINITELY disturbed the CAS during the rebuild. I removed it and reinserted it several times.... and I may have banged it with a hammer a few times trying to get it to sit properly.... BUT I've definitely got spark because I took the plugs out, left it plugged to the coil, earthed it and cranked. Got a nice blue spark. Can the CAS still be faulty even though I've got a spark?

Are the cams at TDC though? The locating pin should be in the vertical groove.

Cams are in the correct orientation with the locating pins at the top

[StanTheMan]

It certainly exists on the NB BP's perhaps not on the 93-97 BP's

this is a trigger plate right behind the damper. You'd miss it if you just looked. I had no idea what it was firs time i saw it. so if you have one sitting in your parts bin....it belongs right behind the engine damper

l7p1tcy.jpg

if you have a trigger wheel you will also have a Crank angle sensor.

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the gap between the trigger wheel & the sensor should be 0.5-1.5 mm otherwise it starts to play up. or if the sensor is faulty It will not run.

[manga_blue]

While I think about it, have you tried hooking up a timing light to see where it is actually firing?

Nope, I've not bothered to yet because I was so certain of correct timing. What exactly will a timing light show?

Looking at the plug sparking will only tell you whether or not there's a spark there but not whether or not the spark is happening at the right time. If you take out the plugs and spin the motor on the starter with a timing light on then you can determine if the spark is occurring somewhere near enough to TDC on #1 for the engine to fire. It's common enough for the spark to be up to 180deg out after a rebuild. As a rough alternative you can swap either the plugs into the coilpacks or the 1/4 and 2/3 leads out of the coilpacks to eliminate the 180deg possibility.

If you can confirm both that there is a spark and that it is happening at the right time then you can eliminate ignition as a possible cause of no start and focus on fueling.

[Skifey]

IT! IS! ALIVE!!!!

6 months later and she's back on the road finally!! I can't thank you all enough for your support, advice and help Seriously thank you!

I'll keep the series of events as brief as I can without leaving out details. I ended up staring at the engine for a good 4 hours one day before I basically gave up and gave my contact mechanic a call. He had a tow truck on the way in 1 hour and so I had to put the car back together; bonnet on etc. In the process of doing this I thought 'screw it' and rearranged the spark lead order on a whim and tried kicking it over. IT DAM WELL STARTED! then it immediately turned off. I did it 3 times before I gave it some gas after kick over and it ran but it sounded like it was running on 2 cylinders, I wasn't sure.

I figured I might as well let the mechanic finish the job and diagnose any faults. I was resigned despite the momentary success. Tow truck took it away and 2 days later I get the call that it's ready to be picked up if I want to. He wanted to keep checking it over but childish me couldn't wait. I arrived and turned the key and the beautiful thing sat there idling in all of it's former glory (not really though, it desperately needed a wash).

The mechanic said;
- The radiators fans were blowing the wrong way this whole time. How? Absolutely no idea, he only discovered it because of his cigarette smoke being pushed away. This I suspect was culprit Number 1 in this entire overheating for a year dilemma. Go figure!
- He changed the order of the spark leads into the coil packs, I'll take a photo and upload shortly
- He 'put a screw' into my air flow meter to keep it open. He was shocked that it even ran since the plug/cable going into it was disconnected. Don't think he's ever seen a megasquirt before to be fair.

The car is now running albeit with a few problems. Fuel economy is noticeably worse which the mechanic attributes to him opening up the air flow box. I'm still yet to open it up and see exactly what he did. It ran fine in the past how it was so I'll have to check that over.

The bigger problem though is the idle and startup. It only starts up if I give it gas when cranking and it idles sporadically throughout traffic sometimes dropping as low as 600. It also 'droops' when coming out of gear to a stop and almost stalls. Example; you're cruising at 60, knock it out of gear and break. Revs go from 3100 to practically zero then back up to ~800 idle. It all just seems a little off. It's stalled in traffic a few times as a result which it never ever did in the past.

Either way, I'll be back with more info shortly but if anyone has ideas as to the idle/rpm problem is the meantime, hit me! The Haynes manual hasn't given me anything.

[project.r.racing]

Sounds like low fuel pressure for startup issues.

And sounds like air bypass value for you idle drop issues.

[StanTheMan]

Well he’s got a megasquirt. Start up sequence & idle valves setting is what I’d be looking at.



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[bruce]

Yup, sounds like tune is out-of-tune.

[Custardtart]

The problem is we can’t really help because the engine has been tinkered (putting it kindly)with so we have no idea if left is right or right is left, hence the fans. Given a mechanic solved the initial problems I’d suggest taking it back to them.