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Electrical Issue - 250 Crossflow

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Hi guys, been chasing this issue for the last few months now, I'll give you the summary quickly:

 

250 crossflow, halls effect dizzy, msd Digital 7, HVC 8261 coil

 

After about 15 min or so of driving the motor just cuts out. It then will not start; cranks fine, occasionally farts but does not fire. After a few minutes of waiting it occasionally fires again before getting 5 min of driving in and process repeats. Factory temp gauge says motor is absolutely fine so definitely not a temp issue

 

We made a quick connect from dizzy to msd for 12v ignition and trigger wires, noticed the connector was rubbish so we made another using MSD style connector. Problem came up again.

 

Next time it wouldn't start even after an hour of cooling. Noticed this time tho that tacho wasn't registering cranking rpm, found ground wire from dizzy was faulty. Side of the road fix, fired and got it back home. Remade a real good ground wire. Unfortunately problem persists (tacho registers cranking rpm fine)

 

This has lead to countless side of the road moments and have eventually crawled it back home everytime. Today I've let it idle for a while and waited for the issue to pop up again. When it died and wouldn't start again, quickly had the multimeter and test light with me and went around. The ground connection to dizzy reads fine. The 12v ingnition to dizzy also fine as well. Engine won't fire; so have ruled them out. Waited abit, let it cool down and it fired; so put it back in the garage

 

Any ideas guys?? I pulled plug out when it doesn't fire to make sure it is an electrical issue, and as expected no spark from plug (they are all brand new).

 

Thanks in advance, I enjoy problem solving but this one has left me scratching my head; would much rather it doesn't work at all so we can track down issue, but unfortunately have to have the motor running for a while for the issue to come up.

 

 

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Module on side of dizzy, take it off put new heatsink paste on it... sounds like overheating module.... If not recheck msd module.

 

Does the msd7 take a curve tune or just for basic spark?

 

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Thanks for reply jack, I don't run a module on the dizzy, I eliminated it and made spade terminals straight onto dizzy. Msd module I'll have to take a look then I guess cheers

 

Msd digital 7 has pretty much all the features

 

EDIT: while I'm here I should confirm that the MsD still has the red led flashing even when the motor won't fire. The tach also reads cranking rpm when not firing either; since this is picked up from the box, the box should be recognizing the fact that the motor is turning

 

 

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+1 coil.

Had one not totally fail but go weak enough to suddenly not fire the engine one day (but tested ok when cranked). Threw another one I had lying around from an EA 6-cyl and the thing kicked to life instantly. I did test the second one before starting and the difference in quality of spark was obvious.

Had another one on my Corty just instantly fail while driving along one night to a girlfriend's house. No warning, no signs of failure, just one minute hooning along and the next, parked in a suburb far away with no life. Came back next day, new coil in, off she went.

Coils are bitches of things and will fail at the worst of times. I prefer oil-filled over the solid core ones, as they seem to give a bit of warning before giving up the ghost.

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Ahhh cheers for the replies, spewing boys really was hoping it wouldn't be a coil as it's a good one! The coil was in use in 2006 for a couple of years in a drag car, then in probably 2015ish I brought it back and threw it on corty. So it's not exactly new but was hoping being a top of line MSD it would be fine.

I do have a couple of standard coils, each with different style posts, however I'm not sure whether they also work straight off the MSD box just as an MSD coil would?

Anyone know of a way to test those HVC coils in any way? Going to have a quick search online as well

Thanks again


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Sorry mate, was just checkin you hadnt plugged into the module and was overheating.
Deans onto it.
Standard coil should be fine, get ya out of trouble for now.
Just if motor revs high and hard..... save for a nice coil.

Jack.

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Thanks jack, I've lent the coil with the male post to a mate, but just remembered I have another mate with a spare HVC style coil so hopefully test that one out first since it's the same type of coil.

 

Could it possible be anything else guys while we're here? Does anyone happen to kno what is it in a coil like that that would prevent it from working only when it builds up heat? Just so bizarre that it works 100% then nothing at all before repeating the process over again until you leave it overnight

 

 

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Coils have thousands of windings inside that are separated by a very thin insulation that can break down both over time and many heat cycles. All it may take is a slight movement internally due to expansion from heat and the windings short out on each other, reducing output voltage or completely dying. Also there can be a break in said windings that might touch when cold but again when the whole thing is hot, open up and create an open circuit.

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Thanks for the explanation Greg on top of it as usual. Delay with mates coil will hopefully have a crack at it this week.

Grimy I haven't done the msd check, that is a great idea tho. Correct you just tap the white wire to ground and check be coil lead. I actually have an msd spark tester somewhere here as well. In fact, I'll give that one a go next time the thing fails so that'll be two things to test in one go


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Cheers Greg will give it a go on the weekend. I didn't want it to be the coil but now I'm just hoping it is cause I'm sick of it hahaha, can't wait to see the wagon and the rest of the crew again been a while! Maybe we should buy cars that's work :P


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You test the coil by a resistance test via multi-meter but...as I found out it can bench test just fine and still fail in use.

The Ohm rating for the test's is on the MSD page or join the forums and ask as I did.

For street use a alloy bodied coil is recommended as it suits long periods of use the poly unit is for short bursts only. Yes all this info is on the MSD site and the forums.

 

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So some unfortunate news. Went and let the car idle to build up temp, 15 minutes in stalled as it usually does, wouldn't start. So then unplugged my HVC coil and put on mates MSD master blaster that was brand new out of the box, ran for 3 minutes and stalled just like it does with the HVC. So coil wasn't the issue.

I have an msd spark tester that goes onto the trigger wire, essentially by passing the distributor. Would spark fine but as soon as I get the motor to the point where it stalls, quickly hook up tester, the test plug would not fire. Wait a few minutes and fires fine. So not a dizzy issue either.

Only left the ignition box itself and the main coil lead. Tried another lead and same issue persisted. Unfortunately only left the digital 7. Hooked up anther MSD box and the car idled fine for 25 minutes no issues. So somehow the Digital 7 looks like it's packed it in.

Although the box is about 12 yrs old, I'm still sure it should have lasted, but perhaps the last couple years driving in 30+ degree might have gotten to it, not sure to be honest. But will be buying a new 6al2 programmable and new coil to get it back on the road for summer. I've figured this is a more street friendly set up so will be doing this.

Thanks for the help everyone, keen to hear if anyone has had similar experiences


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That sucks mate, electronics are a bitch like that. One minute yes, next minute a very expensive no.

On the upside, you could still use it on a drag car (not enough time to get hot).

I gather that it's going to be a plug-and play scenario (ie both use the same program and maps)?

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Cheers Greg what can you do mate aye spewing. Would've loved if there was an MSD repair center locally

One connector will be slightly different by the looks of it so not entirely plug n play. However, considering I need to re install the software, and more than likely going to remake that sheet metal piece on the firewall (will be full of unecessary holes now), it'll probably turn into a bit of a weekend job instead. Let's just hope it all survives this time aye; least it'll have warranty now


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Mate before you chuck ya msd... take the top off and on there should be heatsinks in there.
It will be the paste on those is crappy and cause unit to open circuit once warmed up..... thats why I asked about the dizzy module....
Its a common problem with heatsinked items.
Worth a look or check the internal fuse is not semi broken.

Jack.

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Thanks for that Jack, will give that one a crack then hopefully tonight when I get back. Maybe it is something as simple as that aye!
Michael


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Hi guys, long story short borrowed a spare msd digital 7 to swap with mine and test. Problem disappeared so it looked like I had a faulty box.

Ended up buying a brand new 6al2 and brand new Blaster SS coil to go with it. Re did effectively all the wiring, loaded up a tune and fired up. Engine now only runs for about 10-15 seconds and then cuts out, no stumble or miss, literally as if you've turned the red on. Some observations:

- I have the laptop plugged in with software on. As soon as the engine dies, the laptop loses connection with msd. I.e. It goes from 6530 etc to None in that little box where it tells you what product is connected. The software does not freeze or anything because you just flick the reds on and off then it reconnects.

- just as the engine dies, the software leaves you with the final figures before being disconnected. Battery is always above 13V

- battery has been checked with 2 testers, also tried running it with my battery jumped onto another running cars battery, no difference.

- tried bypassing the ignition wire and running the whole deal off the permanent 12V battery incase of faulty accessory wire, problem persists.

- we've wired the setup in a way that a relay is triggered on by the ignition and passes full battery voltage thru the relay into a 1 to 6 distribution blocked with fuses on each output. This block then Powers the msd, triggers on the msd, triggers on 12v to EST distributor, and gives 12v to a little switch panel. All these are on separate outputs

- had a second person with a multimeter on the power block to test voltage while the engines running and when it dies. Even when it shuts off, it never reads below 13.9V (obviously drops to 12.5V immediately after engine stops). But voltage never goes below 12v that would trigger off the msd.

- I have replaced everything but the distributor itself

I'm sort of stumped now cause none of the symptoms seem to be pointing to a common issue and everything is brand new, even to the wires and plugs, except for the dizzy. Could the dizzy be the issue here? Potentially losing ground ? Could the brand new box we stuffed? Any ideas please hit them thru cause I'm scratching my head now.

Engine Itself seems fine, there's fuel and all. Just the way it shuts off just sounds very electrical and seems all too similar to the previous problem, except now it only lasts 10-15 seconds

Thanks guys
Michael


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Hi guys, long story short borrowed a spare msd digital 7 to swap with mine and test. Problem disappeared so it looked like I had a faulty box.

Ended up buying a brand new 6al2 and brand new Blaster SS coil to go with it. Re did effectively all the wiring, loaded up a tune and fired up. Engine now only runs for about 10-15 seconds and then cuts out, no stumble or miss, literally as if you've turned the red on. Some observations:

- I have the laptop plugged in with software on. As soon as the engine dies, the laptop loses connection with msd. I.e. It goes from 6530 etc to None in that little box where it tells you what product is connected. The software does not freeze or anything because you just flick the reds on and off then it reconnects.

- just as the engine dies, the software leaves you with the final figures before being disconnected. Battery is always above 13V

- battery has been checked with 2 testers, also tried running it with my battery jumped onto another running cars battery, no difference.

- tried bypassing the ignition wire and running the whole deal off the permanent 12V battery incase of faulty accessory wire, problem persists.

- we've wired the setup in a way that a relay is triggered on by the ignition and passes full battery voltage thru the relay into a 1 to 6 distribution blocked with fuses on each output. This block then Powers the msd, triggers on the msd, triggers on 12v to EST distributor, and gives 12v to a little switch panel. All these are on separate outputs

- had a second person with a multimeter on the power block to test voltage while the engines running and when it dies. Even when it shuts off, it never reads below 13.9V (obviously drops to 12.5V immediately after engine stops). But voltage never goes below 12v that would trigger off the msd.

- I have replaced everything but the distributor itself

I'm sort of stumped now cause none of the symptoms seem to be pointing to a common issue and everything is brand new, even to the wires and plugs, except for the dizzy. Could the dizzy be the issue here? Potentially losing ground ? Could the brand new box we stuffed? Any ideas please hit them thru cause I'm scratching my head now.

Engine Itself seems fine, there's fuel and all. Just the way it shuts off just sounds very electrical and seems all too similar to the previous problem, except now it only lasts 10-15 seconds

Thanks guys
Michael


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Haven't swapped your mates one for test yet?

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Haven't swapped your mates one for test yet?

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Not yet mate definitely next on the list, just quickly going to try ground distributor straight to battery cause I have a funny feeling where I'm grounding it may be an issue, but after that going to chuck his dizzy on. Just have to punch my gear on it cause he's one just has the standard strength one


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