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Timing value at idle


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After a few months of not touching the 90, I've ended up taking it to a garage to look at it, they seem to think the problems with it could be the timing, so after looking on megatune and seeing it was around 11 degrees btdc they are saying it should be around 6, which from the googling I have done would seem about right for the 4.6. So can someone explain to me, so I can explain to them :) why my supplied maps are idling at 11 or so? It's back in Friday so need my facts right for then. Thanks mike

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That's both fridge I think, as the trim value is 0, ill post up some pics of the relevant settings...

When i went through all this before, I checked the timing with a gun, and it showed pretty much what was shown on megatune, but the garage is going to check it again just in case.




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  • 2 weeks later...

Mine idles around 12 degrees btdc mike and seeing as the trigger wheel is bang on the trim value is 0 thus it is 12 degrees on the pulley also

I set up my dizzy for about 12 degrees btdc once and it was all good but went happy medium at 6 seeing as 3.5 was supposed to be 0 tdc!

As such, I don't think it's that

I'm just completely at a loss pal :(

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Mine idles around 12 degrees btdc mike and seeing as the trigger wheel is bang on the trim value is 0 thus it is 12 degrees on the pulley also

I set up my dizzy for about 12 degrees btdc once and it was all good but went happy medium at 6 seeing as 3.5 was supposed to be 0 tdc!

As such, I don't think it's that

I'm just completely at a loss pal :(

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Well we checked the timing etc, all sound so yep it's defo not that.

strangely maybe? With the timing set to -10 at idle, the hunting stops? Maybe that's normal I don't know.

Garage suggested maybe cam timing was out as its one of the timing chain sets real steal sells with three positions but I'm sure that I'd of put that in right too, also the guys on the v8 forum don't think that'd cause the problems I'm having.

Something that has niggled me a bit is wether the inlet manifold isn't sealing because the block/heads have had too much taken off? The blocks a turner top hat one as are the heads, both were taken to acr to be looked over, pretty sure they said they gave the heads a very light skim.

But I'm clutching at straws really.

I'm gonna refit the wb try tuning again see what table I get, if its still looking bad as it did originally, Roland at acr has said take the engine down and he'll sort it on the dyno, needless to say I don't really wanna do that but its looking like the only way.

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Hunting can be a few basics, when a garage suggest things like cam timing you know they're clutching at straws.

Can you post up your MSQ?

Are you using PWM idle, and have you faffed with the settings? Likewise have you faffed with the EGO Correction settings?

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The motor has been tried on a base map direct from nige as far as i know fridge and still problems persisted!

It's been a while since I looked at the motor but if my memory serves me right the air leak issue was fixed.

It does have PWM valve fitted but mike was running without it at one stage...

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Yep two maps have ben used, both supplied by nige. I have the pwm, but as advised originally its not connected up and pipes are blanked at the minute.

All settings are as supplied by nige too at the minute, except ill have to change the lambda settings for the wb.

Connected the wb today and started it up, it seemed to idle not too bad, but the laptops now playing up so I couldn't see what's going on in the settings.

Presuming the laptops boots up tomos ill go for a drive and use autotune to see where it ends up at.

Cheers mike

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This is as you know going around in circles.............

A few basic facts

If you look at the kit you have, the ECU and the loaded program you had when you 1st fired it up, then, if you have connected everything properly, and have no issues with the mechanicals within the engine IT WILL RUN FINE.


Not perfect but dmaned good, I have now seriously lost count of how many similar instal have been done, just as the above, and they RUN FINE, if they DON'T then there has always

been an issue - 99% of the time install error(s) sometimes Corruption of firmware / internal program again as a result of install errors corrected but that then had already had a knock on effect

And of those where there was a problem, and not an install issue, then it was mechancial - air leaks, timing set up issues, wrong map / seetings and in one case no oil so the lifter didn't and wouldn't fill as no oil and therefore didn't rev over ticlover. In essence if you have installed things right and have one of my programs then IT WILL RUN quite nicely, which yours isn't / doesn't

I say again, if it is running really badly there is a BASIC fault. Indeed many peeps just use the program base master map I give them, as they find its lovely and does the job and is more than good enough.


Your engine has had problems, if I recall so many many people said "Air leak" which you said it didn't, then found it had and fixed the air lek, that means there WAS a problem and you have sorted it, I'll lay money on there being another or more than another, and you have to go back to basics, be systematic and follow a process rather than stabbing at ideas to fix and going off on tangents, without a systematic proess, assuming that NOTHING is taken as correct, and everything checked rechecked and proven OK its not to be trusted.

Yes the cam could be advanced, but thats a waaaaaay off basic checks, and fitting a wide band lambda is NOT going to sort your issue.

To run sweetly it should on turn of key, tunning will only improve the engien if eveything is as it should be, you cannot "Tune out" a fundemental problem or fault....

Additionally there is oittle real difference is basic terms tunning with a NB or a WB - the NB and the software will tune nicely, takes much longer than with a WB, and, and this is importnat, you also cannot just "pop" a wide band on inplace of the NB and go tunning, it has to be set up correctly, with the correct settongs put into the ECU basic settings and calibrated, if not then it will tune WRONG and give potentially damaging resukts, and if there is as I belive a simple basic problem why your engine isn't behaving as it should be even worse on top, what exactly could go wrong is unknown as we don't know what the issue is, but there IS an issue and beware of just shoving a wide band on and going and giving it large.

At best it will mask the issue and solve one pob and creat a load more.

Its entirely up to you, but

I suggest youb start a new thread

Explain very very carefully WHAT the issue(s) are. This is after reloading the master MSQ I gave you, so in effect you are back at the 1st start up, then we can have a collective look at the problem and suggest a route to sort.

Saying "No its not that" is daft, you don't KNOW its not that, you might THINK its not that but as you actually have no idea what the issues are you can't dismiss anything.....


How much does this garage no about Megasquirt, programming of the ECU wiring configurationm, sensors, values and settings generally ?

If the answer is er not much then what on earth can you expect them to do ?

I would love to see you engine running as it should do, somewhere here is an old enormous thread of whats wrong, you got nowhere, and frankly WB will get you nowhere, you have to idenitfy everything as being correct EVERYTHING, not jump about and fiddle with something that masks the issue and you think thats solved it, thats not going to do it on the majority of times.

So, I suggest

reload everything back to as supllied byMoi

New Thread

VERY detailed explaination of all the faults, the more detuial the better, and then follow the suggestions checks and advise to the letter given by those here inc me, then you actually stand a chance of finding whatever it is...its not going to be quick, and we may go down all sorts of wrong routes, but something somewhere is set / connected / wrong...otherwise it would be rinning "Fine"!

Not meant to be curt or condesending in anyway, just I can see your off on the waaaay wrong track again

Thoughts ?


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Ill do that nige, as you know its been on going that long I'd sort of given up on it for a few months.

Ill be honest I'm not sure it is Megasquirt, this is why I took it to the garage, who are a good independant lr garage, in the hope they'd see it and say "oh it's such and such" you dosey bugger haha.

I've been running the base 4.6 map you sent, but I'm tempted to keep the wb on because it gives (at least me) a good indication of what's going on in the mixture.

Ill get it going tomos, do some videos etc and start a new thread

Cheers guys.

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