Backfiring problem Rv8
Discussion
Ok...I have a rover v8 with 8 throttle bodies and a supercharger running through a plenum.....
Its just wired for bank firing with wasted spark at the moment.
It has a DTA Ecu which I'm just in the process of setting up.
Problem is Im getting backfires from 2 and 4 cyl. Seems consistant no matter how much fiddling I do with the idle.
Any suggestions folks?
Its just wired for bank firing with wasted spark at the moment.
It has a DTA Ecu which I'm just in the process of setting up.
Problem is Im getting backfires from 2 and 4 cyl. Seems consistant no matter how much fiddling I do with the idle.
Any suggestions folks?
Start with the basics, correct cap on correct plug (and correct leads to coil packs)?
Has the cam timing been disturbed?
Are the valves on the affected cylinders seating properly?
Configuration for the ign ECU been set correctly for the right firing order and engine type? (sorry, don't know the DTA set up routine but it's entirely posible to get this wrong on some)
Has the cam timing been disturbed?
Are the valves on the affected cylinders seating properly?
Configuration for the ign ECU been set correctly for the right firing order and engine type? (sorry, don't know the DTA set up routine but it's entirely posible to get this wrong on some)
cazzer said:
Well.....
It's running perfect now......right up until it backfires.
Then it runs perfect again.
Til...well you get it....
What details would you like to know Mr Turbo? I'll gladly supply anything requested
First off.It's running perfect now......right up until it backfires.
Then it runs perfect again.
Til...well you get it....
What details would you like to know Mr Turbo? I'll gladly supply anything requested
Is it wired correctly ?
What trigger system ?
How many coils, and are they wired correctly ?
Are all engine sensors reading correctly ?
Has anyone competent actually tried to map it yet ? ( if not, its no surprise it isnt running properly )
Have you confirmed ignition timing is correct with a timing light ? if not, why not ?
What sort of AFR's are you seeing ? At idle, and then when this backfire occurs ?
In fact...all of the very very very basic thngs that need checked when installing any management system
Is it wired correctly ?
Yes, Definitely. All wired, tested, properly soldered joints. Checked for shorts and proper earths.
What trigger system ?
36-1 crank trigger wheel.
How many coils, and are they wired correctly ?
2 ford dual coil packs. Wired properly and connected to the right plugs too
Have run the spark test on the all and they're all sparking strongly.
Are all engine sensors reading correctly ?
Yes. (I did originally have the crank sensor the wrong way round, but cured that one)
Has anyone competent actually tried to map it yet ? ( if not, its no surprise it isnt running properly )
Yes me
No, seriously, I'm only going for getting it idling properly at this point.It will be mapped on a rolling road.
Have you confirmed ignition timing is correct with a timing light ? if not, why not ?
Err...no....cos I haven't got one
What sort of AFR's are you seeing ? At idle, and then when this backfire occurs ?
I'll check for you.
Just to put this in a bit more detail.
It is idling and running sweetly, right up until BANG. Then idling sweetly again, then Bang
Have you identified the cylinder(s) that the misfire occurs on? If it's just one, I'd be looking for something mechanical and valve related, if it's a pair and especially a pair firing off the same coil phase, I'd think it's an ECU/wiring configuration problem.
Worth checking that the spark advance table figures at/near idle haven't acquired any unwanted minus signs
Worth checking that the spark advance table figures at/near idle haven't acquired any unwanted minus signs
Steve_D said:
Cylinders 2 and 4 will not be on the same coil but could be on the same coil pack. Is the pack earthed properly?
If they are the Ford coil packs with the big plastic clips on the leads then they are normally quite reliable.
Steve
Same coil pack yes....If they are the Ford coil packs with the big plastic clips on the leads then they are normally quite reliable.
Steve
Good call. I could change it over so it fires off the other one.
See if it makes a difference.
You simply cannot first run any such system without first confirming ignition timing immediately upon running.
Yes you can guess the position of the missing tooth, but you'll never guess 100% right.
Always confirm with a light. And also baring in mind the wasted spark will read double actual timing on that light.
Although some say that is only on dialback lights, and not static ones.
Ive only ever used a Snap On dialback, so dont know.
if you baseline timing at 0deg, then it wont matter, it should of course flash at TDC.
So assuming timing is correct, your backfire if it isnt a mechanical problem, is simply lean mictures because it hasnt been tuned yet.
Yes you can guess the position of the missing tooth, but you'll never guess 100% right.
Always confirm with a light. And also baring in mind the wasted spark will read double actual timing on that light.
Although some say that is only on dialback lights, and not static ones.
Ive only ever used a Snap On dialback, so dont know.
if you baseline timing at 0deg, then it wont matter, it should of course flash at TDC.
So assuming timing is correct, your backfire if it isnt a mechanical problem, is simply lean mictures because it hasnt been tuned yet.
stevieturbo said:
You simply cannot first run any such system without first confirming ignition timing immediately upon running.
Yes you can guess the position of the missing tooth, but you'll never guess 100% right.
Always confirm with a light. And also baring in mind the wasted spark will read double actual timing on that light.
Although some say that is only on dialback lights, and not static ones.
Ive only ever used a Snap On dialback, so dont know.
if you baseline timing at 0deg, then it wont matter, it should of course flash at TDC.
So assuming timing is correct, your backfire if it isnt a mechanical problem, is simply lean mictures because it hasnt been tuned yet.
Cheers...Yes you can guess the position of the missing tooth, but you'll never guess 100% right.
Always confirm with a light. And also baring in mind the wasted spark will read double actual timing on that light.
Although some say that is only on dialback lights, and not static ones.
Ive only ever used a Snap On dialback, so dont know.
if you baseline timing at 0deg, then it wont matter, it should of course flash at TDC.
So assuming timing is correct, your backfire if it isnt a mechanical problem, is simply lean mictures because it hasnt been tuned yet.
I'll keep you updated when I've fiddled tonight.
stevieturbo said:
well...ya gotta start somewhere.
But until you have baselined everything and know where you are starting from...it will be a struggle.
At least hoepfully now you have a sound base to work from.
Made a huge difference to how it was running...the difference was more noticable than just the absence of bangs.But until you have baselined everything and know where you are starting from...it will be a struggle.
At least hoepfully now you have a sound base to work from.
I just want it to run enough to get it 4 miles to the rollin road.
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