Injector cleaning in situ?

S

SJones

Greenie N00B Member
Greenie Member
I got a unique situation here, I've put one of these engines into a mark 3 mx5, this project took way longer than expected and I have finally come to start the engine and it won't start

Using forscan I can see there is pressure all the way up to the fuel rail but after turning the engine over a fair bit there is very little fuel getting to the cylinder, you can get a wif of petrol but that's it.

I know from some temporary piping I used that the fuel that was in there had started to gum up, the issue if that egr pipe at the side of the manifold, the way the engine is oriented I'm not sure I will be able to remove it without taking the engine back out due to clearance and accessibility, most injector cleaning substances I've seen require the engine to run, at this point it won't do that. Is there any way to clean them without removing them and in an engine that won't start?
 
1) the injector "cleaning solutions" while engine are running have minimal efficiency
2) lol what? No, really think what you're asking about there
3) the only way to really clean injectors to remove them, ultrasonic clean them and then flow test
4) you might be able to remove the intake manifold with the pipe attach and just detach it from the egr
 
Thanks, unfortunately there is a lip over the top of the engine, had to cut some out to fit it, no way can I pull that pipe upwards and out, wouldn't be able to rotate it around the engine either, dropping it down would be the same issue as the intake wouldnt come out going down and back
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I see you've got it rotated 90 degrees that's cool too see you cram it in there. Pesky EGR, one of the first things I deleted
 
Not so much the egr, the HPFP was the main issue with the intake facing into the firewall, had to cut and weld the firewall to get this fitted, theres enough clearance at least half way up to change the starter motor from underneath the car, I can feel the egr pipe but not sure yet if I can get a spanner up there. I need this road legal in the UK, probably foul the emissions or some regulatory law if egr is not there, can't even vent to atmo, catch can and recirc...just issues after issues but it's almost done
 
Can't you get at the hpfp at all? Is this the first start you're trying to sort out or did it run before?

Wondering if your fueling issue are from the hpfp not so much Injectors. There's a pesky little ground in the hpfp bracket that's notorious for causing issues if it's not clean and tight. Spill valve connector sometimes doesn't seat fully either if it's been broken.
What's your koeo fuel pressure?
 
Here is the fuel rates reading from forscan this is during approx 5 - 10 second crank

uc


I read elsehwere over hear that there is that ground wire, its difficult to get behind the engine, the HPFP is better access at this point than the other side, I was able to take the EGR on/off with the engine in - I havent looked at if its possible to get the HPFP off at this point - I have moved a ground from around that area, it was connected to a black square box that was then bolted on - I have bolted this to the chassis at this point and tested for a ground and looks good
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(Random pic from the net - The connector furthest to the right in the above picture - is this the ground that you are on about?)
 
Just a heads up, this was from a cx7 so there might be small variations between that and the 3/6

So you know where the ground runs from - to, what harness it's attached to?
 
Only different between the motors is cx7 has a smaller turbo. Gen 2 ms3 has different pistons, valve cover and turbo inlet pipe
 
I have read the cx7 had a smaller turbo but not in the UK market, here we got the same as the other mazdaspeeds.

With that said, are the wiring harness between the models interchangable?

One minor thing I picked up on the drive home with the cx7 was the DCS system turns back on after a short time, in the mx5 this wasn't the case, id assume that the other mazdaspeeds wouldn't auto turn it back on either?
 
Ground im talking about is right by the hpfp itself on a bracket no harness plug, comes off the ignition coil section along with the spill valve plug. No black box on it

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DCS will turn back on if you push the button again, although if you hold it for >10 sec on gen2 speeds you cannot reenable it without restarting the car
 
This morning I went and had a look as I thought the ground you guys where on about was the one I mentioned previous.
Turns out I missed that ground completely! Awafrican your picture was really helpful there.

the engine now tries to start but cuts out a couple of seconds its very rough during that second or two, I came back to it after work with my laptop and obd reader, got some graph data and going to look over this - see whats happening but Im glad I dont have to pull the injectors at this point.

I am considering getting the engine rebuilt in the future, maybe add some mods/upgrades at that point - probably bigger injectors, but for now there is is pleanty of stuff to get on with to get this project road legal.
 
Good luck with bigger injectors.....

Check the crank position sensor for dirt
 
That pesky ground, it's certainly notorious on this platform. Glad the pic helped

Unfortunately there are no after market injectors for that engine :( many have looked, heck the even looked at custom ones but the price was too damn high. For fueling you'll want to upgrade the hpfp internals before you do anything else power wise.

How big is that MAF housing you have? Wondering if the MAF calibration is off as well, could always try start it without the MAF plugged in.
What are your plugs gapped to? Should be 0.026-0.028"
 
plugs are stock NGK SILTR6A7G (95369) they are specced for this car but have not measured them, the maf housing as far as I remember matched the original one that was in the intake from the CX7 - my suspision lies with a bit of custom pipe I made with the BOV return and other lines going to it - I got a feeling there probably isnt a good seal here. basically I put a large plumbing pipe connector through the silicone hose, the shape and flexibility around that join wasnt great, I also put some sealent around it to help but I have my doubts here.
Got some alternatives in mind to fix this but it depends on the outcome of what could be causing the engine not to properly start.

Would unplugging the maf just mean it goes in to a basic guessing mode, I would of thought disconnecting it would throw a CEL and stop it from starting?
 
Car will start and run with maf unplugged. Will throw a cel but whatever at this point
 
Great news, we are up and running thanks to your advise.
Done some more readings and noticed on one occasion there was a error code relating to the throttle body, this was a second hand replacement of ebay as I damaged the housing for the connector on my original, the connector is in a very tighr spot and I dont think it was fully on, pushed it further on today and she started up and idled on the second attempt.

Started off ifling rather high but after a few more startups she is now running as I would expect. havent taken the RPM too high yet, theres now a engine temp sensor thats throwing an error, this will have to wait as the engine/exhaust was hot at this point and I will probably have to climb back under the car to check this now. coolant is working its way around as the hose is warm.

Really want to throw a thank you to you guys here for helping, would never of founf that ground otherwise!
 
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