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Incorrect injectors for plug-in


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Hey guys how are you all?

I have a question in regards to my injector impedance ill try to keep this post as short as possible.

I currently use the Vi-pec plug-in ecu on my VL turbo, I recently had to upgrade my injectors as my old low impedance 1000cc ones where maxed out. I went an purchased a set of bosch 1600cc injectors an I made the point to the dealer they need to be low impedance for my ecu an he assured me they would be fine as technically there not low or high because there rated at 9 ohms which didn't sound right to me but said he sells plenty of them to guys like me with no issues.

So I fitted them to the car an took it to be tuned on the dyno. when it was being tuned the tuner maxed these ones out as well an had to bump up the fuel pressure to get it safe which cant be right, All I changed with the set up was a bigger compressor wheel on the turbo (from a standard 35/40 wheel to a billet t04z wheel) an 1 extra psi of boost bumping it up to 32psi they couldn't possibly be maxed out. The car is fitted with 2x044 fuel pumps surge tank an -8 fuel lines (E85)

After I had it tuned it also developed a random misfire/splutter in 1st gear only which my tuner put down to the ecu or loom (he really doesn't like Vi-pec for some reason) so I changed the loom to prove a point an it was still happening an I know its not the ecu being faulty.

We decided to take it to the track to see how it would go down the quarter an if it misfired to just get out of it. Well after the 2nd pass it lifted the head (again) an damaged the MLS head gasket pretty bad as well as torching the head a bit. After going through my data log I noticed I was seeing the injector duty cycle as high as 140% which is extremely scary. Unfortunately I didn't have my wideband meter yet so I couldn't log AFR's but after seeing my gasket an head it looks to have gone very lean.

So basically my question is have these brand new injectors caused all these problems because the car when being cruised on the street drives fine?

I should also point out this was tuned on the standard 2.5 bar map sensor because my tuner couldn't figure out how to wire in my new 5 bar map sensor. I'm currently taking the HP Academy's starter package courses as I am sick an tired of having to rely an pay someone to tune the car that doesn't seem to care about what his doing so ill be tuning myself from now on.

Sorry for the long post guys hahaha.

Cheers Shaun 



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Sorry to hear bout your mishap with your engine.

If a ""TUNER"" tells you they don't like ViPEC or LINK it is purely because they can't understand the ECU and it's software.

If you know how to use the software and physically setup the ECU as far as terminating MAP sensors etc then these ECU's are the ultimate.

Seriously you own a very sophisticated and capable ECU especially considering the price tag compared to others.

The fact that he said he didn't like the ECU or couldn't work out how to fit an external 5 bar MAP sensor should have made you run.

Anyway that is a different topic.

When youse installed the injectors did youse modify the Fuel master setting or leave it at it's previous setting.

You mentioned that it lifted the head, this terminology is only normally used when excessive boost pressure is used and there is insufficient clamping force via the head bolts and or studs.

Torching the head and blowing the fire ring out of the head gasket can at times be caused via excessive lean conditions, however more likely to be detonation derived.

Do you have pictures of the damage, do any of the pistons have damage on the outer edges around the ring lands.

Can you please also take close up photos of each sparkplug.

If the engine was lean the ""TUNER""  should have known that and rectified the issue.

After all that is why you took it there, to be tuned.

Also during the tuning process he should have been checking data logs for injector duty etc.

Did he use detonation equipment when tuning.

Can you please post pictures of damage and supply your PCL file for a check of his tune.

Can you list your engine setup and include compression ratio and max boost and rpm used please.



P.S. Well done on joining HPA, you wont be disappointed.




Edited by Dave Kriedeman
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Hi Dave thanks for the quick reply.

I couldn't agree more I personally find the link/vipec sortware very easy to use but he is microtech through an through because from what I understand there quick an easy to use, an I have quickly come to realise his not the great tuner everyone talks him up to be unfourtnatly I have found out the hard way.

im currently wating on Mark at JPC to get back to me when he has the XS harness in stock so I can wire in the new map sensor myself.

In regards to the fuel master setting im not sure whether he adjusted it its currently at 7ms but I do know he never adjusted the injector deadtimes they still have the generic numbers in the 2d map an being high impedance the injector drives should be set to saturation but this ecu is locked to peak an hold. 

Lifting the head isn't an uncommon thing in this workshop unfourtnatly, normally when it does it they just pressurise the cooling system an pump all the coolant out of the overflow but this time it actually burnt up the gasket a bit and burnt a nice chunk of my brand new head which required 7 thou to be machined off the get it flat again. I am using ARP head studs torqued to 90 foot pounds. Luckily all the pistons look to be fine so I got off lightly there I believe its a combination of going lean an possibly to aggressive on the timing which im pretty sure is out by a couple of degress because he didn't lock the timing when tuning it in the configuration tab (I was seeing around 12 degress with the timing like instead of 10).

Nope no knock detection is used he doesn't even own any an he doesn't use data logging he doesn't believe its needed for some reason which is just plain stupid to me

After showing my machinist who builds an tunes motors himself the head geasket an head he said there's defiantly something not right with the tune in the car.

The motor is a Nissan RB30 with, Forged pistons, Precision  H-beam rods, 242/242 114lsa cam (I think that's the right cam specs),mildly ported head, GT35/40 with billet T04z front wheel @32psi. RPM limit is 8000rpm, E85, 2spd powerglide,445kw atw  The comp ratio is 7.1 or 7.5.1 . The motor has been ran after it lifted the head while I was trying to check for problems after it lifted the head so not sure they will be able to paint much of a picture for you.

I have tried attatching the pictures for you but there file size is too big, I have also tried to attach the tune PCL but its also saying that's to big even though its only 39kb am I missing something here? When I drag the PCL over its keeps highlighting as iVTS when I just use the VTS software. I can send the pics direct to your email if you like.

Thanks again for your time Dave its much appreciated

Cheers Shaun


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Cheers Dave I have sent the PCL file an pictures to your email hopefully they work this time.

Thanks for that Simon im glad to hear that I was hopeing I wouldn't have to fork out for a 3rd set of injectors.

Would having those injectors fitted though be causing my logger to see 140% duty cycle though or could that be because the inj dead times an master fuel trim have not been set up correctly.

Your not wrong there he has already been a massive help an it is greatly appreciated:D

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It will depend on the over all mixture, fuel table figures and the master.

However if the mixture is ok (not massively rich)

It might not be the injectors but the supply to them or the Injectors are too small.

Dave will be able to spot this from the info you have sent.

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