Velocity AP

 

 

Do NOT "discount" the codes. They are telling you something IMPORTANT! Perhaps it's pre-mature detonation due to not having replaced the stock spark plugs with a set DESIGNED to run colder. The ECM switching an injector off could also be indicative of an injector failure, perhaps? I do know that Jag has replaced some injectors for others under warrantee

 

Anyone know where the exhaust pressure solenoid is located on a 5.0L?

 

john johns did you do colder plugs with the pulleys and tune? its been mentioned, the stock coils/plugs will misfire when pushed hard under load. Possible easy fix?

 

I’ve considered also doing the smaller pulley. But it seems to be more risk than reward. I’ve already went 1 unit colder on my spark plugs. Don’t know if I should do it or not.

 

Yes, I did the one step colder VAP plugs and gapped them properly.

Ive reset all the codes. Going to see if I can get cylidner 4 to misfire when pushed hard under load again - and try a new coil there.

 

Ok, I replaced the coils on cylinder 3 and 4 with OEM Jaguar units. Took it back out. At super high RPM on the highway, its still misfiring on 3 and 4, and now says cylinder 1 as well. As soon as I pull over and restart, its fine. Is it related to a tune issue, or maybe module or control board? Seems like a resistor is bad, or the control module voltage may be screwing it up.

 

All was fine before you Vapped it right?

 

Yup. I sent an email this morning. Hopefully they have an answer soon.

 

Injectors can't keep up and going static maybe?


How many miles on the injectors?

 

Any update on this? I've installed the crank pulley with the stock V8 spark plugs (my guess is that they are 44k miles old) and am getting misfires with the car going into limp mode (Restricted Performance mode, no CEL though).

Am wondering if its the spark plugs or any other issue. Will try and replace the spark plugs in the next couple of days.

 

Do you have the stock tune or a modified one ?

 

Whoops, should have mentioned, I have the crank pulley, Eventuri intake, 200 cell cats, according VAP tune and Aquamist water injection system.

Edit: also seem to persistently have an "air flow too high" code stored in the ECU. Not sure if it's improper installation of the Eventuri intake or an air leak in the Aquamist system

 

I'd refit stock air box and remove the aqua mist, if it then runs fine, you know the issue is not the tune, but the hardware.

 

+1. With both pulleys, VAP tune, and pushed hard, I have no issues at 24,00o miles.

 

It was indeed the VAP tune. Too much timing uptop. Got with stuart and chris, and chris had me a new tune in a day or two. Pulled a few degrees of timing from up top, as it was pushing the stock coil packs too hard, and then shutting down the fuel injector, which is causing your limp mode. I replaced ALL my coils with brand new OEM limits, but it made no difference.

When I take it to the dyno, I will log it to see the absolute max we can push a V8 w/ no cats & dual pulleys. If you havnt changed the plugs for the additional boost, you absolutely should.

 

Thanks for that, was very helpful. I have isolated my issue now to the Aquamist system, I think there's a leak somewhere in the rear leading to the air flow issue. I did change the spark plugs (went with the V6 ones) but not sure if they made any significant difference, don't seem to have done.

I'm really interested to see your logs and how much power you can make out of the V8! What mods do you have barring the dual pullies and tune?
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