Truck surging wot with J/A lvl 5 and 6, any thoughts? Doesn't feel like transmission slipping and my fuel guage is installed as of today (waiting on parts:cry:). RPM's are in sync with surging and not running away...

Truck surging wot with J/A lvl 5 and 6, any thoughts? Doesn't feel like transmission slipping and my fuel guage is installed as of today (waiting on parts:cry:). RPM's are in sync with surging and not running away...

What's J/A lvl 5 and 6? Could you be a bit more specific? Do you have any codes? Sometimes a defective APPS causes surging and presents P0121 and P0122 codes.

What's J/A lvl 5 and 6? Could you be a bit more specific? Do you have any codes? Sometimes a defective APPS causes surging and presents P0121 and P0122 codes.

J/A = Juice with Attitude LVL 5 and 6 are the levels Try disconnecting the J/A and see if issue returns. Does it happen at certain speeds ?

As far as codes I have had 0121 previously but reset the apps and it was cleared. The speed it tends to happen at is 70+ when accelerating on the freeway (But only on lvl 5/6). I can create the surging on the high levels at lower speeds if I put it to the floor although I haven't noticed it until approximately 45mph. It didn't have this issue prior to installing the 125hp inj. I finally got the 6AN adapter I for my fp guage:hyper:, so the fp is 20psi at idle and 14/15psi at WOT even when the surging is going on.

The first thing I would do is pull the J/A and see what it does. That way you can usually determine if it is there all the time or not. Sometimes the boxes just aggravate an existing condition.

The first thing I would do is pull the J/A and see what it does. That way you can usually determine if it is there all the time or not. Sometimes the boxes just aggravate an existing condition.

So I took the J/A off and no surging, but it also wasn't doing it with the J/A set on 4 or below. I did take the J-hook off and so far that seems to have fixed the issue. I had talked with some turbo guys here in Tampa who told me with the HY hooked it could build up to 70psi of back pressure and could be the cause of the surging when I was putting that much throttle to it, simply just choking it. I have a few more test runs but now I am maxing at 27 psi of boost down from 34 but not surging.

So I took the J/A off and no surging, but it also wasn't doing it with the J/A set on 4 or below. I did take the J-hook off and so far that seems to have fixed the issue. I had talked with some turbo guys here in Tampa who told me with the HY hooked it could build up to 70psi of back pressure and could be the cause of the surging when I was putting that much throttle to it, simply just choking it. I have a few more test runs but now I am maxing at 27 psi of boost down from 34 but not surging.

Bet you it was the EJ/A defueling due to high boost or EGT (boost/egt limits) - not the turbo/hook

Yeah I suppose it could have, my EGTs never got over 1368, but don't know about the high boost. I would think the J/A would not have a limit that low (34), I have seen some guys with that box combination pushing 40psi plus with no issues. Either way, no hook = happy driver . I have a HX on the way, maybe put a boost elbow on that and see if it starts doing the same thing. ....we shall see.

Yeah I suppose it could have, my EGTs never got over 1368, but don't know about the high boost. I would think the J/A would not have a limit that low (34), I have seen some guys with that box combination pushing 40psi plus with no issues. Either way, no hook = happy driver . I have a HX on the way, maybe put a boost elbow on that and see if it starts doing the same thing. ....we shall see.

Its configurable You can set either to whatever value you want Lot of people set at 35-40 psi in order to help prevent head gasket failure.

Its configurable You can set either to whatever value you want Lot of people set at 35-40 psi in order to help prevent head gasket failure.

:doh: you know I forgot about the alert settings on that darn thing....I am going to go check that right now. Well its was set at 52psi, but I guess that doesn't mean something could be faulty and was causing it to defuel. IDK, it doesn't seem to be doing it....for now anyway.

usually this problem is experienced when trying to use the cruise control with the juice (or probably other power modules too) set on higher power levels mine can do it really bad sometimes and i've read other posts around concerning the issuethe cruise control issue is just the edge fueling too hard..boost rising..speed overshooting the cruise setting and rather than easing back into the throttle it hammers onto it when the speed comes back down and does it over and overthe cruise control doesn't compensate for the added fueling of the box and with larger injectors it'll make it even worsehowever your issue is that its surging while you hold the pedal to the floor? almost as if you were flooring it and letting off repeatedly?

Yeah it was surging with just the pedal, it also does it on the cruise too. If I have my box set to 4 on cruise it won't do it. The short of it though is John was spot on...I checked my boost but didn't check my EGT setting which was at 1350. I pushed it up to 1450 and do not have the problem unless I get into it real hard low in the power band. Keeping the overdrive off so the boost stays up till I hit about 52mph (2100 RPM) seems to keep the EGT's down. These new injectors are a little hotter than I am used to. I do have a HX35 on the way though and will be doing a water meth inj project this weekend though if all the parts make it in:). Should take care of the EGT's....for now:lmao: