Engine/Transmission (1998.5 - 2002) POWER! Or a lack thereof. Needin' advice

[Fishin Guide]

Well, it's time to start to work on the rig again.



I have been fighting issues with my truck trying to make power. It just plain ol won't do it. As you can see from my sig, this is the level I am "stuck" at. Nothing to date has helped and I am looking for a different perspective. I think I have tunnel vision.



Short list of what has been done is the VP to every engine mounted sensor I can think of. Everything except the cam position sensor needed replacement due to fault codes, open circuts, ect.



Here's the bottom line. I make the same power on a M3 as a M6. Heat is the same as well. So, it appears to be fueling related. I do not have enough.



The lift pump has more than enough volume and this has been confirmed via flow rates and pressure. (no less than 37psi WOT). The VP change has zero effect on overall power output. Well, I gained 5 HP and lots better driveability!! So, the mechanical side of the fueling equation seems to be intact.



This leads me to electronics. I am running the TST/ Smarty combo. I have tried a couple of ECMs and still no change. Also tried a known good drag comp alone and lost a few HP. My pump tap is rock solid and there is no change tapping the wire as opposed to the pump cover. I have also tried 2 TST's. Since fueling boxes only extend the duty cycle at the VP, I think the issue is pre VP. A redline would bypass the factory fueling curve, but it has not been tried yet.



So, what am I missing on the electronics side that would have an input on the ECM's ability to fuel to it's potential? PCM? APPS? IAT? MAP? What else? And how do I identify a faulty issue?



I have not had time to mess with the truck lately as I have tons of stuff on my plate. However, I am asking for help fom my fellow BOMBers cause it's more irritating than anything else. Heck, I had an issue hanging with a 350Z that was coming around yesterday and I have to get my power back!



BTW, at one time, I could peg my pyro. I can no longer do that. I am lucky if I can hit 1300 degrees with M6's in the truck. And, it'll make peak power at around 98-99mph rear wheel speed measured by the dyno rollers. It just goes flat. Does not build power, but does not lose any until way out beyond 130mph. But then again, it does the same things with M3's. I have ruled out the injectors as an issue. I think I could fill a 5 gallon bucket in a few seconds with the M6's. I just don't have enough pressure.



It's like it's defueling. But, I don't know exactly what the deal is.



So there it is. Any ideas? I am sure someone out there has had to deal with this issue and found a solution.



Thanks folks!



Dave

 

[TJarecke]

I don't know if it effects hp at all, but I believe the VP is supposed to run a max fuel pressure of around 14 psi. If the pressure is too high would it bypass prematurely or something like that? Like you said the pieces are in place to make the power and it sounds like it is getting to the vp but it is not getting to the injectors. ????

 

[J.Keith]

Yea what ^^ he said.

I'm no expert with the VP by any means so somebody jump in a correct me if I'm wrong. It would seem to me that with the fuel pressure that high it could cause the timing piston to stick? I don't know just a guess.

However if you were making better power before with the same fuel pressure that would kind of rule that out.

Have you tried a COMP box? I'm sure you have but I've ALWAYS made better power with a COMP than anything else. Even a Redline.



Another thought, maybe the new VP that you put on is junk? probably not but it's possible.



I feel your pain man and I'll be watching this thread closely for suggestions.

I'm getting ready to pull the head on mine because I'm losing boost and all thats left that it could be is the headgasket.

I have no difference running M4's or M1. 6's.



Good luck!

Jeremy

 

[JCutter]

Im in the same boat. I think ive done about everything and now im stuck except to p-pump it but the only two dyno #'s i have are on mustang and only able to put out 508hp. I know there is more but at a block like FG i too will be watching this.

 

[Fishin Guide]

To answer a few of the questions.



The fuel pressure has had no real effect on power output. In fact, I have made the most power with pressures above 20 psi. I have tried a regulater in place and there is no effect of loss of power. To my knowledge, there is no internal bypass in the VP to allow for high pressures.



Changing injectors from a M4 theough a M6 have made no change in power. I get more smnoke off the bottom, but no more heat. And that's the thing. With a M6 the Comp TST on kill and the Smarty on level 9, I max out my EGTs at 1300. It sould be buried.



I lost power with a stock and a Smarty'd ECM coupled with a known good drag comp.



Dave

 

[JCutter]

With my 220 inj and the other two boxes on 9 my egt only hit 1650 on the roller. Playing around i can peg it past 1750 (where it blanks out). When i added the nitrous it just jumped to max hp faster. So i need bigger inj. which im told that 220 is max for the vp or do something different.



I courious how doug (jetpilot) got over 800 with his vp

 

[J.Keith]

I've been messing with mine all day and while not on the dyno I did get it to feel a little better. Just adjusted the valves again. Had 2 tight exhaust valves and thats about it. It has the M4's in it now and just dosn't feel like it's making what it should. I'm hitting 50-55psi easily but I can just barely get the EGT's over 1100. With the Edge on 6 and the Smarty on 8.





Right now I'd be suprised if it's making 450+

 

[AFarmer]

With my 220 inj and the other two boxes on 9 my egt only hit 1650 on the roller. Playing around i can peg it past 1750 (where it blanks out). When i added the nitrous it just jumped to max hp faster. So i need bigger inj. which im told that 220 is max for the vp or do something different.



I courious how doug (jetpilot) got over 800 with his vp

Easy - he flogged th hell out of that truck with NOS. Ok - I'll throw out my numbers that I've seen and we'll try to compare apples to apples. Mach 7s, DGZ/B2 twins on the dyno made 632 on diesel only. My EGT's were never over 1300. How are you regulating boost with your twins?? You should see around 60lbs of boost and no more or you'll be pushing passt the efficiency point.

 

[Fishin Guide]

Easy - he flogged th hell out of that truck with NOS. Ok - I'll throw out my numbers that I've seen and we'll try to compare apples to apples. Mach 7s, DGZ/B2 twins on the dyno made 632 on diesel only. My EGT's were never over 1300. How are you regulating boost with your twins?? You should see around 60lbs of boost and no more or you'll be pushing passt the efficiency point.

Yes, Doug was throwing nitrous at his truck. And that makes sense, but I am nowhere near that HP! LOL



Is the 1300 on the dyno or the street? I cannot see 1300 on the street with everything on kill. I am using a modded internal gate with a DGZ/B2 setup. I have thought drive pressures could be a factor, but if I had very high drives, shouldn't my temps be uncontrollable?



I have pop offs in place right now regulating overall boost. I know, not the most effecient way of doing it, but I still can't imagine being 100HP low due to this.



Also, box off and no Smarty nets under 400 HP on sticks alone.

Add the Smarty and it goes to about 435.

The rest comes from the TST.



I appreciate the help!





Dave

 

[Fishin Guide]

BTW, there is only a 5HP change from 45 lbs boost on the dyno to 70 psi.



However, I get lots of heat below 60 psi.



Smoke completely clears early and I can only see a light haze at night with everything on kill.



Dave

 

[JCutter]

I know he used nitrous. I was only meaning what sticks because ive been told that 220's got the max out of the pump (will not flow more). I know its all hear say but i have talked to doug about the nitrous and he did tell me i would get the whole 200 shot with the right lines and set up. im not doubting that because i did get about 220 hp with only the rated 150 hp nozzle just down lower in the rpm. My turbo cleans most of it up when lit. I only gained about 20 hp off the bottle in the upper rpms.



Im just looking for more fuel to feed the needs of the bottle

 

[2-ND TIME]

lack of power.

Hay this is something I have been fighting since new. Does your engine rev but produce little power? Is there an rpm that it ( does ) start to accelerate? Mine labors terribly till then, if I ask it to work hard. This starts at over 1400 rpm to ac ce lerrattte sort of O well it now is working half right. Does your buck at any rpm? Mine has an arc in the electrical system I have seen it on an oscillascope so they can't BS me any more. If a dollarshop has ????? ( mind has gone blank, late) it turns there drb into a scope most don't have the parts anymore for it ( most convienent now that I know about it) they then can look at the electrical and see what it looks like. Keep all the replaced parts and kleen the sensors. PM me if I can help further but I am out hunting so SORRY for the great delay. I may get to find bull winkle. Oo.

 

[Graphic man]

i just read a post on another form... . same issues went to a big stick with no change in ET's



he had no codes and everything ran great, except for a loss of power



he changed out the VP and gained 4tenths in the 1/4, i am sure thats about 50-75hp, due to the fact he was in the low 12's.



it just goes to show ya that you can have a weak VP with no codes and still run fine but when you get the HP cranked up it makes a difference.





Scott

 

[paulb]

Dave,



Have you tried disconnecting the alternator to see if you are getting some "line noise" from it?



Just an FYI, I played with boost settings at the track last weekend. Setting the wastegate so that max boost was 75psi, with the pop off's closed, was . 12 slower in the 1/4 mile, then with the same wastegate setting, and the pop off's set to 65psi. Max EGT's were ~1400 degrees in both situations at the end of the track. I just mention this because I know people have suggested that the pop offs are related to your problem.



Paul

 

[GIT-R-DONE]

Could it be possible you are at too much boost. More air than fuel, ratio?

 

[Fishin Guide]

Dave,



Have you tried disconnecting the alternator to see if you are getting some "line noise" from it?



Just an FYI, I played with boost settings at the track last weekend. Setting the wastegate so that max boost was 75psi, with the pop off's closed, was . 12 slower in the 1/4 mile, then with the same wastegate setting, and the pop off's set to 65psi. Max EGT's were ~1400 degrees in both situations at the end of the track. I just mention this because I know people have suggested that the pop offs are related to your problem.



Paul

I have not tried the alternator thing. What's the procedure and what am I looking for?



I think I am okay for overall boost. Someday I'll build a hot pipe with a non wastegated housing on top and an external gate and I'll also incorporate a wastegate for the primary. That will allow the pop offs to be a thing of the past. But for now... .



Dave

 

[Fishin Guide]

he changed out the VP and gained 4tenths in the 1/4, i am sure thats about 50-75hp, due to the fact he was in the low 12's.



it just goes to show ya that you can have a weak VP with no codes and still run fine but when you get the HP cranked up it makes a difference.





Scott

I don't disagree that it could be a VP issue. This is a reman unit with less than 10K on it, but it could still have issues.



Dave

 

[Fishin Guide]

Could it be possible you are at too much boost. More air than fuel, ratio?

I don't think I could have too much air.



I could concieveably be creating excessive high drive pressures by cranking the boost up, but since I get no power change from 45psi to 70 psi, I do not think that is the culprit.



I just have a lack of fuel. Either in the VP due to mechanical issues or electronics not allowing enough fuel to enter the cylinder. It would not matter what injector I run, it would do exactly the same thing.



I think this is a fuel volume issue pure and simple.



Dave

 

[paulb]

I have not tried the alternator thing. What's the procedure and what am I looking for?



I think I am okay for overall boost. Someday I'll build a hot pipe with a non wastegated housing on top and an external gate and I'll also incorporate a wastegate for the primary. That will allow the pop offs to be a thing of the past. But for now... .



Dave

When the alternator is charging it can put a lot of electrical "noise" into the system. Electrically disconnecting the alternator (take the wires off) will remove that noise. You might not even see the noise on a scope, unless you have it on while dynoing.



I only mentioned the pop-offs because I actually went quicker in the 1/4 mile using them. I can't see anyway, that they could be your problem.



Paul

 

[Fishin Guide]

When the alternator is charging it can put a lot of electrical "noise" into the system. Electrically disconnecting the alternator (take the wires off) will remove that noise. You might not even see the noise on a scope, unless you have it on while dynoing.



I only mentioned the pop-offs because I actually went quicker in the 1/4 mile using them. I can't see anyway, that they could be your problem.



Paul

So what if there is an abundant amount of electrical noise? What is the fix if that's the case?



Thanks for takign the time Paul. I have no clue what the interconnects are here. :-laf



Dave