# Troubleshoot my boost problems in 01 Frontier SC



## Adam (Apr 30, 2002)

I've had my truck for about a month now. I've installed a boost gauge, and have a new pulley sitting on the counter waiting to go in, but I'm a little hesitant. I don't seem to be seeing as much boost as I should be. I'd like to see if something is wrong before moving ahead with that. (Or I'll just end up doing it next weekend anyway *shrug* but I did put it off this last weekend because of this). Here's what's happening... 

When I first start up, I only see a max of about 2psi. Now I've only got a 12 mile commute to work, so many days that's _all_ I see. If given a good chance to warm up, I'll see as high as 5psi. Isn't the stock boost supposed to be 6-7? Now I'm assuming the ECU is lowering the boost until the engine gets up to operating temperature, is this a good assumption to make? Does anyone know anything about this ecu that I dont?

Anyways, as it is, I'm rarely even seeing 5psi, but I'd like to know why most of the time it's just 2, I'm thinking it's the ecu, let me know what you think.


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## Flix (Oct 17, 2004)

NA is better.


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## Adam (Apr 30, 2002)

Shut up tony


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## Kenn (Mar 23, 2005)

*boost problem*

I would first check tthe supercharger belt tension to make sure it is tight enough. I put the 12psi pulley on mine and was only getting 8-9 psi because of belt tension. If that is not the case there is an actuator on the side of the supercharger that operates a valve This could be your problem I think the Actuator valve is about $60 from the dealer. Hope this helps.


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## Adam (Apr 30, 2002)

Kenn said:


> I would first check tthe supercharger belt tension to make sure it is tight enough. I put the 12psi pulley on mine and was only getting 8-9 psi because of belt tension. If that is not the case there is an actuator on the side of the supercharger that operates a valve This could be your problem I think the Actuator valve is about $60 from the dealer. Hope this helps.


Thanks man, the more I think about it, the more I think it's a few small problems. For example, my belt does tend to slip a lot, like when I finally do hit 5psi and I've got it wide open, I can see it start to creep to 6 and then *SKREEEEEEEE* the belt slips and drops to 1-2psi. Also, when I did the boost gauge I didn't use teflon tape or anything on the pipe fittings behind the gauge at the time because I was going to fix it later. I just never got around to it. So I could just be reading a little low.

Which pulley is the 12 psi one? I've got the 2.3 from pulleyboys.


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## Adam (Apr 30, 2002)

I tightened up the supercharger belt, and now I'm seeing 6psi all the way up to redline, no slipping at all. Every once in a while though, I'm still limited to 2psi. I don't know if my guage is misreading or what, but this is kinda annoying.


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## spec240sx (Aug 22, 2004)

Adam said:


> I tightened up the supercharger belt, and now I'm seeing 6psi all the way up to redline, no slipping at all. Every once in a while though, I'm still limited to 2psi. I don't know if my guage is misreading or what, but this is kinda annoying.


1) your correct on the stock PSI. 5-7
2) your Guage should be done 100% right before you move on, as you know.
As for the Pulley. I would LOOK heavily at ASP before I put on the pulleybro's If you still are at that point.
Just some info.


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## Adam (Apr 30, 2002)

spec240sx said:


> 1) your correct on the stock PSI. 5-7
> 2) your Guage should be done 100% right before you move on, as you know.
> As for the Pulley. I would LOOK heavily at ASP before I put on the pulleybro's If you still are at that point.
> Just some info.


The pulley actually arrived over a week ago, so too late on that one. I really can't see it being the gauge, but it can't hurt to double check anyway. It looks like I'm going to attempt to do the pulley on saturday anyway, but judging how my 'installs' went (or did not, as the case may be) the last two weekends I'm not going to hold my breath.


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## Kenn (Mar 23, 2005)

Adam said:


> The pulley actually arrived over a week ago, so too late on that one. I really can't see it being the gauge, but it can't hurt to double check anyway. It looks like I'm going to attempt to do the pulley on saturday anyway, but judging how my 'installs' went (or did not, as the case may be) the last two weekends I'm not going to hold my breath.


There is also an actuator on the side of the supercharger that opens and closes a valve depending on engine load. This actuator has a spring and a diaphram in it. I had the ocasional 3psi annoyance to and it turned out to be this actuator which of coarse can only be purchased from the dealer to my knowledge. It was $68.


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## Adam (Apr 30, 2002)

What about doing that so called 'boost mod'? It involves rerouting some hose over to that thing on the side of the sc. I don't have the link here with me at work...


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## Kenn (Mar 23, 2005)

I would be curious to see that "Boost Mod". Post the Link PLZ


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## Adam (Apr 30, 2002)

Kenn said:


> I would be curious to see that "Boost Mod". Post the Link PLZ


http://www.picturetrail.com/gallery/view?p=999&gid=926649&uid=135343


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## Adam (Apr 30, 2002)

It'll hit 10, but I'm still having that issue when it drops down to 2 after some driving 
edit: Oh, I uh, installed my pulley today btw.


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## Adam (Apr 30, 2002)

The test drive:


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## Kenn (Mar 23, 2005)

Adam said:


> It'll hit 10, but I'm still having that issue when it drops down to 2 after some driving
> edit: Oh, I uh, installed my pulley today btw.



I have the dropping to 2-3 psi after some driving too. The actuator on the side of the supercharger is adjustable I think under boost the actuator is not adjusted properly and the diaphram over extends itself due to the added boost. I adjusted mine and it happened less frequent. I will adjust it again to see if I can't solve this annoying problem.


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## Adam (Apr 30, 2002)

Kenn said:


> I have the dropping to 2-3 psi after some driving too. The actuator on the side of the supercharger is adjustable I think under boost the actuator is not adjusted properly and the diaphram over extends itself due to the added boost. I adjusted mine and it happened less frequent. I will adjust it again to see if I can't solve this annoying problem.


How do you go about adjusting it?


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## Dustin (Dec 14, 2003)

Adam said:


> How do you go about adjusting it?


GO LOOK AT IT! im going to assume with normal hand tools, i think it works in the same way a wastegate does on a turbo, so that would be the first thing to do is go look at it, and figure out what you're workin with.


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## Adam (Apr 30, 2002)

You assume too much.


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## Adam (Apr 30, 2002)

bingo

I'm going to check my plugs when I get home, make sure they're the correct heat range and gap. 

Apparently the boost mod I was talking about (the link of which I just noticed is broken, I'll fix it when I get home), will bypass this whole thing, but it's not necessarily a good idea either if your engine really _is_ knocking. So I'll try and fix the source of the problem first.


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