Well ever since i installed my boost guage i have had a CEL. I have also noticed choppy idle and that its hesitant until it hits full boost. I have brought it to a mechanic but they said that it was my guage and they seald off the guage. But light came on like 3 miles down the road. So my question is that i am completely out of ideas. The mechanic ran the code and came up with a vac leak by the FPR. I have checked very hose next to that stupid thing but it still appears. I have also change plugs, wires, valve cover and gasket, and ran some Restore through it. Can some one please help me figure out this problem? Thanks Matt

Remove the gauge and see if it goes away.

The shop that I brought it to did that and I got about 5 miles down the road and the CEL came back on. I am really stumped! Thanks though! Matt

It might be a vac leak elsewhere. I'd check every vac line you have.

Thanks, I ll try looking! Anything I can try? Matt

I also noticed today that when i unscrewed the cap to fill it with gas, there was alot of air that came out. It sounded like I had big ballon deflating. Any ideas why or is this normal? Matt

thats pressure within your fuel system. Thats normal...

Evan B
97 GS- FOR SALE
90 GSX-sold
Stamford CT
EvMan2345@aol.com

I have been doing someresearch and i found that the sock vac is just about at -20psi. My guage reads that the vac at idle is at about -21psi so that would mean that there couldn't be a leak....right? I am really stumped about this problem...i have even thought about getting rid of the car altogether. Any more ideas would be great! Thanks, Matt

Originally posted by EclipseRacer95
I have been doing someresearch and i found that the sock vac is just about at -20psi. My guage reads that the vac at idle is at about -21psi so that would mean that there couldn't be a leak....right? I am really stumped about this problem...i have even thought about getting rid of the car altogether. Any more ideas would be great! Thanks, Matt

My gauge reads about 18-20 vac. 21 may mean there is a leak somewhere in your vaccum hoses... try soapy water.

What do i do with the soapy water.....if there was a leak wouldnt it read less vaccum? Matt

where exactly is the line tapped for your boost signal?
Is it here?...



Don't mind all the loom and crap. :P It's all been long gone. I took this pic about a week after I had the car.
The pressure when you take off the gas cap is normal. In fact, if you didn't have the system pressureized, that too would throw a CEL.
I think you either have the tap in the wrong spot or the knocked off/loosened a line by accident.
Don't give up and sell the car so easily, this is a minor issue...

Oh man, I just got a flat tire. Time to sell the entire car. :(



If something like a little hesitation and a CEL makes you want to sell your car, you shouldn't own it in the first place.

Originally posted by Jeff_99gs
Oh man, I just got a flat tire. Time to sell the entire car. :(

don't sell it dude. You'll make a lot more if you part it out... ;)

21 mmHg does not means a leak present, In fact it is perfectly healthy and your rings are sealing. I'm willing to bet there isn't even a leak anywhere. How does your idle RPM look like when warmed? And what was the CEL related to?

I have yet to hear a case of Boost gauge install yielding a CEL when performed correctly.

If you had a leak in your vaccum source, your numbers wil be lower (meaning toward zero), and your idle will be higher. Plus you woudl hear it too.

Woops, I had a brain fart.

Edit- by the soapy water, I meant put it on the hoses and see if any bubbles come up.

Well, my idle fluxuates from about 750-900 back and forth( really shakey). I did take that line for the guage and it seems to be connected pretty good. When I am driving the car it will hesitation until it hits boost and then pull but not as much as it did stock. I just cant figure out this problem. I have owned two DSM and the one I sold also had bad hesitation before I sold it. I followed up on it and the owner of it now had to replace the whole ignition system and still is having problems. I am not in a hurry to sell it, but dont have the money to constantly be fixing petty problems. Thanks for all the help so far! Matt

For it to idle around 700-900 is pretty normal.

I still want to know why it threw a CEL. That could be the source of your problem.

And Tune-Up?

I know! Its so fustating! I brought it in to get the codes run and they said that it was a vac leak near the FPR! They took it into their own hands to completely disconnect my boost guage. Well, obviously that didnt work otherwise I wouldnt be posting. But if they said that the codes were from a vac leak....WHERE IS IT!!!:wallbash Could it be a faulty TPS sensor, because I would bet any money that it is still the stock one. Matt

you could always just ditch all the vaccuum lines and emissions crap. ;)

Originally posted by eclipzGST
you could always just ditch all the vaccuum lines and emissions crap. ;)

too easy. everyone likes to search for a needle in a haystack. ;-)

What do you mean.....like take all vac lines off and cap them or replace all the vac lines.......so it can't be a faulty TPS? Matt

How do you check the TPS sensor? Matt