vacuum line diagram for '98 gtp

leo

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Oct 30, 2008
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Does anyone have any pictures or diagrams for proper placement of all the vac. lines for a '98 gtp. The car runs, but as soon as it boosts, it seems like a severe missfire or cutting off power or something... it is very annoying to drive the car under 1/2 throttle at all times and not have enough power to make a pass or even merge on the highway... any1 else have this problem in the past any fixes or pics/diagrams of proper vac line routes??? Thanks in advance!
 

TommyGloves

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Aug 23, 2007
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See attached PDF for diagram. HTH.

(1)To EVAP Canister (At Rear of Vehicle)
(2)PCV Valve
(3)To Vacuum Brake Booster
(4)Throttle Body
(5)Supercharger Bypass Actuator (Bypass Valve Actuator)
(6)Supercharger Bypass Solenoid (Boost Control Solenoid)
(7)Fuel Pressure Regulator
(8)Supercharger Assembly
(9)EVAP Canister Purge Valve
(10)Manifold Absolute Pressure (MAP) Sensor

Make sure to check the rubber "T" fitting under the SC snout. They tend to become brittle and crack.
 

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leo

Member
Oct 30, 2008
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0
question... if it was a bad plug or wire, wouldnt it be creating "missing" all the way through the power band... not only upon boost? my "bogging" happens ONLY when the car boosts. thats why I was curious about the vac line set-up. I will check the plugs n wires tho.
 

Turk

Lt. Ron "Slider" Kerner
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Jan 21, 2008
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question... if it was a bad plug or wire, wouldnt it be creating "missing" all the way through the power band... not only upon boost? my "bogging" happens ONLY when the car boosts. thats why I was curious about the vac line set-up. I will check the plugs n wires tho.

I'm not sure about GTPs, but when my SS had a bad wire, it was missing only at idle and when I first accelerated. Everywhere else it was fine.
 

Bru

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question... if it was a bad plug or wire, wouldnt it be creating "missing" all the way through the power band... not only upon boost? my "bogging" happens ONLY when the car boosts. thats why I was curious about the vac line set-up. I will check the plugs n wires tho.

Not always. My wire was burnt halfway through and it ran fine as long as I wasn't in boost. Once boost hit the engine started to break up.
 

Freebeer187

The Bolt Rounder
Feb 2, 2009
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Schaumburg
question... if it was a bad plug or wire, wouldnt it be creating "missing" all the way through the power band... not only upon boost? my "bogging" happens ONLY when the car boosts. thats why I was curious about the vac line set-up. I will check the plugs n wires tho.

You would think it would but im my situation it was not. I had the EXACT problem. The spark plug housing cracked. The actual metal inside appeared to be untouched (of course it was used and needed to be replaced) but the housing was causing the problem. When the plug was removed it collapsed into pieces.

Look at the thread I posted for more info. You can see all the troubleshooting I went through.

I had the car scanned while driving. At a small idle to wide open throttle there was 0 missfires being reported and 0 knock. We tried allot of things but for some reasons me and the guy I was working with forgot to check the plugs.

Before you jump to conclusions, purchase new spark plug wires and new plugs. Dont forget to gap them. Even if it does not fix your problem, it still is never a bad thing to have new plugs/wires.
 

leo

Member
Oct 30, 2008
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0
ok, set all the vac. lines properly now... they were a mess and not all accurate, but it runs smoother now... Still has the main missfire on boost... had no time to do plugs n wires today, hopefully il get to it tomorrow, but good thing I got the vac lines in order now at least...
 

leo

Member
Oct 30, 2008
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0
before i did anything today i got these 5 codes...

P0134- something to do with O2
P0135- another O2 code
P0300- engine missfire
P0446- some Evap code
P1133- S1-S2 and B1-B2 or something like that... sorry, i didnt memorize them.

cleared everything and il drive it home from the shop and back tomorrow to see if i get more codes or repeaters.
 

Freebeer187

The Bolt Rounder
Feb 2, 2009
5,334
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Schaumburg
P0134, P0135, P1133 - Either the front o2 is bad or was unconnected and you ran the car.

How old is the fuel pressure regulator and/or fuel filter?

Good idea. Replace the fuel filter. Even if its not the problem, once again its a good idea to do. You can also check the fuel pressure while the car is running. You need a tool for it (i had a friend check mine).
 

leo

Member
Oct 30, 2008
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0
does anyone else have a pain in the ass time pumping fuel and have the nozzle unclick every $0.48... and have to costantly re-click and re-adjust the angle ur pumping and speed and pitch of the nozzle??? wtf... il check fuel filter tmw, depending on price for new 1, i may replace it... but its a spark/misfire issue tho.
 

Freebeer187

The Bolt Rounder
Feb 2, 2009
5,334
10
Schaumburg
does anyone else have a pain in the ass time pumping fuel and have the nozzle unclick every $0.48... and have to costantly re-click and re-adjust the angle ur pumping and speed and pitch of the nozzle??? wtf... il check fuel filter tmw, depending on price for new 1, i may replace it... but its a spark/misfire issue tho.

Never have I heard of or have had this problem
 
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