gtp problems

[dmaynard]

Ok my problems are well ihave a 0 to 60 time almost 13 seconds with a gtp 3.8 sc motor i just tested the fuel pressure key on motor off its 39 to 40, after 5 mins it drops 34 or so. when i turn the key on motor on its 45 +- 3 when i rev it up it goes to 55. the car feels like it has no throttle response i cant make the tires spin in rain with trac cont off.. anyone have any ideas i changed the fuel filter and and plugs oh the charger makes a little noise like little rocks in it but iwouldnt think that would like affect half the horse power and the gas mpg is really bad about 13 in the city. I took to auto zone had no codes when i tested it... any ideas guys help please!!!

[tblake]

Your 0-60 time looks normal to me.

You forgot to tell us what year your GTP is.

Sluggish accelleration and poor fuel economy is often caused by a clogged cat converter. GM exetended the warrenty on converters of 3800 GP's manufactured between a certain year range due to known issues. Check the tips and maintenance subforum for more info.

BTW, Welcome to AF.

[dmaynard]

i thought 0 to 60 was around 7 seconds?? its a 1998 with 65k miles on it. the cat is gone to

[richtazz]

I think Tim read that wrong, maybe as 1/4 mile not 0-60. 13 seconds 0-60 is WAY slow for any Grand Prix, let alone a GTP and Tim would definitely know that. The converter issue mentioned above affects 01-02 Grand Prix's (and all GM W-body cars) and GM extended the converter warranty to 7 years/120k miles on these cars to cover the issue. Regretfully, even an 02 would be beyond the 7 year time period now, and your 98 is not covered under this extended warranty anyway.

[dmaynard]

I dunno i am just asking for help, 40 psi key on engine off sound right? 35 after sits for 5 mins then turn on 45 rev get 55 more or less 0 to 60 13 seconds not good... no cat convert. any ideas?

[dmaynard]

I mean what else do you guys need for info im not to much into cars but im mechanical im a tool maker. I step on the gas and there is nothing there at all psi maybe low? 40 prime 45 to 47 while idle and 55 at rev. I cant bark the tires at all i hammer the gas and there is like nada.. even in rain cant break em loose the Boost gauge will not even go up half way when i rev it up to the rev limiter and when on the high way going 55 hammer it i get 3 dashes of boost on the gauge mpg is poor around 12 to 14 in the city. The cat has been taken out.I went to autozone had the codes read nothing came up so im just looking for a little help.

[Mickey#1]

There's not a whole lot we can do without being able to see some data via a scanner. You could pull all six spark plugs & check their condition. Two dark ones from the same coil would point towards a bad coil. While the plugs are out can check compression to make sure there's no serious mechanical problems. Make sure the air filter isn't filthy & check for vacuum leaks.

[rkvons]

I would investigate the rocks in the supercharger and also look at your air filter.

[tblake]

sorry yeah, brain fart, 13 sec 0-60 is too slow, for some reason I was thinking 1/4 mile which 13 seconds would be about right.

65k on a 1998? Want to sell it as-is?

Try unplugging the MAF sensor and then start the car up. After the idle stabilizes, take it for a drive and see if anything changes.

Also I am curious, you say the CAT is gone, yet autozone scanned it and it did not come up with any DTC's, not even P0420 (cat efficiency below threshold) code. How did you do this?

[BNaylor]

Originally Posted by rkvons

I would investigate the rocks in the supercharger.

It sounds like a supercharger issue since the boost as indicated is abnormal.

Originally Posted by tblake

sorry yeah, brain fart, 13 sec 0-60 is too slow, for some reason I was thinking 1/4 mile which 13 seconds would be about right.

Not unless he has a couple of thousand dollars in mods. For a stocker more like around 15 secs for 1/4 ET or maybe high 14s if you are lucky.

[tblake]

Originally Posted by BNaylor

It sounds like a supercharger issue since the boost as indicated is abnormal.







Not unless he has a couple of thousand dollars in mods. For a stocker more like around 15 secs for 1/4 ET or maybe high 14s if you are lucky.

Guess I better be quiet before I'm demoted.

My Girlfriends Mom's bonneville with a 3.8 non supercharger runs 1/4 miles in under 13 seconds stock in my dad's shop on his dyno, and we have always torqued down his LIM with an impact wrench and have never had any problems.

[BNaylor]

Originally Posted by tblake

My Girlfriends Mom's bonneville with a 3.8 non supercharger runs 1/4 miles in under 13 seconds stock in my dad's shop on his dyno, and we have always torqued down his LIM with an impact wrench and have never had any problems.

That sounds like old "Waffle Head Frederick". I think his twin works for me.

Everything is my father, my friends or I read it in a car magazine. No practical experience, automotive education or common sense. Get this. He did his first DIY oil change in his '96 Cavalier a few weeks ago. But the service was 8000 miles overdue and then he dumped the old oil in his front yard.

Not it gets really good. He thinks he can get a new GMC Terrain for dirt cheap and have leverage over the dealership with piss poor credit, no down payment and the Cavalier as a trade-in. Another .

I'll be glad when he gets terminated from employment which won't be soon enough. He can't even pass a security clearance check.


And I forgot to add he checks the engine oil level with the engine running. Effing moron!