mj114679

ok so when i am driving and give it WOT it goes to about 4600 rpm and boggs out like it hit a rev limiter, does it from a stop or on the roll... i got my trans rebuilt.. still does it... took it to a tuner i thought maybe my rev limiter was before my shift point for some reason... nope! so wrong again.... took it to a shop he said fuel pressure regulator... nope!!! i ve spent like 2300 on this damn thing already.... still have the problem.... some say opti spark $250 some say fuel pump $180... UGH!!!!
BTW no engine code but an low coolant level switch light on...
and it back fires all the damn time!!!


can anyone help me!!!!:bang
THANKS GUYS

ss.slp.ls1

iTrader: (36)

At first I was going to say check the fuel pressure, I had a similar problem with my pressure dropping to 20psi at ~5k rpm causing a stumble. But since you said it's back firing all the time, I'd be very suspicious of the opti. My car would stumble and backfire all the time under acceleration. Took off the opti and one of the plastic rivets had broken on the rotor pointer.

mj114679

Yeah i put it on a fuel pressure test and when the key shut off it was at 45 psi. when it turned on and drove around or rev'ed up it dropped to about 38 psi. could that be a problem?
Btw how hard is it to take it off? what do you need?

BALLSS

...if your valve springs are stock...replace

94LT1Bird

iTrader: (4)

i once had a problem with my car poppin or sputtering at high rpms.....i changed my plugs and wires...and it went away

mj114679

hey ball ss.... can u give me any reasons why the valve springs??? thanks guys pretty soon i will be changing opti spark along with plugs and wires. if that dont work then fuel pump and fuel filter. if that dont work keep checkin youtube cause am gunna blow this bitch up!!!

BTW thanks guys!!

ss.slp.ls1

iTrader: (36)

Here is the best deal you will find for a genuine OEM opti:

http://cgi.ebay.com/ebaymotors/95-96...mZ350172822694

Just make sure to remove the cap and thread lock the rotor screws before you install it.

vipergtx500

high rpm break up sounds like opti. "if all else fails, replace the opti..."

SHDY 5.7

Not trying to hi-jack

I have the same issue. Mine happens later in the rpm band though.

About 5700 or so,no back fire or anything,it just starts to cut out kinda similar to hitting the limiter. My limiter is set at 6200.

My opti is new,plugs are recent and the last I checked the wires were good(recently replaced).

I was gonna wait to trouble shoot though until I install my valve springs to see if maybe its just valva float.

Anyother suggestions?

Green3spd

iTrader: (7)

Had a similar problem with my 94 A4.. Had my tranny rebuilt and it went away..

I've heard the Lt1 need new valve springs after 100k miles.. I replaced mine recently(112k) and Ill swear my car picked up some...(took me awhile so it prolly was just in my head, lol).
Im not one to say, "ITS THE OPTI" but its narrowing down to that...

slooter

Had same problem..........all said and done it was the opti......!
Aftmrkt's ones don't last either.
Just my 2 cents
Tony

SHDY 5.7

I hope its not my tranny. That only has about 5k on it!

As far as valve springs getting weak at about 100k,im at 104k on mine. That's why I said ill dig deeper once I swap those. Just seeing if there is anything else I should look at.

Thanks for the tip.

Dale

MadMike 97 Z28

iTrader: (3)

check into that its common for the sensor to get contaminated and read incorrectly or it could be the begining of coolant consumption due to blown head gasket.

That pressure seems low but I couldn't find the spec on here with a quick search.

Who told you that!? My car made 276rwhp and 317lbft at the wheels with 117,000 miles and only mod was a CAI. But if he thinks that it needs valve springs Ill let him have mine for free if he covers shipping I bought new springs when I got my cam.

ss.slp.ls1

iTrader: (36)

The spec for fuel pressure is 43.5psi with the vacuum line disconnected from the fpr, but anywhere from 41-47 is fine. 38psi with the vacuum line connected sounds acceptable, that shouldn't be the cause of your miss/stumble.
I seriously doubt its the springs either.

mj114679

OK Thanks all that helped. i will be buying a new AC Delco opti spark soon and installing it. should i go ahead and replace plugs and wires also? if so what are the best plugs and wires i could ****** up for my mods?

ss.slp.ls1

iTrader: (36)

Did you look at the Ebay link I posted for you? That is a genuine Delphi opti.

Get NGK TR55 plugs and MSD 8.5mm wires.

1badzee

iTrader: (12)

Ive (along with all my friends) have had good luck with AUtolite 606 plugs.. cheap, simple and they work great

mj114679

about how much are these plugs yall are talking about and how much are wires?

MadMike 97 Z28

iTrader: (3)

whatever you do DONT GET PLATINUM OR IRIDIUM PLUGS! all you need is standard plugs they perform the best and have a stronger spark I use NGK tr55's and tr6's for spray. as far as wires go I have msd 8.5's and don't have any issues with them but I don't think its necessary unless your wires appear to be damaged.

ss.slp.ls1

iTrader: (36)

The NGK TR55's are like 3 bucks a plug.
The MSD 8.5 wires are like a hundred bucks.