I have an 89 Formula 350 with 65,000 miles. I have an Ported Edelbrock Intake, AS&M Runners, Ported Plenum, New 22lbs MSD Injectors, MSD6al, Headers and other stuff. When I go to the track it seems to die after 4500 rpms and it sounds like I Cant get enough air or enough fuel. My pressure is set at 46 PSI any suggs? Thanks Best time with this combo and a 3.27 rear is 14.030@98 with a 2.188 60*
BTW timing is at 10* and I have the stock Chip

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89 FORMULA 350
99 Grand Prix GT

 

two things, one: i have been told tpi doesn't like high rpm pulling or two: knock sensor is kicking in and retarding timing in top end. just my thoughts.

 

Does the Edelbrock intake include long tube runners or are u still using the stock ones? If not, the stock runners dont flow over 45000rpm regardless of your intake, exhaust, heads, etc.

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1989 Chevrolet Camaro IROC-Z
L98 - 350c.i. TPI, rebuilt 700R4 auto w/shift kit, Dual catalyst Monza PaceSetter Cat-Back, SLP 1 5/8 Coated Headers, 3.23 Posi rear, Hypertech chip with 160stat, MSD 6A, Under-Drive pulleys, AFPR, K&N's, !Air Box w/ Ram Air, moddified MAF, !TB Coolant, Spohn Dual Cat SubFrame Connectors, Alarm, Keyless entry, remote starter, 92 Z28 AeroWing, Brand New Paint (6/21/01)

Future: ZZ4 TPI w/EGR, T56, 3.42 or 3.73, Spohn strut tower brace and LCA's

1989 Chevrolet Celebrity Eurosport
2.8 MPFI, no mods
225,000 miles and still ticking!

More info and pics on my webpage:http://go.to/iroc-z

AOL IMer: GPA 0point0

 

That's where the stock cal starts turning down the HP, so GM didn't have too many warranty claims. Also, when old enough the fuel pumps output degrades with age.

 

I have AS&M Runners. I'm thinking fuel pump so I'll switch one out this winter.

 

try getting a custom chip to add more fuel up top

 

Yeah, get a different chip. The stock chip is maximized for stock components.

 

it's called a TPI intake

17.5 inch runners = not enough air at high RPM's = not enough fuel at high RPM's = no power at high RPM's

get a miniram / super ram / ramjet with shorter runners and you will have power till way up there

 

My thoughts exactly, even a fully ported long-runner setup isn't going to make any power in the top-end. Sure, it's got the torque that everyone worships and its good on the street, but when it comes to the strip, the long runners just don't cut it.

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'89 Firebird Formula 350
L98, WS6, Red/grey, t-tops, and a 3.27:1 rear
K&N, TB bypass, no MAF screens, CAI, full Accel ignition, no cats, Hooker Supercomp shorties, Hooker 3-inch catback
ET? 14.8 @ 93mph
Also own '83 Firebird 2.8 2bbl. 155K miles.
ET? Break out the calendar!

 

sounds like a fuel supply problem they can and do pull higher than that. my friend has an 89 formula 350 and that pulls past 5000 his is all stock. he since did small things like fuel psi and a chip and it still goes past 5000

 

I have the same stupid problem, but my engine is all stock!! I know it shouldn't pull too much after 4000RPM.. but it shouldn't just fall asleep and give up. I had the car in, and the fuel pressure was at 40psi when the engine was hot.

What about that knock sensor? Is that repairable? Would the GM Dealer Mechanic pick up that problem with a diagnostic computer?

Could I have a weak MAF sensor? it was replaced, according to the guy I bought it from, about 1 year ago.

Will the exhaust I am putting on it tomorrow help? I am getting 3" mandrel bent stainless from y-pipe back with 3" catalytic and Flowmaster muffler. Maybe the cat is a little on the restrictive side?

It just seems to "choke" at 4000RPM and do nothing. My friends T-Bird screams throught the RPM and squaks the tires into 2nd gear with an automatic... why can't my car do that?

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1988 Pontiac Trans Am GTA L98 5.7L, Black on Black with 113,000kms

 

do you really wan't to take it to the gm dealer and have them take your car to 4000+rpms I work at a dealer and let me tell you some of the guys and most likely the one that gets your car has had very little schooling and or thinks they know every thing. they will beat the living sh!+ out of the car. I would only have the shop forman look at it. and yes if they know what they are doing they will find it. we have a few at my shop that are not even jiffy lube worthy. not to scare you but, people think dealer mech. are something special I am glade my stalls are in the back of the shop away from those nuts. If this was a story board I would leave one every day.

 

LOL!!

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89 RS

STILL Looking For:
An 87 IROC-Z28 350 TPI

 

Check your cat, mine was plugged and the car had good low end power but dropped off fast as the RPM went up.

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1988 Formula 5L/5sp 3.45 gears, SLP cold air kit, MAS gutted, TPIS air foil, TPIS AFPR, MAC headers, Mac under drive pulleys, MAC cat back, Relocated MAT.
Best ET street tires 13.85
Best 60 FT street tires 1.930
Best MPH street tires 99.29

 

The one mechanic that was working on my car, I believe he's good.... I've had him work on my other cars, and he knows his stuff.

As for a clogged cat, we'll find out if that's the problem thursday, when I get it back from the exhaust shop with 3" stainless mandrel bent exhaust from the y-pipe.

I am also thinking a dying MAF?

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1988 Pontiac Trans Am GTA L98 5.7L, Black on Black with 113,000kms

 

What are your cam specs? If you are running the factory cam then, hey, no big surprise. Your car's entire intake system was designed to make peak Hp right around 4800, When you changed out your runners and base, you gave your engine a lot more airflow potential, but your stock cam probably just refuses to pull past 4800. If you have stock heads,the intake runner on your heads poses about the same problem, stock is around 165cc. Great for air velocity, not so hot for high-rpm power. Fuel pressure is a possibility, and I would check that first, but I'm going to bet it's design related rather than malfunction.(I've seen 13.4 at 103 on the stock fuel pump) Your intake track, if it is stock, is yet another probable restriction. Try taking off the intake before the MAF and see if that improves things. Try hooking up a fuel pressure gauge on the passenger side fuel rail. Mount it on the hood and watch (or have a friend watch) fuel pressure readings during your next run. Also, I agree that 10* may be a little too much for your engine to tolerate, set it back to stock and see if this help to cure the problem.

 

My only comment on this at this point is that his intake system (Long Tube Runner setup) is not the problem. He has some other issue with timing retard on the top end, lack of fuel on the top end, possibly lack of cylinder head effeciency, and most definately a cam that is not designed to make any power over 4500rpm. A LTR setup that has been ported and/or upgraded like his will give you enough flow to pull past 5000rpm and put that car in the low 13's (with all the other necessary mods like exhaust and whatnot...). A Super Ram or Miniram is not necessary on EVERY application people. My setup pulls hard up to 5300 - 5400 and it has a mildly ported, stock, non-siamesed base (Yes, I know my car would be even better with an intake upgrade, but I am merely proving a point here). Obviously a MR or SR has more potential in the long run but there is no need to tell him to spend all of that money and time tuning it when it will likely not give him any better performance than what he has now without upgrading the more likely culprits of his lackluster performance. Actually, a 14 flat is pretty good for his setup anyways if it has the stock cam and heads on it yet.

Laterzzzz........

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1987 GTA L98 MD8 GH3
355 '97 Vortec 4-bolt block, TRW(suck) forged pistons 10:1 CR, TFS 23* Heads, LT4 Hot Cam, Ported plenum and intake base, SLP Siam Runners, BBK 52mm TB, Edelbrock TES, gutted Cat, Flowmaster, CAI w/K+N cone, AFPR, TB bypass, !AIR, !A/C, !EVAP, ARAP, 2400 stall, Alum. Driveshaft, Fourth Gen 3.42 Rear, Spohn LCAs and Panhard, Hotchkis STB, '99 Camaro seats.

G-tech time:
(w/ lotsa wheelspin)
13.45@109.3mph

 

HEy guys... Went to the strip last night.. as doing better than last time, getting numbers like 15.7secs.... let my car rest for a bit.. got in.. and I did 2 amazing runs.. a 15.2 and 15.08. These runs, i could feel the difference, like the engine was running like its supposed to.. as soon as a spun the tires to clean them up, the RPM's climbed a lot quicker than usual and I ended up doing an all out burn-out, and not even trying to. My question is... what the heck started working properly those 2 runs... cause i did 2 more after that, and the car was running back to the way it was... slow climbs throught the RPM's... It bugs me.. cause i think I could have broken thouught the 15's and into the late 14's.. but the car went back to gutless stage. Any ideas? Anyone else have/had a similar problem?

I was thinking TPS, bad MAF, Fuel Pressure Regulator, Bad Ignition Module?

Any input would be a great help.

Oh yeah... the new exhaust sounds killer on the track, I am very happy with it. Anyone in the Southern Ontario or NY area, and wants a nice exhaust system, let me know, I'll refer you to the shop.

Later all

 

No, No, Maybe, and definately No.

If you tps was bad youd have way more problems than no power above 4500rpms, same goes for the MAF. You might benefit from more fuel pressure, but i seriously doubt thats whats holding you back. A bad ignition module will cause your car to hesistate and stall while running. You need to hook up a scanner to your car to see if your getting knock retard above 4500rpm. Stick a fuel pressure gauge on it to and tape it to the windshield and do some full throttle runs, it should stay around 42-43psi. 37 at idle.

 

Well, you could spend sevral hundred dollars on guesses, plus countless hours replacing stuff.

My suggestion is to use a scan tool and see what's going on with things.

A scantool, IMHO, is necessary for anyone trying to tune their car past stock performance, heck, it's almost a necessity for troubleshooting problems in ECM controlled engines.

There are some ways around using a scantool and tuning, you can bypass the knock sensor, do some WOT runs, part throttle runs, etc, stopping and reading the plugs.

But heck, when you can just plug in and not get dirty and get about 90% of the info you need, why not?

And you just know that anytime here, Glenn's gonna jump in and force you in to PROM burning

 

Thanks guys... I am bringing the car to the dealer today after work... maybe tomorrow after they are done the plugs, decarbonization and fuel filter, I will request a driving test with the mechanic in the passengers seat with the diagnostic tool. The knock sensor sounds like the most correct solution... are they hard to change? Is it possible that it car work properly for a little bit?

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1988 Pontiac Trans Am GTA L98 5.7L, Black on Black with 113,000kms