Ok I have a 89 Formula with a LO3, has around 25,000 miles. The problem I am having is that at 4500 in 2nd gear it starts to pop back through the Throttle Boby. I have timed it, run the valves, replaced the coil, cap, rotor. Put a new fuel filter air filter and PCV valve in it as well. I was told that the factory module will start to break down at 4500. So if anyone can help me figure this out I would be very greatful.

Thanks I DRAG 2


Mods include

NGK V-power plugs
Accel Wires, Cap and Rotor
K@N Air Filter "Open Element"
ADS Stage 4 Super Chip
TCI 700r4 Tranny
Hayden Tranny cooler
3" Exhaust into a Flow Master
Governer cut off switch
Toqure Converter Lock up switch
15" Grant Steering Wheel
Energy Suspension Master Bushing Kit


Thats all I can think of right now.........Please Help.

 

True, the stock ignition system is not good for much rpm above 4500 if any. Mine would fall flat on its face at five grand. Also I believe that your cam and cylinder heads don't flow good at those rpms. Most of the stock motors aren't good for power past 5000. Somebody will correct me if I'm wrong.

 

But like I said I can rap it to 5600 in first but then in 2nd it will fall flat on its face, but only in 2nd. I know the motor is good up to 5600 but what gives. If it was in the heads and cam it would do it all the time and not just in one gear.

I DRAG 2

 

Simple, question if it is a automatic trans. Gear ratios. First gear in a 700R4 is 3.06 (nice and low) second is around 1.96 (an lot higher). The engine is under more load in second gear, so any piece is going to show up more. Your car probably won't do it in first because the motor turns up at a good rate of speed.

Also, take a look at your rear it is probably a 2.73 That is just to high of a rear end, a 3.23 would be much better.

Simple put there is to much gear drop from first to second in a 700R4. That is why you see more turbo 350 and 400's as drag trannies. Gear ratios are closer. Hope that does a little better job of answering the question.

 

Ok that sounds ok? so what is the best way to fix the problem besides changing out the tranny and do you think its in my ing. system? Would a MSD box help or am I just FU@#ED.

I DRAG 2

 

No, keep the trans. A decent ignition system would probably help. But a little (numerically) higher gear would probably help. I persanally went from a 2.73 to a 3.23 and was very pleased. Gas mileage around town was about the same, but highway dropped a little. That is the good part of a 700R4, overdrive. you should probably try a combnation of each.

Places like summit and jeg's sell aftermarket ignition modules and coils. That is probably the easiest and cheapest way to up grade a ignition unless you are running a real hi po motor. Try to stay away from accel products. In my personal opinion they suck and are not dependable. Been stranded because of them more than once. Do the gearing later. It does cost more, 3.73 are probably to much gear for a daily driven 305. start with the ignition and ask around to people you know. Hope that helps.

 

Hold on, chief. You're WAY off in the weeds here. The stock systems are prefectly capable of supporting 5500 RPMs. Your problem is likely very simple:

1. Lack of fuel supply. Fuel delivery system is under the greatest load at WOT and high RPM. That's where you notice a problem first. Replace the fuel filter FIRST (which you did). Then, get an appropriate fuel pressure guage, hook it up and DUCK TAPE THE GUAGE TO THE WINDSHIELD! Fuel pressure at idle is MEANINGLESS. You HAVE TO check it at WOT under load at high RPMs. If it's not keeping up it will be obvious- the pressure will take a nose-dive as RPMs climb and that's when your engiene will start to miss. Find out why and fix it.

2. Ignition problems. The coil could be going south (which you replaced), as could the module, the pickup or any one of a zillion little elewctronic components including the plugs and wires themselves. But concentrate on the fuel first. I think that's where your problem lies.

Fuel supply problems can OFTEN reveal themselves ONLY in certain gears. My carbureted Malibu used to fall on it's nose at the top of first, but be fine elsewhere. The hard acceleration and the long draw from the tank by the stock mechanical pump combined to produce a first-gear only stumble. But sometimes you can rev to the top of first so fast that the supply will keep up jsut long engough to prevent a stuble but then come back and get you at the top of the next gear.

 

Ok I will try the fuel test and see how that goes I will post my results soon. DAMN I HOPE ITS NOT THE PUMP I don't want to have to drop my tank, that would suck. Hoping the ing. system is taking a dump.


Thanks for the help guys...........still open for more opions, if anyone has any???


I DRAG 2

 

PRAY it's the pump! It's an easy fix. You buy an aftermarket in-line pump, mount it to the frame rail and leave your stock one right where it is.

 

Well I had my pump tested by the local speed/machine shop and they said the pressure is not droping at all it has more than enough at 4500. So any other ideas. PLEASE HELP ??????

I Drag 2

[This message has been edited by idrag2 (edited April 27, 2001).]

[This message has been edited by idrag2 (edited April 27, 2001).]

 

Did they test it UNDER LOAD? Just revving the engiene to 4500 in neutral doesn't mean squat. Also, dyno testing doesn't mean squat since it doesn't deal with the extra load placed on the fuel system as the car is accelerating and generating g-forces that make it harder for the pump to shove the fuel up the fuel line to the engine.

Anyway, if that turns out really NOT to be the problem then you need to beg, borrow or steal a scan tool (I like Diacom) and spend some time driving around with it connected to get familiar with the readings. Then, once you've done that you'll be able to start narrowing things down by looking at what changes there are in the readings when the problem pops up.