hey everybody, I generally don't post on here....most things I can find using the search. Anyway, I've got a 91 Camaro RS 3.1L that has had a peculiar problem with it ever since I bought it. First off let me say, I had to reset the base timing when I bought it among other things. For the most part, the car runs and idles very well and has respectable fuel mileage for this type of car.
I've always noticed a high-rpm bog with this car, as if its running out of fuel or something...its most noticeable when merging onto the freeway. It almost feels like I've got a bad plug wire but they have been individually checked. It has smooth power at WOT until it hits 4500RPM then the bogging starts in until it shifts at around 5000RPM. I've replaced the following parts to correct this: Distributer Cap & Rotor, Ignition Module under Distributer, Plugs, Wires, TPS sensor, PCV valve. The PCM has not thrown any codes, although the INFL REST light occasionally turns on and off. Could this be a bigger problem, such as a worn timing chain? Car has no obvious problems, 40lbs oil pressure (hot idle) and about 190°F coolant temp when warm. Car has 94,950 miles.

 

my 92 RS Does the same, pulls fine untill higher rpms then it like struggles...looking forward to seeing responses in here

 

Im not sure at the other problem, but the INFL REST light deals with the air bag. It comes on at start up to check if its in working condition.

 

The High RPM bogging is normal, do some searching before you ask. The intake and heads on these engines are VERY restrictive.

 

I did or else I wouldn't have posted.

 

It appears to have been a bad ignition coil. I replaced it about a week ago and have not had the bogging problem anymore. As far as the INFL REST light, it pretty much stays on now, I know how to read codes from the DERM module but do not know what the numbers mean, I'm thinking a bad ground may be the problem on that issue.

 

Thats strange. My car does the opposite. You can feel it pick up alot more power at about 4000RPM. Not even at WOT it will just pick up power without mashing the gas.

 

It's running good now?

 

So far so good, I never knew there was a problem until I started to merge onto the freeway. The old coil looked to have a small crack in it on the bottom. Why GM decided to rivet those things in is beyond me.

 

I had that problem once after I first built my single side pipe exhaust. It had a dual tip turn out. Well it just didn't rev out right in the top end, ended up knocking a hole into the end of the pipe, so it shots out straight and has two turn outs.

If you got an older no name system them mufflers can rust out inside n plug up some. Or even a old dirty cat.



Here is link to thread about it

https://www.thirdgen.org/forums/exha...ight=side+pipe

 

do you have the stock air intake...filter and all? that will restrict it up around 5k, also.

 

Thats a real good point. And engine is just an air pump and has to flow free on both ends to move.

I do have true cold air / ram air and a very very low restriction airfilter screen.
Which just grabs stuff that could do damage stuff. Since air only come from out side on hood and Im not in a dusty or sandy enviorment I don't worry about crap.

sometimes if I see a dust cloud like from a farmer in a field or other I stuff the clutch in and turn it off till passed. Im not dumb just daring and so far many many years of fun.

If often reminds me of a dirt bike as once in that power band it pull hard to redline and beyond before it falls off. Gotta have ridden a real dirt bike to know what I mean.

 

There are many things in combinations that restrict these cars at the notorious 4500 rpm wall when stock. Without resorting to heads and intake work

The addition of a modern style catalytic convertor alone will help greatly (All new cats are high flow units- get rid of that old 80's stlye honeycomb cat if you still have it.

Catback systems help next- but again only very minor changes- but with enough changes done together the rpm range does start to creap up evry 100 more rpm's on top end.

Smaller crank pulley is the biggest bang for the buck in power and milage increase. DO NOT USE THE ALT REDUCTION PULLEY- notorious for problems, just use the underdrive crank pulley.



Larger TB and upping fuel pressure also helps- Making sure your current fuel pump is in strong condition and you filter is not clogged helps greatly. If these are going bad then nothing else you do will help- make sure the basics are working.

Better ignition (hotter coil0 and also not advancing the timing too much). I have seen many on here set their timing as high as 14-15*. Thats way too much and you loose top end. The motor will flatten out. Even with everything I have added to mine I run 13* on 92 octane. I will flatten out sooner on 87 octane at higher at 13* and runs better still at 12* with 87 octane than at 13*

Headers made a major difference- but I already had many mods that helped free up the topend when I installed the headers- it more became married in componants once they were on. I turn 6000 rpms on a fairly stock longblock no problem. The only thing done intenally is the addition of 1.52 roller tip rockers.

I also have an extremely lightweight low power robbing trans/ convertor and rear drivetrain setup. It is extremely exotic and helps my motor spin up quicker in taller gears even. This is what makes my car fast for a 2.8 (note: I did not say "fast", My quote was "Fast for a 2.8")

Open up the TB, headers and bump the fuel pressure will give a substantial notice in power

That will get you started in the right direction. I also use genuine AC Delco sensors and ignition modules- they are the best and are workhorses. I do not like AC Delco plugs though- I use regular(non-platinum) Autolites- they are workhorses also and I use a 53,000 Volt coil (not the 38,000 v factory unit).
I use to hit that same 4500prm wall with the same 2.8 motor I have in the car now until I made the upgrades I stated above. I now pull right up to 6000 no problem WITHOUT head work. Granted, headwork will give you much more power and is worth every penny on a bench flow when ported correctly and matched, but rpm increase can in fact be obtained pulling up to 6k without head work and I am proof of that. Our biggest hurdle is the weightof our cars combined wioth these tiny displacement engines. Put these engines in a 1000 lb lighter car and the move very well-aka the Fiero's.

 

That is a myth and a lie spread by the idiots who repeat them.

If you have a 60* that falls on its face at 4500 RPM something is wrong with your car. Though I bet allot of them do fall on their face from being beatin and abused for over 20 years. Not many folks take care of their cars right or even know how. Why ones that are taken care of run strong for 200,000+ with no problem. No good running 60* runs like that. I don't care what you say, thats hella dumb.

You been hangin out on a s10 board to long. As they will fall flat around 5 but are geared for off road. Still seen many 60* S10,s15 Jimmy..... drive through a swamp like a monster truck.