for the the past 3 months i have been having problems with a lack of tq and struggling up the rpm range

well from the dyno graph u can see where its stuggleing gaining and losing hp and tq from the grpah going up and down. plus from stock, lost 9 lbs of tq and .2 hp with these new mods(headers,coil,removed cat and raised fp). fp was a lil rich with the quater trick but was steady at 11.1 so i serously need some assistance on fixing this problem with my loss of tq when going though the rpm range.



stock was 188.3hp and 239.6tq
new spec 188.1hp and 230.5tq

 

Thats one wicked torque curve you have. Hope you figure something out man.

 

can any one explain this graph ???? im lost

 

bad plugs or wires???

 

That's real rich. Turn the fuel pressure down. 13:1 is best for power, 11:1 is almost drowning it.

Check your initial ignition timing and advance it to 8-10, check your plugs and wires for burning and arcing, there is an ignition problem/miss going on.

 

how whould i be able to notice where the buring / arcing is coming from. what do i look for ? timing is set at 6 degrees, and i just replaced the cap rotor and plugs but not the wires, also a buddy of mine told me to replace the plugs again casue they could be fouled out due to the bad wires.

 

open hood at night when it's dark. start the car and look for a light show. from, your buddy.

 

Ya you're running way rich!!! Drop that fuel pressure!!!

 

well the problem is back again this is

i changed the tps first, it stopped it for a lil bit then came back so i changed the wires that help for a week or so and now its doing it again the power still feels like/ looks like the graph on the tq line.

im gona try swapping out the msd coil to stock 1 see if anything happens. just after 2500 it struggles with no tq behind it. and it only does it sometime not all the time, i can see and feel the diff when this happens. im runngin out of ideas any 1 can help

 

ooops

 

umm.... look at my signature buddy i dont have a JET CHIP. i have a JET AIR FOIL. so that wont help me.

my timing is set to stock setting

 

Have you taken the quarter out yet?

 

Check the tps again. I replaced mine only to have the new one go out a week later.

 

i went through a few sets of wires when i put my headers on because they kept getting burnt--do you have anything holding them in place?

 

This option gets my vote...

 

thanks for the replies, no i havent taken the quater out so still runing rich. but it was doing this b4 i even put the quater in.

all the wires have good clearance from the headers, but the do get hot from the heat off the headers.

the tps is about 2 weeks old i replaced once and that new gave me a high voltage code when it was properly set,so relplaced it again the next the day still 2 weeks ago, but istill fell the loss everyday

idont know what to do swap out the msd coil? i dont know ?

just another thing the car has 135k on it, can the injectors be the prob, they are the original injectors, any way of checking them casue they might be not sprying correctly?

 

Try the stock coil and see what happens. If that does'nt work I would take the quarter out and then put a fresh set of plugs in. While your that far in there you could pull the fuel rails up and prime the fuel system to see if the injectors leak. Even if they don't you might unplug the coil and turn it over to see what the injectors spray like. Either way get that quarter out of there, its killing your power.

 

I will take out the see what happens ill try the stock coil and see what happens.


i ran 15.2@91 with the quater in there i hope it wont drop

 

Mine showed just as rich on the dyno but still had a nice curve to it.

What wires are you using? Sometimes the cheap sets crap out as fast as you can put them on same goes for the cap and rotoe especially so of you have a hotter coil.

 

Wow, it was rich before you put a quarter in the FPR and you added it anyway? Adding more fuel pressure is like increasing the size of your injectors, didn't you know that? Search on the web for "injector calculator" and you should find one of many online java sites that can help you calculate the new flow rate of an injector running on pumped up pressure.

I would seriously check out those injectors with that many miles on them. Actually, I probably wouldn't even bother with doing all of that, I'd probably just buy a new (or at least new-er) set off of Ebay or something. I'd start to get used to DIY PROM too if I were you...

 

bnoon- :nono: it was lean b4 i put the quater in, it was like mid 14's on the air/fuel ratio. i put it in to see if i can come close to normal.

but i dont think thats the prob.

now injectors chould be a possible casue they are origial/ or something with ignition? casue the graph shows it i really dont know what to say or do lol

 

Ahhhhh, O.K., you didn't explain it in the other post.

The ignition is a source of at least one problem... getting a good pickup lead. Sometimes high resistance wires or plugs can lead to very jumpy readouts like that, other times it's that the dyno tech put the pickup lead to close to the distributor.

 

it has to be someting there man i just have to replace the injectors or replace the whole distributor ? i need to fix this

 

It's pretty easy to tell if you need a new distributor or not. The tech articles linked to from the main site go through testing the ignition module, which is the most usual point of failure on an HEI system.

You can also check the distributor out physically, by making sure the cap doesn't have corrosion on the leads, making sure nothing is cracked, and making sure the rotor is in good condition as well. Also, make sure the distributor shaft doesn't wobble side to side and that the distributor drive gear doesn't have any slop in it. The shaft should have some slight up and down movement to compensate for camshaft play, but the movement should not be side to side at all.

Back to the fuel issue... if your car was running lean with the bolt on mods you listed, I would be concerned about a clogged injector, or perhaps a partially shorted coil on one of the injectors. First step though is to get rid of the quarter in the FPR though, because you're going to end up washing your cylinders of oil and causing more engine wear.

There have been a few people on this site to show pics of their home injector cleaning methods. There have also been write ups about checking injectors for leak down as well. Electrically, the injectors are easy to check. They should all register about the same in the 14-16 ohm range if I remember right. Simple Ohm meter operation there. Just disconnect the injector harness from one injector, put the two leads on the small pins on the injector, write down the Ohm reading, clip the connector back on and move to the next one. Anything reading low than 14 Ohms is bad IIRC.

 

Your quarter times dont seem to be that off, just your ET. 91mph id say is a high 14, like 14.8-14.9. With your mods, Id say thats about right.

Your dyno is insane. Its like the engine is missing for a couple hundred RPM's. How good is this dyno? As said before, your running rich. Check your timing and check your plugs. If they reak of fuel, then its a fuel problem. Your graph looks like a roller coaster, which is technicaly impossible if your foot is on the accelerator durring the whole thing. ITs like you backed off. Do you feel any loss of power while driving? Id redo that dyno, cause that one looks like it sux!

 

bigals87z28- yes dude i feel it like the graph shows! i dont know how to explain but that curving up and down is what i feel when i drive it happens 75% of the time driving this is the prob im having.

the dyno is good its a very popular place and every other 3rd gen has no prob with it, dyno sheets are correct. my first 1 was not like this one, it was just going up normal no probs, then now i lost tq and some hp.

 

then Id say your about 4 cyl short of some power or something. Check your plugs man, and wires.

 

i did a complete tune up, cap ,rotor,fuel filter,and plugs. idid not do wires yet casue money was tight, so next week came around i got some wires and slapped them on same prob. even got a new tps still same thing.

fuel pump about 1 year old
and igniton module about 1 year

 

I watched a dyno run like that before .....it was all spark related ...... in/out in/out



just trying to add what I have seen

 

just a thought... check the dist its self. the cam gears could be chewed up and its slipping... just a thought.

 

When I first installed headers onto my car, no matter what I did, the car always had a miss.

I changed the plugs with ACDelcos, put in a MSD coil, and MSD wires and it took care of it. Just a thought.

 

i dont know man, i put the headers on it ran fine untill begining of this year around march it strated to do this but i had headers on there already.

plus i have the msd coil on there now, ac rapid fires i have bad luck with em i foul them out qucik for some reason so ...........

also will any drivetrain problems can cause this, maybe a bad tq converter, tranny is a rebiullt 700 from this time last year dont think its bad ,or drive shaft?


or if the tranny is not getting the right amout of line pressure from the tv cable can that casue some sturggleing of the tranny?

just someting i have on my head just a thought..

 

well, i had it looked at a good mechanic that i trust and he told me what u guyz been telling me it has a miss.

we power braked it and gave it gas and he heard it had a lil miss to it .

so where do i start to look for it at?

also we put it on the snap on scanner everything was ok and numbers where good no codes.

he also told me the rockers has like a tap to it to adjust them if had had the time and other than that its ok

also he said he whould reccomend injector cleaning for the car.

i dont know if this is another problem on top of the 1 ive been havin or this is it ?

 

take the motor out, rebuild, and put it back in. problem solved

 

Just a random thought make sure your positive cable is not touching the headers.

 

Heres another random thought... I had this same exact problem as you. The car runnin like crap intermitantly. Well the motor evenually blew up on me And as I was pullin the motor out I forgot to unbolt ground wires from the passenger side head. and on that bolt I noticed a ground wire that was cut, it was orange or a tan color. Now I have no clue if this has anything to do wth anything but I figured it was there for a reason. Also I think I cut it while removin all of my smog components, and u said u did headers. Which makes me think u were back in that area and maybe it cut a ground wire back there? I would just check it out to make sure, this probably wont help but check it out so I at least know...

Jason

 

fbirdta- ill check around for that wire but im pretty sure every thing is back to where it was, i removed the smog stuff recently, but still i had the problem since feb of this year around the same time when te headers went in.


biffta- the i don know if the positvecable or the negative 1 is close o the header but not tuching, i will hav to double check it ,the only thing on one of the cables is oe of the spark plug wires i zipped tied to it, but would a spark wire make it miss once an a while?

also i got a afpr for free, its a crane one it sucks but igot the psi around 48 now with vac off.

kantrax- lets just say project 350 is on the way

 

My bet is on the injectors. If you can feel the miss at idle, start unplugging injectors. If you hit one that doesn't slow the idle down, it's weak or plugged. (unplug the IAC first)
How about a plugged fuel filter?

 

My last TA had walmart wires when I bought it and I chased amiss through everything but the wires that would come and go and my father in laws new Vette is showing the same thing with another set of those wires.

 

bird91- ill try that havet check it like that yet, but what u mean by un plugging the IAC first then pull the connectors of the injectors or unplug th iac see if anything happens,if not then do he injectors?

 

yes unplug the IAC so it won't raise the idle when you start unplugging injectors

 

allllrighty

 

Definitely too much fuel. Best thing to do is reburn the eprom to get your AF ratio up. Around 12.8:1 with some tweaking to see what your motor wants specifically (some like a bit more/some a little less).

Also, it would have been a great idea to do a "scan" while the engine was running. Your "bumpy" curve could be the result of the knock sensor pulling timing while you are fighting detonation.

 

i already bumped the fuel preesure down from 52 to 48 psi so that help there and the scanner tool i have to see becasue i tried to drive with it and it says cant drive while in diagnotic mode ?

 

ttt

 

like i said in the pervious post i tried hookin up the snap on scanner and for some reason it wont let me drive in dianostics mode so cant read nothing ? is there a reason why i cant?



also an update on my car

the tq loss is still around but what im seeing lately is the idle is rough and goes backand forth from 650 to 1000 then stays at 9 then repetes the prosess

 

I'd be willing to bet that it is spark-related, check everything down to the gap on your plugs, but that fuel mixture does need fixing also.

 

hey bud, sry for digging up this old thread, if you still have that car and the problems with it, id say change the injectors, or atleast ohm test them. I had the EXACT same problem with mine, turned out to be 1 bad injector!