Slowmaro:

Did you check the block surface/heads matching?.

I had problems with a bad machined block surface. You could see your engine running in the night (without lights) and check for littles blue flames around the heads gaskets.

Try injecting some propane ( propane torch) down the throttle body right when it starts to die. If it then recovers you have a fuel delivery problem.
(fuel pump) if that does not help, its an ignition problem.
What about egr? is it hooked up? is it operating at idle when warmed up. When it shouldn't.
Could be a sticking valve.

Doesn't sound like a head gasket problem at all.

Waiting for someone to ask about work you didn't mention you did...? It's stuff like this that makes it hard to help you, we only know what you tell us.

The nice thing about the "mommy bought me an IROC, I broke it, help me fix it" crew is you guys don't last too long here.

whats funny is , #1 i dont own an iroc, #2 i have over 1000 posts, #3, ive been here for a year and #4 why does your mood fluctuate so much kevin? maybe think about prozac or somehing.

egr valve isnt on the car, ...its been gone for awhile now when i switched to the performer manifold.

i didnt bother to post *i blocked off the air tubes* because thats pure common sense to know, if i took off the smog stuff, which i stated long ago, that i would have to block the air tubes, ....its not my lack of telling all information thats the problem here. you MUST know that if i had taken off the smog equipment that the air tubes had to be plugged.

there are no blue flames comming from my engine bay lol, id know that for sure. i work on my car at night half of the time due to the heat and ug being a huge problem in sc.

plus if flames where hitting the gasket like that, it would have melted by now, making it very apparent what the problem is.

In my opinion, having struggled to make a stupid CC-Quadrajet work for *** knows how long the best thing that you could do is toss the TBI into a lake. I would understand the attachment if it was a TPI, but, hindsight being twenty-twenty, you probably would have more than made up for all of the losses in sensor-replacement cost, etc. and by narrowing the potential field of problems you would have most likely solved whatever is wrong, which, I suspect, simply has something to do with your TBI/chip. If I were you, and I couldn't afford a nice carb, etc. but wanted my car on the road, performing decently (most likely quite a bit better than it was before), I would go down to the wrecker, get myself a quadrajet, vaccum advance HEI and stock intake, clean them up, modify them as necessary, and bolt them on. I now have a Holley and Performer RPM on my car, but when the problems wouldn't go away for me, that's what I did, and it worked like a charm. And to top it off, it only cost me $50 Canadian, which included a pretty darn nice set of Accel wires that were attached to the distributor and greasy but proved to be 100% functional with no leaks, burns, etc. I know that it would feel like "quitting", but in the end, you'll have a functional car that most likely performs better than your car will even if you do get the TBI running.

Bottom line: even if it's not the TBI/computer, etc. if you make the change, your list of potential problems will drop exponentially and you'll be able to focus on the mechanics of the engine rather than forty different sensors and their myriad associations with one another. Consider me a simpleton, but as a knowledgeable "basic" car guy, but only a passable, if that, electronics guy, I know what worked for me.

Opinions are worth a grain of salt, so please don't get upset if you disagree, this is just what I would do and should merely be accepted as a suggestion; not criticism.

If your coolant sensor is bad, you need to replace it. Not rewire the fans. The coolant sensor that sends a signal to the computer giving strange readings is the one that controls how much fuel your computer adds in due to temperature differences (running temp differences). However, you said your car is getting into closed loop, so maybe that isn't hurting you. If the car runs much better when it's hot, the sensor may be bad, though.

If you check the resistance of the sensor, it should be between 1000 and 5000 ohms with the car shut off, and go down as the car gets hotter. If it doesn't behave like this you should change it.

Be rational. If the car ran fine before, it has to be something you touched. If the compression is good, rule out the heads and move somewhere else. If the car runs better at higher rpms, try adjusting your idle and the timing. Do a search on the tbi board for common problems, you may find yours.

Have you yet considered that there may not be any major problems with your heads or gaskets?
If the engine isn't rattling, smoking, or misfiring then it may be just fine.
How well do you have it tuned at WOT? Have you scanned a WOT run yet?
I'd first check the total timing at WOT,
then check the O2 reading at WOT.
Have you done any reprogramming of your chip yet?

From what I remember of TBI programming is that they have VERY weak timing curves in the chip. It doesn't give you nearly enough down low, then it keeps advancing up high when it shouldn't. The result is very poor performance AND/OR spark knock.
Some people reprogram their chips, but the best fix I know is to get a good aftermarket distributor.
Swapping to a carb should indeed help the performance significantly as well.

I'm just considering the possibility that your lack of power is the result of poor tuning.

ok so, the fan temp switch is the sensor that isnt hooked up, the reason its not hooked up is because the port that it goes in, in the passenger side head, has a plug of some sort --not spark plug-- and this plug thing is so well rusted in, therre was no possible way to get that sucker out other than Drill it out, or have a machine shop take it out. machine shop wanted over 100 bucks to do it.

the cars gives no indication that this is a problem , no ses lights, no nothing.

id really hate to switch to carb, it just seems like moving in the wrong direction, even though i seriously may end up doing it.
the more i modify it, the less the computer is going to agree with the mods, and basicly just restrict them.

no i havent reprogrammed the chip, i had a chip made from tbichips.com a year ago, long since any mods have been done.

the reason i suspect a head/gasket is because the car ran perfect before the head swap, i have taken the manifold and sitrubutor out many times and have gotton it all back in sync within at the very most 2 days. and thats when i seriously didnt know what i was doing.

and if yal ever detect any bit of aggression from me, its not ment for anyone but kevinc. that guys arrogance and know it all standards just **** me off.

I've had to drill one out before, it's a pain, and I don't even want to imagine how bad it would be with the heads in the engine bay. Unless you have severely deformed the inside of the plug, some repair shops will have the tool that goes in there. I tried that but I had already screwed it all up. So I drilled it with a drill bit that would easily clear the threads so I wouldn't damage them, then I took a chisel and smacked the shizer out of it until it came out in pieces.

Maybe this will give you something to do that will produce good results and get you in a better mood. I get so pissed sometimes I seriously think about taking a crow bar to the windshield, I get super pissed.

Have you at all considered that your ecm has went Kaput??? It happens....and nothing you try will work.

yea, the inside of the square bore plug is now a complete circle. i tried everything to get that sucker out, nothing would work.

oh i almost got into a fight with my car yesterday, i seriously found myself yelling at my car in my front yard being all like "bring it on bitch!! you want some ?? huh huh??" then walked off going ..Wtf am i doing lol.

nah that thing would be almost impossible to drill out with the heads still on the engine. i prolly shoulda just went ahead and drilled it out while the heads were out of the car but i didnt feel like messing with it since ive had my fan wired to run constantly for the longest time.

the sad thing about the ecm is, its pretty new, ..i mean 3 months old.

whatever this problem is, its been a problem , and it didnt become a serious problem until the head swap, ...even before the head swap my car would idle like pure crap and smoke black out the tail pipes for 5 seconds after i shut it off and started it real quick. then after the 5 seconds, it would go back to normal, and i spent a month trying to track down that problem, replacing about every single thing along the way.

im seriously suspecting my fuel pump right about now. i mean everything else has been checked and replaced.

yesterday i took a break from trying to track down problems and made my stock fuel presure regulator, an adjustable one, and it actually turned out great. i didnt do it exactly like the TGO tech article says to go it though, ...i drilled a slightly larger hole about 1/2 inch deep into the base of the cup, and wedged a small nut in it, ..then drilled a hole through the injector pod where the FPR housing sits and stuck a long screw through it so you could adjust it alittle better and easier.

i just with you could do it with the car running and without having to flip the tbi over. oh well, this is better than paying 100 bucks for the one from turbo city.

i spent the day playing with the fuel pressure seeing if it had any direct effect on how the car idled, and of course it didnt help, no matter how high or low the pressure.

so i did, what i never wanted to do today. i actually put the car, in the shop.. yes yes. for once i couldnt fix the problem, only because i have no clue as to wtf the problem is. so i told them, ...you call me when you find out whats wrong, ...ill pay you for your time finding the problem, and ill fix it at home.

so of course i left out the part about me swapping heads, because we all know they will completly blame them, and say thats the problem.

i handed them the keys, ....said "good luck, youll need it" and walked out. lmao....i called them 5 hours later asking if they had a chance to look at it yet, ...just to get a laugh at someone else having to deal with the problem, and they had the nerve to say "we are looking at it now and itll be tomarrow morning before we know whats wrong with it" ....Rofl. Tomarrow morning? ill be seriously impressed if they find the REAL problem by tomarrow morning. im sur they will blame it on some random bs like "oh well your smog crap is gone, thats why it wont run correctly*

so tomarrow morning, this shall be an even funnier post. because there is no way they will have found the REAL problem.
im about to start a poll and see how many of you feel that they will blame some inconspicuous sensor not being hooked up, and hand me the keys and a 100 dollar bill.

my bet is the first thing they will say start off with "well, i don't know what kind of moron worked on your car before but..."
just kidding, but I think you should try to work with people to try and sort this out, not try and test people. (including your mechanics).

1) I vote x a Fuel restriction such as a clogged fuel filter.

2) I vote x the shop's reply will be: We need rebuild the complete engine = about $ 1.000 - $2.000.


(The temp sensor that is in the side head is only for temp. gauge. It isn't into the ECM electrical circuit and change will be useless in order to solve this problem).


Please, inform us tomorrow about this.

Thanks

nahthe temp sensor in the passenger side head is the fan switch, you are thining of the sensor on the drivers side head...i the fan temp switch goes to the ecm...not sure though

im sure they will claim some bs, if they dont ill be impressed.

the reason im not telling them about the heads being swapped is because they dont need to know. weve established theres nothing wrong with the heads, and if there is, they will know.

i am very curious to kno what the think they have found though.

the fuel filter is new. but im very willing to bet the pump is dying.

which is weird because youd think at high rpm the car would struggle more, when in fact the car DRIVES perfect, its just when you stop at a red light, it bogs, gags, and dies.

i did however inform the mechanic f everything that i had checked, the problems, the data from my scanner, etc.

Slowmaro,
So what did the mechanic say?

SlowMaro this may sound stupid, and I may have just missed it, but is the coolant sensor on the intake by the goose neck connected, and is the plug to it good? it is the one that goes to the ECM. mine had a short(the plug its self) a wile back and made my car run like total crap. ran lean/rich back and forth constantly and would eventualy stall after a little wile and was hell to get restarted.
Im sure you know but there are 3 temp sensors on our cars.
1. drivers side block=gauge
2. intake=ECM
3. pas side block=fan/fans

ok so i got my car back. total bill 81 dollars. 60 dollars just to look at it, and they took the liberty to splice my collant temp sensor on the manifold. cost 20 bucks, man was i pissed about that....2 lil wore connectors, and 1 minute of work...20 bucks. i got shafter.

so heres what they claim was going on.

1.) those wires were corroded and that was making me run super lean

Fact. i have a scanner, it woulda thrown a code, the wires were fine. if that sensor goes bad your car reads -40 degrees, i know because i had it unplugged once and scanned the car.

2.) altho my distributor cap is new, they claim that the spark was Arching and firing incorrectly, and creating a double spark and not delivering it to the plugs efficiantly.

i almost believe this considering that i had replaced everything but the cap in the past week.

3.) rot was bad, also creating the double arch.

4.) i need better wires than 7mm , even though brand new, i need something to deliver a higher spark

Fact. 7mm and 8mm will deliver the same amount of spark regardless. perhave HALF a volt less.

so i said screw it anyways, went and bought a cap, rotor, and a roll of 8 mm plug wire and spent yes, 1 1/2 hours assembling my own wires. this is a big bitch due to the under sized boots i have.

guys at napa --dumbasses-- told me to feed the wire all the way through the boot, and put the metal thing on the end, then pull it back through. BAD idea...half the time the damn metal things just got stuck in the boot, pulled the wire clean out. also, ...its ALOT easier to put the metal thing on and push it in the boot, and you dont risk pulling the wire out.

i had one hell of a timewith the single straight boot i have, i had to take a knife to the inside of it and hollow it out more....that one wire alone took 30 mins. Sad.

so all in all what did i learn? i need a scanner that shows my spark delivery at the time it is delivered and the amount of spark that has been delivered. that....would be damn cool.

so after i got it back, and they had claimed the sensor was messing up the idle, they claimed they had fixed the idle...lets just say it got 10% fixed. it doesnt idle HORRIBLY and cut off now, it just go RrrrRRrrrr every once in awhile.

i still think there is a problem elsewhere even though they said the car ran great. --lol at them-- if it idles poorly, i dont consider that running great.

i will report back after i slap these wires on and put the cap and rotor on. PLEASE let this WORK!!!! ahhhhhhh!!!!!!!

--prays i didnt somehow have a half assed connection in one of the wires i assembled and have to yank em back apart again-----

7mm should be fine, you're right about that. But if you've got wire problems that'll make it run rough at all rpms, not just idle.

If the fuel pump is bad, you should be able to hook a fuel pressure guage up and see that it can't maintain pressure correctly.

The sensor doesn't cause a code unless the temp is way off. -40 may do it, but something like 30 degrees high wouldn't, and would affect performance. The sensor that the ECM uses to read coolant temperature is in the intake. The heads just have a fan switch and guage sender in them. The computer does nothing with these, other than turn the fans on or off.

Just a quick calculation on your compression if your using a .039" gasket instead of a .015"

Assuming you had 9.3:1 compression(took the number from the tech articles on TGO) then I ran the numbers through a compression calculator

changed the gasket from .015 to .039 and the compression dropped to 8.83:1!!!!!

yeah but a lil loss of compression like that would affect it always, not just at idle after its hot.

and yes, everything i did, DIDNT work. new wires, plugs, cap and rotor. NOTHING!!!!! ignition module is new, NOTHING heh!!! nothing works wtf!!!!!!!!!!!!!!

im about to push this car off a cliff i swear! i am so pissed off right now, ...it just sits there...and goes...RRRRrrrrrrrRRRRRRrrrrrrRRRRRR at a steady, VERY steady pace......o2 sensor is reading 400, then 900, around 400, around 900....every time it bogs, it goes to 400, when it runs ok, 900....

so ive figured it out, ...my car is a pos!!! nothing more to it than its a pos......wtf else.......

wtf else can i try...wtf else can it be....

sorry, I wasnt trying to solve your problem with that....

I would flip if i lost .5 of compression....I would be making sure of the specs of the gaskets i got, and if they were wrong I would be tearing it apart.....but thats just me

I like compression......:hail:

this is like....a steady 4 good revolations, then 4 bad... 4 revolations at 600 rpm, 4 at 475.

wtf

After all the needless money spent and all your aggrevation, it would've been cheaper in the long run to dump the tbi setup. I can't remember which distributor you said you had but I would've scrapped the ecm and converted to a simple carb setup. The smog crap is already gone anyway. I won't read all the posts again but after swapping heads, did you reconnect all the ground straps and grounding wires behind them? I'm sure you did, but just figured to ask.

Same four phases every time:

1.) Cool, I got a thirdgen!!

2.) I worked on it, now it won't run!!

3.) It's a POS!! Someone help me fix it!!

4.) (silence)

Shut up!!! I just bought my 3rd gen, 89 FF 350 TPI(hoping to keep Fuel Injected). I came back from the dark side, had a mitsubuishi eclispe Gs-t(turbo). I only had it bc it got 31mpg never "riced it out" AT ALL, didnt even know there was a following with it till i started reading about them...

All my experience is from my S-10 V8 (Sweet S-10 V8, as name implies) and working on my carbed 86 Z28

yeah i reconnected the grounds , i was actually wondering if anyone would think of that though. but yes, they are connected.

so ive definatly positively narrowed it down to the ecm, if i hadnt already narrowed it to there already.

i unplugged my o2 sensor, ...i have no idea why...just to see what would happen.

for one i didnt get an error light...Strange, for two, the car ran BETTER, didnt idle bad at all. the damn o2 readings on the scanner were actually changing...from 470 to 450 then back. which i dont understand how, it wasnt even connected.

but, it did stay in open loop, so im assuming in open look its running on Pre set variables. im thinkin maybe...leave the bastard unhooked, ...run in limp home mode, seems to run great like that lmao.

i think if the ground wires were well grounded, ...it wouldnt ever go into closed loop mode, ...which it is doing.

So...you're on Phase 1.

Slowmaro:

Perhaps the mechanics were in the "right line".

Probably you have a faulty connector or wire that it was moved when you did the heads swap.

You can start testing the IAC connector:

1) Jump A & B terminals in the ALDL conn.(it will go to 0 step, you can see it in your scanner).
2) Disconnect IAC connector
3) Disconnect the jumper wire in the ALDL (the IAC remains closed in 0 position).
4) Start the engine with the foot on the acc. pedal and turn the throttle screw in order to permits engine continue running.

Now, you engine is running without IAC and you can check if the problem remains the same. If so, continue disconnecting O2 sensor conn., MAF connector, coolant, etc.

Finnaly, check the TPS signal with the scanner or voltmeter (engine hot, when the problem RRRrrr arrive again).

Whit this procedure you'll check a lot possibles electrical problems in a little time.

(The error light for an unplugged O2 will be on in closed loop).


Regards,

Denis V.

Okay,
Have you had anyone double check your valve adjustment?

if it were the valves it would be messed up 24 7, ..this problem only happens when the ecm goes into closed loop mode

There is one other thing you have not tried yet, faulty distributor.

I know you have replaced most of the parts IN the dist. but I doubt the magnetic pick up assemblies have been replaced. Is there any oil under the cap nead the electronic stuff??? I don't mean sooty stuff but when you look at the center of the distributor, is there any wetness???

On my 84' I had changed all the parts on my distributor and it waas doing something similiar to yours, but completely stalling out because I had a carburetor. Your ecm is not letting the car completely stall because it'll richen up the mixture real quick, maybe that's why you are getting fluctuations on the 02 reading.

Since you have just replaced the ecm, I am going to say that it is more likely to be the distributor than the ecm.

I have had to replace 2 of them in TBI cars. I had to replace one on my 91' RS when it only had 80k miles on it. I had to replace another one on a 350 TBI swap I did and that motor only had 60k miles.

If you end up getting a replacement distributor, don't get a cheapie, basically don't get anything from autozone or whatever, I have had problems with those right out of the box. The best thing to do is: GO TO KRAGEN AND GET AN ACCEL PERFORMANCE REPLACEMENT DIST. It only costs you like 20 bucks more and tit's well worth it. It's not remanufactured, but ALL new....right down to the aluminum molded housing.

That's my recommendation...and if the car has over 85-90k miles on it, do it anyway.

this distributor has like 3k on it....is fairly new. iv echecked every ground wire...all are connected....and if they werent, the emc wouldnt go into closed loop.....if the ecm was fried it wouldnt go into closed look....i hooked a volt meter up to the o2 sensor itself and it read .800 pretty constant, not much fluctuation....maybe 10 or 15 give or take, ..not much though.

Yet when i hooked the o2 sensor back up, and looked at the readings from the ecm, ...it would fluctuate dramatically....from 400 to 800....not sure if that means anything or not....
but i did however come to the conclusion that im throwing the tbi in the closest river, ..and putting my edelbrock 600 on it....it needs a new electric choke though.....i have the dist....i just dont kno whow to wire it into the 92 wiring harness.. and no one can tell me how.

ok when i unhook the IAC with the car running, nothing happens, when i unhook the tps, the car goes nuts and cuts off.

wtf could i have forgotton/messed up heh. it runs GREAT in open loop mood meaning this problem simply cannot in no way be mechanical.

Not really for the topic but 330hp_91RS ... I've had those symptons before with chevy distributors. A quick and easy fix for oil seapage up the distributor is to remove distributor, then remove roll pin, gear and shaft. Then simply drill an 1/8" hole slightly below the mounting flange, where it mounts to the intake manifold. Then reassemble. I generally do this whenever I have to pull one with some miles on it, so I don't have to remove it again later.