ok let me give you the run really quick. ive used this site before and you guys always help me out pretty quick.

i have a 1989 camaro, with a 1980 305 engine in it, with the 1989 tbi intake manifold. a couple months ago i blew the head gaskets. so i started with rebuilding the engine, turns out it was in worse shape than i thought. i have bored out the engine .030 with new pistons of course. there is also a new crankshaft and harmonic balancer as well. the heads where shaved and tested. new flywheel and starter. thermostat, etc.

after about 6 weeks of rebuilding this engine, everything that could go wrong has gone wrong.

last night i finally got everything finished and dropped her in. after hooking everything up and tighting all bolts. i tuned it over to see if would start before i put on the exhaust pipes. she turned over quick with no delay or hesitation. also after rebuild i put castrol edge synthetic oil in it. idk if thats going to make a difference or not. i hooked up all the vacuum lines like im suppose to. the only thing i couldnt find any information on was a post right behind the throttle body and egr. its about 3 inches long, and has five air holes coming out of it. 4 of those holes are closed off and have been since i got the car and it was running fine. in all the vacuum diagrams i have found for this car, there is ntn that says anything about that post anywhere on it. the 5th air hole on it runs 2 ways, it goes to a hose that runs into the firewall and then splits off from there then goes around to something that has a throttle linkage cable hooked up to it. i cant for the life of me figure out what that is. or if i even have it hooked up right.

now for the real problem. after starting it and letting it idle down for a sec, i decided to take it for a test drive, in doing so i found a huge problem. when i step on the gas, i go from 60psi oil pressure down to 30psi, and the car takes forever to get up and go. i have to keep mashing the gas to get it to start moving and when i let off it sounds like its going to die on me. i no everything on the engine is tight even the valve covers. but ive gone through for hours trying to figure this out. one more thing i might add, is that while this car was sitting for almost 2 months straight, i never did anything with the gas, i heard this could possibly be the problem but i am not sure. the gas was almost empty when this started so i just left it alone.

thanks in advance

 

The thing with the throttle cable hooked to it is probably your heater control valve. Do you have your MAP sensor hooked up? It should be connected to a manifold vacuum source. It probably goes to the vacuum manifold you're referring to behind the throttle body, or it may connect to a port on the throttle body itself. Also, make sure all vacuum leaks are sealed up.

The drop in oil pressure is probably due to the motor falling on its face. You shouldn't be running synthetic oil in your new bottom end. Your new cylinder walls need to break in along with your new rotating assembly. The synthetic oil won't allow the parts to break in together. Run Valvoline 10-30 or just straight 30 weight for 1000 miles, then switch to synthetic.

 

I was thinking the "thing with the throttle cable" was possibly cruise control.

 

well i think i have most of it figured out, turns out my neighbor is a master tech and came over and checked it out, and said my time was way advanced. he put a timing light to it and said it was suppose to read 8 degrees. but it was at 54. when we put it back to 8 it started running a lot smoother. oil pressure went back to its place for a lil bit then kept going back down. turns out i had a dead cylinder because one of the spark plug wires was sitting against the exhaust manifold and it got melted and was arching on the manifold. fixed it and now its running great. except i think my water pump pulley is back because i hear the belt squealing when i goose it. and i thought i saw it wobbling a lil bit.
still not sure what the thing behind the throttle body is. there is a hose from the back of the throttle body itself running to the map sensor, but that one behind the throttle body runs to the thing with the throttle cable hooked to it, it could be the cruise control stuff but im not sure.

the thing about the synthetic oil....isnt it too late to switch it over to a regular oil? because ive heard time and time again how once u go synthetic u can never go back.

 

No. It's not too late to go back to organic oil. If you continue running synthetic now, you'll never break in your cylinder walls. The unit behind your throttle body may well be you cruise control modulator. Does it have an electrical connector?

The drop in oil pressure as the engine warms up is normal. You may need to run heavier oil to maintain correct pressure. Oil pressure must be a minimum of 10 pounds per 1000 rpm. What oil clearances are you running? (Stock clearances are about .0015 and are meant for 5-w30 oil. racing engines are generally machined to .0025 and run on 20-w50 oil.) The larger your oil clearances, the heavier oil you want to run. Was your rotating assembly clearanced or even machined?

 

no there is no electrical connector there, just the 5 air hole with 4 blocked off.

and the new crankshaft is stock.

i had the timing good on it, then replaced the spark plug wires on it, then it ran great. now all of the sudden its doing the same thing it was doing before. i start up the car, she idles fine and i go into drive and try to take off, the first time i do it when she isnt all the way warmed up she takes off a lil bumpy but gets up and goes. when i step on the brake at a stop sign or something, she either stalls or takes about a half hour to get up to speed.

now last night after it starting doing this i found the main positive wire sparkin on the oil dipstick tube, it had melted the wire on it. i moved it and taped it up but there is still no improvement in anything, idk if this could be the cause of it or not. but i cant think of anything else.

let me no. thanks

 

Once your plug wire is fried its fried get new ones.

Your motor should be fine with either oil in it, your motor has no idea what youre pouring in. .

THere is a process of seating the rings in you should do though it will help

 

ok but even thought that wire is like that it still starts up np

could that be cause it to put put around

 

Yes, it will get power through it but it will try and ground out on something, tape wont fix it.

 

so that main positive wire to the starter will cause it to jump around and stall out on me like that after its running?

i am just trying to make that its going to be that simple of a fix

 

well, i figured out what the problem is this time. 4 of my spark plug wires where burnt up. so half the engine wasnt working.

now the transmission. i added fluid to it when it was not running. and everything that i pored in there is on the road after driving it. it this because i added it while it was off?

sorry, dont no much about transmission

 

You need to check transmission fluid level with the engine idling in park(Read the dipstick!). Also use a proper funnel. The trans does have a vent and fluid will pump out that vent if it is full enough. By that point your in danger of damaging your transmission.

As I said before, your rings will not seat, nor will your new bearings properly breakin on synthetic oil. You need to run the motor on organic oil for 1000 miles, preferrably, to break things in. Cuisinartvette is correct about the ring seating procedure. To break in rings, you want to find a steep hill where you can drive up and down at a slow pace. Drive up and down the hill in first or second gear, keeping the rpms between 2,000 and 2,500. Let the engine hold back the speed of the car as you go downhill. Repeat this several times. I prefer to go back through the process a few times during the 1000 mile break in.

 

i have switched to organic already.

and i checked it while it was idling in park. the tranny fluid was barely on the stick. so the next morning when i woke up i added it before i started it up. then when i tried driving it, with all the problems it was having. it just came out all over the place

 

get a new lead for the starter , having a bare starter lead can catch your car on fire . and listen to these guys you CAN NOT drop the motor in and just go there are things that need to be done / steps to take or you will be pulling back out again in the future because you rushed it .

 

i on it sounds like im rushing but everything ive done to it ive been taking my time with it. just going through and figuring out all the tweeks and mishaps to it for the time being.

 

Make sure that the trans dipstick is in good shape. The top cap can come loose and the seal can get messed up so that it doesn't seat in the tube as it should. Be sure the car is parked on level ground when checking fluid level. Note the cold, hot marks on the dipstick, that's how much the fluid level changes from cold to hot. Also, be mindful that the crosshatch marks on the trans dipstick are one pint, not one quart.

 

Ditto on the trans dipstick last thing you need is trans fluid on a hot exhaust or cat, thats disaster. Little at a time youll get the bugs worked out, it happens when you take on a rebuild.
Still workign them out myself been on the road a few months.
Youll get it right.

 

ok, sorry it took so long for the reply. the tranny fluid turned out to be the cooling line going in the bottom of the radiator, when my roommate put it in he put it in crooked so it was just steadily pouring out when it was running. so it was running doing the line and made it look like it was coming from the tranny itself. so all that is taken care of. other than im going to have to replace the tranny pretty soon anyway. the fluid smells terrible and i just did a tranny flush on it. but im taking it easy on it for now until i can get the money for it.

everything seems to be running good on it right now except 2 things. ive just put 300 miles on it and i have had to fill up the gas tank probably 5 or 6 times. i have put so much gas in it, its ridiculous. so i went through and checked all the gas lines on it and there is a very very small leak on the return line from the throttle body, the lines are not the original lines on it they where cut and have hoses with hose clamps holding it together on both input and return lines going to the throttle body. but the leak is a small drip every 20 seconds or so. i am calling junk yards today to see if i can find those lines.

as well my fuel gauge is crazy, when i step on the gas (not goosin it) just taking off easily, the gauge goes up, and when i step on the brake the gauge goes down. any idea why it does this? it this normal?

also there is a broken a.i.r. bolt on the exhaust manifold, now i have taken everything to that hole, there is a plastic piece that sticks out, i have hammered in extraction bits and all they do it turn the plastic piece all day and i have no idea how to get it out to replace it. i have tried putting red rtv silicone in it and it holds until i get to 60mph then blows out the rtv. if i put a small bolt that would screw into that hole and hold would that be ok?

other than the exhaust and fuel everything else seems to working. thank you all for your help with this process

 

I assume by A.I.R. bolt, you mean one of the tube fittings. the best wy to deal with anything stuck on an exhaust manifold is an Oxy/Aceteline torch. Heat the fitting red hot and try turning it with vise grips. You may only get it to barely move before it cools enough to bind again. Then you reheat it and try again. Otherwise you could have a welding shop braze the hole shut.

Hacked up fuel lines suck. Fortunately there were millions of TBI cars made so finding good replacements shouldn't be too hard. The fuel gauge dancing is normal with older GMs. There is a delay, or buffer, circuit built into the gauge itself. It fails and the fuel gauge becomes just like any amp meter, reading the current through the sending unit, which moves drastically on acceleration and braking.

 

yea the a.i.r. bolt on the exhaust only has the plastic piece sticking out, nothing left of the metal part of the bolt on it. i was thinking about welding something on it but wasnt sure about that but now that you have said that i will def get that done now. thank you

yea, it is leaking fuel pretty bad on that line, so when the junk yard decides to open up ill get over there and take care of it.

 

Okay, now I'm confused. There are no plastic components in the exhaust system. What is it that you think is plastic? This isn't the O2 sensor is it? The A.I.R. tubes into the exhaust manifold are flare fittings with a steel tube in the middle of each hex flair nut. There is a tube to each cylinder.

 

there the bolts on the manifold that arnt the mounting bolts. idk how to explain it. but one of them broke and when the main bolt broke off and there was some kinda piece that was in the middle of it that is a really thick plastic that just spins around

 

That is very weird. Is there any of the hex left? How large is it? The A.I.R. tube flairs are about 1/2", the O2 sensor is 7/8". The O2 sensor has a ceramic core, like a spark plug insulator. Recognize that no plastic would survive on the exhaust manifold. If it's a broken A.I.R. tube, someone may have tried JB Weld on it. That may be the plastic looking material you see. JB Weld might last for a minute on a manifold but it wont last long. This is probably ceramic or some type of metal you're looking at. It could be an exhaust temp sensor but it would be the first I've ever heard of any such thing in an 80's GM.

Could you post a photo?

 

ok, well after messing with it for a few hours i realised what i thought was plastic was actually metal when it was cooled down. i have the metal pinched to close the leak.

now my main problem is major loss in mpg, and low end power. i MAYBE get a 100 miles to a full tank of gas. no leaks anymore, everything is sealed up. the injectors are fine. the timing is perfect on it. i am running standard oil in it, no longer running synthetic, and i have even started using 93 octane fuel to help seal the rings (as was suggested by a friend). but the fuel consumption is the same no matter the octane level. when i am driving it around for a little bit then it is fine, but after it gets really warmed up my gas mileage goes to hell and when i step on the gas sometimes itll pick up and go and other times itll sputter its way up to speed. now my neighbor mentioned to me that someone might have put a computer performance in it. or something along those lines. now if this is the case, what does it look like and how do i remove it without messing anything else up. or if there are any other reason that would cause low mpg and loss of low end power. thanks

 

I would do a compression check on that motor before you did anything else.

 

how do i do a compression check? and am i looking for

 

ok, something very weird just happened while i was driving it. it was running fine for about 15 miles, when all of the sudden i came to a stop and stop and then taking off became an impossible mission. the car wouldnt would go but very slowly, and the entire car shook violently as i was driving. i thought i was gonna blow another head gasket. but i got it home and put it in park, then checked the tranny fluid, which was fine, started going over everything else, no leaks or anything anywhere. then i could smell something that was like burning plastic. but worse than plastic. then i saw my front driver side tire had smoke pooring out from around it. it was the tire itself but it seemed to be coming from the rotor maybe? i spent a good minuete trying to identify the source of the smoke, with no better theory. i have no idea what could cause that, and cause the engine to bog down so bad like that, and make the entire car shake so bad

 

Hmm? Sounds like a locked up caliper. Does the engine seem to be running okay? Was there a misfire at idle after you got home? Im thinking this problem you describe isn't engine related but a locked up brake.

From the description, I would say to look for a failed brake hose. The inner lining of the hose seperates and collapses inside, creating a check valve effect. The fluid passes through to the caliper under pressure to apply the brake. Then when you release the pedal, the fluid is held in the caliper by the check valve effect of the failed hose. This keeps the brake applied as you try to drive. This explains your slow acceleration. The burning smell is your now toasted brake pads. The shaking is probably a warped rotor from the extreme heat.

You will need to replace your front calipers(the one is now toast from the heat and whatever you do on one side, you need to do on both), both front brake hoses, and both front rotors. Replacing rotors means repacking or replacing bearings(you need to check them for wear or damage) and replacing seals.

 

ok, thank you very much. i already have new pads and rotors and shoes to replace everything. ill pick up some break lines as well.

did you see my other post about the bad mph and low end power and thinking it might be the ecm? any suggestions on that one?

 

The locked front rotor is that issue.

Back to the original problem....If you did not assemble that motor correctly it will run like crap, have no power and really bad mpg.

Get a compression tester, rent one from your parts store if you can't borrow one. Remove (ALL) the plugs from the motor before test, the compression tester screws into the plug threads. If it's an HEI, unplug power wire going to it to prevent you from getting a nice shock, if you are running a coil, unplug coil wire. Prop throttle 100% open and turn motor over a few times with starter. Check pressure reading and go to next one and do the same. Check all, with your rings not sealed yet they might not be that high, I would think mid 100's at least, main thing is that they are all pretty close in readings.

 

A stoped up cat. can cause very slugginsh symptoms also. Could be half way stopped up causing the go then no go. I had a truck that wouldnt go over 35 mph with the pedal to the floor and a bronco(5speed) that would barely take off both due to a clogged cat.

 

@ lunaticinaZ: there is no cat on the car. its been removed.

@ Jeff14R: had my neighbor test the compression on it, everything checked out on that.

ok, heres a status update. i noticed a couple of days ago that everytime im driving for long amounts of time, the check engine light comes on, and thats when the real problems start. the no mph, low end power, no go when i stomp gas, and even the battery gauge drops and there will be a backfire or two here and there. and its starts idiling funny in drive, and acts like there is a timing problems. but, heres the thing. the engine light comes and goes, when its on, the car isnt worth 2 pennys, when its off, it will launch you in your seat and burn rubber through 3rd gear. ive been testing this all day. ill start her up and let her warm up before i drive it, then ill take off and goose it and itll fly away, then the light comes on and ntn, i might as well be driving a ford for cryin out loud. then while still driving, the light goes off and bam shes at full power again. well no one really has a computer tester for that old of a car around here. so i took her to a shop, and they couldnt get a reading out of it with the light on. he said, either bad connection, bad ecm, or bad ignition module. i dont think it is the ignition module because the entire distributor is brand new. replaced it right before i rebuilt the engine. so i tried connecting the 6 and 12 pins to try and see if it would blink so many times to give me a reading. that didnt work either, so he said try and remove the computer and keep it connected, then turn over the engine, and tap the computer a couple times while its running. did that, and i literally thought the car was going to blow up, it was in park the whole time. and the entire thing bogged down and shaked so bad i actually ran away from the car while it was doing this, it went back to idiling normal after a few seconds. so i thought id try it one more time just to be sure. tapped the computer again, and this time nothing happened. it stayed running fine, but from the beginning when i first tapped it, the check engine light came on then went right back off. and stay off, then i tapped it again and the light just flashed but no serious gettin ready to blow up stuff.

i want to be 100% sure that this ecm is bad before i replace it. so please any tips or advice on what i shoud do

 

also, it looks like i might have a blown head gasket, which would explain loss in power and bad mph, but doesnt explain the computer problem and the check light coming on, i lose power, it goes off, i get the power back. there is white smoke coming out of the exhaust pipes on start up as well but doesnt do it while driving nor while idiling after ive been driving. i also tried heating the ecm up with a hair dryer, and tapping on it again, but still no issues shown on it. ive reconnected it and blown out the connecters but still check light still pops up while driving and i lose everything then goes off while im driving and then i get power back.

 

the head gasket i think is blown. is on the passenger side of the engine, when the car back fires it comes from the driver side of the engine. the reason i think the gasket might be blown is because there is oil and dirt build up right under the heads on the block around the front of the engine

 

I don't know how to check the computer, but I had a chevy truck with a 350 and it did the same exact thing your car is. I watched it one day as I was driving and the oil pressure dropped to almost 0 and as soon as that happend it started having the drivabilty issues like your having and the check engine light came on. Then as fast as it started the oil pressure would go back to normal and the check engine light would go off and she would drive normal again. Maybe next time its running keep an eye on the oil pressure.

 

the oil pressure does drop to about 10-12psi while driving and stopped at a stop light, then wont go past 30psi when i get on the gas and the check engine light is on. but when that light goes off, ill see the oil pressure rise to about 25-30psi while at a stop light then go right to 60psi when i stomp on the gas

 

what was the problem with yours?

 

I never found out the problem, I traded the truck for a Dodge But it could be a partially clogged oil filter or maybe a weak or bad oil pump. or the shaft that drives the oil pump may be damaged. If i'm not mistaken if oil pressure drops below a set pressure to computer will limit the rpm's to keep from damaging the engine.

 

The oil pressure switch can cause the ECM to kill the fuel pump if it reads below 5psi. The 3rd gen, or the Chev truck, do not have rev limiters. Certainly not a rev limiter controlled by oil pressure. They aren't that advanced. The Chev truck probably had a bad OP switch which was trying to shut down the fuel pump.

Your RS has a power loss issue, which sounds completely different from the truck's problem. The low oil pressure at idle is caused by too low oil viscosity for your bearing clearances. Be aware too that alot of oil pressure loss is caused by worn cam bearings. Are your's new? You need to read codes and figure out why your engine is losing power. You also need to go to heavier oil.

 

Yeah! that. I knew it would kill the car somehow just couldn't remember how. Thanks for the clearing that up.

 

Yes, the bearings for the cam are new along with everything else. I am running 10w-30 in it rright now. What should I be running? The codes can not be read on it. When I took it to a shop for them to read it, they said there was no communication with the computer itself from the connector. I checked all the wires and all seemed well, I even tried connecting the. The 6 and 12 connectors and get it to blink but had no luck there either. A buddy of mine told me it could be the o2 sensor causing all those problems as well. But I have no idea about that either.

 

I dont know what you mean by "6 and 12 connectors". Your car has a 12 pin ALDL(assembly line data link) connector. Pin A is ground. Eacn other pin serves a particular function. Pin B is the diagnostic terminal. When pins A & B are connected to each other before turning on the key, the ECM is placed in diagnostic mode and will flash codes through the check engine light. Pins A & B are in the top row at the upper right corner of the connector. Make sure the CEL works on bulb check.

Just reread your thread. Id missed some of your posts. It's possible you have a bad ECM. The results you got from tapping it the one time could be a broken circuit on a printed circuit board. This is often how they fail. You may also just have a loose connection somewhere, though the problem seems to only occur when the engine is warm. Dont ever assume because you have a new distributor that it's okay. This problem could very well be a failing Ig Mod or pick up coil. If nothing else looks bad, atleast have them tested. My main concern right now is the quality of your electrical work. Could you have any bad connections? A loose ground perhaps? Check your work. Try reading codes as detailed above.
If your'e losing oil pressure at warm idle, you should step up oil viscosity accordingly. I would say to try 10-40 and see how it works. You can go as high as 20-50 if needed. In my NASCAR spec motor(.0025 oil clearances) I run 15-50 Mobil 1. Did you install a good quality high volume oil pump? I use the Melling pump in all of my wet sump small block chevys. It's factory set at 80 psi.

 

work has gotten busy so i havent had time for anything, and know the transmission is going bad. i put a new o2 sensor in it, gas mileage got just a lil bit better but not much and switched to 10-40 oil. pressure maintains but still no go when that light comes on. i tried running the wire to the 5 and 6 pin as suggested and it started blinking but i still dont no how to read it to get a proper code out of it.

 

ok i went through and counted the blinks, had to do it a couple times because some where faster than other. im going to list the blinks in the exact order i saw the from start (when i turned the key) to finish (when it started back at the beginning)
1, 1, 2, 1, 2, 1, 2, 1, 3, 1, 3, 1, 3, 2, 2, 2, 2, 2, 2, 3, 2, 3, 2, 3, 3, 3, 3, 3, 3, 3, 4, 4, 3, 4, 3, 4, 3, 5, 4, 5, 4, 5, 4.

 

and now as i was driving it home from work, there was smoke pooring out of the vents, and it smelled like antifreeze. the temp gauge never went up, the fan was on, and when i got home and popped the hood there was no smoke anywhere to be seen from the engine or the radiator.