I have a 1989 Camaro 305 TBI. Bought it after it has sat for 10 years in a buddies garage. Flushed all the fluids, replaced the fuel tank, fuel pump, strainer, filter, fuel pressure regulator, injectors, TPS, MAP, CTS, cap, rotor, wires, plugs , timing chain, gears, cover, harmonic balancer and IAC.
Car cranks, starts, idles up then stalls. I can keep it running with carb cleaned but it runs terrible. Checked the injectors with noid lights while I was spraying it with carb cleaner to keep it running, and the noid light went solid, not flashing. Checked spray pattern while cranking and looks good. ECM is a NAPA reman. I can't find anyone that has a fuel pressure tester for this car do I can't check to see if its a fuel pressure fall out or not.
I'm at my wallets and wits end.
Called local Chevrolet dealership where I was told there are no technicians old enough there that would know how to diagnose it.
I've replaced the distributor 3 times because I keep getting told that it sounds like a bad pick up coil. After 3 distributors . . . It's not a distributor.
Any help ?

 

http://www.ebay.com/itm/260732758647

Any gauge you can buy at the store will then work.

TBI pressure should be around 8-9 psi @ idle, 13ish in prime.

Noid light on solid = ECM is commanding max possible fuel but there isn't any

Only runs on carb cleaner = no fuel

Not a dist problem if it runs when you supply fuel (doesn't fit the facts)

ECM was probably a waste of money; put the old one back in and return it for credit.

See my signature for some diagnostic advice.

Might want to pop the TBI off, disassemble it, and soak all the pieces in lacquer thinner for a coupla days while you're waiting on your adapter to arrive.

Probably needs a fuel filter while you're at it.

 

Has new filter. Can't smoke test for vacuum leaks because IAC is never completely closed. Tried to order the pressure tester and none of the parts stores say they can order one. "Too old".
What I don't understand it that it cranks up and starts so smooth and nice but, as soon as the idle begins to drop to its normal idle ( a few seconds after it starts) it stalls. I see the injectors spray as its stalling . When I add carb cleaner, it'll stay running but runs like crap. Missing, wont accelerate. If I quickly pump the accelerator it'll stay running, terribly missing and won't accelerate over @ 900 rpm.

 

There is nowhere to hook up a FP gague on a TBI setup. You can buy a setup made for the task with the proper fittings and such.... pain in the butt. Cut the feed-side line (the larger 3/8" line) somewhere up close to the TB and patch it through your gague "T" fitting with some short pieces of rubber hose. Just simpler, cheaper and easier, plus you can do it again easily in the future.

 

Then that's my tomorrow task.
Quick question , will the low oil level sensor cause any of this? Have been told that its the next most probable cause?

 

Also. I didn't change the ECM . That's just the ECM I found when looking for loose connections at the connector. I didn't replace the OEM ECM with a napa reman. It's just what was in if when I bought it.

 

No. These cars don't have one.

However there IS a low oil PRESSURE sending unit. Easy enough to eliminate as a potential cause though; a piece of wire with male slide terminals on each end is all you'd need. But if that fixes it, you have TWO problems: a bad fuel pump relay, AND a bad oil pressure sending unit, BOTH of which would have to have failed SINCE the last time the car ran. On a scale of 1 to 10 of "likelihood", I'd rate this somewhere between -3 and -5. (quantum mechanical... probably hasn't happened EVEN ONCE YET in the entire history of these cars' existence)

Again, see my signature for mental guidance.

Also, try some new gasoline. LOTS of it, such that whatever is in the tank now, is insignificant.

 

I really appreciate your time and expertise. I'm going to get the fuel pressure figured out tomorrow. Figuring its a relay, ECM, or pump. Now it's just a matted of figuring out what it is and where to begin diagnosing each of these.
Thank you again

 

Ok. Was about half asleep when I read your last post . The fuel pump is about 2 weeks old as is the tank, strainer, filter and fuel. The fuel pressure idea is my next step as I'm down to the pump again ( this is the second one of those in 2 weeks) or the ECM. I appreciate the input for sure.
Thanks again

 

seems like you did everything correct on the fuel system side, except you did not clean / replace the existing fuel lines. if you did you did not mention it in your #1 post.


I would check your new fuel filter to see if it is full of debris (from junk in the pick-up line to the filter).

then clean (blow with compressed air) or replace the supply and return lines from the tank to the TBI. after sitting for so long the sections of rubber line begin to break down from the inside... if you see a lot of black gunk in the filter that is the rubber hose..

now the rubber hoses in the engine bay ... those have no filter..

if the pump is new... test the fuel pressure... you will see it probably drop after some run time... possibly to "0" when you try to give it gas. relays work or they don't work. if the pump primes and runs.. it's not the pump. you have clogged fuel lines.

 

I found an in-line fuel pressure guage and going to put it on to see whats happening. Headed to take off the fuel filter first to see if its clogged. Haven't replaced the fuel lines, going to inspect them while I'm under the car. The rubber portion of the fuel lines isn't that long so I'm guessing it won't be too aweful to replace.

 

correct, but the fittings seize and you can crush the metal line if you get too ambitious with the wrench... much like what happens when you replace the fuel filter..

take your time soak the metal lines and fittings with PB blaster to help free them up.

use tube nut wrenches. to prevent rounding off the fittings.

the metal lines themselves can rust from the inside out.. or the fuel inside dries up and leaves varnish deposits, if too heavy this can clog the lines.. check the pressure regulator.. for debris as well.

 

OK! Here's what I have found. I've been checking the drivers side injector for pulse ( cause it is the easiest to see while trying t start the car ) .Just had someone try stating the car while I looked at both injectors and the passenger side injector had no spray. Checked it with a noid light and no pulse. Now what? Looking more and more to me like the ECM unless there's some trick I haven't run across

 

I'd start with a SIMPLE test - make sure you have power at the pump / pump relay the entire time that the ECM is thinking the car is running.

Since you said it runs smooth - Does this one have VATS? *IF* I remember the VATS stuff doesn't it just kill the injector pulse to stall the engine and it doesn't stop the spark so artificially feeding it fuel should keep it running.

 

each injector has its own fuse on the fuse block, check for a blown fuse. if a fuse is blown finds out why. if not check continuity of the fuel injector wiring..

sometime the harness connectors at the injectors short out against the throttle body, (the insulation shrinks & exposes bare wire).. check the injector connectors / wiring for short to ground. you may have to trace back to the ecm. it may not be connected properly at the ecm,,, bent harness pins or broken wire...

They sell new injector connectors at auto-parts store if you need to repair them.

to rule out a clogged injector swap connectors... if it fires and the other is dead.. you have a wiring / ecm issue.

check the wiring first.. if all this is ok then ECM /// but no trouble codes huh?

the ecm wiring to the engine bay exits the car at the passenger side wheel near the lower door hinge.
You will see the bulkhead fitting. you have to remove the fender splash guard to get at it.. sometime the wiring frays at this location..

 

I swapped the connectors and the problem followed the connector so I know it isn't the injector. I back probed the connector to ensure it isn't a connector issue and still nothing. Traced the harness to the firewall and found no cuts, chews, opens, etc.
Just bothers me that the ECM hasn't stored any fault codes for this. If I crank it over with the EST unplugged, it'll store that code. If I leave the vacuum line open while trying to keep it running, it'll give me a lean code. Just about to say hck with it nd throw an ECM at it.

 

ruling out a short, or blown fuse... you checked the fuses?

My guess is you have a bad injector driver on the ecm...

 

All fuses check ok. Are there separate fuses for each of the 2 injectors ?
I'm also having problems with the fuse box as the radio and dome light come on and off but if you tap on the fuse box, it'll start working again for a short period of time.

 

yes, if I remember TBI cars have 1 fuse for each injector

lol if the radio cuts out but comes on again when you tap the fuse box.

I would look into that.. you may also have a broken injector wire at the fuse..

the fuse box wiring mates to the firewall bulkhead fitting, if this is fitting is loose you could have bad connections.

 

http://austinthirdgen.org/mkportal/m...ine_wiring.gif

10 amp fuse for each TBI injector the fuseblock will be labeled INJ #1 INJ #2

 

All the fuses are good, really wish I had the tool to tighten up the pins in the fuse box but I don't so. . . The ECM will be around 7 tonight. If I can get the dang thing running right, I'll tackle the radio and dome light fiasco afterwards.
The car sat for 10 years before I bought it and the fuse box has some corrosion on it and the labels for what fuse goes where have worn off.
I really appreciate all the help you guys have given. I'll let you know if the ECM fixes the running concern

 

you can clean the fuse block with contact cleaner.. (spray can)

 

Before throwing an ECU at it - check for constant 12V power with the key in the "RUN" position - hook a voltmeter to ground and then probe the WHITE and then RED wires on each of the connectors. Remember - the ECU is just completing the "ground" side of the circuit so there should be power at all times to the injectors when in RUN

 

Well . . . I put the new ECM in, both injectors are now pulsing, car starts runs real smooth as it idles up from start then does. If I keep frantically pumping the accelerator I can keep it running however, I'm back to it won't rev up it just bogs out. I've tried to check the timing and with the est unplugged the closer to 0 I get the worse it becomes. Plug the way back in and meds with the timing I can make it slightly better but it doesn't make it good enough to idle on its own . Quickly losing hope on this car. As is my wallet

 

Plug the est back in and mess with the timing, I can make it slightly better but not good enough to idle on its own.

 

You've still got a fuel delivery problem.

How'd that fuel pressure gauge adapter work out? What's the fuel pressure AS IT'S ACTUALLY IN THE ACTUAL ACT of screwing up?

Don't forget, if the stuff in the tank isn't actually gasoline any more, then it doesn't matter how much of it is getting squirted into the intake; it's not fuel, so it could be drowning in whatever it now is, and the engine will still have a fuel delivery problem.

Leave the timing alone. Hook everything back up like it's supposed to be and put it back where it belongs (i.e. where it was before). All that you will accomplish by messing with it, is creating extra unnecessary work for yourself, that wouldn't be necessary except that you created it yourself, which will then create NECESSARY work for yourself since you'll have to go back and UNDO whatever you did to it once you straighten out the fuel delivery problem.

 

Ok. Fuel pressure is fine. Fuel quality is fine.
Finally was able to get it to idle by disconnecting the vacuum line to the brake booster. Now it revs up and idles. At higher revs, there's still a slight popping noise like timing but like you said. I'm leaving the timing alone until I figure why it's running so rich .
Any ideas. Other than an O2 that's crap I'm outta ideas

 

I'm at a point of the heck with it. I'll just put an in-line fuel pressure regulator, a manifold and carb and just be done with this. It has become way more time and money expense than this car is worth. I bought it because its arrow straight and a perfect interior and dash. Just the pain is faded from 10 years of lack of interest. I thought it would be a nice car to give to my daughter for her 16th birthday. At this point, I still have to put tires, exhaust, and paint. Just has become a money pit and still not running .
I thank you guys for your help. I'll start the transition to the carb over the fall/winter . My wallet is hollering from all that's been done already.

 

I would start by checking the coolant temp sensor resistance (there is a chart for temp vs resistance - and it's not the same one that controls the gauge), then check and make sure the MAP sensor is hooked up and the hose isn't sucking itself shut or has a vacuum leak in it. Also check the TPS resistance for a smooth sweep when opening the throttle.

The TBI engines are pretty simple injection setups - the O2 sensor doesn't come into play until the engine is fully warm and the computer goes into closed loop operation. Also check and make sure the ground strap at the back of the engine to body is clean and tight on both ends.

 

Both coolant temp sensors are new, new map sensor with all fresh new vacuum lines on the entire engine. Everything I understand about the TBI cars is that the throttle body is a controlled air leak with computer controlled fuel input. The computer looks at the MAP, CTS, O2 , and the TPS. The car is full rich all the time. The only way it will start and idle is to open the vacuum line from the brake booster . Even then its extremely rich. I can't wrap my mind around this. I've just resigned myself that I'll just put a carb on it and be done. I've had it.

 

Since its so straight and clean inside, with so many new parts, I may just sell it and start over on another one. Maybe a Trans Am this time

 

I'm going to quit messing with it for a day or two, clear my head. Read back over all the information given to me and look at it again Monday or Tuesday. If I can't come up with something by then, I'll start saving for carb parts

 

OH - so you have to create a vacuum leak to make it run? That means that the IAC (Idle Air Control) valve is not opening up and letting enough air bypass the throttle plates. IF I remember my TBI pickup stuff right it's a stepper motor with a pintle on the end that screws in and out to open/close the air passage way. If you pull the IAC motor out you should be able to apply power and run it in/out (have to get a manual to find out what pins control what operation) Also - if it's all carboned up or gummed up from crankcase vapors and can't turn the motor it will not be able to open up and let the air in so sometimes pulling them apart and cleaning them up and then lightly lubricating them will let them operate smoothly again. Make sure you clean the passages on the throttle body while it's out (to 'cheat' some times you can just use the tube and a carb cleaner can and shoot it down there and let it sit for a bit then start it up and have someone keep it running while you 'wash' the passage down with carb cleaner...

 

New IAC and throttle body was soaked and rebuilt when new injectors and fuel pressure regulator was replaced. I took IAC completely out and it still would start but idle up then stall. Only stays idling (rough) with the vacuum brake booster unplugged from intake.

 

Took the A.i.r. Off the exhaust manifolds as well as the O2 in case it was an exhaust clogged up. Because it sounds either really retarded timing or clogged exhaust when trying to rev the motor. It just bogs down. Had no effect. Just full rich and can't figure why.

 

With the new ECM you now have both injectors firing ( faulty injector driver on previous ECM) also you confirmed fuel delivery is good (not losing fuel pressure)

You should not have to disconnect the power brake booster vacuum line for the car to idle.

You are 90% of the way there, the rest should be pretty simple.


TEST the IAC motor at idle cover the IAC intake port with a finger the engine should idle down & die. If not & you feel no suction on your finger then the IAC motor is defective, not getting power, or short to ground.

If you feel suction the IAC motor is working but out of adjustment.

TEST the the TPS to make sure it is not out of calibration or no power to TPS.

With car in run check the TPS voltage.
working the throttle make sure TPS voltage is in the correct range from idle to WOT, if not adjust it by loosening the mounting screws & rotate the sensor until you get voltage in the correct range then tighten the mounting screws.



The fuel mixture is controlled by the computer, it's running rich becaue it's in open loop and trying to warm up the engine. also. because some sensor(s) are out of calibration or not working The ECM has less info to work with, so the engine will run just not at it's full potential.

ANYTIME YOU REMOVE/REPLACE THE IAC OR TPS sensors they need to be recalibrated.

Instead of "giving up" for no good reason other than you lack sufficient info to service this car, learn how to service the car.

I am surprised no one on this site would not tell you to check / adjust the IAC & TPS since you removed / replaced them.

 

Inconsistent Idle

The first and most telling symptom of a failing TPS is an idle that rises and falls sporadically or maintains a very high or low RPM. This condition can be extreme enough to cause stalling or to cause the tires to chirp when the transmission is engaged. It can be difficult to tell the difference between a failing TPS and a malfunctioning or clogged idle air control (IAC) valve, so electrical testing of both sensors and cleaning of the IAC is recommended.


Maladjusted TPS

The TPS must be adjusted (rotated) so that it reads idle and full-throttle positions properly.
It should be 0.54Volts at IDLE (+- .075V) and 4.0 to 4.9 volts At WOT



IAC and TPS Adjustment

Tom Keliher Mar 31 2006 - 3:07pm

Idle Air Control (IAC)

Tools needed:
1.Torx bit # T-20
2.Paper Clip
3.Small Punch

Take the paper clip and open it up and form it into a big "U" shape. Insert the clip ends into the ALDL in the 'A' and 'B' pins.

Turn on the ignition, but don't start the engine. Wait 30 seconds. Now, go remove the connector from the IAC.

Start engine. You are now going to adjust "minimum air". There is a Torx screw on the side of the throttle body. This is what needs to be turned to adjust minimum air, or more commonly known as "idle speed". It comes from the factory with a protective metal cap over it. If the cap is still there, use a small punch to knock it out. Set the idle speed to 450 rpm, rotating the Torx screw clockwise to raise rpm, and counter-clockwise to lower rpm. Once the idle rpm is set, turn off the engine.

Re-connect the connector onto the IAC. Start engine. Idle speed is now once again governed by the ECM, but your idle should be smooth and steady, approximately 600 rpm in Drive (for unmodified cars).

If you set an SES light by having the IAC disconnected, then after shutting down the engine disconnect the negative battery terminal. Wait 5 minutes. This will clear the ECM of all trouble codes. Re-connect the battery and drive the car for 20 minutes to allow the ECM to relearn your driving style.


Throttle Position Switch (TPS)

Tools needed:
1.Digital Volt-Ohm-Meter (VOM)
2.Jumper Wires (make your own)
3.Auto Xray Scanner (if available) will eliminate the need for VOM and jumper wires.


Turn on ignition, but don't start the engine.

With a scanner: plug in the scanner and read the TPS voltage. It should be 0.54Volts +/- 0.075Volts

With VOM and jumper wires: disconnect the connector from the TPS. Using your jumper wires, make a connection allowing some room for the VOM terminals to contact the jumper leads and read the TPS voltage.

If out of spec, loosen the two screws holding the TPS to the throttle body, and slightly rotate the TPS up or down, reading the voltage until it comes into specification. Tighten screws. Using the throttle lever, rotate the throttle to WOT (wide open throttle). The TPS voltage should be over 4.0 volts. Close the throttle again, and then slowly open it to WOT, observing the voltage reading. It should increase progressively and in a linear fashion. If it sticks or jumps or falls off at all while doing this check, that could mean a bad TPS switch and could be a cause of stumbling and drive-ability problems.

After setting the correct voltage, turn off ignition switch. Remove jumpers/scanner and reconnect the TPS connector as required.

 

SEARCH THIS WEBSITE>>> all the info you need is on here..

In about 30 minutes you should have this car running right.

 

.57 at key on engine off and 4.07 at WOT for TPS .IAC position shows 160 at key on engine off and fluctuates while I'm trying to keep the car running. Still only runs with vacuum to brake booster unplugged. O2 is sweeping but stays towards the lean side which I don't understand die to it running so rich. Vehicle will not idle long enough to set base idle at torx fitting.

 

The injectors should have what voltage on the pos. side?

 

Take the paper clip and open it up and form it into a big "U" shape. Insert the clip ends into the ALDL in the 'A' and 'B' pins.

Turn on the ignition, but don't start the engine. Wait 30 seconds. Now, go remove the connector from the IAC.

Start engine. You are now going to adjust "minimum air". There is a Torx screw on the side of the throttle body. This is what needs to be turned to adjust minimum air, or more commonly known as "idle speed". It comes from the factory with a protective metal cap over it. If the cap is still there, use a small punch to knock it out. Set the idle speed to 450 rpm, rotating the Torx screw clockwise to raise rpm, and counter-clockwise to lower rpm. Once the idle rpm is set, turn off the engine.

Re-connect the connector onto the IAC. (remove the paperclip jumper from the ALDL) Start engine. Idle speed is now once again governed by the ECM, but your idle should be smooth and steady, approximately 600 rpm in Drive (for unmodified cars).

If you set an SES light by having the IAC disconnected, then after shutting down the engine disconnect the negative battery terminal. Wait 5 minutes. This will clear the ECM of all trouble codes. Re-connect the battery and drive the car for 20 minutes to allow the ECM to relearn your driving style.

 

it's not the injectors you replaced them and installed a ECM..

it's not the TPS since the voltage is in correct range.

you need to adjust the IAC motor.


follow the instructions make sure it is unplugged and ALDL is jumped with paper clip
when setting the miminum idle speed.
if the car wont run give the torx fitting a turn or two to raise the RPM then start it and get it to idle at 450...

then you can reconnect it...

 

The car dies to quick.
The only way it will run for just a few seconds is to open ALL vacuum ports and even then its running so rich that it stalls after just a few seconds.
So the idea that its just as small as a slight vacuum problem is not a realistic resolution to the problem. The IAC adjustment and/or base idle adjustment isn't enough oxygen to keep this car idling at all. Even still, the car bogs down to the point of stall if you try to rev the motor. I have to keep hyper pumping the accelerator to keep it running or accelerating.
Leaning towards an exhaust restriction.
Are the injectors supposed to have 12 volts from the fuse box or is it a 5 volt reserved voltage?

 

IAC 160 position ?! you need to set engine RPM and reconnect the vacuum line for the brake booster.

if the car is not warmed up to 180 degrees 02 readings don't mean a thing because it's still in open loop.

 

TRY USING THE SEARCH FUNCTION for TBI injector voltage.

Where are you located? I find it odd the fuse block labels would be worn away, was this car in a FLOOD?!

You ask for advise and then go the other direction.

Why did you open all the vacuum ports... who told you to do that?!

and what makes you believe it's an exhaust restriction?
if you think that ,then just disconnect the y-pipe from the exhaust manifolds and try to run the engine with open manifolds.

instead of screwing around with 3 things at once approach it on thing at a time.

you have too many things jazzed up.. and you probably screwed up the timing are the spark plugs wires installed in the correct firing order?

I would suggest finding a REAL MECHANIC in your area. I can't fix this via remote control.

 

Battery voltage (~12.x volts) - look at the wiring diagram - shows a switched feed to the fuses and then to the injectors, then the other side goes to the computer.


I'd have to agree - posts are scattered and I know you've posted you're frustrated a couple of times and that doesn't help - maybe fill out your profile with a general location and someone might be able to come over and go through the troubleshooting logically with you and eliminate things one at a time....

The reason it runs rich with vacuum lines unplugged - MAP sensor is seeing low vacuum (which it thinks is a load on the engine and adds fuel to accelerate as it thinks the throttle is opened and you're not just idling)

Since I believe you said you had almost everything new - TPS, IAC, CTS, PCM/ECM/ECU, (whatever name you want to give it), injector, cleaned throttle body, etc. I'm pretty sure you've got the right electronics on the low voltage side to make it run well - I'd do a REAL good diagnosis on all the secondary ignition components - cap, rotor, plugs, wires, timing, timing curve, advance function, etc.

I've also purchased cheap imported stuff that was bad right out of the box... had one cap/rotor mismatched so bad that the car wouldn't start with the new stuff on - tore my hair out thinking I did something wrong for about 1/2 hour and finally threw the old parts back on and it ran smooth - couldn't believe something as simple as a cap/rotor would be so badly manufactured that it wouldn't even run... Took it back to the parts store and they said it happened occasionally and I wasn't the first guy to come in with a set...

 

I'm in Ga. I figured it myself to open the vacuum ports due to the eye burning smell coming from the exhaust. I did open the exhaust this afternoon and still will not idle. Checked my timing again, brought it to top dead center and ensured the rotor button was pointing at the number 1 plug terminal.
Don't get me wrong, I am extremely appreciative of all the help you guys are giving me and am doing everything you request. I'm just still getting the same results.
I am a Nissan Infiniti master tech and haven't messed with too many of these things and everything I know about cars tells me that this thing should be running.
I don't believe thus thing to have been in a flood as I replaced the window regulators and saw no water marks , pulled the kick panels on both sides and saw no water marks so comfortably I can say that it hasn't been in a flood.
Also, I have now lost power to the injectors even though the fuses are good and power is coming in and out of the fuse box on both injector fuses. That's why I was asking about injector voltage to possibly run my own harness in case of a breakage in the harness somewhere. I've been powering them through a piggy back to my jump box today.

 

Have you checked timing with a timing light? Have an old fashioned ignition scope at work you can use?

Remember - if the harness is chaffed and grounding the 'computer' side of things - you'll be holding the injector open the whole time instead of metering fuel it's going to just be dumping fuel. Pull the harness off of the injectors - look for splits/cracks in it and bare wire near the connector, then unhook the battery and measure resistance on the 'computer' side (can't remember the colors) - if you have resistance there then there is a short to ground somewhere in the harness...

Since you've lost power again to the injectors - and the fuse is good - then I'd say you really need to take a close look at the harness where it comes from the firewall to the engine (both sides - fuse box and computer side) and you'll probably need to pull the looms off it and inspect it real well...

 

Ok. That's the next and only thing I can thing of left. I can't see or think of anything else that would cause all these different and intermittent problems.
I really appreciate all the input and knowledge on this .
I'll let you know if or when I find it.

 

Sorry, but I did mention to check the wiring harness for shorts ... was told it was OK

Anyone can throw parts however what you need to do is test the wiring,
the diagrams are one this site.. I posted the one you need already start my cheking the injector wiring..on the Fuse block side & the ECM side. if you said the fuseblock has corrosion odds are that is part of the problem you also might have corrosion,loose / broken at connections at the metri pak terminals at the bulkhead fitting where the engine harness goes thru the firewall. this is next to the brake booster... start there... you may fix the dome light and radio problem at the same time. EFI needs electricity to function.