kubinusa

I replaced valve cover gaskets, changed fuel injector filters,pintle caps and o-rings, distributor rotor and cap, new spark plugs, checked the resistance on the injectors, pick up coil, got the ignition module tested and got a new ECM. The engine rotates, but wont start at all. After installing the new ECM I was able to start the car but it just stalled after a minute or so, started again after but all weird and now I can not start it at all. Is it possible the fuel injectors are not installed properly in the manifold and there might be a vacuum leak causing that?

Drew

iTrader: (58)

Check for fuel and spark at the cylinders.

Pull a spark plug or two and give them a sniff... Do they smell like gas? Are they covered in oil and soot? Pop a plug in the plug wire and set it on the engine so the base is touching metal, and have someone crank the engine. Is there a clean spark? When you press the center of the schrader valve on the fuel rail does high pressure fuel squirt out? Are the injectors pulsing when you crank the engine?

kubinusa

just checked the spark plugs and yes, I smell gas and there seems to be a little bit of oil on them, I checked the spark yesterday and it was allright, the gas is coming from the schrader valve as well

flintman

hey sounds like my issue try unpluging the EST bypass wire located pass side near the firewall. Its a single wire that comes out of the harness. My car runs fine with the bypass wire unplugged as soon as I plug in i have similar issue like yours

Drew

iTrader: (58)

Do they spark? or are they so saturated they won't? You might just need to change the plugs.

As a side note... My 3.1 Firebird ran great for three winters, then just before the fourth winter I removed the Bosch Platinum plugs I'd been using and installed NGK plugs. The first time the temp dropped the plugs fouled and left me stranded. I changed the plugs in a -17* blizzard, back to Bosch Platinums and it fired right up and ran great until I sold the car the next summer.

kubinusa

The plugs are brand new, so they should be allright, even though they aren't brand name, also I think that the winter here in Florida won't affect them .. Try to check the spark later, don't have anybody around right now..

Drew

iTrader: (58)

Back when I was fighting with injector problems, it'd take about 30 seconds to foul a set of plugs bad enough the car wouldn't run on them. You can also check to see if they're all the same or if one or two look different from the rest, it might help you isolate the problem to one cylinder or another.

firebird904

Did you check your plug wires to see if they are in proper order? When i did a tune up on my car i had one switched and it wouldn't start and when it did it would stall.

kubinusa

yeah, I that was the first thing that came to my mind, checked it couple times

kubinusa

Checked the voltage on the injector wires and they all have little under 12V, so that should be fine, rechecked the resistance on the injectors and the pick up coil - all good, there is a nice clean spark on the plug and the fuel pressure seems allright as well. I don't know what else to check...

kubinusa

tried to unplug the bypass wire, but nothing changed, still can't start her

Maverick H1L

iTrader: (8)

Have you made sure the dizzy is on the right time? Are the injector connectors on the right sides of the engine? Run a test light betwen the battery positive post and the green or blue wires on a couple of injector connectors (one on each side should do) and crank the engine. If the light flashes, the ECM is pulsing the injectors. If not, you have other problems.

kubinusa

The connectors are definitely on the correct sides, the timing should be allright, I think, I didn't move the distributor and it worked before, will try to check the injector pulse later on

kubinusa

So I ran the test light (using 6/12V circuit tester for circuits w/ power on) between positive battery and green injector wires with the ignition coil disconnected and it seems it works the opposite way, the tester light is on before I crank the engine and as soon as the engine cranking the light just goes off on every single wire, tried it w/ voltmeter and it is same, there is 12V before cranking and when cranking it goes lower and stays low, I guess that's not how it suppose to be

Maverick H1L

iTrader: (8)

Nope, it's not. The ECM grounds the injectors to complete the circuit and open fuel delivery to the cylinders. Check for a short in the injector harness.

Are you still having ignition problems? Remember, "No spark, no squirt." In other words, if there isn't any ignition, there won't be any fuel injection because the ignition module is how the ECM knows the engine is trying to run. You also could have a bad parts store ECM.

kubinusa

I checked all the plugs yesterday and they all spark fine, so the ignition should be fine. Do you think I should try to test the pulse with the noid light or is the voltmeter/circuit tester just fine, cause I've read somewhere that the cheap DVM might not show fast change in the voltage on the display, as well as the circuit tester might not flash..and also as I wrote above all the connecters do have almost 12V without cranking

Maverick H1L

iTrader: (8)

You can try the noid light, but I'm pretty sure that if the test light didn't work, that won't either, especially if the injectors have 12V on both sides.

I personally can vouch for the test light test, and it's specified in the GM service manual if a noid light isn't available.

kubinusa

OK, how do I find a short in the injector harness? I never did that so don't know where to start and what to look for..
thanks

Maverick H1L

iTrader: (8)

Well, take the injector harness out of the engine (connects at BOTH front and back of the engine) and remove the black tubing. Check for any broken insulation on the wires that could be touching other wires. Also, use the DMM on the fuel injectors... One could be shorted. You're looking for 11.8 ohms plus or minus about half an ohm per injector.

kubinusa

So I took out the injector harness and checked the continuity of the wires and it looks all good. The resistance on my injectors is 16 ohms, the manual says it should be between 11 and 14, but I guess it is allright as all of them got exactly 16..I don't know what else to check, the continuity between ECM and the injector harness connection? Don't know how to do that though, don't have that long wires on my DMM..

Maverick H1L

iTrader: (8)

Double check the injector harness. The connector for the fuel injectors is at the FRONT of the engine, where the other 2 harness connectors (for the CTS and the cold start switch) are. You want to check between the pink wires on the driver's side and terminal C of the 4-terminal connector, pink and black for pass side to term D, blue driver's side to term A, and the green wires to term B. Also check between the wires in the 4-terminal connector (pink to blue, pink and black to green). There should be little resistance on each color of wire, but infinite resistance between wire sets (pink to blue and pink/black to green and also between banks of injectors).

With the injector harness removed, check for 12V at terminals C and D of the 4-wire connector in the engine harness, and at the other 2 just in case, with the key on.

And, finally, something easy, check the base timing of the distributor. If the bolt was loose, as the engine ran, it could have spun the dizzy way out of time all by itself.

kubinusa

The resistance in the injector harness is all good. There is almost 12V on terminals C and D and no voltage on terminals A and B.
As of the base timing check, is it the one with the #1 spark plug removed and manualy rotating engine...shoudn't have moved though, it seemed pretty tied..

Maverick H1L

iTrader: (8)

Yes, number 1 plug (or #4 as they have the same crank position, 180* of cam apart). Won't hurt to check and reset the base timing to 10* BTDC (bottom of second V in the timing tab).

kubinusa

So I finally got a fuel pressure tester and hooked it up, the pressure went up to 40 PSI right away after turning the key to on position, but it started decreasing quite fast to about 30 PSI, I tried to crank the engine and while doing that the pressure was decreasing with every attempt. So I am not sure if it is the pump, relay, pressure regulator, leaking injectors or something else. I will start with changing the fuel filter, but would appreciatte any hints how to figure out what might be the problem, thanks.

Maverick H1L

iTrader: (8)

Get a couple pairs of locking pliers or hose clamps (the kind that clamps the hose shut, not the kind you put on the end of a radiator hose). Pad the jaws of the locking pliers REALLY well, and get ready to clamp off the fuel hoses. You may want someone working with the ignition key as you clamp the hoses.

1. Pressurize the system, allowing the fuel pump to prime the system until the relay turns off.
2. When the relay turns off, clamp the larger pressure hose off. If the pressure holds, there is a problem in the supply side (line from fuel tank, filter, check valve in the pump). If pressure still drops, move on.
3. Unclamp the pressure side, and prime the system again, this time clamping the return line. If the pressure holds, the fuel pressure regulator is bad. If the pressure still drops, move on.
4. Prime the system again, leaving the clamp on the return hose, and clamp the pressure hose this time. If the pressure still drops, the injectors are either dirty or stuck open.

kubinusa

I clamped the supply hose and it did hold the pressure pretty well, so is there an easy way how to find out the leak? The other think is that the system fully pressurize every once a while after turning the key on, not every time, is that normal? I can hear the relay click every time though.,.

Maverick H1L

iTrader: (8)

Well, if you can walk by the car and not smell gas when the system is pressurized, then my best guess would be that your car needs a fuel pump. Especially since you've said that the pump running seems to be hit-or-miss with the relay running. Go for a V8 fuel pump, or even a Vette fuel pump... They'll last longer.

kubinusa

So the camaro V8 5l pumps fit and work the same ? If you say they last longer I definitelly go for it, I had mine replaced like two years ago , and the V8 pump seems even cheaper than the V6

Maverick H1L

iTrader: (8)

V8 pumps have a higher flow rate than the V6... So the extra just goes through the return system back to the tank.

kubinusa

I replaced the fuel filter and it fixed the pressure problem, but I am still back there where I was before this. It is hard to get the engine started and when it starts it sounds like it is running like 50% or less of its capacity and it stalls after a bit. All the spark plugs are fouled after that with I believe oil. I have replaced valve cover gaskets before this but it does not seem the oil is coming from there. Still, could that be caused by defective reman ECM?

Maverick H1L

iTrader: (8)

Again, I ask, are the plugs dry black or wet black? Oil on the threads doesn't count at being wet, as that comes from oil in the plug hole as the plug is removed. If the plugs are fouled dry black, there's still too much fuel in the mix. Have you checked the MAF sensor? Those things like to go bad without throwing any codes. Is the car okay after holding the engine speed at about 2000RPM until the temp gauge shows the engine temp above 100*? That's another sign of a bad MAF (been through four of them, I know most of the signs).

kubinusa

The plugs are wet black even on the firing end. How do I check MAF sensor? I just cleaned it with MAF sensor cleaner..The car does not even run on 2000RPM and wont last that long to get that warm. By the way it doesnt have rpm and temp gauge.

Maverick H1L

iTrader: (8)

If all six are that way, either your valve guides or the stem seals are shot. If you're currently running R42 plugs, try R43s, it may help to keep them a little cleaner by allowing them to get a little hotter.

To test run the engine to temp, stick a nickel in between the throttle lever and the idle stop screw, should be about 2K RPM.

To check the MAF, hold the screen end up to a light and let the light reflect off of the orange/copper film in the middle of the board. If the film isn't completely flat, the MAF is junk.

kubinusa

yeah, the copper film in the MAF sensor doesnt seem to be completely flat, so I guess I will get a new one. Also when I disconnected the air hose there was a strong fuel odor, dont know if that's normal

Maverick H1L

iTrader: (8)

Engine's flooded. May not just be due to the MAF, could also be due to a leaky injector or 2, or the cold start (7th) injector in the back of the intake manifold by the dizzy.

kubinusa

So I replaced the MAF sensor for a new (reman) one and after a bunch of unsucsessfull starts, when the engine didn't start at all or started all weird, I managed to get it started what seemed to be ok for couple minutes. Then I tried to shift to rear and the engine went off immediately. Can not get it started normal again. Just sometimes starts what seems to be on really low rpm and when I hit the gas it dies. Checked again the spark plugs and they are dry black, all of them, so I suppose the mixture is too rich.

Also, when I looked at the reman MAF sensor the copper film seemed not to be narrow as the same as the old one, so I suppose it might be deffective as well..I tried to start the engine with the MAF disconnected, it ran really bad just for couple seconds but at least the computer threw the code..

Maverick H1L

iTrader: (8)

The MAF is probably not bad, yet. The remans are made differently from the AC/Delco ones, and usually go bad after a short period of time, as I've noticed with both of the ones I've put on my car.

Did you reset the ECM by either disconnecting the battery for a few seconds or by pulling the inline fuse?

kubinusa

Yes I reset the ECM. I am pretty much able to start it any time now, it just takes longer cranking and it does run poor with a knocking noise and stalls after a while/or when I hit the gas.

kubinusa

When I ground the diagnostic terminal, the IAC valve is clicking like crazy..is that allright?

kubinusa

Also do you know how exactly to test the EGR solenoid using a vacuum pump? The manual says to hook up the pump on the manifold side of the solenoid - there are three hoses on the solenoid, one from the valve, one from throttle body/EVAP can. and one going to the EGR sensor. And if I hook it, lets say to the throttle body one, should I plug the other two? It says to do this with the diagnostic terminal grounded and key on, it should hold vacuum.

Maverick H1L

iTrader: (8)

First question: That noise coming from the IAC is the IAC "homing" itself so that the base idle speed can be adjusted. It's when it doesn't make any noise with the ALDL grounded that you need to worry.
Second question: The inlet to the EGR solenoid IS the throttle body, also known as the manifold. No, you don't need to plug the other 2 ports. The air will go where it's supposed to in relation to whether the solenoid is powered or not, which is why the flow chart is set up the way it is.

kubinusa

So I replaced the ECM for another reman and it is the same. I also bought used PROM unit and fuel Calpak unit but I am not sure if I can put them in - the last four serial # match and the prom is for 2.8 MPFI and that matches as well. The guy said he pulled it from a 86 working camaro..
Another question is about the TDC, I try to set it up and it looks allright to me - took pics of the rotor position when the piston #1 in TDC, but don't know how to post them in here..
Anyways, the car still doesn't run, can start it, runs like crap for couple seconds and stalls, still running rich - at least the plugs are dry black fouled every time I after I start the engine.

enswrob

the rotor should be pointing at #1 cylender at 10 btdc not tdc. it makes a huge difference.

Maverick H1L

iTrader: (8)

It does, but it also doesn't. I've had my timing set up so that the engine ran with the timing WAY after TDC (FWD DIS MEMCAL with crazy firing offset), and it still ran. It ran like crap, but it ran. I've also had the engine running on one bank of cylinders (didn't rewire the fuel injector power connector right... ), and with 2 plug wires crossed. The point is that it STILL RAN.

kubin, have you checked the color of the spark at one of the plugs? Sounds like weak spark to me, and you've said nothing about replacing the coil.

kubinusa

all the spark plugs are covered shiny black till I clean them with some cloth..If you mean ignition coil, that I did replace, pick up coil not, that I just checked resistance on and it was allright

kubinusa

Yeah, pointing that way, just wanted to see if it isn't too far off..hard to tell exactly, but I think it's fine

Maverick H1L

iTrader: (8)

Not the color of the tips of the plugs, the color of the spark AT the tips. If it's not bright white, and it's orange or red, you have a weak spark.

kubinusa

the sparks are good, bright white

kubinusa

OK, I retested the spark and it is nice bright white spark, so I am assuming that eliminates the problems with ignition.
On the other hand with the fuel pressure - it seemed allright and steady after I changed the filter, but now again the pressure drops from around 40 PSI to 30 PSI within two minutes (does'nt happen while supply clamped), don't know if that is the problem that causes my engine run rough and stall in few seconds...

Maverick H1L

iTrader: (8)

Fuel problem is in the supply side (between the pump and the fuel rail). Has the pump been replaced recently, or at all, that you know of? If not, then, like I said before, it probably needs it as it could have a bad pressure check valve among other problems. If the pump has been replaced recently, the hose or line between the pump outlet and the fuel pipe on the sender could be damaged and leaking.

The fuel pressure should hold, without losing even 1 PSI of fuel pressure, for 20 minutes after the pump shuts off (GM spec).