Good evening gentlemen,

I have a 1986 Camaro with the 305 TPI engine that isn't very interested in the idea of starting, let alone being used as a reliable form of transportation.

Here is a little background on the situation:
The car has been parked for quite some time in my garage awaiting a head gasket replacement. After replacing the head gaskets, when attempting to start, the engine would crank but not fire.

Because this was at the time during the coldest part of the winter here, it was suspected that the low temperature paired with old fuel (months old at this point) were to blame for the woes of the engine, so fuel additive and fresh gas were added to the tank. Unfortunately the problem wasn't that simple and the car continued to crank without firing.

I replaced the Ignition Control Module, which again made no difference to the whims of the car. However, when "easy start" was sprayed into the intake, the car fires after cranking, but quickly dies soon thereafter when the starter fluid is consumed. Because of the momentary ignition I assume that the ICM is in working condition.

Thus lead me to a trial & error approach.

The following is a list of attempted fixes and the results:

• All fuses were checked (Including the in-line 20A fuse near the battery): All working
• Introduced 12volts to the fuel pump to test: Fuel pump runs properly
• Replaced fuel pump relay: No change
• Checked continuity in the fuel pump solenoid connector: Working as intended
• Replaced oil pressure sensor: No change

I read that the fuel pump should run for 5 seconds to prime at ignition-on. This is not occurring, nor is the SES come on.
I can't see anything else relevant in the circuit diagram as to what may be a possible cause.
I checked all the fuses for a second time. Are there any fusible links in the wiring harness?

Also of note, due to the constant battery depleting of repetitive cranking, once during one of the many battery changes, a large spark occurred when connecting one of the side posts. Could this have been detrimental?

Any advice would be greatly appreciated, and thank you very much for reading.

 

Well the fact that you can get it to run on easy start is a good sign I would suspect fueling is the issue here..

I'd just check that you still have a spark by removing a plug and resting it on a metal part of the engine, get a friend to crank it over while you watch for a spark across the electrode on the plug.

Assuming you have a spark, just check all the plug wires are hooked up the right way round and that the timing is near enough right (can't be far off as it runs on the easy start)

If you have a spark and at the right time now all we need is fuel.... Have you removed any of the spark plugs after cranking? If so, were they wet with petrol? If not then your injectors aren't firing of they're firing but there's no fuel getting to the rail.

Your pump should prime for a few seconds with the key on. Check all grounds / relay connections again. There is one wire that comes from the ECU which goes to the relay which kicks it in for a few seconds. I've copied this from 84redta (hope he doesn't mind) Bear in mind some of the wire colours maybe a little different on your car..

"Get a digital volt meter, and check the orange and black wires on the fuel pump relay harness. Make sure that is getting 12V. If you green wire isn't getting voltage you may have a small problem like i'm experiencing. You will need to go to your passenger side and drop the ECM. Check terming A1 (green/white wire), turn the key on, if you get 12V, then there is a break between there and the fuel pump relay plug. The way the system works is that the computer sends 12V to the green/white wire, and being the relay is powered already by the orange wire, it will flip the switch and send a signal via the tan/white wire to the fuel pump and back to the ECU. When the ECU gets the 12V back to the ECM via the tan/white wire is when it will activate the 2 second activation ("prime"). So therefore if you test it with the relay out it should stay at 12V at the green/white. Check your green/white wire at terminal A1 at the ECU and if you have 12V, then you must replace the wire (what i'm doing right now for mine...so it does happen although it may be rare) all the way from the ECM to the fuel pump relay plug. Hope this helps."

 

The pump should run for two seconds during its prime phase when the key is turned to the ignition on position.
Let's talk about that SES light, or lack of it. You've stated that the 20A continuous battery fuse in the holder and the ECM fuses are both in good functioning condition.
With your ignition in the ON position, probe circuit 340 and 439 using a test light connected to a good ground. Circuit 340 connects to the B1 terminal at the ECM, and is an orange wire. Circuit 439 connects to terminal A6 in the ECM and uses a pink/black wire. With the ignition on, the test light should light up when you probe both of them. If both fuses are good, and the test light does not come on, you have a faulty ECM or faulty ECM grounds.

 

change the fuel pump and go from there...

 

Didja miss this part?
Fuel pump works, changing it would be throwing money away. Sounds to me like wiring or possibly ECM. One other thing to check is ensure the fuel pump ground is good, when I was troubleshooting mine it would run with 12V direct from the battery but not with the near-12V after running through the circuit. Ground wire resistance checked at ~2ohm to other grounds, but I had to clean the ground connector to get it to work.

 

To me it sounds like ECM or Power to the ECM.
SES does not come on at all, correct?
No SES light could mean no power to the ECM, bad or removed SES bulb, Defective cluster, short or open in the wiring..

 

I had the same problem with my 89 suburban. Try checking the valve lash, this was my first fuel injected chevy build and i had tightened them too tight. A key indicator will be that the engine rotates very easily. Also had the same problem with the fuel pump not getting that prime also no light and other stuff that required a power source. From the wiring diagram it had a power wire running from starter to ecm but i couldn't find it anywhere. I ran a fusible link wire from small connect on back of alternator near the top to my battery and wala I had power. Also make sure you got all your ground wires connected.

 

Thanks for all the responses. I had some time to work on the car, the following is what I did as per the above posts, and the results:

• Tested the orange and black wires @ the fuel pump relay
  • Working as intended (Getting 12v)
• Tested the 10a ECM fuse
  • Working as intended (Hot on Key-On)
• Tested the green/white wire @ the ECM A1 Terminal
  • Working as intended (Not getting 12v)
• Replaced the ECM to rule out any malfunction
• Repeated the above tests with the same results
• The car continues to crank without ignition (With the exception of using starter fluid)

I am grateful for the replies to this thread, so far they seem to cover every possible problem. Inasmuch I am confused when looking at the wiring diagram after performing these tests, because (with my limited knowledge) the wiring diagram seems to indicate that there could be no other possible reason or cause for the car to not start. I will repeat the tests for another go, in case there was human error the previous times, but any additional input anyone can offer would be greatly appreciated.

 

I wonder if your MEMCAL is bad. Generally no flashing SES light with key on means that the PROM is not being read or non-existent. Also you replaced the ECM, have you tried checking for any codes that might have been set while you were trying to start the car? If the car will fire on starting fluid, then I would venture to say that the only other possibilities would be bad grounds, or shorts in the injector wiring.With this car being an 86, it is not a VATS issue. I would check your grounds and check your injector wiring. If its all good then id say your MEMCAL is shot.

 

Im currently having pretty much the same problem with my 86 TA 305tpi. The difference tho with my car, it will start when it wants to. When my car starts and is being driven, it runs great.

When i turn my ignition to on before trying to crank, my fuel pump does not prime either, atleast on the second etc. attempts when it wouldn't start the first time and im paying attention to it. I also have no stored codes and my ses light does work. The one difference, that i may have just missed is, my car also cranks slow. But even when the car is cranking real slow the car will still start if it feels like it.

Plugs, coil, cap, rotor, icm are all new as of last summer. i replaced the ecm last summer with a used one out of an 88GTA, but because of the year difference i had to use the memcal out of the old ecm because the 88 has the security feature that my 86 doesnt. The battery itself is 2 days old, my old one was only working at half. Had a friend tell me to run a new ground from the battery to the block. The only ground strap i could find only reached to the A/C mounting bracket and made no difference.

Im planning on putting in a new starter probably tuesday to hopefully fix the cranking issue. Is there a way to test the memcal itself? If/when the car starts and i can get it somewhere i can work on it, i plan on testing the circuits mentioned above first thing.

Also, i cant say for sure, but it does seam like the car is more likely to start when i jump it from another car or when its on a charger. And if the car has been running up to temp. and shut off, i wont even bother trying to turn the key for atleast 3 hours cuz its just not gonna happen.

 

When you gave the pump 12V did you do it at the relay? If so, did you use the fuel pump prime wire (thin red one not connected to anything) to test the pump? If yes to both of those, you should check to see that your relay has 12V on the gray wire with the key on.

 

I have the same problem. no light, no prime, no run.

 

Solved: For me at least.

Today I went through everything. Sanded all the grounds I could find. Traced the power all over the place. Jumped the fuel pump. Took apart the ecm.. still no ses light or prime. So about to give up for the day I boosted the car with my moms van because the battery was getting low and when I turned the ignition on I got an ses light and prime. Turned the key and she started right up and ran perfect.

So boosting the car worked to fix it for me.

EDIT!!:
It happened again a week later (no check engine light in ignition position.) I checked everything again and was about to give up again for the day and I started knocking on the ecm and the light turned on and when I turned it over it fired right up.

 

well, for a thought, i have a 350tpi. i wanted to see what would happen if i tried to start my car without the chipped key. i could not get my car to start with the chipped key. I had to charge the battery overnight and try again. I remember from autos class in highschool, if a car is flooded, give it more gas to start it. maybe, you need to hold your accelerator to the floor when turning it over. worth a try. i was really pissed, but it was all my fault. btw i read a lot of what you wrote but not all of it, hope this helps. Flooring the car while it is turning over got my car to start again, not a problem after that. good luck :P

 

I have the same sort of issue. '89 Formula 305 tpi. Cranks, fuel pump runs, but will not fire. It's been sitting up for about a year, city code guy comes by, someone in the neighborhood has complained about it not moving, bla, bla. Charge battery, won't start. Same scenario as above. Start checking stuff for loose wires, etc. Pull distributor cap, yuck!. Nasty looking junk in cap. Replace cap and rotor. Car starts right up. Code guys wants me to move car, so I do, but don't think to park it facing other direction, just moved it over. Duh! He calls next day, I tell him it is running, he takes my word for it, but says it would be better if I turn it around. Tell him I'll do it. Go home that evening and try to start it and won't start. Same thing as before. When it starts it runs fine, although the oil pressure guage starts to drop after it warms up. That is why it has been sitting. Could the oil pressure sensor be defective and keep the car from starting? What about the crank sensor?