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87 firebird v6 wont start


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fuzzy1
User

Oct 12, 2019, 11:28 AM

Post #1 of 11 (245 views)
87 firebird v6 wont start Sign In

1987 Pontiac Firebird 2.8L with only 108000 miles.7 years ago car ran like a dream then performance slowly started to go away. Wife had the converter checked and removed, replaced with straight pipe. Performance then returned to normal. about a year later performance started to deteriorate again. had a bad fuel pump and ignition coil failed. replaced it. Performance returned but this time for only a short time. Replaced fuel pump second time and performance never recovered.
current day 10-12-19
car has sat for 6 years so here is what has been done this week. #1.fuel Tank removed and derusted.#2. new fuel pump installed. currently have 41 psi at fuel rail.#3. checked for spark, spark tester showing better that 30,000 volts. #4. have spark at plugs.#5. new fuel filter. #6. removed ignition module from dist for testing. passed test. while i was in there i replaced pickup coil because wire connector fell apart in my hand.
#7. removed cold start injector on rear of intake.. have excellent fuel pattern and lots of pressure. #8. plugs and wires are only 6 years old with hardly any miles on them.
#9. I have injector pulse on 4 of the injectors that i checked.
#10. dropped steering column, checked for ignition switch issues. all looks good. no melted wires or anything wrong. #11. new battery and starter installed.

So now here is the rest of the story. Randomly if you crank the engine it will in fact fire and run for 1 second. I have determined that if you hold the key in the start position it seems to what to continue stay running until you let go. I have only done that twice as i dont want to tear up a new starter. Again this is only random. Most times if you just crank it wants to start, you can hear combustion happening in the exhaust but it will not hit. If while cranking you mash the throttle to clear flood mode combustion noise goes away. I have unplugged every sensor on there and replugged and to no avail, it WILL NOT START. So what am i missing? thanks


(This post was edited by fuzzy1 on Oct 12, 2019, 12:53 PM)


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Oct 12, 2019, 12:48 PM

Post #2 of 11 (215 views)
Re: 87 firebird v6 wont start Sign In

Have you checked this thing for any stored codes?

Check the pink wire at the injectors for power with the key on.

If that is OK, try unplugging the oil pressure switch and starting it.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



fuzzy1
User

Oct 12, 2019, 12:56 PM

Post #3 of 11 (207 views)
Re: 87 firebird v6 wont start Sign In

as stated in step #9 i have injector pulse. I must have power cause the ecm controls the ground causing the noid light to flash. I will in just a moment go and unplug the oil sending unit but what am i looking for while im there?


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Oct 12, 2019, 1:00 PM

Post #4 of 11 (203 views)
Re: 87 firebird v6 wont start Sign In

I didn't ask you if you had injector pulse. I did read that but since you are stating that it runs in "start" position only, I need to know if the injectors are still getting power in run position.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



fuzzy1
User

Oct 12, 2019, 1:29 PM

Post #5 of 11 (199 views)
Re: 87 firebird v6 wont start Sign In

ok.. unplugged oil sending unit.. the 2 wire one.. left the single wire one alone. no change.. no codes in current or in memory.. yes red wire is hot on injector with key on in run position


(This post was edited by fuzzy1 on Oct 12, 2019, 1:36 PM)


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Oct 12, 2019, 3:22 PM

Post #6 of 11 (169 views)
Re: 87 firebird v6 wont start Sign In

OK, according to you, you have spark, fuel pressure and injector pulse. That only leaves compression.

I would first try spraying some starting fluid into the intake first just for insurance on fuel.

PS, that injector feed should be pink, not red.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



(This post was edited by Hammer Time on Oct 12, 2019, 3:23 PM)


fuzzy1
User

Oct 12, 2019, 4:09 PM

Post #7 of 11 (161 views)
Re: 87 firebird v6 wont start Sign In

yes its a pink wire. Compression is good. i have not checked it but I know that i know its good. youll have to trust me on that one. Well after checking on some other things. i lost power to the fuel pump. i checked the inline fuse, removed it and installed with the key on and i could then hear the relay and pump power back up again. i did this a few times. then turned off the key then back on again and all is working again except i have no pressure at the rail. I will install the big gauge tomorrow at the tank connection to see whats happening there.. Im just glad i didnt reinstall the rearend. Just have to drop the tank.. 5 minute job.. oh as far as starting fluid.. i just use a spray bottle of gas and get it up in the plenum.. no change


(This post was edited by fuzzy1 on Oct 12, 2019, 4:12 PM)


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Oct 12, 2019, 4:29 PM

Post #8 of 11 (155 views)
Re: 87 firebird v6 wont start Sign In

Nothing you are telling me adds up.

If you have fuel pressure, injector pulse, spark and compression, your car would be running and if your only problem was fuel, the car would run if you sprayed fuel into the intake so you need to go back and find out what you are doing wrong.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



fuzzy1
User

Oct 13, 2019, 5:06 PM

Post #9 of 11 (115 views)
Re: 87 firebird v6 wont start Sign In

Lack of fuel pressure has been repaired. I've been so frustrated over this thing I had fuel in it but apparently not enough. So now pressure is back but still a no start condition. You are correct, nothing adds up. I was in the same boat 6 years ago at this exact point. Had everything it needs to run but won't. So now I'm looking for HELP


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Oct 13, 2019, 5:09 PM

Post #10 of 11 (111 views)
Re: 87 firebird v6 wont start Sign In

No, you just need to go back and find out what test you did wrong because you have to be lacking one of those functions. Believe me, if they were all there, the car would be running so something didn't actually pass the test. Time to start over and do all the testing again.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



Tom Greenleaf
Ultimate Carjunky / Moderator
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Oct 13, 2019, 8:31 PM

Post #11 of 11 (99 views)
Re: 87 firebird v6 wont start Sign In

Wow, lots in all that.
The whacked reasons for this no fire but all checks out incl:
* De-rusted tank?? Huh? Plugs both rusted and or so fuel soaked leave then out a day. New ones in even if already new the could self ground with no spark.


* "Compression is fine, trust you" I do but not the compression yet. Years sitting stuff happens. Lifters collapse for example and leak right down again. Get a pressure + again wet.


* Use starting fluid not gas in a spray bottle adds to flooded confusion.


(other whacko reasons) > Timing jumps all around. > Valve timing? Still nylon cam gear? >Distributor shaft not turning?


Question with all the trying: Is oil now too full as in fuel soaked?


Just some "out of the box" reasons for the whacked results so far,


T







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