1987 Bonnie LE was misfiring, now wont stay running?

[Djkthegame]

1987 Bonnie LE vin "3" with delco II swap (new wires and plugs, icm tested and works, coils replaced) but now she will start up and run for a while but then stalls out it will start back up but stalls again within seconds. The car will restart and run for a while after it sits for a while but then it just stalls out til it dont want to start again? I dont know what to do next and by the way all im getting from the flash codes is 12 which i believe means no stored codes. anyone got any ideas?

[myfirstbonnie]

Check the fuel pressure.Try running it with the MAF unplugged.

[crash93ssei]

Check the fuel pressure.Try running it with the MAF unplugged.

Agreed.

[Djkthegame]

i cleaned the maf after i put the coils on today, and i started it once before i plugged the wire back in, it started but was rough. even after the coils there is still a misfire but it did calm down some compared to how it was before... she is very low mileage for the year only 76k, alot of the parts are still original if that helps. about 3 days ago before this started i had to replace the belt tensioner pulley the bearing on the original one exlpoded and the pulley seized up and snaped the belt. i dont really think the last part is related to causing any other problems but i'd rather give too much info then not enough.

[myfirstbonnie]

about 3 days ago before this started i had to replace the belt tensioner pulley the bearing on the original one exlpoded and the pulley seized up and snaped the belt. i dont really think the last part is related to causing any other problems but i'd rather give too much info then not enough.

I actually had this happen because the alternator didn't like it's bearings. My belt broke my CPS. This version of the 3800 did not have the protective cover over it, pull the right front wheel and remove the dust cover and take a look. All it needed was to bend one of the tabs on the HB to mess up the CPS. Remove the HB to get a good look and inspect the sensor and the rings on the back of it,

[Djkthegame]

im not sure what you are telling me to do?

[Djkthegame]

what does HB and CPS stand for?

[Jrs3800]

Not sure what direction to tell you to go in...

The 87's Computer is pretty much slow and on the stupid side, as well it doesn't really tell you a lot about whats really going on.. So keep in mind its like the difference between an old apple IIE and a computer from today...LOL... Bad comparison I know...

The 86-88 Vin 3 3.8 V6 will not run without the MAF, if it does it'll be horrible.. The MAF sensors on these are a very common failure, pretty much all of them bit the dust during ownership... But more than most of the time the ECM would throw a code 34..

Being that the car starts but dies, we can hazzard a guess and say the ICM is ok, its the ICM that actually starts the car... There is a possibility that the Crank sensor may be bad... But again, its hard to say for certain whats going on with the car...

[Djkthegame]

it will start but will only stay running for about 10 minutes. i cleaned the maf sensor yesterday and replaced all the coils from the delco II swap i got another set out of a 94 buick 3800 vin "L". i took the icm to autozone and they ran the test on it 5 times (the icm is from a 90 buick century 3.3 which is what i had to get for the swap on the 87) and the icm passed all 5 times. as the can dies the idle slow starts to drop until it shuts off, and when i restart her shes throwing off a pretty foul emission smell. but once i restart, it will only stay on for a min or 2. so i am pretty confident that the plugs, wires, coils, and icm are good.

[Djkthegame]

and oh yeah there are still no flash codes being sent.

[Djkthegame]

I have the gm service manual for the 87 and i found a picture show where the cam sensor and crank sensor are and that was where the belt ended up when it snapped a few days ago, im gonna put the 87 in the garage and take the wheel off and see if i see anything and i will let you guys know what i found out

[Djkthegame]

well i couldnt find anything, so i have no idea if either the cam or crank sensor is bad. and it looks like a monster project to do either one

[Djkthegame]

Im doing to try one more thing first, Don (Jrs3800) was telling me that the autolite 605's i have in here arent designed for the engine I have its a 3.8 SFI and not a 3800, so i went and got a set of the stock AC Delco plugs the R44LTS and will see if that does it. Also my dad(a retired mechanic) told me to wait til i heats up and shuts off again to spray the crank sensor with starting fluid to cool it down and see if it starts back up as a way to test the crank sensor.

[Jrs3800]

Thats a good recommendation your dad made...

Replace those plugs, and then do your testing... Like I stated the 605's really are not spec'd out for the 87 3.8, so going to the stock AC Delco plug can rule that out as a problem..

But at this point I'd say the possible items are the Plugs, TPS or the Crank sensor...

Still looking forward to the cure... Keep picking away at it... I know I don't see a lot of these LG3 3.8 Bonnevilles these days...

[Djkthegame]

ok i made some major progress today and things seem to be going in the right direction lol

1. put the new stock delco plugs in and put the heat shields back on the wires(i didn't have them on before). The car started up fine and the misfire has seriously calmed way down now. I had it running for a good hour and a half and it never shut off once.
2. after about an hour of running i stop by the shop in town, they do alot of bonnevilles i was going there to get a price on a crank sensor install. i had the car running the whole time i was sitting there talking to the lady that works there she has a bonneville too(i almost bought that one she got but its cool cuz she's like us she loves the bonnie's too. Im gonna lend her my service manual over this coming weekend so she can find a wiring problem she's having in hers. so anyways while im sitting there the check engine light came on and i swear i said "good ur finally gonna tell me whats wrong with you" i got a 34 the mass air flow sensor is acting up which aint to bad at all.
3. im gonna go back outside in a few and pull the air intake housing off and clean out the throttle body too, also i'd like to see if it all gunked up
4. and i also got a 45 rich exhaust which they think is tied in to the mass air flow prob.
5. best of all the lady there didn't even charge me for the scan(these are good ppl this is why im lending her my service manual so she can look at the wiring diagrams to solve her problem, i was telling her she's got to register on the site here. i told her us bonnie owners look out for each other), they got the snap on plug in machine there and we went thru all the codes and trouble shooting.

most importantly of all the car didnt shut off, so im getting close to a solution here lol

[00Beast]

Like we said in chat, find a MAF with the same number that is a true Delco unit.

Also, if you look in Techinfo, you can read codes with just a paper clip by jumping a couple pins in the connector and counting the flashes.

[Djkthegame]

so what, dont buy the maf at autozone?

[Djkthegame]

the one i have now isn't a true delco, and the throttle body was black inside so i cleaned it out and the tubing between the maf and tb

[00Beast]

Correct, go to a Junkyard and get a MAF that says AC Delco or Delphi on it.

[Djkthegame]

i can order a new one from rock auto for like 80 bucks, i might end up doing that, there is go guarantee a junkyard maf will even work if i can even find it