BushyTea

Well I have search the forum and haven't fully run across someone having the same problem so here goes.

I just rebuild my 3.1 V6 and it has good compression, good fuel, new plugs. The distributor and cap were new when parked about a year and a half ago.

The timing has not been fully set yet but the timing is in enough for the engine to start up but it runs extremely rough and maybe one out of 5-6 start up it will barely stay running enough to get out and try to do the timing If I give it gas and rev it alittle it will stay running but doesnt smooth out. Engine light doesn't pop on and I have run a code reader on it but nothing comes back.

Any advice or comments are greatly appreciated.

Thanks,
Mike

Ovrclck350

You're going to need to go ahead and disconnect the ESC (Electronic Spark Control-it's the brown wire on the passenger side of the engine bay) then play with the distributor enough to get the engine to where it will stay running.

Once you have the timing set on enough to where it will idle, then you can set the timing......what it seems like right now is it's on enough to run with gas, but not to idle.....

BushyTea

Thanks for the quick reply.

I disconnect that wire but it seems the only way it wants to even try and run is if i turn the distributor over as far as it will go to the left (counter-clockwise).

It also won't start without some help from the gas pedal being pressed.

Well update......took off a vaccum hose from the back of the intake. The little hose that plugs into that T connection. Take that hose off and it stays running on its own, still alittle rough but runs on it's own power so one step forwad.

Ovrclck350

Sounds like you may have your vacuum hoses routed wrong or a sensor not plugged in (it happens a lot).

Someone will post a vacuum diagram or it will be on your fan shroud.


If its not one of those, then you're a tooth off on the distributor I'd bet.

BushyTea

Well didn't find any sensors unplugged or other vaccum lines in the wrong place.

The engine while running sits and surges. It goes up in rpm's then back to bogging and about dying then regains itself and jumps up again.

Any attempt to get the timing to 10-12 degrees are failed attempts because 12 is as low as you can go and it pretty much kills the motor and any lower instantly kills it.

Project: 85 2.8 bird

check to see if the map sensor is crapped

screaminformula

are you certain you are firing on all 6? possibly a bad plug wire or something of that sort? i tend to agree with the bad sensor (a lot can happen when an electrical part is left to sit out in the elements [moisture] for a year and a half you say?) or a tooth off on the distributor. actually, now thinking about it, the way you talk about the timing not being really adjustable, im pretty certain about the being a tooth off thing...try the things suggested on here and keep us all posted...good luck!

Josh

BushyTea

Thanks for the replys!

Yeah the wires and even plugs have warranties so I will exhange them with no cost. Probably go ahead and change some of the cheaper parts such as the rotor just for kicks.

The distributor might be bad I dunno. Actually about 2 years ago I had to replace it. It sat in a garage for that full year but moisture can get anywhere so could have ruined it but it has a warranty on it to so might as well exhange it too.

The car just seems to be all over the place on idle so I dunno. The cap is giving a spark but don't know if the spark is making it's way to the end of the plug.

I will keep you posted as it seems these cars have minds of their own so I am sure there will be something else but hopefully all goes well.

screaminformula

well, good luck with it all and hopefully you get her all back to kick-*** mode ASAP

Josh

Dale

iTrader: (12)

On That t vacume line, it routes to the hvac controls. You can easly break that t, inside diafram could be broke, or the lines inside could have rotted by now creating a leak (mine have pulled away from the control box).

If your having to turn the distrib to far, you may have stabbed it in wrong. I have done this countless times.

drdave88

iTrader: (3)

sounds like the distributor may be off a tooth. id check that out before you go spending money you dont need to. ive done it a few times as well.

BushyTea

Well pulled the distributor and turned it one tooth over and sat it back it. Seemed to have been some of the problem.

Now it just runs rough, idles at around 1000 drops alittle then hops back up past 1000rpms and for a sec. sometimes hits the 1000 and sounds smooth. I think it might just need the plugs changed even though they are new because I know the drivers side 3 (#'s 2,4,6) are pure black.

Checked for vaccum leaks but came up with nothing. So making progress but still a few probs.

Gumby

did you install a new cam in this motor with new cam bearings???

I have heard and read several times that is important to get the car running the first time and let it idle said ammount of mins. The constant start up n die can ruin a good run in of the cam bearings.

Real picky motor guys will change them if the motor does not fire up n run right enough the first time. They will go ahead n get it tuned but quickly dismantle the motor and put in fresh bearing to run it in again..

ljnowell

Its not the cam bearings that are the problem, its the flat tappet camshaft itself. It requires a 2000-2500 alternating break in period.

FbodTrek

Sounds like a combination to me. Timing will be one of the major things, followed by what sounds like a vaccumn leak. If not a vaccumn leak, you probably just have a bad miss.

The_Wraith

EGR TUBE cracked?

BushyTea

Well found a really stupid mistake and the plugs were gaped at .35. Fixed that and car starts up fast and runs smooth enough to time.

Only small prob now is while it idles it kind of surges. Never really tries to die just idles up and down.

I did put new plugs and rotor at the moment.

ljnowell

um, plugs are supposed to be gapped at 35.

BushyTea

Went to Autozone to get the new plugs, shows to gap at 0.45. Even on their online web store.

I have a chilton that says the same. Ran like crap gapped at 0.35 now runs extremely better. Huge improvment.

ljnowell

I would call that extremely odd, maybe there is something in your equipment that makes it run better that way, but .035 is the right gap.

ljnowell

Sorry, I just saw that you were running a 3.1!

BushyTea

It's cool, wish it was a V8. This little V6 has given me nothing but problem from the get go.

It's like it doesnt want to be rebuilt or something. I have done many other engine rebuilds and they all run perfectly fine and still going after years since the rebuilds but this 3.1 just doesn't seem to wanna be fixed.

I just can't figure out why it runs rough. At idle , throttle just whenever it is never smooth but it won't die either.

Gumby

DO you have a good coil???

Should run an accell or other aftermerket coil.

Also a good idea to move it out of the heat zone.

I actually carry a new spare just cause it was free.

BushyTea

Yeah, the coil really isnt very old. Replaced it right before the engine went out.

I just replaced the pcv valve and O2 sensor and still the same thing. Just does not want to smooth out at all.

Gumby

Might need to just get it running well enough and then go out n beat on it for a while. Blow the cob webs out of the motor

BushyTea

Yeah, I also thought of that because everything I check seems fine so all i can think is stuff just needs to get working again.

It sat for about a year before I got around to building the motor and putting it back in.

Gumby

Yep that seams to help when cars has sat for a while. blow out an mice that made a home in your muffler.

BushyTea

I run it but it just sits and goes up and down in rpms and I recheck the timing and go to adjust it and when I get close to 10 or 11 degrees it struggles.

The plugs are black and it blows black stuff all over anything behind the car. Have 2 black streaks in all the places I have started it and ran it.

Gumby

the up n down rpms is normal, they all do it till warm. The 02 sensor gets no signal so the computer is on loop mode.

Mine does it though I wont let it. I hold the rpms at 2000+ for a few mins and then leave. If not it would idle up n down from 1500-1000 for 4-5 mins till warm.

the 3rd gen computer is mighty dumb. set the timing where it should and drive it.

85berlinetta2.8

3.1is gapped at .45 and 2.8 is .35?

hmm maybe thats part of my running rich and rough idle problem?

im pretty sure i gapped my 2.8's plugs at .45

BushyTea

Well update, No good news really. Car still runs but over a few minutes slowly makes it way to dying no matter how much you turn the dist. Eventually you can turn no more and the motor just slowly get rougher and eventually dies.

I am maybe starting to think it could be a fuel problem. The fuel pump was only a few months old when parked but over time could he fuel have cloged it up or maybe even the filter.

Just ideas, I know I am running out of them.

85berlinetta2.8

ecu? fuel pressure? spark wires test good? firing order right? rotor button on good?

85berlinetta2.8

cat? tps? maf? err map? sorry

iac?

BushyTea

Yeah, i am starting to check some of the sensors as that seems all that is left.

It seems to start up just fine even alittle better since I exchanged my plug wires for new ones. Still runs for a min. then slowly makes its way to dying. I can keep turning the distributor and gain alittle more idle but again, slowly after a min or so it bogs and dies.

BushyTea

**Update**

Added new cap, and wires. Had coil checked and it is still good and I replaced the fuel filter just for kicks. Checked to make sure it wasn't 180 out but seems to be fine.

After replacing and checking all these things the car won't even start. It turns over fine and even has a sputter like its about to start about every couple seconds.

Gumby

Timing chain????

85berlinetta2.8

check firing order

put the ignition to the on position for a few minutes to see if the car is building pressure then try and start

Doward

#1 cylinder is on the passanger side, front, btw.

Firing order is 1-2-3-4-5-6

TomP

Don't worry, both 3.1 and 2.8 are 0.045 gap. I think that guy was giving out V8 spec.

Was a new balancer put on the motor? If not, check the balancer for slippage, bring #1 up to top dead center (remember what Doward said, #1 for 2.8/3.1/3.4 is front passenger side cylinder) of compression stroke, and make sure the mark in the balancer lines up with 0 degrees on the timing tab. Make sure you've got the compression stroke.

What cylinder were you setting timing with?

Oh and the "distributor being off a tooth" is the same thing as twisting the distributor a bit with it still in the motor. No need to remove/reinstall the distributor! The only reason you'd have to remove/reinstall the distributor is if you can't twist the distributor housing any more b/c the spark module connectors hit the engine.

Try starting "fresh" with timing.

1. Remove spark coil wire. Disconnect the tan/black EST bypass connector by the heater blower motor. Remove #1 spark plug.

2. Bring #1 up to tdc of compression stroke. Put a cotton rag (not paper towel) in spark plug hole, or put your finger over the plug hole. Turn motor clockwise with a breaker bar until the rag blows out or until you feel pressure against your finger. Put a phillips head screwdriver straight into the spark plug hole and slowly turn the motor clockwise. As soon as the screwdriver stops raising up, that's TDC. Make sure the balancer mark lines up with 0 degrees on the timing tab. If it Doesn't, go get a new balancer!!

3. Pull the dist cap. Spin the distributor body so the rotor will point to the #1 cylinder's cap terminal. (Obviously you'll have to keep putting the dist cap back on and taking it off to estimate the position.) This will set the timing to 0 degrees BTC. The motor won't run like this.

4. Slip the dist cap back on and twist the distributor cap counter-clockwise a bit. Remove the cap, check to see that you turned the dist body enough so the rotor is now going to point between the #1 and #2 cap terminal. (Wires go clockwise around the dist cap.) The rotor should be about 1/4 inch past the #1 terminal, heading towards the #2 terminal.

5. Since the balancer points to zero degrees, and you've spun the cap so the rotor points betwen 1 and 2, this means that the spark has already fired for the #1 cylinder. We're guessing at 10 degrees advance by doing this. Like I said, the motor won't start at 0 degrees.

6. Make the hold-down bolt a little snug, bolt the cap on, put the #1 plug back in and reconnect it's plug wire, reconnect the spark coil wire, and try to start the motor. If it doesn't go, stop cranking the motor. Turn the cap a little more counter-clockwise. Then try cranking the motor again. (DO NOT spin the cap while a friend cranks the motor!! I got a HELL of a shock that way; it threw me backwards off the car. I'm so glad it was just a stock spark coil!!) As soon as the motor starts up, throw your timing light on it and set the timing. You should be able to get it to 10 degrees advanced.

BushyTea

Thanks for the advice guys. It's all been a great help so far.

Just wondering if a V6 cam gear and crank gear dots should be lined directly up and 12 and 6 or if they should both be at 12. I have searched the forum but get different answers.

I have been told about my timing chain and the dots on the crank pully and cam pully. I set them right as far as my manual shows me. The manual says the crank pully dot and the cam pully dot should both be pointed at 12 o'clock for #1 at TDC. If you point the crank dot up and cam dot down thats #4 at TDC. So I wouldn't think that is the problem.

x55Cam

I just happened to stumble on this topic and read about the problem that I once experienced also ( idle jumping up and down)
or oscillating. It wound up being that the throttle body idle setting
was too high and had to be readjusted a bit lower. Since the ECM
is trying to compensate using the TPS as reference, it will readjust
to no avail since the idle is set to high.

Just a thought on some other possible cause.

BushyTea

Well, old thread but had somethings come up and just got back around to trying to find the mystery problem with the v6.

Unfortunatly still no luck. Starting to feel like trashing the v6 as it just seems easier at this point. lol