stranded - engine starts but bucks and stalls out

[eaglescout526]

Yeah not seeing that idle screw in the ISA doesn’t help the idle much. If anything that makes the throttle very much if not closed all the way. 

[luckycamper]

10 minutes ago, eaglescout526 said:

Yeah not seeing that idle screw in the ISA doesn’t help the idle much. If anything that makes the throttle very much if not closed all the way. 

 

wow, I can’t believe it’s been running w/o that screw the whole time! I wish I had a couple pictures of what the engine bay is supposed to look like, to compare.

 

Battery light has been on for over a month. I’ve been refreshing the grounds to try and get to the bottom of it but so far no change. Has still been driving fine and the alternator and battery are putting out just fine when I test.

 

Any idea what size screw that is? or how to find out? Perhaps i could pick it up at a hardware store

[eaglescout526]

I honestly have no clue about the screw actually. Screw doesn’t show to be serviceable in the catalog at all so it is unknown to me. All I can say is it’s a fine thread screw with a domed hex head on it for the throttle plate. Crown has new ISAs but I’m not sure if their screw is the same as the original. But yeah that screw keeps the throttle plate open slightly to allow a nice smooth idle. 
 

Have you cleaned the actual positive cables? Just because grounds have been cleaned doesn’t mean the power side is corrosion free. 

[luckycamper]

32 minutes ago, eaglescout526 said:

I honestly have no clue about the screw actually. Screw doesn’t show to be serviceable in the catalog at all so it is unknown to me. All I can say is it’s a fine thread screw with a domed hex head on it for the throttle plate. Crown has new ISAs but I’m not sure if their screw is the same as the original. But yeah that screw keeps the throttle plate open slightly to allow a nice smooth idle. 
 

Have you cleaned the actual positive cables? Just because grounds have been cleaned doesn’t mean the power side is corrosion free. 

have not cleaned the positive cables yet but i plan too. 

[eaglescout526]

Definitely give ‘em a clean and see if there’s any improvement. 

[luckycamper]

There’s smoke coming out from below the manifold so a leaky gasket or cracked manifold has entered into the realm of possibilities. Is there a way to verify this before I tear everything apart? 

 

-coolant and oil seem fine

10 minutes ago, eaglescout526 said:

Definitely give ‘em a clean and see if there’s any improvement. 

will do

[howeitsdone]

I agree with eagle, vacuum leak for sure, plus IAC. Possibly sounds like an exhaust leak, hard to tell from a video if it's down-pipe. But the vacuum (or lack of) would cause your engine to try and keep up like it is. If you've got it, and are comfortable, using a propane torch is a great way to see where the leak is coming from (NOT lit) with the torch set on low.

[eaglescout526]

Without doing the above idea, just basically taking a good look around to see what you find. Is the smoke blueish? If it is it’s oil burning from a leaking gasket.  If it’s another color it could be anything then. I’ll have to take a pic of a cracked 2.5L exhaust manifold I have. I think those manifolds rarely crack. Unless someone else has more experience. 

[luckycamper]

hey guys, thanks for the tips. Just got home from work and will try some things in the morning. I don’t have a way to legit test vacuum rn but maybe I could get my hands on something or squirt some carb cleaner around. I’ll try to do a more thorough check tomorrow of the vacuum lines tomorrow but truth be told, there are things just hanging disconnected since I bought it and even w the diagram it’s not easy to make sense of. I’ll also try to go through more of the electrical and see what turns up. 

 

8 hours ago, eaglescout526 said:

Without doing the above idea, just basically taking a good look around to see what you find. Is the smoke blueish? If it is it’s oil burning from a leaking gasket.  If it’s another color it could be anything then. I’ll have to take a pic of a cracked 2.5L exhaust manifold I have. I think those manifolds rarely crack. Unless someone else has more experience. 

 

the smoke coming up from under the manifold still concerns me but I’ll try to hunt down any vacuum leaks over the nxt couple days and report back

[Manche757]

Might the catalytic converter or muffler be filled with rust that collapsed and block the exhaust? I went through that soon after buying a MJ

[luckycamper]

On 10/19/2021 at 5:30 AM, Manche757 said:

Might the catalytic converter or muffler be filled with rust that collapsed and block the exhaust? I went through that soon after buying a MJ

pipe is broken off right after the muffler and its hollowed out. I also thought maybe the cat is toast though I knock on it and don’t hear anything rattling around. Still a possibility…I might pull it out and take a look but it’s so rusted i’m afraid it’ll fall apart. (wasn’t planning on addressing it until i do an engine swap nxt spring)

[luckycamper]

On 10/18/2021 at 3:37 PM, eaglescout526 said:

Without doing the above idea, just basically taking a good look around to see what you find. Is the smoke blueish? If it is it’s oil burning from a leaking gasket.  If it’s another color it could be anything then. I’ll have to take a pic of a cracked 2.5L exhaust manifold I have. I think those manifolds rarely crack. Unless someone else has more experience. 

 

I checked out the positives and everything looks fine (unless there is something I missed). I’ve gone through the vacuum lines and nothing seems to be causing such a dramatic effect. I have not checked the canister, possibly I can get to it tomorrow. With that said, the diagram on my truck doesn’t exactly seem to match what I’m looking at. Idk if po did a bunch of deletes or just forgot to reattach hoses. It would be immense help if I had a few pictures of a clean detailed picture of the 2.5 engine bay to cross reference. 

[fiatslug87]

@eaglescout526

 

 Bueller, Bueller

[luckycamper]

Thoughts so far: 

 

-The day before the engine suddenly went mad, I did an oil change regular ol’ 10w30 and added some 4cylinder Restore additive (which I’ve used on i6’s before w good results). A little research uncovered that sometimes, albeit rare, it can mess w the sensors. It’s a shot in the dark for sure but I have extra oil so I’ll prob do a change tomorrow. 

 

-I’ve been leaning toward mechanical failure over vacuum leak bc of the abrupt change in performance but even though I went through pulling hoses, spraying around joint fittings and cluttered areas, etc., I do not have access to the correct tools to properly address this possibility. I assume there are leaks, due to the evidence of the previous owners work, I just don’t know if something small I missed would potentially be enough to cause such drastic effects.

 

-It’s loud like an exhaust leak so I fear a leak in the exhaust manifold bc it seems like hell to replace. I tightened down the bolts on top but the rest seem inaccessible w/o tearing the whole intake, throttle body apart. 

 

-No blue smoke. No grey smoke. Coolant is good.

 

-Can smell it’s running rich.

 

-Only starts if I continuously pump the gas and keep it at high idle once started. It shakes violently and erratically. And stalls if it’s not getting gas. Though once warmed up it will idle low for a min before eventually stalling.

 

-The screw to the isa was missing but I found one of the correct thread. The screw does not seem to affect the current performance of the engine in it’s current state.

 

If anyone has any recommendation on what nxt step makes the most sense I’m all ears. Rn I am leaning toward a fuel/air situation causing misfire, etc. with the symptoms I’ve described. Could be a sensor issue. Could be vacuum. Kind of at a loss rn. Might get to borrow a fuel pressure gage soon so I could officially rule that out…hope to get it running soon bc it’s cold and rainy where I am and it’s not my favorite bike ride to work lol.

 

 

[howeitsdone]

An easy misfire/no spark test is to remove and re-install a plug from the distributor cap or block one-by-one when running. If the performance stays the same, then that plug is good. If it does change, then you've got an issue somewhere between the spark plug and distributor usually. Else, it's something internal or fuel related. But can still help to narrow down a particular cylinder if that's your issue. Sounds like you may need a 2nd person for that since it won't stay running.

 

 

[eaglescout526]

1 hour ago, luckycamper said:

It would be immense help if I had a few pictures of a clean detailed picture of the 2.5 engine bay to cross reference

I’ll get you some pics. I was working on an 86 this evening actually to get it back up and running to conquer the roads

 

1 hour ago, fiatslug87 said:

@eaglescout526

 

 Bueller, Bueller

Lol was working on an 86 and had some other things this evening. 
 

1 hour ago, luckycamper said:

The screw to the isa was missing but I found one of the correct thread. The screw does not seem to affect the current performance of the engine in it’s current state.

I am currently rebuilding one. The last two prongs on the ISA are the motor, put power and ground to each one and see if it does anything. If not, it will need to come apart for a possible rebuild. 
 

But the screw for the ISA does absolutely help, just the ISA internal motor has to be working in conjunction. So if it isn’t properly adjusted it’ll either run rough or run way to high of RPM. 
 

 

[eaglescout526]

 

 

Let me know what other pics you need. These pics are mostly of the vac system and I can make sense of it better than the diagram does.

[luckycamper]

21 hours ago, PocketsEmptied said:

An easy misfire/no spark test is to remove and re-install a plug from the distributor cap or block one-by-one when running. If the performance stays the same, then that plug is good. If it does change, then you've got an issue somewhere between the spark plug and distributor usually. Else, it's something internal or fuel related. But can still help to narrow down a particular cylinder if that's your issue. Sounds like you may need a 2nd person for that since it won't stay running.

 

 

will do thanks!

[luckycamper]

@eaglescout526 thx man, these pix are a big help. There is def some discrepancies in comparison to my truck. I’ll thoroughly go through the lines again and cross reference these pix tomorrow but right off the bat; the pvc valve doesn’t go directly to my airbox, there is a canister thing on the pvc air in, the two ports on the head of the tbi cover are open, the airbox has no hoses beside whats pictured inside/out, the hose I’m holding in the last picture was just sitting loose in my airbox when I first popped it open…

 

 

[eaglescout526]

Ah yes 1986. Such an odd animal. I should be able to still help.

[JimB]

My 86 2.5 did the same thing. Found that one of the fuel injector wires was grounding intermittently and it would cause the injector to pump to much gas and flood the engine. Pedal to the floor and crank and sometimes it would start and make it home. I found it by looking into the throttle body with the key in the on position. (not running)

And it was spraying fuel. Pulled back the wire loom and found the bare wire. 

[luckycamper]

6 hours ago, JimB said:

My 86 2.5 did the same thing. Found that one of the fuel injector wires was grounding intermittently and it would cause the injector to pump to much gas and flood the engine. Pedal to the floor and crank and sometimes it would start and make it home. I found it by looking into the throttle body with the key in the on position. (not running)

And it was spraying fuel. Pulled back the wire loom and found the bare wire. 

interesting i will give that a look! 

[luckycamper]

update:

Took a few days to finally get to the bottom of this. No compression on cylinders 2 and 4. Only 50 on the other two. Not good news but closer to figuring this out. Tomorrow me and my buddy are going to open it up a bit more, chk the timing chain etc. Saying my prayers tonight.

[eaglescout526]

Wonder if the head has ever been serviced. 

[Pete M]

time to pull the head for inspection    with any luck it's just the gasket.