2.3L ('83-'97) 1990 2.3 Odd Misfire Issues - New Engine

[Mr4btTahoe]

Update... oil made no difference.

On the suggestion of another.... I did a dollar bill test. Held a piece of paper up the the exhaust.. while it's running smooth, it's constantly blowing outward. When it's misfiring, it'll suck the paper into the pipe (nearly out of my hand) which typically indicates an exhaust valve issue. Exhaust valve or valves aren't sealing and the exhaust will be pulled back in.

Yay.

Called the parts house and they are going to find out what the manufacturer is going to do. We'll see.

 

[Mr4btTahoe]

Update...

So finally got a hold of the manufacturer of the engine (LKQ btw is who remans ALL of the engines for the parts stores such as o'reillys, autozone, etc).

They agreed that it appeared to be a valve train issue. First they had me replace lifters... no change.

They are now sending me a cylinder head which is apparently 2-3 weeks out at best.

Another interesting bit... thankfully I have an LLC otherwise they were NOT going to warrant labor on any of it. They have not been fun dealing with.

I'm going to be posting videos on all of this on my YT channel when it's all done and I'll post the links here when they are up.

Thanks again for the input.

 

[Shran]

What type of lifters did you use for replacements?

Bummer that they are hard to deal with. Customer service has just gone away completely. Build junk, take no responsibility for it seems to be the MO.

 

[Mr4btTahoe]

What type of lifters did you use for replacements?

Bummer that they are hard to deal with. Customer service has just gone away completely. Build junk, take no responsibility for it seems to be the MO.

I had a set from Sealed Power sitting here so thats what I threw in it. I'm pretty certain it's a valve height issue (poor machine work) so I wanted them to replace the head anyways... that way I can measure it up before doing the work. We'll see. They say its going to be 2-3 weeks to get the head in.

 

[Shran]

@Mr4btTahoe any updates on this?

 

[Mr4btTahoe]

Sorry for the long wait.... they ended up sending a long block because they couldn't get a cylinder head.... and it took this long to get one. Just got it swapped in and running decent. Sent the original new one back Monday and now just waiting on reimbursement for the labor. Thankfully I've got an LLC or they wouldn't cover any of the labor or what have you.

I'm putting together videos on the whole ordeal so I'll post those here when it's all done.

 

[Mr4btTahoe]

And here we go... the whole drawn out process. Lol. Since the videos, I've replaced the exhaust system and ECU (to fix a weird CEL issue that wouldn't pull codes but kept the light dimly lit). It's running decent. Still does the weird cold stumble if revved up over 2200rpm or so ... but it goes away almost instantly and doesn't stall. The owner of the truck is going to put miles on it and see what happens.

 

[Shran]

Wow, what a bummer. Glad to hear you found a fix for it. I will be curious to see what they find wrong with the first one. Hopefully they will let you know... sounds like their customer service is pretty terrible.