New stroker running very rough help please

[knever3]

So I drove it to work the other day and my oil pressure scares me. How much oil pressure should you have on a fresh rebuild? I am getting 40psi cold start and 19psi warm idle, 2500rpm looks like 22psi. 5w30 oil with comp break in additive.

From every other healthy 4.0 I've owned this is considered low. I still have problems with overdrive/torque converter lockup. I will look at my TPS again before driving it.

Any help with the oil pressure would be great, I've contacted the machine shop and I need to report back.

[SilverXJ]

19psi isn't bad, but I would expect a bit more from a rebuild. Just keep an eye on it. I also would put a mechanical gauge on and see what it says.

[knever3]

That's what I intend to do tonight if things work out. I NEED TO KNOW!

[knever3]

Ok a sigh of relief! I put my mechanical gauge on it last night and my gauge in the cluster is way off and not accurate. At startup I have 62psi, warm idle 35psi, 2500rpm warm 50psi. Whew!! Now I just need to find out why my transmission is shifting so crazy and my idle is erratic and high.

I need to search the forum to see what kind of numbers are good for the A/F ratio. This morning and last night I started it and it was at 9.9, running VERY rich. When I drive usually it runs at 12.5 but the other night it was at 14.4 while driving a short distance. I really need to spend some time dialing everything in and checking all my sensors.

[knever3]

So...


An update and advice needed for tomorrow guys.

I took my truck to the shop that had it built and he said it was probably the flexplate and I already checked that. I had the flexplate magnafluxed and it was fine (like I thought). So I removed the motor and took it to the shop again. He said give me a couple of days to take it apart and I will get back to you. A month later I called him and he said he drained the oil and saved the filter. Removed the pan and noticed that #1 and #6 piston skirts were badly scored. So it's back at the machine shop again.

I would like to check on the machine shop to enquire about a few things. If you recall I took them a '96 block, they tipped it over torquing the head bolts and broke it. Well they decided to take it upon themselves to source me a different block and not tell me until I came to pick up the engine. They gave me a '94 block and I was steaming mad! I purposly chose the '96 for it's strength and lower NVH for the stroker. Anyway these are my questions guys

What should I ask the machine shop when I get there?

Should I really be worried about the '94 block and should I have a main girdle since the '96 had one?

This should be covered by the shop's verbal warranty he told me it would be right so what should I do if it isn't?


I am so stressed about this whole scenario I cannot bring it to words. Hopefully this will all turn out OK and I will be happy when it's all over, but deep down I know it's going to be a mess!!

[Cheromaniac]

Should I really be worried about the '94 block and should I have a main girdle since the '96 had one?

The 4.0L block had a 9-year production run without the girdle and those engines could still last 1/2 a million miles, so I wouldn't worry about that.

This should be covered by the shop's verbal warranty he told me it would be right so what should I do if it isn't?

Put boot to asses!

I am so stressed about this whole scenario I cannot bring it to words. Hopefully this will all turn out OK and I will be happy when it's all over, but deep down I know it's going to be a mess!!

Don't lose faith but if the engine doesn't turn out OK, social media is a powerful tool for spreading bad publicity about the shop so you could use that as a threat to twist their arms.

[nicpaige]

Just a suggestion, I have been in your same situation and my recommendation when dealing with your builder is to remain calm but assertive with your facts straight. Going berserk usually just gets you ignored. Hopefully he does you right, if not then its on to plan "B".

[knever3]

Well no update since I took your advice and kept my cool and didn't go to the machine shop to poke around. It was very difficult not to go to see how the engine was doing. I really didn't know if the engine was going to be apart or just in the corner somewhere and since the shop was just over an hour away I didn't want to take the chance being home with the family. So I decided to sit home and wait for the phone call from the shop I took it to that he promissed. Thursday and Friday has came and went and no phone call. Par from the course, no communication until I call.

I'll let you know what happens from here on, I will be working all this week so I will wait until Friday to call if he doesn't. I have a hard time not saying "You know, you told me you were going to call me last Friday!" He has changed his attitude 180 degrees since I picked up the engine, go figure. At least he's consistant with respect to communication, NONE!

[knever3]

The engine guy called today.

The word he got from the machine shop was either of three things.

1.) Bad quality (low octane) fuel
2.) Wrong timing causing pre-ignition or bad knock sensor
3.) Bad injectors or fuel delivery

So they ordered replacement pistons for #1 and #6 and they are going to hone the cylinder liners and re-assemble.

Since I already have a wideband O2 monitor I have these questions for you.

I have the Renix system so I don't know how to make sure the knock sensor is doing it's job if at all!
Would you keep the Renix system?
If I do indeed upgrade to OBD1 I would need everything from a newer Cherokee including engine harness, computer, fuel pump and sending unit, gauge cluster and while I am at it newer Aw4 and Tcase for the electric speedo.

That seems like a lot of work and money for what's it worth, but if it gives me an easier way to keep tabs on the engine I'm willing to do the work.

What should I do?

Since you all may not know exactly what I am dealing with here's my build.

http://comancheclub.com/topic/16711-fir ... estoration

[knever3]

Well Well,

This just took a turn for the worse I didn't expect. The guy called today and said my short block was back together and it should be done by Friday. Then he dropped the bomb, he said because it was fuel system or engine management related to the failure that I would need to pay $1,300 to get the motor back!!!

He failed to mention ANY money involved only two days prior!!! He said he would take care of me when he listened to the truck before I pulled the motor out, he gave me his word he would make it right. Yeah by charging me!!

I am totally about done with this, he burned his bridges with me a long time ago. What a jerk.

Where do I go from here?