97 Ranger 2.3 rebuild nightmare



I recently bought a '97 Ford Ranger from a guy for ‘really cheap’. 44 miles later it developed some rowdy rod knock.

Being hard headed, I decided to rebuild another engine and install it myself. I had zero experience at such things, but figured ‘how hard could this be?’… famous last words.

I finished the rebuild and tried to start it today. Before starting it I:

1) disconnected the coil packs and cranked the motor over a few times.

2) Removed the oil filter

3) Cranked it a few times to confirm that oil was pumping and the pump was primed.

Then I reconnected everything and cranked the ignition. It started but immediately began to make a loud klank/knock sound. My brother (who was in operating the ignition) cut the ignition off as soon as he heard it. Since I only got a second or two of the sound I wasn’t able to locate it or get a good fix on what it really sounded like, aside from it NOT sounding like the rod knock I had before.

A few mins later (maybe 5) we cranked it again and it started again. This time, there was no abnormal noise, but the idle was rough. It idled for a few seconds and then died. We tried again and it didn’t restart.

I am mostly sure that the wiring is correct and that the vacuum lines are properly connected. I have no idea what it could be at this point.

For what its worth, the engine is from a 95 ranger and the ECU in the truck is from a 97.


Any chance this could be a valve lash adjuster rattle? Usually when rebuilding an engine it’s recommended that lifters always be replaced but it’s quite possible to reuse them if there is no pitting, sticking, etc.

I’ve always soaked lifters overnight in clean oil during an engine rebuild as this can eliminate some or all of the air and allow the lifters to pump up much more quickly.
About all I can suggest is try to determine if that rattle sounds like it’s coming from the valve cover. If it is, then the lifters could be at fault.

At that point it’s either remove them and soak them overnight (while making sure oil is being pumped to the valve train) or run it a few minutes to see if they shut up or not.
Hope that helps.


Distributor rotor rotation is clockwise on 2.3 engines. So, usually the firing order ends up being 1243 instead of the correct 1342. Be sure that gets done right.


The noise was only present for that first second or so before my brother killed the ignition. I am guessing it was caused by oil not being everywhere it needed to be? In any case, it did not return when we tried to start it again.

Now it idles rough and then dies.

Pleasedodgevan, it is distributerless. The coil packs are correct per my hayes manual.


I am completely out of my league here - but can you put together an engine & its associated parts built to operate with OBD-I systems on an ECU that runs OBD-II? Isn’t the computer going to be completely confused?

I’m sure a full answer to that could get really long, so no one should feel compelled to write a book about if its only for my benefit. But I just have to wonder…


I think it took a few seconds for the filter to fill before oil was getting to all the necessary places. The oil pump can be operated with a drill to fully prime that engine. But you’re up and running now so keep an eye on the oil pressure and enjoy your successful job. It might outlast a new engine.


“Rebuild” can mean MANY things…What does it mean to IHatemyRanger??

Block bored, new pistons, crank turned? Head rebuilt, new cam and followers? Or something less than that…


He got it running, C-man. He did better than most back yard overhaulers I’ve seen. And I’ll bet you’ve seen some real basket cases yourself. I actually had a man bring me his car with the engine in the trunk in pieces. The rod and main caps were off and mixed and the lifters and push rods were in cans. He wanted it rebuilt for half price because he had done half the work.


Replaced journal bearings, all gaskets, piston rings, checked clearances. I didn’t do anything with the head. The engine I put in was working fine, I just wanted to make sure that the seals, gaskets, rings, and bearings were good while I was there.

It ran, just not well (then it died). I am checking timing and cylinder pressure tomorrow. Anyone want to take bets?


The 95 and 97 engines were the same. Both should be the same OBD level.


But OBD went from I to II between '95 and '96, so the system is not the same. The question isn’t about the engine itself so much as about the whole array of sensors and associated stuff that is hooked up to the computer. The engine guts can easily be the same, but the engine is “managed” by computer, and the '95 and '97 management systems are different.

But I also said that I am beyond things I really understand there - just a thought about the rough running part. Confused ECU/PCM. I could be wrong about that.


Good to know. If everything checks out tomorrow, I will try swapping back to the old wiring harness. The harness that came with the truck (97 harness) had been spliced a few times. The harness that came with the new engine (95 harness) is the one I used. There was one sensor, it looks like a temperature sensor (coming off the radiator hose), that the 95 harness did not have a connector for. Everything else seemed to match up.

I will defiantly look into this, thanks!


A lack of a temperature reading (if that’s what it is) will create havoc - it is one of the pieces of info that the PCM uses to get the air/fuel mix right. Maybe you should try to go to a PCM from a '95? If you’re state requires emissions testing I doubt you’ll ever get through it this way.


Just finished looking it over with a mechanic friend.

Timing is good, compression is good. Huge list of sensors that are out of range or no-signal.

I am willing to bet its the 95 harness to blame. I will pull it off next week (weather is taking a bad turn tonight through the weekend) and install the 97 harness. The harness makes sense because it idles a little rough until it warms up, then it gets really bad and dies.

I have the sensor codes if anyone wants to see them.

Thanks again for the ideas and help, yall are so much more useful than the combined efforts every ford forum that I have found.


Question. The engine is a 95 and the truck is a 97 with the questionable OBD difference.
Did it run fine, other than developing a knock, after you bought it with no CEL on?

A 95 engine is not necessarily a problem if the 97 sensors, intake, or whatnot were changed over when the 95 engine was dropped in. By the previous owner I assume.


When I bought it, the stock motor was installed. I purchased the 95 engine from a junkyard and intended to just replace the major gaskets/seals prior to install. Once I started replacing things, I decided to go ahead a do the rebuild since I was already there.


That’s a loose definition of rebuild. Unless you left something out, all I see is main bearings and rings aside from the gaskets.

Rings without R&Ring the cylinder bores on a junkyard engine with no known history? Dang, that’s a gamble I wouldn’t be willing to take. Even if those cylinders looked perfect, I would check the bores for ecentricity and hone them before investing the time, energy and money in new rings. What were your compression readings? BTW- tight bottoms and loose tops are only good when we’re talking about women ;-D I hope those heads were in good shape!


I honed the cylinders when I put in the new rings. I also checked the block and head to ensure that they were not warped.

I’ll see if I can get the compressions numbers, I didn’t do the test. He just told me they looked good.


The head is the most important part. You ignored it… Plus the technology issue with ECM and sensor differences…Good Luck…


About those heads. When first started with no oil pressure, the lack of pressure on the lifters could have allowed one or more rockers to jump off. They would clatter until pressure had them trapped or getting tossed off. Open that valve cover. If rockers are off they can be re-installed easily. No special tools required.