Hello folks,

I am new to the forum, thank you everyone for coming together to create a supportive community! Before you continue reading, thank you in advance for any words of wisdom you may share.

I just bought a manual 2002 B3000 with 153k on the clock. It has a rough idle when warm. When it cold starts it feels fairly normal, once it warms up it feels like a cammed V8 or something. Warm it idles around 700 RPM. When I checked it out I figured it was either bad ignition or a vacuum leak, and that I would get a decent deal on a somewhat simple inexpensive fix. Guy wasn't really mechanically inclined, he fixed the broken driver seat recliner bolts by proping the back up with a piece of wood fencing, I decided I would fix this by inserting a larger metal rod with a cotter pin (as Ford should have done in the first place, damn those were a pain to get out).

I went to a parts shop and had them run their OBD2 scan and it uncovered the P0302 and P0306 codes. I pulled the plug from cylinder 2 and it looked old, but not bad. It was a light brown/tan maybe it looked a little lean, but mostly normal. First I cleaned the MAF, and the IAC to see if that would help; not much difference (if any) there. I looked for vacuum leaks and only found one very minor leak (also no difference when fixed), but I am going to check again since I know they can be illusive. Just discovered the unplug the IAC method for testing for vacuum leaks, I will try this later today and report back. I pulled the PCV valve and did the rattle check, it did rattle so I cleaned the area as well as the PCV and reinserted it until the replacement shows up. There was however some oil in the line (not sure if that is normal). I replaced the coil pack, and the wires (plugs are still in the mail, will be here Thursday). The truck started much more readily (seemed like first crank), but that still did not solve the problem. Since I was replacing ignition components I reset the PCM, as I understand the learned fuel trims can bugger things up. I disconnected the negative terminal and jumped it to the positive terminal for about 15 minutes. Once reconnected let it idle for about 15 minutes (up to temp), turned the AC on for about a minute, switched the AC off and just ran the fan for about a minute. I then drove around fairly gently for about 15-20 turned turned the fan on for a while and then the AC. Rough idle continues, although sometimes I would pull up to a stop sign and it would feel fine, and others it would feel like the cammed V8 again. Above about 1300 RPM the vibration goes away and it feels what I would imagine is normal (though in the back of my head I know something isn't right). It didn't seem like the truck was gutless, I could accelerate up about a 15-20 degree incline in second gear around 1500 RPM without trouble (although I wasn't romping on it so that may have been all it had). I listened to the fuel injectors for cylinder 1, 2, and 3 and they all had about the same intensity and tone of rythmic tick, (I also previously metered them to read 11.1 ohms). I bought an OBD2 scanner, when I monitored the fuel trims (through the torque app) I found that [following their reporting scheme (bank) x (sensor)] 1x1 jogged a little but stayed within about +/-5, same with 2x1 but I saw it jump to +13 once. The odd part is 1x2 went to -100.8 along with 2x2 and 2x3 after about 10 minutes of idling, 1x3 never changed from zero the entire 30-40 minute run time. There is also a 2x4, which made no sense to me since it is a V6 (it also stayed at zero), and I don't think a V7 exists unless we are talking about a missing V8. Boost, which I assume is actually vacuum was at about -9.5 PSI at idle, I didn't really watch it while I was driving.The updraft O2 sensors bounced around between 0.7 and 0.1 volts very frequently, and I saw one of them read zero once. The intake air temp measured about 46 F sitting in my driveway. It was a cool day, but I think it was probably closer to 50-60 outside (with wind chill that makes sense). When I got back I tried pulling the dipstick since I heard that can cause a rough idle, nothing changed. There is a very faint smell of gas in the oil, which could be excessive blow-by or a failed open fuel injector (to my knowledge). Oil could also be old, there was no coolant in the oil or oil in the coolant. I didn't think failed open injectors would tick, but I have been wrong before. I have also never had to diagnose faulty fuel injectors. I can't get to injectors 4, 5, and 6 without removing the intake manifold to listen to them. At the end of my testing there was no CEL and I also checked for pending codes of wich there were none.

I think my biggest concern at this point is that the valve stem retainers have shifted (I have read these motors are prone to this), but I figured if that were the case it would have some backfires through the intake and it would run much worse than this. I have read the two wire temp sensor can cause idle issues when failing, but stupidly I did not monitor the reporting coolant temp from the OBD2 port. The bolt which stops the throttle plate doesn't appear to have been adjusted so I don't want to mess with that since it could easily be at the correct setting and I would only exacerbate the issue. I am thinking about seafoaming intake, fuel and crank case just to clean it out, but I will have to find a shop that will let me since I am not comfortable smoking out my neighbors (they'd probably call the fire department).

I am not hearing the tell tale squeal of the cam position synchronizer, but I purchased a replacement regardless since it also provides oiling, and since I don't know when it was last replaced (if ever) I really don't want to deal with an oil starved block (I may have heard one squeak but it could have also been the belt). I have read that this can cause an rough idle when it is on its way out, but only replacing it will tell if that is my issue (I kinda doubt it at this point). Monday I will be able to run a compression test to get some more information. I also purchased a replacement PCV, and fuel filter since they are both cheap, those will be here Monday as well.

If you have any questions for me, or tests you would like me to run I will follow up. I really want to give this truck a good life and another 100k+ miles. Thank you for your time, for reading all of that information, and any information you might have to help my truck!

 

The 1995 and up 3.0l Vulcan uses Waste spark and a 3 Coil Pack
These cylinders share the same coil in a 3 coil pack
1/5
2/6
3/4

This is why the firing order on the coil pack is the way it is

So 2/6 had misfires
That should point you at spark plug wires or the Coil pack or the Computer itself
Having 2 fuel injectors fail at the same time would be hard to justify

2004-2006 3.0l Ranger engines did have the "recessed Valve seat" issue, but that would be unlikely in 2002, possible but unlikely
And since 2 and 6 are on opposite sides of the engine vacuum leak would not be the issue
Or MAF or PCV or any common system, since it did set specific cylinder codes, not P0300(Random/Multiple Cylinder Misfire Detected) or P0316(random misfire has been detected on startup )
You can remove all spark plugs and then do a compression test on each cylinder, that will tell you if there is a valve issue.

Since you did change coil pack and spark plug wires on 2/6 then that only leaves the computer, so the wire for #2 coil to computer may be an issue or computer circuit itself, but........................

The Crank sensor should be looked at first, front of engine near crank pulley, behind the crank pulley will be what "looks like" a gear, its a Tone Ring, the crank sensor reads each 'tooth' on that ring, and there is one missing "tooth" that tells computer when #1(or #5) is at TDC
Computer times spark using that Tone Ring
So make sure it is in good condition, no debris/mud in between teeth
Do NOT change this sensor, if it fails you will have a no start, and thats not what you have

Cam Position Sensor(CPS), this was added for better sequential fuel injection, it turns at half the speed of crank so has better "resolution" of engine's position on each stroke
But some software uses CPS to adjust spark timing, so trumps Crank Sensor after startup, this is year by year, you can unplug the CPS and then start engine, if it starts and dies or won't start then your year does have software that set CPS as main spark and injector timing, so it could effect spark, and 2/6 fuel injectors
But long shot since 2 and 6 on the CPS are 180deg apart


On the coil pack are 4 wires, RED one will have 12volt when key is on, the other 3 are from computer, they each Ground one coil in the pack to power it up and then CUT the Ground to Fire that one coil.
I would expect a P035x code if one of these wires was an issue, but hard to say

The 3 wires should be
Tan/orange stripe
Tan/white stripe
Tan/green stripe

They should all be Grounds with key on engine off
So from the RED wire to each of those wires you should see Battery Voltage on a volt meter, test battery first, if its 12.6volts then thats what you should see

 

Alright, no vacuum leaks. IAC unplug killed the engine immediately. Crank position sensor looks fine. Also, unplugging the cam synchro it still ran.

I just metered the connector. With the key in the on position I see zero volts across any of the connectors. I can find battery voltage from the red pin to the grounding strap. This hopefully is my problem.

I am going to look up what to do next, but maybe you'll tell me before I can figure it out. Thanks for your help!

 

Afraid of that, you will need to use a test light, on each GROUND wire for the coil pack, and crank the engine over to see if computer is Grounding and unGrounding
each coil, It will flash pretty fast, 3 times a second, so volt meter won't work.

 

Okay, they all flash. Not three times a second but they all do flash.

 

The coil and computer was the only connection for #2 and #6 misfires

I guess compression test next

 

Could it be the PCM causing the problem still? I guess I'm wondering if there could be a connection issue in the harness or PCM that is causing the problem, even if it does flash for each coil.

 

It is, of course, possible for the PCM "driver" for #2 coil to stop working correctly once engine is started.
Wiring issue should have showed up on the test, not as long a flash on the test light or just different from other two wires flashes

If you have an old style timing light you could hook it up to #2 or #6 spark plug wire and then start the engine.
Point it at ??, Strobe should show a steady flash, no missed beats which would be no spark, and you would see it as well as feel/hear it if #2 and #6 misfired

 

Come to think of it, since my problem happens warm the test I ran wouldn't illuminate the issue. I cranked it when cold, so I need to repeat the test with the engine heated up.

Now if the light appears to flash less often, or visibly dimmer, what part would that indicate needs to be changed? I suspect that the harness would be good, but I can't find a pinout of the PCM socket to check the resistance of the line.

Would it be a bad idea to open the PCM and visually inspect for burst capacitors, and burnt or broken solder joints? It could be the case that there is a solder joint on the PCM that expands just a little when the unit comes up to temp and is causing this problem. Now, this is speculation and I could for sure be wrong, but if it were poor compression from something like a leaky headgasket, worn valves, or bad rings, wouldn't it run rough when it was cold too? I guess the only way to know if the compression is bad is to test it, I'll be doing that tomorrow.

Well, something I am considering doing is just buying a refurbished VIN matched PCM for $175. Partially because I only have one key for the truck, and the refurbished one comes with two paired keys that are uncut. From what I have read, Ford/Mazda charges about $150 to pair a new key. So in my mind, why not just buy the whole PCM with keys, and spend another ~$20 to get them cut. I would like to have two sets of keys, and this way it potentially fixes my problem. That said, I also read that a locksmith or shop can sometimes pair a new key for less. I am curious what your thoughts are on this since you very likely have had much more experience with this.

Thanks again for all your help, I really appreciate having the advice of someone with experience and not having to track this down by myself.

 

Almost any locksmith can Clone your working PATS key, or can add a key to your PCM

Coil grounds
Tan/white wire goes to pin 28 on PCM
Tan/orange pin 52
Tan/green pin 78

Fuel injector 2 is white wire to pin 101
Fuel injector 6 is light green/orange pin 99

I would do the cold engine compression test
And then warm engine test if cold engine test didn't show issue with 2 and 6
Testing is free except for the time it takes

The no miss when cold and miss when warm shouldn't be a PCM issue, maybe wire connection, but usually a mechanical issue
Could be lifter is not opening valve enough when oil thins out, might "tick" but might not, this fouls up ignition
Or valve is not seating after it gets hot, lowers compression below 100psi
Most engines have 1/2 the static compression when running, so if you have 150PSI on test then when running that cylinder will have 75psi, when it gets near 50psi running compression it can start to misfire.

But the 2 and the 6 thing still bugs me, lol
They are matched pairs, both are at TDC at the same time, which is why they share a coil in the coil pack
So for those 2 cylinders to both come up as misfires may be random BUT it really seems long odds

I know its a new coil pack but may be test it, Primary OHMs should be the same on all 3, as well as secondary OHMs, same on all 3

 

What do you mean by this? Measure the resistance across which terminals?

 

On the Primary coils from 12v contact to any Ground contact you should see .9 to 1.6ohms test all 3 grounds/coils, they should all be the same, .1-.2 difference at most

Then test OHMs between each coil's 2 spark plug wire connections, should be 9-10,000

short Video here: youtube.com/watch?v=c1zhgsnyZWw

These number look right, and it has a bad coil in the pack as well

Coil packs are like injectors, the OHMs can vary but all should be close to the same, reason for that is that OHM Meters vary and are not all that accurate at ohm this low, lol

 

I have heard that multimeter have a hard time measuring low resistance, so that makes sense. I measured the new and the old coil. The new coil is lower resistance than the old one, but they are both self similar across contacts. So it would seem the old one was also fine.

I am beginning to wonder if it is the O2 sensors. I checked my temp sensor, it gets up to about 195-200 when idling. In my OBD2 scanner app under emissions tests it says oxygen sensor not passed since last DTC reset. It also says the same about the catalyst, evap system, and the O2 sensor heater. It could also be the case that this app doesn't read the Ford OBD2 well. I still haven't gotten the check engine light back since I reset the PCM, I've given it about an hour to an hour and twenty minutes of run time. I replaced the plugs (except cylinder 4 which didn't want to come out and I wasn't about to round it out with my 12pt deep well sockets), still not happy.I also need to run a compression test still. I guess I will take it to a shop and see what they say . Hopefully it's something simple that I missed, but at this point I don't really know where to look aside from the compression test. I'll probably test the compression then check the signal to the ignition coil once it warms up.

 

Shops can do an electronic compression test, or you can with laptop and correct software
Takes about 10 minutes including hook up to ODB2 port, lol, but they charge an hour

This uses the same method the PCM uses to detect misfires
You have the Crank sensor and Cam sensor that shows rotational speed
A good compression cylinder adds XXX speed to the rotational speed
Lower compression adds XX
Misfire adds X

So they run the engine at warm idle and then at say 2,000rpm steady, Laptop software gets the speed and any repeating lower speeds which can show specific cylinders with lower compression
The actual compression is unknown, lol, but it does show a number, which its based on factory compression ratios for that engine not actual compression PSI

Still a valid test for lower compression in a cylinder, but.............while it does monitor spark feedback it can't monitor fuel, so grain of salt that lower speed added is strictly compression issue on this type of test

Gauge in spark plug hole is still the best method in my opinion

 

Sorry for being gone for a while. So I ran the compression test, numbers are pretty bad cylinder 2 is 80 psi and cylinder 6 is 60 psi without oil and 90 with oil. There are some other bad cylinders as well, but they would be fine if 2 and 6 weren't so poor. Shop wants to replace the heads, but the bottom and needs work too, bank 2 has bad rings (not sure why just one bank would have bad rings and not the other). Anyhow, I am debating buying a donor truck that was rear ended, but this puts me in an odd spot.

Since the truck will be registered in California, and it is a Mazda truck, I need to figure out if the DMV will consider it an engine change because I'd be using a Ford donor vehicle. California requires me to visit a BAR referee for engine changes, but not engine replacements. So, I have to do some leg work there.

My alternative would be pull and refresh this engine, buy if I can find a donor vehicle for 700-1500 that gets me back on the road quickly and gives me time to rebuild this engine for the future. Any thoughts on info on what I should do would be appreciated. Thanks for all the help!

 

Would need a compression average to tell you if 80 or 60 are bad

In Calif you can use a 2002 to 2008 3.0l OHV Vulcan engine from a Ranger or B3000
Rule is the "new" engine must be same year or Newer to be allowed
2008 was last year this engine was made/used

But there are no numbers on the engine that denote the year, and if you are doing the swap yourself then no one and I mean no one could tell the difference, from a 1986 3.0l and a 2008 3.0l unless they were on a mission to find out, lol.

For used 3.0ls, you want to avoid used 2004-2006 3.0l Vulcans as they could have bad valve seats
So that leaves 2002/3, and 2007/8 used 3.0l Vulcans, no, you can't use 3.0l duratec, lol

Flex or gas only doesn't matter to you
8th digit in your VIN will be U or V
U is gas only 3.0l Vulcan engine
V is Flex fuel 3.0l Vulcan engine

You will be swapping over your upper and lower intake to the "new" engine, and maybe the oil pan
You do this for the wiring and fuel injectors, oil pan is for 2WD or 4x4 difference

You can also get a rebuilt Long Block engine
A Long block will be a complete engine with heads and valve train in place, usually includes oil pump, but not always
You would used all your bolt on parts, i.e. front engine cover and water pump, oil pan, valve covers, intake and exhaust manifolds

 

Here are the compression test results.

Numbers are all over the place. Some of it is top end, some of it is bottom end. Cylinder 1 looks good though hahaha.

The shop I took it to tested only cylinder 6 and said it needed to new heads. They pulled out wires to determine cylinder 6 was a dead misfire. Although head work would probably get it running much better, it needs more than new heads to make it right in my opinion, and I'm glad I didn't just blindly trust them.

When I get the chance to pull the heads I'll test the valves. Hopefully the heads aren't cracked, although since all of bank 2 is low it could just be a head gasket on that side. Cylinder 2 on the other hand probably is a valve.

How possible do you think it is that I could lap the valves and replace any that are bent and save myself from getting more serious head work done?

Judging by the increase in compression on bank two when wet, the rings aren't to happy. I think currently my plan is pull the heads, try and restore the valve seats, put it back together and run engine restore in the crank case to try and bring the bottom end compression back up. Should I go that route or just find the donor truck and pull the engine?

As for the comment you made about not being able to tell the difference between the Ford and "Mazda" engine, the Vin would still tip off the DMV or the smog inspector if they saw it right?

Is there another engine that is a good easy replacement for this truck? I heard the Taurus had a motor that was easily swapped and better, but you're probably more well versed in these than anything iveI heard.

Edit: To be real, my dream would be to put a 2UZ-FE in it, but mating the 2UZ-FE to a manual transmission is somewhat difficult. Then I'd also have to convert the dash to read the Toyota ECU which would be doable but not the easiest.

 

Looks like valve issues to me not rings, if its rings the low cylinders would come up close to the 150-160 mark
You should do the WET test on "good" cylinders as well, so you can see what the rings in a "good" cylinder are losing not just on the low cylinders
WET test should always go up in PSI, rings always lose air pressure, even in brand new engine, its a temporary seal at best

I would price out complete 3.0l heads, exhaust valves are likely burnt and leaking, not a head gasket issue
You can do valves and seats yourself and grind them, but I would have them pressure tested first, and check with the shop that does the test, see what they charge for valve job

You can't tell the difference in a VIN U or V engine from looking at it, and same engine is in a Ranger 3.0l or Mazda B3000


2002 Ranger uses analog dash, no computer connections except 1 or 2 warning lights, 2004 and up were interfaced with computer

 

Oh I agree that the top end needs attention first, I just figured a 25-30 PSI difference in the wet test is rings. Looking at cylinder 2 the wet test difference was 5 PSI which seems like the rings are okay, but you're right it's not conclusive only indicative. Could just be the case that that valve will only hold 80 PSI. Could also be the case that the oil is helping the valves seal in some round about way. I'm in the process of moving which is why I bought the truck... Didn't really work as planned but I've changed them accordingly. Once I get settled in at my new place I'll look around. I found complete reman heads for about $250 a piece. My goal was to be cheap and reliable but not fast (the old motto; fast, reliable, cheap, pick two). So my thought is if I can just buy three or four exhaust valves and lap all of them again and get it running right/passing CA smog then I'm golden. At that point though there are probably other things I should service like the timing chain/water pump/oil pump. I don't have an FSM so I need to look into what needs doing before I just do this one job and have to take it all apart again to do another.

My concern with doing the engine swap is more so bureaucratic. I am unsure of California's view on the Mazda/Ford partnership. Even though it is the same engine it's from a different make and the DMV may perceive it as an engine change which requires me to see a BAR referee instead of just getting it smogged. At that point I should just put an Ecoboost or a UZ motor in it and go to town. I know, those swaps are about three to five times the cost. Likely I won't go that route, but I've considered it. Would be pretty slick to have a 2.3L Ecoboost making an extra 100hp and ft•lbs on the original specs plus good fuel economy. Although I'm sure the diff wouldn't be excited about it. I'd also have to find another trans and custom driveshaft. Maybe just find a donor mustang, but again I'd have to make a custom circuit for getting the dash to work, or swap the mustang dash. Doable, but time consuming and not really worth it for this particular truck. Now if it were a clean example with a bad engine I would be much more inclined to make that happen hah.

 

They won't even know you have switched engines, unless you tell them.
You are going to be using your original wiring, and computer.

Your truck won't even know you put in a different engine.

 

I thought there was a VIN on the block that would not match the VIN in the engine bay. I am moving from WA to CA which is why I suspect they will check.

 

There is no "VIN" on any engine or transmission, as long as you use the same model engine you can swap it out
Calif will only check if you have 3.0l OHV(Vulcan) engine, with all emissions devices for that year working properly

All 3.0l Vulcan engines, 1986 to 2008, were assembled at the Ford engine plant in Lima, Ohio
They were used in Fords and Mazdas, no way to tell if a 3.0l Vulcan came from a Ford or Mazda unless its still in the vehicle, only thing you can know for sure is that it was assembled in Lima, Ohio

The blocks and heads have casting numbers, basically its the sand mold design number, seen here: https://therangerstation.com/tech_li...3.0build19.jpg
You would have to disassemble some engine parts to see casting numbers, but it won't tell you the YEAR of the vehicle it was from, or if it was from a Ford or Mazda
It would tell you the first year it was used to make a block, like XF1E block cast was first used in 1999..............but may not be in any 1999 Rangers, may only have been in 2000 and up Rangers
Ford engine assembly plant would use the XF1E blocks until they were all used up and only then use the 2XF1, next casting model, so you could find a XF1E block in a 2004 Ranger, or Mazda

Heads are swapped all the time because engine was overheated and head cracked or warped, so casting numbers on these have even less meaning than block numbers, you could find a E6AE head on a 2008 3.0l, wouldn't be unusual or against any "rules"