just got the 4.0 back in the 2002 jag s type and everything is "running"
It was a used engine with 100k and needed valve stem seals on one bank because it was smoking. replaced left head, head gasket and seals and set timing and now am trying to work out the kinks,
have rough idle and stumble at about 1600 RPM or 45 miles per hour.
misfire codes is cylinder 1 and 2 (right bank, not the head I retimed or resealed). took a guess and swapped coils with spairs. no luck.
fuel pressure 55-60 psi so ok
fresh gas
put noid light on injectors and 1 and 2 injectors are firing/working.
swapped injectors off old engine that were working, still get code 301 302
disconnected coils 1 and 2 while engine is running and no change in idle. but CEL could "see" that they were dicsonnected.
I have not checked that coils/wires are getting signal fropm ecu but that is next
anything else I am missing ? I am liooking for an educated guess before my next guess.
I am not a Jag guy but nuts and bolts/ford engines are pretty much the same
thanks for your help

 

Update:

I have been assuming that cylinders 1,2,3,4 are right bank and 5,6,7,8
are left bank for my 2002. However, did it change after model year 2002.5 to
right bank 1,3,5,7 and left bank 2,4,6,8 ??
How do I know what model year I have ? pre-2002.5 or 2002.5 and later ?
Vin number ?

 

more informatiuon

short term fuel trims are rich ( high) on right bank with missfires and normal on left bank
this would lead me to believe lean condition on right bank so it is dumping fuel to compensate
correct ?

 

A 4.0 is pre-2002.5MY.

Much easier to post actual trim values. (One person's "rich" is another's "adding fuel"...)

 

Left bank at 1600 rpm: 4-8
Right bank with misfire: 12-25
I believe that is rich

My guesses;
I used old plugs.
I nicked wire harness installing engine, it was a tight fit, had to drop rack and pinion.
Timing is off ? though I didn't touch that bank and after setting timing , and rotating engine by hand on engine stand, the " flats " on cam were right on the money

How can you check spark at plug?
How can you verify coil is getting signal ?

 

Your problem is a 100K mile 4.0L engine. Have the timing tensioners and chains been changed?

When you had the engine out you should have changed the primary and secondary tensioners along with the chains and slippers. Now it will be much more work!

Stop running the engine until you can inspect them. They may have failed and you may have jumped a tooth on the gears. If you are lucky!
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I inspected the chains, ramps and tensioners and they seemed ok, no cracks, etc
However, I think it is running " tractor like " whick leads me to believe timing is off.
Was trying to save some $$ but we all know that never works.. And yes , swapping chains , etc now is going to be a total PIA !!
Should be able to determine if timing is off with valve covers off and crank pin in place , correct. ??

 

Any words of wisdom on checking primary and secondary before total disassembly ?

 

It is possible to assemble the 4.0 Litre normally-aspirated engine with the VVT unit incorrectly positioned causing the cam advance to be incorrect.

Did you follow procedure outlined in JTIS for assembly of primary chain mechanism?

 

Yes , followed procedure on primary and secondary left bank, did not disrupt right bank timing, left it alone. However, bone yard engine and would not be the first time that I put something back together the way I found it and it was wrong. Looking back, should have reset both banks.
In damage control mode now!
What is best plan of attack. ?

 

Pull right bank valve cover.
Insert crank pin
Follow jtis procedure
Lock everything down?
Am I on track here ?

 

If all other options suggested by other posters have been tried and exhausted, disassembly and reassembly with timing set correctly on both cylinder heads.

 

12-25 is LEAN.

It's adding fuel. Misfires look like lean. (Only way it can measure: O2 sensors. Think about misfires & that!)

So, cure misfires and then look at trims.

You can get a COP tester to check coils. Plugs may be the cause but usually on these cars it's coils. Sometimes it's faulty wiring to coils due to doing work. Of course, if timing is wrong then coils etc are the wrong place to go hunting.

 

I ran the engine last night with 2 new iridium plugs on cyl 1 and 2. no change. Switched coils from 3 and 4 , no change. lifted coils off of plugs with engine running and get a good arc/pop on cyl 1 and 2 (I know not very scientific) interesting that it is firing but no change in idle or engine speed. I am leaning towards fuel injector issue. I am going to swap out two more good injectors on cyl 1 and 2 and confirm it is getting fuel. I will get to the bottom of this and report back so you all know what is wrong !!
thanks for all of the input.
I once rebuilt put a porsche 996 engine and had missfires. It took the Porsche board and me at least three weeks to figure out that I had put the the oil tensioner cam plunger in upside down ( always advanced, cam allocation fault) and had pre and post cat o2 sensors reversed.
duh

 

Can you inspect to see if the cams are in time?

Here is a picture of them out of time. This is a Lincoln LS but it's all the same. This also shows the white plastic tensioner that has now turned redish orange. It's the two bolts close together inbetween the camshaft caps. Up by the chain.





What color are the tensioners? Here is the metal version.


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The tensioners are plastic, yes I reused thebecause they looked ok and no cracks , probably a bad idea since they would've been really easy to change when the engine was on a stand.
I went ahead and put new intake manifold gaskets on it. Did not help my rough idle or misfire.
Vacuum held steady at 16 inches it idle and increased to18 inches a 2500 rpm's , both readings steady.
At idle,
Short-term fuel trim bank 1 : -1 to +6, long-term -8 to -10
Short-term feel trim bank 2:
+1 to -6, long-term +29 to +30
All measurements at Idle, 800 RPM.
I have no cam tensioner rattle or click.
Question , what should vac reading be at idle and 2500 rpm?
If someone out there has a 4.0 jag , a quick check at the brake booster hose is appreciated.

Also, would timing off cause misfire and lean on bank 2 ?

Thirdly, bank 1 is driver side and 2 is passenger , correct?

Thanks for the help

 

Yes Teebird6
next step is to pull valve covers remove cam sensor, insert crank pin, and then see if the flats are across from each other ....if they're not well, there's my problem!

 

By the way, forgot to report back that I did swap 2 known good injectors and 2 known good coils. With no fix to my misfire.

 

What are the LTFTs at 2500rpm?

So far you're b1 (R) rich & b2 (L) very lean

Banks are as per Vehicle Spec PDF & JTIS (& ISO/SAE).

 

Bank 1 long ftms -10 to -11
Bank 2 long. Ftms +24 to + 25

Had a Spare MAF , no help