Over two months now, hundreds of hours spent, cranks but not start.................HELP
I have:
Drained the fuel tank of every drop (had some water in fuel)
I have good fuel pressure (not a relay problem)
I have cleaned the injectors & put new o-rings on(good fuel pressure)
New fuel pump & filter less than a year old (plenty of fuel @ the rail)
New coil, cap, rotor, plugs (I have spark)
New CPS (crankshaft posistion sensor)
Battery is always charged up and it turns over fast (trust me on that)
Checked out everything in manual (Hayne's, plus countless internet threads)
It has been doing this for over two months, it has never ran since Feb 21st. It has started and both chugged and ran smoothly for maybe 60 seconds, but never ran more than that. Now this is it, I am ready to set it on fire but it probably wouldn't burn.

 

rcarpenter:
Well... once this car is running, you'll never have to do anything to it for years! That's one heck of a tune up. I feel for you. Even though the starting/chugging behavior smells fuel-related to me, the only two ideas not on your list are the plug wires themselves (including the one from the coil to the distributor) and the ignition amplifier. Have you checked these?

What we need here is some creative thinking. I'm hoping some of our more seasoned members will chime in with thoughts. If I were you, I'd post this over at Jag-Lovers if you haven't already. There's a guy there named Bryan N who is an XJ40 god who may be able to help.

Cheer,
Scott

 

As you stated that it ran for 60seconds and then stopped, did you check to see if you were still getting fuel. It sounds like there is a fuel stopage. I would check both feed and return and the fuel filter also.

 

I remember asking him that the first week of March. I didn't see a reply

 

 

Hey you're upset. Just walk away from her for a while.

I have more experience with domestic cars than XJ-40's but I just had this problem with a Ford Tempo. If this was my car (I hope it doesn't happen to me on my Cat) this is how I would attack it.

Let's start with some basics.

1. Did you put the spark plug wires back on correctly?
2. How much compression do you have in all 6 cylinders? Be sure to remove all spark plugs before testing.
3. Pull the valve cover and see if the valves are actually opening and closing. If not you have a broken timing chain/belt.
4. Is valve timing correct? Slipped timing chain/belt.
5. Is ignition timing correct?
6. How much fuel pressure? Not enough pressure may tell the computer to NOT fire.
7. Have you confirmed the injectors are actually opening and closing when cranking? Use a noid tester, or listen for clicking by using a piece of garden hose - stick one end of hose by the injector and the other to your ear (don't reverse ends if you don't wish a dirty ear) or use a stethoscope.
8. A vacuum leak in a cylinder will cause a lean misfire.

See, You have lots of things to check before setting your Cat ablaze.

 

One more thing just came to mind: will the engine run on a couple of squirts of ether?

 

Good morning,
Trick's suggestions made me think of another 'simple' item that could prevent the car from starting. It is important that if you moved the distributor in any way that it is returned to the exact right position. Beyond that, the distributor cap must be perfectly positioned and seated in the correct position. That sounds dumb, but I made the mistake once of thinking I had returned the cap to normal but instead had it just a bit off, preventing my car from starting.
cheers!
Scott

 

Thanks for the quick responses, I'll try to answer all if I can, let me know if I'm off key on something.
I have not replaced the plug wires yet, I only replaced the coil because it was not measuring the correct resistance across.
I have not replaced the ignition amplifier because it's $200 and my method of troubleshooting is killing my family budget. The book only says how to check voltage into the amplifier, not out.
The distributer can not change the timing according to the manual, anyway I have not moved it and the cap is snug with the knotches in the right spot.
Yes it will start with ether, but not too well.
Yes one day after I took the fuel rail apart, it ran like a kitten for maybe 25 seconds, so I am assuming the timing is all good, along with compression.
The fuel pumps, as far as returning, I don't know.
The last official time it ran, I reached in and turned on the car-(it used to start with no effort) I warmed it up for a few minutes and that was it. There were no key indicators that I was having any problems. It never died at a light or anything. I have never worked on this type of car, but I grew up the son of a shade tree mechanic. Cars used to start up with two things, spark and fuel. Now their performance needed a lot more, but that combo could get them fired.
Me, I was a mechanic in the service, rode Harleys for 30 years, I was the guy who could get any of my friends jalopies started in high school. This is the first engine of any kind whatsoever, that I can't get to at least start. Don't let me down, I know it's something you readers can nail down. There is a light at the end of the tunnel, but I'm afraid it's the train.

 

Please explain more fully.

 

On the ether start,
Yes I will start, but not run. If I take the entire air intake assembly off and spray directly through the mass flow butterfly it will continue to, and bear with me on terminology, ignite. But it is not running and I do not want to continue spraying starter fluid. If I just spray shots into the air breather under the filter it will start momentarily but not run.
Also it was asked if the plug wires may have been crossed, but they are labeled quite well and i changed the plugs one at a time.
One more bit that might help, the two times it actually started and idled and accelerated for maybe 20 to 30 seconds were- After I did the injectors and was just turning the engine with the fuel rail nut loose to bleed and second was after I replaced the distributer cap and rotor. Other than that the only starts were with ether or less than 10 seconds

 

Sounds like a fuel problem to me. Low pressure, restricted return line, short between ECU and injectors, something along those lines.

 

This now appears to me, also, that it is a fuel delivery problem.

What I suggest doing now is:

1. check the fuel pressure at the rail. I think it's supposed to be around 40 psi? You could have a faulty pressure regulator.
2. check to see if you're getting a voltage signal to the injectors. No signal from the ECU - no fuel to the cylinders.
3. if no signal, check the engine coolant temperature sensor. It's a variable resistor located in the rear of the thermostat housing. It may be burnt "open". This is one of 3 sensors I can think of that the ECU reads for sending a fuel pulse.

 

I have now completed all the suggestions from readers and still no start. This has gone beyond frustrating. Now besides things I listing as being done earlier, I followed Trick Freestone's advice and everything checks out. I completely inspected and taped up the main wiring harness and have voltage to each injector, the coolant sensor reads 2k resistance, has the 5v input, I have the fuel pressure at the rail and the return line is free. I checked the fuel pressure regulator and cleaned it out, the diaphram looks good. Now if anyone out there can answer these; The ECU cost about $1,800 used and there is no way to test it that I know of..suggestions, also I don't have anyway to test the ignition amplifier's output, again any suggestions. Last does anyone know how to tell if the spark is "hot" enough. I am not sure that the fuel will ignite. I may be tracking the wrong thing, it will not even cough while turning over. I do have spark at the plugs, but it seems faint?? Help

 

Sheesh, she's really being a stubborn bugger. I thought by now you would have found the culprit. Take heart, you are making progress -- you're starting to know what it isn't.

OK, you need fuel, compression and spark (and no vacuum leaks in the intake).

Why did you replace the CPS (crankshaft position sensor)? Is it any good? I've bought brand new, defective parts at the parts store before.

Before buying an ECU, let's go back. How many of the following can you check off?

The following excerpt came from



1.11 Fault Diagnosis (page 22)

a) Engine will not start

1. Defective coil
2. Faulty ignition amplifier or fuel ECU
3. Faulty injector(s)
4. Loose or broken electrical connectors or leads
5. Damp ignition leads, distributor cap
6. Battery flat, corroded terminals
7. Defective fuel pump, vapour lock in pipes
8. Blocked or split fuel filter
9. Valve timing incorrect
10. Valve clearances incorrect
11. Valve seats burnt, valves sticking
12. Broken piston rings
13. Plug leads incorrectly connected
14. Faulty, jammed starter motor
15. Sparking plugs defective or gaps incorrect

Additionally,

1. What is your engine's compression for each cylinder with all sparking plugs removed?
2. I would turn over the engine via starter with the valve cover off in order to inspect valve springs and cam lobe operation. I don't think you'll need a sheet metal dam to keep the oil where it belongs.

 

NOTE: (you probably already know this)

Source: Ignition Coil, Alternator, Starter Manufacturer - RIBO Auto Parts

 

Thanks again Trick, here's the scoop.
I replaced the CPS because in my first post back in February someone said that might be it. It was a brand new Lucas CPS and I didn't suspect it being defective. I don't know how to check that sensor. Your diagnosis
1. Replaced the coil
2. Wish I knew how to check output of the amplifier, I will buy one, they are around $125 if everyone eggs me on enough, the fuel ECU is 1/4 my total investment in the car so far. ouch
3. I removed all the injectors, they looked good and I replaced the o-rings after I cleaned them and the pressure regulator.
4. I COMPLETELY went through the ignition/fuel wiring harness it is factory spec now
5. Ignition leads look good? cap & rotor are new & correct
6. New battery and I take it out & put it on my bench with a trickle charger when I'm doing this hit & miss work.
7. New fuel pump that I put in December when I had this exact problem, the car then started after I replaced the pump & filter but not until i sprayed a ton of ether to get it running, which I thought was wierd but I'm an idiot
8.New fuel filter and I haved cranked fuel into a clear bottle
9.The valve timing shouldn't of changed overnight so to speak, I did check TDC and it was right
10, 11, 12 Again it was running very smooth before this event, so I don't know, but I can open the top & look
13. I have checked & double checked the plug wires they are very well numbered and in the correct order
Starter motor is working and YES I only crank mayby 10 seconds at a time. I read changing the starter requires the tranny to come out so I have really babied these crank damn won't start episodes
15. New spark plugs, correct make & brand and I checked the gap on installation
Additionally,
1. I only check compression on a couple of cylinders with the other plugs in, I will test all of them with out plugs this weekend
2. I guess i can take the valve cover off, I'll have to buy another gasket first, but they love me down at the auto parts store.

 

rc,

Well, you're checking things off the list alright.

You've got your hands full and I'll try to look up some testing information on the amplifier, etc.

In the meantime, I have a few more questions/comments/suggestions/fyi:

1. I realize the fuel pump is new, but I don't remember your writing you tested fuel pressure. If you did, what is the value? Not enough pressure will cause an ECU to not open the injectors. We just went through this on a Chevy Blazer.
2. When you finish one of your crank damn won't start episodes, do you smell gasoline? Did you pull the plugs to see if they're wet?
3. You didn't jar your Inertia switch did you?
4. Somewhere I read that a faulty Air Flow Meter, which is connected to the ECU, can cause a no-start condition. I'll attempt to confirm.
5. There is a 6.8 kiloOhm resistor fitted to the fuel line somewhere that is also electrically connected to the ECU. I'm looking for more info on this.
6. Did you locate your ECU, and pull/inspect your harness connectors? At one time I found where corrosion had eaten up two pins on a Dodge computer -- took out the voltage regulation function.
7. I'd go buy some black engine silicone gasket adhesive and reuse your old valve cover gasket until the day comes (it is coming) that she's running properly.
8. The above reference writes the car is put up on ramps, dip stick assembly is removed and front suspension rear mounting inner bracket is removed in order to get at the starter. No mention of pulling tranny.

 

Thanks Forest,
1.I did replace the fuel pump & in february I borrowed a pressure gauge set-up and I can't remember the cranking PSI, but it was pretty high. The other checks called for were with the engine running which eludes me
2. No, surprisingly I don't smell too much fuel, not like on anolder car where you can smell "it's flooded"
3. No and I have checked the inertia switch, if its tripped the doors unlock and you can not turn the engine over
4. let me know if you find anything on that, I can't
5. Same as above, and thanks
6. Yes during my completely untape every square inch of the wiring harness, remove the passenger compartment and glovebox athon I found the fuel ECU and it looks hooked up OK
7. I was thinking that too
8. Yeah I just read that, still I am taking it easy on the starter.
Thanks again

 

You're welcome, rc. Oh, and it's Forrest -- no problem, just clarifying.

OK, read your last post.

Here is a diagram of the engine management system for a 3.6 litre. Even though some of the lines are dashed (and not supposed to be), it shows the main players in getting the engine to fire and run. Note the inclusion of the Air Flow Meter and the mysterious 6.8 kilohm resistor.

Also I've attached a small pdf describing the operation of the management system during engine startup.

Note 2/3 of the way down on page 6 it reads: and on the last page it reads:

WTF. Excuse me, but what error codes are displayed on your Vehicle Condition Monitor (VCM) display?