Good Afternoon

still chasing a no start 89 xjs v-12 situation.

she really wants to start, but no go.

I've seen multiple posts indicating that if the tachometer isn't bumping

200 rpm. +/- when turning over then the CPS is bad, I've replaced the sensor still no bump on the tach.

I have fuel pressure, I have voltage at the injectors, both coils show

fire, I can hear the injectors clicking, new fuel regulator, extra fuel going

back to the tank. New wires / plugs / injector rail has been rebuilt.

I'm missing something simple. ( car has been sitting for 10 years. ) .


Thanks, Steve.

 

Have you pulled a plug to check for spark? If you have spark at the plug, the plug smells of fuel(indicating that the injectors are firing) then the next items are timing and compression. If you have spark at the coil but not the plug that means the cap/rotor are more than likely bad. And last but not least.....12 plug wires are easy to mess up. I would verify the firing order.

 

Appreciate the response

Yes fire on A & B bank at the plug.
I do not smell fuel on the plugs, but can hear the injectors clicking.
Seems like great fuel pressure, new fuel regulator and it makes the cycle back to the tank.

Have double checked the plug wires, but will again, it is a maze with 12 wires.

Have you any experience with the AAV in reference to a no start?

Steve.

 

All the aav does is allow more than normal air to be sucked in making for a higher idle until the warming water closes the opening up and the idle lowers to normal. If it isn't working it usually is jammed open and lets too much air in at idle and goes up to 1500 rpm, but doesn't prevent a start. Quick fix for this anyway is to stop up the tube to the aav in the air filter housing. My 82 didn't need this part at all, crank, start run and idle.Bud

 

Stale fuel?


Cheers
DD

 

Here's an easy trick. Pop off one of the vacuum lines where it feeds into the top of the intake manifolds and squirt a FEW drops of gas in, then try to start it. If it fires up and runs for a few seconds then you know your ignition is working and its a fuel delivery problem.

After 10 years its possible the injectors are clogged with varnish and need a good cleaning.

 

Great input, thanks!

1. ran all the old fuel out, changed the filter prior to a re-start attempt.

2. Happened across a re-built fuel injector rail assembly and replaced it

with the plugs and wires.

3. the cap and rotor look really good, getting fire off of both coils at the cap.

4. Have tried starting fluid, no difference in activity.

5. Great tip on puttin a few drops of fuel thru the intake manifold to
determine where I'm looking!

will try a.s.a.p. this evening, thanks!

Steve.

 

I think you should smell fuel on the plugs. May I suggest you undo an injector from the intake, shove the spray end into a small jamjar, and get someone to turn over the starter? You have to be absolutely sure fuel is spraying before you go any further.

Clicking injectors does not mean fuel is flowing for certain, and dry plugs seems to indicate it might not be.

Courage, as my French mates say!

greg

 

I agree with Gregg, BUT...if you tried starter fluid and had no response then something else is amiss. Try the gas as I suggested, but if starter fluid didn't work I suspect gas won't either.
Which brings us back a few steps. An engine needs a few things to run, fuel, compression and ignition. If you know for a fact that there is spark at the plugs (in the correct order) and adding fuel either through injectors or manually via the vacuum port or starter fluid and you still don't have so much as a pop...I will suspect something more serious like a timing chain.

 

Is the water temp sensor on the left front cooling manifold plugged completly in? At least on my '87, if the ECU doesn't "see" the sensor, the engine won't start.

In the event the sensor itself might be bad, you could jumper across it and see if that helps.

Thanks,

John
1987 XJ-S V12, 62,000 miles

 

Great tips

Can't wait to hit the garage, should at least answer a few more

questions.

I'll update a.s.a.p.

Many thanks.

steve.

 

I was able to check a few things over the weekend.

1. put a bit of gas down a vacuum hose, no difference

2. checked the water temperature sensor, looks good.
also had one from a known running car that I used just in case.

3. pulled an injector, I am getting fuel.

4. She wants to start a bit more seriously when I first start cranking

than when it turns over 3 or 4 revolutions, then less desire.


5. Question, I put a new set of plugs in gapped at .035 now seeing
both recomendations for .035 and .025, thoughts?

6. I got a new rotor button just for giggles, the other one does not show
any issues, as well as the cap, both look good.

7. I had marked both the distributor and the intake manifold position prior
to pulling the distributor, I guess possible that someone had been
there first, I will go back to the begining and re-time.


Any additional thoughts please feel free to chime in.

Thanks, Steve.

 

Gap is supposed to be .025 from what I read. You forgot to mention that you pulled the dizzy. That would definitely be an area that I would suspect. I've installed the dizzy 1 tooth off and even 180 degrees off on other engines with similar results. Any other items you performed that you might have forgotten to mention? They are all clues. Good luck!

 

Hmmm...yes, pulling the dizzy was important to know!
I'd suggest turning the distributor all the way one way and trying it, then all the way the other way. If it starts, or seems to want to start more, then you know you may be off a tooth.

 

great input,

going to re-gap

triple check the wires.

sorry for the lack of info on pulling the dizzy, my 71 had the frozen

weights, and I thought that this one did as well, surprise no weights

I'll keep swinging.

many thanks.

Steve.

 

a motor needs only a few things too run air/fuel compression ignition take away one and you have nothing. if its been sitting 10 years pickle the motor meaning fill it too the plugs with kerosene and then give it a really good oil change after draining it. the rings might need too re seat themselves no oil will give a low compression reading as well. make sure it is timed correctly and has spark blue spark! clean the air breathers as well as take the cap off the distributer and check the conditions under the cap might bee some rust.

 

check the rails that run along the intake runner theres two they parell the fuel rails almost. mine blew this out and it wouldn't start until it was fixed. someone here should know what im speaking of I cant think of the correct name at the time.

 

Went back to the beginning, pulled plugs, re-gapped

went and got a compression checker, no compression on 6 plugs.

able to see into the hole, valve is visible in each one. I don't know if

it is the exhaust in each case, but definitely in number one.

I presume stuck down because of time, any tricks to get the valve freed

up without pulling the heads? car has 18,000 miles on it.


thanks for the help.

Steve.

 

steve best bet is too pickle the motor let it sit for a week. then drain it give it a nice oil change and try her again compression reading should be 110psi or higher any lower indicates a rebuild. wet comp test gives a true reading(oil in cylinder wall) so use a funnel and put some marvel mystery oil in each cylinder through the plug holesfill it re install the plugs and crank once or twice the take a reading.let it run through the whole firing order then test it out

 

6 cylinders no comp? all one bank?