Just got the old girl fired up after new fuel pump (in tank) installed and new fuel, new filter, and number two is missing. Pull the lead on that plug and nothing changes still rough idle. Put another lead on , a second hand one off a wreck, and still same problem, when i hold the lead near the plug I can hear the spark so I think thats ok. What would be the next sequence of things to check? 1992 xj40 4.0

 

If she was fine pre-fuel pump I'd have a look at the injector/injector harness/plug first - maybe some crap got past the filter and plugged the #2 injector?

On the "dark side", a compression test wouldn't hurt either ...

Larry

 

Yeah thanks lawrence have swapped /checked plugs leads defintely getting spark ok . Firing order correct. Problem definitely at number 2. Never taken off an injector or rail not sure how to test .

 

Hi mickvic

I'm tired so I'm struggling to catch up with your description. When you pull the lead on the cylinder 2 spark plug, the engine continues to run with the same rough idle and no drop or change in rpm, but when you hold the lead near the plug you can hear the spark so you think that's OK (meaning that you believe the spark plug is firing?). A definitive test would be to pull the spark plug, reconnect the lead, ground the plug body and check for spark to confirm the plug is firing.

Larry's suspicion of the fuel injector or wiring makes good sense. You could try disconnecting the fuel injector electrical connector with the engine running to see if there is a drop in rpm. If there is no change, do the same at another cylinder and if the rpm does change, then you may have confirmed a problem with the cylinder 2 injector.

Cheers,

Don

 

Power to the injector is good. What would be the correct ohms reading across the two little terminals on the injector? Had a listen the injector is making noise but a different type of click to the other injectors.

 

got a reading of 3.9 across terminals on injector, take off 1.2 for resistance of lines on the multi meter

 

I can't recall the correct DC resistance for the injectors but it's good that you have continuity. You could just measure a couple of other injectors to see if they're in the same range.

If you really want to know, there are a few online references for fuel injectors where you can search by the Lucas or Bosch part number to find various specs on your injectors: impedance, fuel flow rate, etc.

Here's a little information on XJ40 and X300 injectors that I collected while trying to replace the injectors on our '93:

Welcome to Jag-lovers - Members Photo Viewing Page

And here's how I cleaned and rebuilt our injectors at home:

Welcome to Jag-lovers - Members Photo Viewing Page
Welcome to Jag-lovers - Members Photo Viewing Page

Cheers,

Don

 

Thanks Don, as always you are a great help. I whipped the fuel rail and injectors off (first time for everything, thanks to mr man on you tube ) and found a nasty piece of crud blocking number two. Yukeeee . Il just clean em up and replace I suppose though its tempting to lash out and buy new....

 

I am looking at some new old stock part number is EAC4866 would they fit my car? The part number on my injectors is: 73230a and 028015157

 

Ask the seller to give you the part numbers on the injector bodies to confirm they match yours. I had a hard time buying correct injectors because sellers did not identify them under the correct Jaguar part numbers and were not always willing to provide the Bosch/Lucas part numbers that are molded into the injector bodies.

Cheers,

Don

 

The part numbers for one seller match exactly, but now im looking at this set: Bosch III Best Upgrade Fuel Injector Set for Jaguar 3.6L 4.0L I6 | eBay ebay link. What do you think? I asked him what they flow rate was he just said they are an improved item and fit my car.

 

If the photo in the eBay listing is of the actual injectors he is selling, they do not appear to be the correct size and style to fit an AJ6 engine. See my photo album on fuel injectors for photos of AJ6 and AJ16 injectors.

 

The photo is a generic photo Don. From the ebay seller: "These UPGRADE fuel injectors will flow at the same rate as the stock injectors for the vehicles listed in the ad even though these are not the "stock" injectors. The picture is just a generic one. The difference between an UPGRADE injector and a STOCK injector is the quality of the injector. High quality materials (injector body) and internals (coils) make these injectors an UPGRADE. The flow rate remains the same. The fit remains the same. Thank you for your inquiry. Have a great day!
Beth~
Customer Service Manager" Keep you posted on how they go.

 

Well, given that the Bosch/Lucas injectors in our '93 are still going strong after 23 years and 197,000 miles, it's hard to imagine any injector performing any better than the originals.

By the way, based on my previous research I believe the correct flow rate of injectors for '90-'92 cars is 240 cc/minute.

We'll look forward to your report!

Cheers,

Don

 

When installing the injectors, should you smear the rubber o ring seals with petrol or light oil?

 

The Workshop Manual says to lightly lubricate the injector O-rings with engine oil.

 

Thanks don. Got them in, no leaks, runs a lot smoother than before. The new injectors seem to be made out of a hard plastic type compound, much lighter than the old injectors in the hand. Noticebaly more noisy in operation than the old ones, took her round the block seems to be running fine.