SOME RECENT UPDATES, Still having issues.

So, the issue has been when i accelerate im losing power to the engine. At first i thought this may be a fuel issue or mechanical issue but with the trouble shooting Ive done it does not seem to be the case. the engine will hesitate once i attempt to accelerate, not at a specific time or certain rpm, totally random. i can be in idle and rpms will drop and then climb back up. i can get the rpms up to 2500 and itll be fine for a little then drop and then climb back up, then drop again. ive changed out some parts and after changing the fuel pump i noticed that it sounded like number 4 or 5 fuel injector was making alot of noise. i know they will pulse as they should but this is a very prominent ticking noise. not a tap or knock but a ticking. its in sequence with the firing order. and it gets faster as i accelerate. im pretty sure its the injectors because when i place my hands on the fuel rail or injector lines i can feel it pulsing in sequence with the ticking. now when i place my hand anywhere else on the engine i cannot feel it at all. not a bit. just normal engine vibrations. now if this is my injector ,(or injectors), i now ill need to replace them. i guess my big question is that if the injectors were going bad would i be having this issue at random or in sequence with faulty injector? this is what ive done so far to resolve this issue:


replaced main fuel filter (again)
replaced fuel pump (again)
replaced pressure regulator
replaced vacuum lines for regulator and anywhere else i can get to
oxygen sensor

This is on top of what i had already done listed below.......




So my 85 xj6 has been running pretty good until recently. It started to hesitate when accelerating. When its in park or neutral I can rev the engine and bring the rpms perfect as soon as I put the car in drive and attempt to accelerate, even the slightest acceleration will cause the engine to seem like its stalling out. I can watch the rpm's drop and come back up like its losing fuel.

This is what I've done so far:

Replaced filters in bottom of tanks
Replaced spark plugs
Fuel pump and main filter changed last summer
Replaced air filter
Checked timing, sitting right at 17

I'm a novice at best when it comes to this car but I am pretty good with mechanics. Anyone have any ideas. What baffles me is that I lose no power when in nuetral or park. As soon as I put it in gear is when it starts to lose power during acceloration.Thanks again in advance for any help anyone can give

 

When you replace the tank screens and the main filter, were they badly clogged/contaminated?

If they were, it was probably rust. If it was rust, your new filters and screens might be getting clogged again. I'd pull the main filter and empty the contents into a clean container for a look-see and go from there, depnding on what you find

Cheers
DD

 

I can say they were pretty dirty. when i drained the tanks i placed a towel over the collection pan and noticed some small pieces of rust aswell as some decent size brown scales collected on towel. Ill check the main filter tonight after work. Honestly my mind didnt even think of checking. One other thing i failed to mention as it was just brought to my attention. a buddy of mine had a similar issue with a different make of car ( chevy ) but he stated that it was an issue with his emission system getting clogged. now on mine the emission control system has been removed. could this be the culprate? its ran great for years and just recently started having this issue.

 

It could be the MAF box. I had similar symptoms way back in the late 80s with my 1980 XJ6. Trouble is the guys who used to service these old analogue EFI systems are all either retired or dead, but you may be lucky. It is a Bosch system made under licence by Lucas, so a Bosch fuel injection specialist should know something about it.

Bosch L-Jetronic is the name of the system

 

Excuse the late response. Now would this account for the fact that when in nuetral or park I can bring the rpm's up fine with no hesitation?

 

It is an awfully long time ago, but as I recall, any load on the engine caused lack/no power. I could freely rev the engine when in neutral.

Of course with no load you are not actually generating any power, all engine power checks at the factory have the engine coupled-up to what is called a "brake" which measures the power at various revs, and also the torque.

It sounds like the fuel side, not ignition. Two things need to come together at the injectors: -

1. Good supply of clean suitable octane-rating fuel at the correct pressure, which is maintained by a blow-off/fuel return valve, and

2. Injector pulse of the correct length at the correct interval. This interval is based on the ignition coil pulses from the distributor.

It is all pretty simple on the L-Jetronic, no fuel maps and various devious devices (to go wrong) which are supposed to save on fuel.

 

ok im still having issues. I updated the original post to whats going on. please help. anyone with any ideas.

thank you