If the back 4 plugs are fouled and wet then there is no spark or at least not at the correct time.

 

Since you have thrown that on the table, pray tell.

Correct procedure? I have seen a couple, what's your take?

 

As your check confirmed that all of the plugs are firing, but the plugs are wet you either have an ignition timing problem or leaking injectors. Seems pretty strange that leaking injectors would line up on the back four cylinders so I would suspect a timing issue. Mkae sure you have the firing order from each distributor correct.

Given that the problem is worse at part throttle compared to idle it also could be that the coil on one side is weak (bad coild wire?) that has enough power to fire at idle but not enough to fire at higher cylinder pressures under part throttle (maybe worst at high load).

 

Thanks Michael for your offer on your injectors...I might have to take you up on that offer if some injectors turn out to be bad...I will let you know when I pull them.

Thanks Roger for you suggestion to check on coil and timing...I have not checked the timing yet but I will now that you mentioned it.

My plugs, as I said earlier are ALL firing but I will double check the order again....I have driven the car short distances and if the plugs were installed incorrectly, I seriously doubt the car would be moving down the road at any speed..starting maybe, moving at speed doubtful.

It never hurts to double check connections and such and I will get to it on Friday.....

One more question: does anyone know what/where those 3 wires on top of the fuel rails are used for?? The wires I'm talking about are hiding under the black plastic fuel rail cover. There are 3 wires running along each fuel rail side and have a clip connector. One of the wires on each bank has the black protective sleeve worn out exposing the layer of wiring under it....The actual wire is not exposed but rather the protective shield around it...I'm not sure if that means anything or makes any difference to the injectors but it found it odd that only the middle wire is exposed like that....

Will try to trace the wiring on top of the fuel rails on Friday as well and check back with an update!

Thanks for your time - VK

 

If you have an S4 you can simple get a cheap set of Mustang good used injectors (they are 19lb too) and use them for testing. Just change the O rings first. You can pick up a set at any wrecking yard or even on ebay for next to nothing. If they turnout to be the problem, you can then decide what to do.

 

the wire that your talking about that runs down the injector rail sounds like the knock sensor rear on the right fuel rail it connects between the last 2 cyls on the right under the fuel rail cover. You have probably already done this but do you have 2 good ground wires on the coils one for each head to chassis? if any of the ground wires have suspect connections you should make new wires and try regrounding the heads/coils. Have you checked all of the fuses in the CE panel for corrosion? and all of the relays any that have corrosion should be replaced pull every relay and check for corrosion any relay that has corroded pins should be opened to see the internal condition if you have any corrosion of the CE panel dont wash the car untill you figure out if the blower box bottom seal it water tite, Also get about 5 gallons of fresh gas in the tank, goodluck, Stan

 

The last time I had this problem, it was due to timing - both cams needed adjusting. If nothing else has changed, there is no chance the belt notched a tooth, it shouldn't be timing - but you should consider it a possibility.

 

wonder if someone might have swapped a few wires for him on the distributors, just switching one wire wit another will cause this problem

 

if you have a 91 sitting there, i suggest you swap over the lh and ezk units. the time scale that you have suggested and the problems mentioned seem to be about when it is getting up to normal operating temp. iirc that is when the Lh takes over control of the fuel and ignition. Had very similiar issues 6 months ago, and spent weeks swaping and changing various parts untill there was nothing left to change. BORROWED MY MATE BRAINS FOR THE DAY AND ALL WAS WELL. Car brains that is. £340 rebuild from John Speake on the LH unit and all was well. Have suggested this to another rennelist member who was having similiar problems and it fixed his too.

 

Sorry ,, that should be £320 rebuild from John Speake