Stanger85

My car runs on 4 cylinders, the 3,4,5,7 are not working. I checked firing order (H.O) and timing all good. Car ran fine when I put it away for winter. Changed everything, good spark to all plugs, good fuel pressure, good vacuum. I can unplug the fuel injectors on the dead cylinders and their is no change in the motors performance. I have previously checked all the injectors and cleaned them, plus I had an injector from my Bronco laying around and plugged it in to the harness and it did not work. Could this be a computer problem. Also I have good compression on all cylinders.

jakeachy

I bet ECU problem, borrow a buds for a day to see?

Stanger85

Thanks for the fast reply, I'm not that familiar with computer controlled cars, but trying.

mjr46

To many are quick to condem the ecm which 9 times out of 10 isn't the problem!!! the ecm is always the last to condem after checking the basics!!! do you have spark on those cylinders?? also have you verified injector pulse on those cylinders via a noid light......and if 4 cylinders are dead on a v-8 it should hardly run

jakeachy

he said he had spark^

dimebag

i agree w. mjr... ecu is my last thought right now

check the basics... you cap/rotor(corosion)... do a compression test, and leak down test.. make sure your injectors are acutally working... yes a noid light would be used like said above.

how long did the car sit? id almost wanna say check your valve springs, id bet money, if their anything stout at all, and you didnt back the rockers off for long storage, that the springs on the open valves arent up to par anymore, they loose integrity just sitting compressed for long amounts of time.

and lastly... bent valve?

mjr46

maybe so ......but injector pulse on those cylinders would verify operational ecu cause the Pip signal is sent from stator amplified through tfi and sent as input to ecm where it is interpreted an injectors are sequentially fired,,if spark is good and inj pulse is good you can rule out ecm issue for the moment and then I'd focus on the plugs of theose cylinders and or compression on the cylinders exibiting the prob...ie compression test.. could have bent valves if motor was over reved or any number of things internally wrong.....so compression test would be ideal to do on those cylinders to see if they have potential to produce power

Stanger85

I have checked all of the above including compression (155psi) per cylinder. It has new plugs,wires,cap,rotor,ignition module,coil,removed the catalytic converters,fuel filter,new intake upper and lower gaskets, checked all vacuum lines. I also checked all grounds,visually checked spark at all plugs. And you would be suprised at how well it runs with only 4 plug wires removed. And where could I pick up a noid light.

AdderMk2

just for ****s and giggles, what are you running for a firing order?

1-5-4-2-6-3-7-8 ?

mjr46

just make your own with a low wattage bulb and check firing order as adder states