hi guys,
I'm rebuilding a 98 D1 that hadn't run for 7 years prior to the rescue.
I had the heads rebuilt and redid the headgaskets, changed water pump while I was there. I also dropped the pan, cleaned the pickup tube and put it all back together.

The plugs are new Champions, wires are Kingsborne 8mm.
I have not yet changed the coilpack.

On first startup the fuel filter was badly clogged, so I replaced it, added seafoam and a half tank of good premium gas. The heater core had a pretty bad leak, blowing smoke through the vents so I bypassed it and then also reset adaptive values.

Now when i start the truck, it idles around 750rpm with a noticeable mis/vibration at idle. Eventually, the ecu will throw a P1316 misfire code but with no cylinder identified.

I'm going to pull the plugs to see if one is fouled but how likely is it that an Injector is clogged given that the fuel filter was completely blocked ?
I'm tempted to replace the coil pack and see how it runs but I'd expect a corresponding code for the cylinder if the problem was in the coilpack.

Any ideas on next steps ?

 

I pulled the new plugs on the drivers side and from left to right (1,3,5,7) you can see the variance in colour on cylinder 3.

I did have to replace a clogged fuel filter so bad fuel has been run through the system.

Is a clean plug #3 indicative of a problem with the corresponding injector ?

I have not changed the coil pack, but the plugs and wires are new.

 

Update on this:
I changed the coilpack to the one from my parts car and no more misfire code but the idle is still noticeably “lumpy” and still no power over 2krpms

i did get a new code, P0116 which is the ects. I gave my spare ects away so I’ll have to order one.

I’m also going to fill up the tank from half in case this is still the after affects of old fuel.

 

Replaced the ECTS with a known good one and the P0116 is gone.

however, my P1316 misfire code is back and the engine still has a palpable miss at idle as well as running. I can’t test drive the car because I need to replace stuck calipers but in a short run there’s just no real power.

things I haven’t changed yet:
i haven’t replaced the new plug wire for number #3 cylinder with the old plug wire. (Remembering that cylinder 3 plug was clean)

I haven’t replaced the injector on #3

TPMS is observed to be changing properly (I’m using an ultra gauge to watch the values)

i haven’t syphoned the tank to remove the remnants of the old gas and the crud from the bottom of the tank

i haven’t checked fuel pressure. (But I don’t believe that fuel pressure explains the persistent miss and 1 miscoloured plug)

So I’m going to change the plug wire, in case I got a bad wire, if the problem persists, I’ll look at the plugs again.

after that I’m stumped.
sticky valve, bad injector ?

 

check the injectors. mine did this, then i found gas in the oil,and major problems ensued
(note my signature)

 

how’d gas get in the oil? Leaking injector Stuck open dumping fuel into the engine when It’s not time to fire?

I switched out the number 3 plug wire with the magnacore that was on the car when I bought it as a non runner. No change.

I’m thinking injector or stuck valve now. I’m going to hunt through your old threads now to see if I can learn something

 

I dont have anything posted about it, but yes suspect leaking injector

 

check if you pinched the crankshaft position sensor wire when putting it all back together too

 

Just to close this thread out, I pulled the intake and fuel rail back off to problem solve.

The intake had a warp in it on the passenger side. I didn’t have a spare one so I smeared a thin coating of rtv around where the coolant ports contact the valley pan gasket and reinstalled the intake. This time around I torqued the intake around the coolant ports first, then the exhaust ports.

lastly, I installed a set of gen 3 19lb Bosch injectors, reinstalled the rail and plenum and tested.

no more misfire!

I suspect that the #3 injector was bad , or at least clogged/ stuck open.

added bonus is no more coolant weep from the intake either.