Engine rough running - How do I Check Codes

[laserchill]

My 88 ranger is running rough. one second it is running great then it starts what I would call "missing". I narrowed it down to #4 cylinder by pulling spark plug wires and noticing engine rpm drop on all but #4. I pulled plug and replaced. I replaced wire. I checked fuel injector...seems same as all others. Tried the "Sea Foam" game with vacuum line and full tank. Engine is fresh rebuild with new heads. I really don't think it is a compression issue but I guess it could be. I used new head bolts with new gaskets and correct torque procedure on head, upper/lower intake, etc.
Seems now problem is getting worse. haven't ck to see if spreading to other cylinders. I have read that I need to "check codes" Don't have the code meter and don't really want to buy one. Someone mentioned a check light. I have DC meter.....
Need some direction

 

[freedom5]

My 88 ranger is running rough. one second it is running great then it starts what I would call "missing". I narrowed it down to #4 cylinder by pulling spark plug wires and noticing engine rpm drop on all but #4. I pulled plug and replaced. I replaced wire. I checked fuel injector...seems same as all others. Tried the "Sea Foam" game with vacuum line and full tank. Engine is fresh rebuild with new heads. I really don't think it is a compression issue but I guess it could be. I used new head bolts with new gaskets and correct torque procedure on head, upper/lower intake, etc.
Seems now problem is getting worse. haven't ck to see if spreading to other cylinders. I have read that I need to "check codes" Don't have the code meter and don't really want to buy one. Someone mentioned a check light. I have DC meter.....
Need some direction

I had a similar problem with my '87 2.9 - changed all of the sensors, wires, plugs etc.. and still had problems. I finally solved the problem by running about three tanks of fuel through it with B-12 Chem Tool gas treatment. It gradually got better every day and now runs great with excellent acceleration and smoothe idling even on first start up. I'm convinced that ethanol causes an eventual cellulose residue to clog the injectors. I now put a can of Chem Tool in every three fill ups since all gasoline now contains ethanol. I don't know if this will solve your problem but it's worth a try.

The easiest way to check the codes is with a OBD-I code reader. They are not carried in parts store now since they are considered obsolete but you can find them pretty cheap on-line.

freedom5

 

[laserchill]

update...I am running second can of B-12 Chem Tool......I checked codes...BTW found pretty good explanation in my Haynes manual 36070 chapter 6. Learned a bunch about the emissions system. Anyway... had code for bad ECT (Engine Coolant Temp Sensor) Installed that. Seems better but I think that miss on #4 cylinder is a bad fuel injector. Looking now on how to troubleshoot fuel injector. Any help out there?

 

[laserchill]

update....installed new fuel injector for #4 cylinder. I still have no firing on that cylinder. I did perform a vacuum test which stayed steady at 18inchesHg.....well within range....which should tell me that I have no cylinder problem. I cked fuel injector wire it measures same as wire from other injector that is firing. recap that engine is fresh rebuild with new heads and head bolts. Pulling my hair out here trying to figure out why I have no firing on number 4 (I even tested it at 2000 rpms). obvious lack of power and missing............any ideas????

 

[laserchill]

BTW....purchased cool code reader from auto parts....Acutron.....it's a cheapy but it works. I have "11" for KOEO and "11" for continuous memory. I then had a "77" on engine run code. I think that is an operator error for the "goose"test but not sure.

 

[laserchill]

Of course, the "11" is a "clear" code

 

[John Smith]

Did you

Check the Diz cap for #4?...how about checking #4 for spark?...(you had never said)..have you done a compression check on all 6"?....how does it drive under load?

kudos for buying the code reader...i couldn't want to be w/o one to work on my own 88..a real time saver..

 

[laserchill]

Hey John...I did check all spark wires to ground and found a good consistent spark from all 6 wires....checked them all at 2000K RPMs as well and had good spark which should clear the wires, diz cap and rotor. I also changed plug(Motorcraft AWSF-42) for #4 but I guess it could be bad. I have not done a compression test on any cylinders....I was under the impression that a vacuum test showed valves/rings good if i had good steady vacuum in 17 to 22 range.
As far as being under load, the #4 cylinder is not firing at any RPM and under any load so I have lack of power.

 

[John Smith]

well, you've pretty well covered it..

except maybe a compression check...all it takes is fuel , ignition and a good cylinder...was this running well before you changed the heads?...or did your gasket change?..and was it running fine for a while after?..i should re-read your original post i guess..you haven't swapped wires in the cap by any chance?....just sayin...

it's kinda like a computer...go back to a "restore point" when all was well "right b4 that NEEDED UPGRADE"...

 

[laserchill]

Hey John.....it ran great after rebuild for approx 2 months. then all of a sudden there was no firing on #4 cylinder. I did originally leave a ground wire off and fixed that after realizing it....but that made it run very rough.

 

[John Smith]

I would do that compression check

just to see if anything is wierd with that cyl. Since you have had the head off and I assume had the valve train apart..you may also want to check the lift height of the cam for #4 making sure it matches the others..if you have a good cyl it should fire ..(unless you sucked a cork in that intake runner...kidding but..)

 

[John Smith]

Hey John.....it ran great after rebuild for approx 2 months. then all of a sudden there was no firing on #4 cylinder. I did originally leave a ground wire off and fixed that after realizing it....but that made it run very rough.

? grounds are usually not optional...you may want to recheck your wiring harness for issues comparing it to another "known good"..etc

 

[laserchill]

Ok did the compression check and found #4 at half all the others 90# as opposed to 180 psi on other cylinders. Pumped some air into cylinder and heard (and felt) air coming from air breather tube. so....looks like my problem is with the intake valve on the #4 cylinder. Go figure with new heads :/ any suggestions??

 

[John Smith]

I would ..

loosen the adjustment on #4 intake valve..and cycle it over...also check the lift height on #4 compared to the others...

mightve got a valve a little tight when the head was put back on?...they're hydraulic..has happened b4...anyway i would loosen the valve and let it run a little see what's up...if it's burnt...go to plan b...take it off and see whose fault it was..(assuming not the guy that adjusted the valves.)...sorry, just sayin....could also be a valve guide galling..or other valve seat issues..as a result of the valve job...another note...if you think it's just sticking open...you MAY try loosening the valve rocker on that valve and give it a tap or two with an appropriate hammer...just to see if it may seat but if it's run for a while this way it may have to come apart. In the old days when you did a valve job..you started it with the valve cover off...and had an oil can handy to lube the valve stems till it got warm and the oil was flowing well..(you could tell if a vavle would befgin to "stick") but that was before hydraulic lifters so you had to adjust them soon and regularly..hydraulics are great but can't make up for assembly and adjustment issues if it goes south...

If I ever pull the valve covers off of my 2.9 I think I'll be forced to "adjust'm while it's running"..something we used to do on corvairs etc..loosening in increments till they click constantly..then tighten approx 3/4 turn or so in increments letting the motor catch up as the lifter compresses..some go to 1-1/2 turn etc...get a spare set of valves covers and cut a slot on the top side giving room to get the socket on each adjuster..(less oil flying about that way...)

After thinking about it some more..adjusting the lifters "while running" on an older 2.9 may actually help cycle the lifters operating range enuf to help with that "tick' many seem to have..? couldn't hurt..at least the valve would be adjusted properly on an older warn valve seat...

(I may be wrong about the 3/4-1 1/2 turn range for this 2.9 hot adjust..I was using the Chevy lifter range adjust..so check your book for specifics)