Hey all,
Got some work to do on the old beast and I am looking to replace the injectors. First off, the problems I have had with this thing started when I decided to do a tune up earlier this year. Truck ran fine except for a few shut offs and stuff, which I figured was a vacuum leak and would get around to it sooner or later. Had no codes and ran smooth. Well I put a long block in this thing in 2002 at 181,000 on the ode and figured I do a tune up(210,000). Changed out the bosch plugs for autolites coppers and new cap and rotor(wires were not that old) After this the truck developed a miss, and I figured it was my tune up. So i replaced the plugs again, this time with motorcraft plugs, new wires and another new cap and rotpr. Nothing. Still misses, and sometimes it misses and cuts off and idle.

I have been beating my head over this for 6 months now, and Have come to the conclusion that a bolt I used to replace a snapped intake bolt may be the culprit. The funny this is when i come to a stop at idle it will not miss for a few seconds and then get worse as I sit there idling. Really annoying. Also heat and wet weather seem to affect it. I origionally thougt it was the wires crossfiring but I have tried many configurations and no luck. ALso, I noticed that number 8 cylinder was wet with gas when i changed the plugs the second time. Could this be from it not firing or the injector sticking open? I tested the FP not running and its fine.

Anyways, any ideas here that I might not of thought of? Im out of ideas other than tearing it down and starting over at the intake. I also plan on replacing the injectors if I do. What are my options there? Anyone bought some or are there deals? They seem pretty expensive.

 

I bought some reconditioned injectors from five-o motorsports on ebay a couple years ago and had good luck. The price was reasonable and much less than a new set.

 

what is your timing set at? should be 10-12*btdc with spout connector removed. are you positive you have the correct firing order. and none of the plug wires are touching or crossing each other. Have you replaced the fuel filter and pcv valve? when you installed the new motor did you repalce the O2 sensor as well?

 

I got a set of rebuilt injectors a few months ago from bjcda, on Ebay. http://stores.ebay.com/Mr-Injector
About $10 each. Seem to be like new. He was quick to ship them also. Highly recommend him if you don't want to do them yourself.

 

Before anything I would do a compression test on number eight. You might have something else going on. It only takes five minutes to do a compression test and at the very least you will know something.

Vince

 

Replaced the all the sensors except the map when i put in the new motor. Compression check is something I want to do but am pretty certain its not low compression. PCV system i had to use a 5/8" hose to replace the broken brittle hose that was there before. I replaced the PCV valve when i replaced the motor, I will check that out as well.

Found the accel injectors on summit. They any good? I will check the other sites as well Thanks guys.

 

If it were me, compression would be the first thing I would check.

If you want to fiddle around you could swap injectors and see if the problem moves.

Vince

 

UPDATE:

Well, here is what i have concluded so far for those that this thread might help. I have been over this entire forum and talked to many about this problem. My conclusion is a bad fuel injector. I have replaced plugs, rotor, wires, removed TB, cleaned the IAC, and all filters. Still not codes. I have found number 8 plug wet with gas, and just a month ago this truck will not run on 87. It will not miss at 70-75 mph. It will if i let my foot off the gas. So last week I decided to rip it apart.

Ordered new ACCEL fuel injectors(21lb/hr), new fuel pressure regulator, from summit. I got the upper intake off today, and whoa, all i can smell is gas. Im pretty sure that i have a problem with the number 8 injector based on all the evidence. Tomorrow I will know more but i thought id share.

 

check for a chafed injector wire, if it grounds out it will command a longer injector "on" time.

 

UPDATE:

Well, the swap is complete. Drives much better and the miss is almost gone but still there. The upper plenum was horrible. The egr passage was blocked, and i had to scrape out and use heavy doses of throttle body cleaner and seafoam. Although the miss is still there, the pinging is not, i took it out on the highway and tried to get it to ping. Glad that is done.

Ben-jamin, I did check for damage to the wiring harness and injectors but didnt find anything.

Now i know i have a small vacuum leak in the dash somewhere because the ac will blow out the defrost when i first turn it on. Its real slow to change over the to the front vents and i hear a pop when i turn it on. Also, i have a little vacuum actuator on top of the airbox with a white vaccum line that seems to be in real bad shape. Where can i find these parts, as i know the dealer wants alot for them?

I will continue looking for leaks and do a compression check soon to make sure i have nothing else wrong.

Oh and now I notice a small looping when its cold, but not everytime. Im taking it on a 160mile trip tomorrow so hopefully it will reveal more insight.

Thanks again