One cylinder running cooler, injector problem?

[jdb]

7.3 IDI, manual, extended cab, has 420,000 km.

All eight injectors replaced 9 years ago at 235,000 km, "BB" type (at that time, I didn't know there were different types).

On holidays this summer, long way from home, truck started running rough, "bunny hopping" in low gear, lots of smoke. Tried cracking the injector lines one at a time to see if I could find a bad one. They all made it run even rougher. Took it to a shop and they used a hand held infrared thermo sensor to measure the cylinder temperatures. Two were lower than the others (#4 and #8), they suggested replacing injectors. Got 2 from the local ford dealer special order (gave them my VIN so they should have gotten the right ones, but talking to my local dealer's parts dept the documentation is confusing). So the two I got were "E" type (still didn't realize there were different types, and didn't know what my truck had). Put them in myself, and it was running better.

Fast forward to now. Truck is running rough again. Cylinder #1 is now cooler than the rest. Bought 2 more injectors, "BB" this time (now I know the difference, so got ones that match the originals which are the correct ones for the truck). Replaced the injector in cylinder #1. No improvement; thought it might be a bad injector, so replaced it again with the second new injector. Still no improvement.

I have read that its best to replace all eight injectors at ones. But it's an old truck with lots of km, so I don't want to put more money into it than I need to, especially at $120 each for injectors - i.e. I don't want to throw away two almost new "E" injectors.

So ... anyone have any ideas what the problem may be and how to fix it?

 

[towcat]

does your "bunny" smooth out at higher rpms or does it hop worse and smoke like crazy?

 

[jdb]

does your "bunny" smooth out at higher rpms or does it hop worse and smoke like crazy?

Smooths out, less smoke.

 

[towcat]

you need injectors. how is the blowby on the motor? remove oil filler cap when running and observe. all will have blowby. there simply is not enough tension on the rings to stop it at idle. raise the throttle 200-300 rpm off idle and observe. if it goes away, your motor still has a ton of service life left in it. if it doesn't change, you have a problem and there is no reason to sink anymore money into it.
good luck!

 

[IDIBRONCO]

With 190,000 km on them, you need to replace the injectors and the pump. You can them from Mel (Agnem) at Conestoga Diesel for way less than $120 a piece. The pump will cost more. Although I don't know what it would cost to have them shipped across the border. You can always call and ask.

 

[riotwarrior]

you are paying way to much for injectors....***** is the term.

i suggest maybe either Mel at Conestoga diesel or Justin at at R&D Perfoma ce IDI ...or Russ aka Typ4 here for injectors....

where abouts in Canada are ya...maybe add that to your i fo.

JM7.3CW Eh!

 

[jdb]

Price was after taxes, before core rebate, and rounded up, so more like $100 CDN.

JM7.3CW???

Sunshine Coast, BC

I've read that I should get a "matched set" of injectors to make sure they pop at the same pressure. Wondering if that is my problem here. But whether I buy from a dealer or mail order, how does one ensure that they are a matched set, and if they aren't, what can you do about it?

 

[riotwarrior]

Matching pop pressures ensures timing events equal...

Buy from whom suggested snd u get nice matched sets.

U can buy or build pop tester and if same brand of injectors shim accordingly....best you leave to those in the know....the 3 mentioned