1988 F250 XLT Lariet, 460, C6, 4x4, reg cab, long bed

I have a new re manufactured 460 in my F250. It fires up at the flick of the key, and idles at 750. I noticed at idle it seemed rougher than I expected, the whole truck vibrates. And the exhaust smelled awfully rich. But, this is the first 460 I've had my hands on so I wasn't sure if I should be concerned.

I'm concerned now. I took it out for it's first road test and it had very little power. Got it home and parked it.

Later I came back to it with my Infrared temperature "gun". I fired it up and after about 5 minutes I got the following temperature readings from each cylinder at the exhaust port (headers).

280* @ cyl #4..........270* @ cyl #8
164* @ cyl #3..........126* @ cyl #7
207* @ cyl #2..........240* @ cyl #6
205* @ cyl #1..........100* @ cyl #5

And for a little background, I've been over and over the ignition. New distributor, new cap, new rotor, new wires, new plugs. Timed properly. And it appears in good working order.

No codes present for KOEO.

Obviously there is a problem when one cylinder is nearly three times as hot as another (#4 and #5 for example).

 

Run a compression and leak down test...also the temp numbers after 5 minutes of being off is not a reliable indication of anything, header tubes bleed off heat quite quickly.

 

Did you do anything with the injectors? New, refurbed or 100k+?

Check fuel rail pressure?

Yeah, bring your 460 EFI injector question back here.

 

Some background: The engine is newly installed re manufactured, I've done a compression test and it was 148 on all cylinders. The injectors are re manufactured and the proper stock replacements (ebay seller). There is fuel pressure at the fuel rail, but I don't have a tool to measure exact pressure.

Last night I pulled the injectors and I was going to check resistance Ohms but my multimeter is dead. My plan is to start with the injectors and work my way upstream until I find the problem. Shopping list includes a new multimeter and fuel pressure testing tool.

 

Update: I got my -analog- multimeter working, it had a blown fuse. Right up front I admit electrical is my weakness, but I can at least read a needle on a gauge.

I've checked each injector for continuity. Each of the injectors associated with cold exhaust ports have zero continuity. And, as you might guess, each of the injectors associated with hot exhaust ports do have continuity. The continuity for each of the functioning injectors all measure the same resistance, "1".

I also rigged up a battery and an injector pig tail to put current to each injector. And, no surprise here, the injectors with continuity responded to the current *click, click, click* And the ones with no continuity did not respond to current.

I guess its time to leave some eBay feedback.

 

Not sure what you're using to power the injectors, but don't use battery voltage. Use a 9 volt battery & a momentary switch.

Glad you're making progress.

 

Yes, I used a 9 volt battery. I don't have a momentary switch, I just flicked the pig tail wire across the battery terminal, no prolonged contact.

 

Sorry if I wasn't clear. I took the temp readings while it was still running.

 

My mistake