xveganxcowboyx

Time to revive this one. Blowing out the fuel lines from the front and adding a filter helped some. Power was on and off randomly when trying to accelerate. I assumed the injectors were still pretty plugged.

I picked up a set of Volvo 746 injectors, added new o-rings and filters, shot some carb cleaner through them with a 9 volt battery and installed them. Now the truck fires for a second, then dies. It's very consistent. Crank for a few seconds (always took a couple seconds cranking) then it gets that nice "firing up" sound. Right when it gets to the engine speed that would normally sustain an idle it dies. Maybe a second of running. If I keep cranking it will catch and almost start once every 3 or 4 seconds, then stop at the exact same point.

I checked the fuel pressure as best as I could. The fuel pump primes to ~40psi with the key in the run position and holds that pressure while cranking.


The burnt line idea isn't bad. The cluster is out because a mystery wire was smoking under the dash when it was plugged in, but that occurred before I bought it and didn't affect the running. I'll poke around though since I want to repair that issue eventually anyway.

cruiser54

Are you really a vegan?

xveganxcowboyx

Ha ha, I am. Much more vegan than cowboy. I mostly wrangle tofu.

cruiser54

I have been for over 2 years myself.

xveganxcowboyx

Right on. I wouldn't have expected that among anyone in the Jeep community. It's nice to see someone break the stereotypes.

cruiser54

You forced me out of the closet!! LOL.

I do it for health reasons only. I don't care what anyone else eats.

xveganxcowboyx

I'm much more motivated by the environmental consequences than my own health. I have pretty strong opinions, but tend to keep them to myself unless there is a real discussion happening. I respect anyone who makes it a point to inform themselves and make a rational decision rather than doing what's "normal" for their social group and considering anything else wrong or weird. It's very common among people eating a traditional American diet, but I've seen it with vegans and plenty of others too. Bandwagon decisions annoy me.

cruiser54

As in Forks over Knives?

xveganxcowboyx

I don't think I ever watched it. I've been vegan for over a decade so some of the "food revolution" stuff I have missed.

xveganxcowboyx

I fear my post may have gotten buried in our vegan banter. Does anyone have any ideas about the "almost running" condition? Otherwise I feel like I might have to clean my old injectors as best as possible and put them back in.

DFlintstone

The fuel pump get's power directly from the start relay while it's cranking, then it switches to the fuel pump relay while it's running. Me, I might jump power directly to the rear of the ballast resistor and try it. (have the key on while it's jumped)

Also double check that you didn't knock the map tube off while doing the swap....

xveganxcowboyx

I checked the vacuum lines and nearby electrical connectors right away So those should be ok.

I like your fuel pump idea. Unfortunately my ballast resistor has already been bypassed so i am not sure which writes feed the fuel pump and i prefer not to cut in underneath the truck. Any ideas on how to identify the wiring?

DFlintstone

First, please do double check that brittle little map tube from the inside of the tb, up to the map on the firewall, It's very important.

"my ballast resistor has already been bypassed so i am not sure which" If it's actually been bypassed, it's an orange wire.

I can't see your year. Must be an 87. The fuel pump relay is the second one back in that row of four cube relays. It's the 87 socket that powers the pump, you can jump to that socket with the relay out. 30 is on a fused link, (should be hot), and the ECU grounds 85 to energize the relay coil and send power up through to the pump. 86 may well get power from the ign..not sure there, but this might be worth checking. (if jumping works)

This diagram is in my sig btw.

xveganxcowboyx

I went to double Check that vacuum line again (third or fourth time). It's in good shape. I noticed while moving things about that the electrical connector to the map sensor was in place, but just a tiny bit loose. The clip doesn't seem to be in great shape any more. I reseated it and its idling great now. Time for a swing around the block!

Thanks for the help. It's nice having knowledgeable people helping, especially so quickly.

DFlintstone

Hey supper! I was about the first guy to run the 746's....I'm sure you'll notice a difference!